This PDF file contains the front matter associated with SPIE Proceedings Volume 10832, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

In order to enhance the restoration quality of Wiener filter, and widen the range of its application, an improvement is made on its basic model, then discuss how adaptive Wiener filter works on motion images, which is based on detecting blur’s direction and depth, and on recursive iterations. As for the process of motion-blurred image of the fast-moving object, experiment indicates an ideal effect can be achieved by this method.

Under coherent light illumination, several approaches need either angle scanning or diffuser rotating to reconstruct the image through opaque scattering media. We propose a linear model to restore the hidden object through the actual power spectrum with disturbance of the scattering layer. The experimental results confirm that, the algorithm quickly converge to the only correct reconstruction solution with the accuracy power spectrum pattern of Fourier transform, and the method can reconstruct the high accuracy image of the object hidden by the scattering media with one-shot power spectrum.

This article depicts a experiment of utilizing multi-spectral image(MSI) system, which can benefit from compressed sensing to reduce data acquisition demands, with the employment of a dispersal prism and push-broom compressive sampling system, to realize image super-resolution both in spatial and in spectral.

Dynamic Range is an important index to evaluate the performance of scientific CCD imaging system, which reflects the detection capability to the signal. At present, the description of DR is mainly expressed by the ratio of CCD full well capacity to readout noise at home and abroad. On the basis of clarifying the imaging process of scientific CCD, a method that defines linearity critical point as the last point where the Linearity Error doesn't exceed -3%, minimum exposure point as the point where the SNR equals to 1, then precisely expresses and calculates DR is introduced. Afterwards in the lab, 100 light and 100 dark images of CCD at different exposure time are collected by using the integrating sphere and other equipment, the relationship between the signal and exposure time is calculated to find out the linearity critical point and minimum exposure point and calculate the DR of CCD. The result shows that the DR of the measured CCD is 61.76dB, which corresponds to the theoretical analysis and verifies the validity of the test. Finally, the factors influencing the DR of CCD are analyzed, the advice to improve the DR is introduced.

Polarization imaging is another photoelectric imaging detection technology. It has obvious technical advantages in revealing camouflage, penetrating haze, and getting target details. It can gain multiple polarization features images and achieve target detection and recognition through specific polarization information analysis methods such as synthesis and fusion. Because there is a mis-match problem between the polarization features images, polarization image registration performs first. However, existing methods such as mutual information registration and related registration methods are hard to solve the problem of mis-match because of distortion of the polarization imaging lens. In this paper, we present a matching optimization SIFT polarization image registration algorithm found on the standard SIFT registration algorithm. In the sub-matching description, a reversed matching is added, that is, matching in both directions performs to form a symmetrical matching. In the matching set of positive and negative directions, matched feature points pairs satisfying both sets extract. The pair of matching points are only when the pair of feature points are the best matching points. This increases the matching accuracy of feature points and reduces the mismatching rate of descriptions. At the same time, numbers of feature points add in the algorithm using the gray leveling method. Registration experimental results show the registration accuracy of this method is better than the mutual information registration method.

Classic neural network algorithm can not correct the low frequency noise,and it is easy to appearance ghost artifact phenomenon. In this paper,we present a new improved algorithm which can eliminate the low frequency noise and ghost artifact.We add a learning layer which can preprocess to the input layer.In this layer, use the Gaussian filter folding the down sampling image and resampling to the image so that the new input image have global correlation, it could assure the accuracy of the estimate real scene image,this can help us to eliminate the low frequency noise in the input image. Then we judged the frame motion by the edge detection, setting a threshold to compare with the MSE of the edge frame difference.Considering the result of the comparison,we use the difference step size to update the gain and offset parameters. Experimental results show that the new algorithm can improve image quality effectively

Infrared digital camouflage is an infrared camouflage method .It controls the infrared radiation of the target so that the target infrared image appears to be fragmented, and simulates the background infrared characteristics through different combinations of the fragments. Digital camouflage is a digital camouflage texture composed of pixel lattices. The camouflage texture forms an irregular overlap, and the edges are blurred and broken, which can better simulate the target background. In this paper, we use human visual perception and spatial color mixing principle to establish the HSV color model. The background color is quantified, and then the main color of the background is selected as the camouflage color. Finally, the infrared digital camouflage is generated by determining the size of the pixel unit.

Wide-band Imaging Spectrometer is a medium resolution multispectral imager on Tiangong-2 Space Laboratory, which was launched on September 15, 2016 by China Manned Space Engineering. In this paper, the authors introduced the application indexes of Wide-band Imaging Spectrometer, and enumerated its typical application results in land and resources, ocean and coastal, lakes and inland waters, agriculture and other application fields. Which fully shows its application value and potential in classification and identification of large and medium scale ground objects in various remote sensing application fields.

Based on the carbon dioxide mass mixing ratio concentration profiles of Hefei Science Island from 2013 to 2016, the distribution characteristics of carbon dioxide in the subtropical monsoon climate and the characteristics of carbon dioxide source and sink in Hefei Science Island were analyzed from the night, season and year respectively. At lower altitudes, CO₂ builds up during nighttime hours as respiration is trapped within the nocturnal boundary layer. Throughout this nighttime the CO₂ concentration at 390m shows that only little variation. After sunrise, convection begins to spread the CO₂ trapped at low levels to higher altitudes. When the measurement height was more than 100m, the obvious seasonal change was shown, with the minimum in summer and the maximum in winter, which the difference in concentration of about 19.32mg/m³ . The annual distribution of the concentration of carbon dioxide from 2013 to 2016 had no significant difference in the gradient change of the height above 100m, the correlation coefficient was above 0.9, and the CO₂ vertical concentration goes up with a rate of about 4.35mg/m³ per year. Through data analysis from three different timescales, it could be concluded that the concentration of carbon dioxide near the ground was greatly influenced by the atmospheric environment. The seasonal distribution of carbon dioxide concentration was the result of a combination of atmospheric movement and the activities of plants and animals. In the process of long-term carbon dioxide cycling, there was a current that the near-surface carbon dioxide transported to a higher altitude.

Since the concept of wavefront coding was proposed, many types of phase masks have been reported to extend the depth-of-field of imaging system. Unfortunately there exist some unpleasant image artifacts in the final decoded images, especially for asymmetric phas1 e masks. In this paper, we illustrate a technique that involve shifting a phase mask laterally in pupil plane to introduce axial defocus to an imaging system, which can further be used to determine the defocus map according to the amount of image artifacts. This eventually enables recovery of extended depth-of-filed, artifacts-free decoded images together with a range map. Theoretical analyses and experimental results indicate the effectiveness of this method. Keywords: wavefront coding,

To get the knowledge of sky background spectral radiance and its usage in retrieving atmospheric parameters, a wide-spectrum fiber spectrophotometer was calibrated with the field view of one degree. An experiment was performed at the fine days after a heavy snow weather process, and the horizontal spectral radiance direct to the south was measured periodically during the whole days. We found that when the sky was fine, the short-wavelength sky radiance was significantly higher than the long-wave band. This is because the intensity of the scattered light is inversely proportional to the fourth power of the wavelength. A sunny day with red sky in the morning, the snow began to melt., the short-wavelength sky background radiance was lower than the long-wavelength band. The absorption band of water vapor in the spectral data is apparent, which implies the possibility of retrieving atmospheric water vapor content from these data. Using MODTRAN, the Continuum Interpolated Band Ratio (CIBR) near the 940nm water absorption bandwidth was estimated, and the water vapor column concentration was retrieved. Comparison the results with what was measured by the POM2 sun radiometer show satisfied consistence. The method of retrieving water vapor content from the background spectral radiance provide us a way to have a deeper understanding of the absolute radiance of the sky background.

Aiming at the design requirement of miniature reflective optical system,a new type of off-axis three-mirror anastigmat (TMA) and freeform surface are adopted, the F#1.8,and diagonal field of view7.5° is realized.Light overlap many times within the optical system,the full field average RMS Wavefront abberations is 0.017λ(λ=10μm). Compared with other optical system, the new freeform TMA has small size, high transmittance, large field of view, large relative aperture, no centered obscuration, low stray, radiation, wide spectral band, etc.

Virtual binocular stereoscopic camera models that can be used in generation of stereoscopic images or videos of virtual 3D scenes by use of computer graphics techniques are presented and analyzed in detail. It is found that the paralleloptical-axis model is most appropriate for synthesizing stereoscopic images or videos of virtual 3D scenes. Mathematical formulae for calculating the camera position and ‘lookat’ position of both the left and right virtual cameras therein are developed. Light-source visibility filtering with a depth variation constraint is proposed to speed up the ray-tracing-based soft shadow rendering of virtual 3D scenes and meanwhile to eliminate the drawback of generating fake shadows associated with the original light-source visibility filtering method; dual light-source visibility filtering scheme is suggested to make shadows reflected in a mirror surface correctly feature penumbra. The stereoscopic video experimentally generated by use of our method shows pleasing visual realism and impressive stereoscopic effects.

In this paper, the influences for one LWIR thermal camera in different integrate time are studied by using surrounding temperature simulator and blackbody of independent research and development, which compared to theoretical results. In experiment, the image of camera is obtained by using different integrate time and same temperature of blackbody at surrounding temperature of-30°C, 0°C and 20°C, the result show that the output voltage is linearly proportion to integrate time in those surrounding temperature. The experiment is studied for different blackbody temperature at surrounding temperature of-30°C, the result shows that: the slope of “integrate time vs. DL value” is increased with the target temperature. The noise of output image is increased with the increasing of integrate time. Whose agree with theoretical result. According to the conclusion, the DL value of random integrate time can be derived by known two integrate time DL for one blackbody temperature. And the calibration in random integrate time between two integrate time whose calibration curve are known, which is verified in experiment: the blackbody brightness deviation between test and derivation is less than 1%, which corresponds to blackbody temperature deviation between test and derivation is less than 1°C. The experiment results show that the measurement efficiency can be improved by using appropriate integrate time.

We proposed and demonstrated an integrated high energy efficient and high linearly polarized InGaN/GaN green LED grown on (0001) oriented sapphire with combined nanostructure converter and polarizer system. Different from those conventional polarized light emission generated with plasmonic metallic grating in which at least 50% high energy loss happens inherently due to high reflection of TE component of the electric field, a reflecting metasurface with 2D elliptic metal cylinder array (EMCA) that functions as a half-wave plate was integrated at the bottom of a LED such that the back-reflected TE component that is otherwise lost by a dielectric/metal bi-layered wire grids (DMBiWG) polarizer on the top emitting surface of the LED can be converted to desired TM polarized emission after reflecting from the metasurface, which significantly enhances the polarized light emission efficiency. Experimental results show that the extraction efficiency of the polarized emission can be increased by 40% on average in a wide angle of ±60° compared to that with naked bottom of sapphire substrate or 20% compared to that with reflecting Al film on the bottom of sapphire substrate while an extinction ratio (ER) of higher than 20 dB within an angle of ±60° can be simultaneously obtained directly from an InGaN/GaN LED. Our results show the possibility of simultaneously achieving high degree of polarization and high polarization extraction efficiency at integrated device level and advance the field of GaN LED toward energy efficiency, multi-functional applications in illumination, display, medicine, and light manipulation.

For solving the difficulty of acquiring single-band spectral light field images, the spectral light field images using compressed sensing based on overcomplete dictionary is proposed and simulated. Firstly, multiple sets of light field images are collected as a sample set for training overcomplete dictionary, and the overcomplete dictionary is generated by training the sample set. Then, using random matrix of periodic arrangement as the measurement matrix to realize the reduced-dimensional sampling of the signal. Finally, single-band spectral light field images are reconstructed using compressed sensing reconstruction algorithm. The peak signal to noise ratio of the reconstructed images is 30.5 dB. The experimental results show that the spectral light field image reconstructed by this method has sufficient parallax and can recover the spectral information carried by the image. And the sampling rate of this method proposed is only 4% of the image size. This method proposed effectively solves the problems that the image capturing process of the spectral light field is complicated and the data volume is large. This method provides a new way to reconstruct high-resolution single- band spectral light field images with low sampling rate, and provides experimental data and new ideas to further increase the depth information of spectral images for generating 3D spectral images.

With the development of unmanned aerial vehicle (UAV) in aeronautical monitoring field, the performance requirements are continuously improved, each application scene also puts forward higher and higher requirements for target detection accuracy and speed. The traditional target imaging method is difficult to meet the image quality requirements, and the artificial target recognition method can’t cope with the rapid changes in the detection environment. Combined with the development of deep learning and polarization hyperspectral imaging technology, a ground target detection method based on Faster R-CNN was proposed. We proposed region proposal network (RPN) module for model training. In the target detection phase, the proposed feature map is obtained by pooling operation of interest regions. Finally, we used the proposed feature map to complete the target category classification. Three scale models were used in the experiment, and through polarization hyperspectral camera, the image data of target in different scene conditions was acquired in indoor and outdoor simulation environment for training and validation of models. The experimental results showed that the proposed method could achieve ideal detection accuracy and speed when the ground target was effectively detected.

Mid-infrared (MIR) laser spectroscopy is a powerful analytical tool for trace gases sensing, since a number of atmospheric pollutants and greenhouse gases have strong fundamental vibrational transitions within this spectral range. Here, we report the development of mid-infrared spectroscopy techniques coupled with a broadband tunable external-cavity (EC) mode-hop-free quantum cascade laser (QCL) operating between 6.96 and 8.85 μm. The ECQCL sensor was evaluated for quantitative and qualitative analysis of volatile organic compound (VOC) components. For signal processing, a self-established spectral analysis model integrated with various algorithms was developed for VOC spectral analysis. A good agreement was obtained between the experimentally observed spectra and the standard reference spectra taken from Pacific Northwest National Laboratory (PNNL) database.

High-resolution, real-time and three-dimensional imaging in thick scattering specimens is of great significance in biology, yet meeting these requirements at the same time is fraught with challenges. In this work, we describe a method that combines structured illumination microscopy (SIM) with dual nonlinear effects, two-photon excitation (2PE) technique and stimulated emission depletion (STED), to further improve the imaging resolution in optical-thick samples relative to SIM. Utilizing a line-scanning geometry shaped by cylindrical lens to form structured illumination pattern, the imaging speed is greatly improved. Theoretical study and simulations are both performed to demonstrate the capability of this method to enhance resolution laterally and the potential for applications in real-time imaging for living tissue.

In this paper, a series of experiments on dispersion compensation in terahertz time-domain spectrometers are performed. The Influence of femtosecond laser pulse width on the performance of terahertz time-domain spectrometers is systematically studied. A terahertz time-domain spectroscopy system was constructed using fiber-coupled photoconductive antennas. Through the adjustment of the grating spacing and the replacement of different lengths of fiber cable, the laser pulse width acting on the antenna was multiplexed from 130fs to 2.46ps, and the performance of the terahertz time domain spectroscopy system under different pulse widths was tested. The experimental results show that, with the increase of the femtosecond laser pulse width, the signal intensity of the terahertz time domain waveform and the high frequency part of the terahertz spectrum decrease significantly. Quantitative comparative analysis was performed using the average signal-to-noise ratio, validating the necessity of using dispersion compensation and femtosecond laser pulse width testing in the terahertz time-domain spectroscopy system.

Based on the bright pupil effect of human eyes irradiated by infrared light source, a pupil location method suitable for ophthalmic measurement equipment is proposed. Using 850nm infrared light source, a pupil location system based on bright pupil effect was designed. Firstly, Pulse-coupled neural network (PCNN) algorithm is used to segment the acquired image and obtain the preliminary pupil position. Then the Canny algorithm is used to extract the contour of the pupil's edge. Under normal circumstances, the pupil of the human eye is elliptical. Therefore, the optimal elliptical fitting of the pupil preliminary contour obtained above is finally performed. After the ellipse fitting, the coordinates of the ellipse center are obtained, and the central coordinate of the ellipse is the precise pupil position. The experimental results show that this method can obtain higher pupil location accuracy and speed.

Modulation spread function (MTF) is the function of spatial frequency used to evaluate the spatial quality of an imaging system. In measuring the MTF of the digital images, the slanted edge method is widely used. The traditional method projects the pixel values to the direction perpendicular to the edge and construct the edge spread function (ESF) in a subpixel resolution by binning pixels. However, the pixels within in a subpixel bin is not always distributed uniformly, which introduces errors in measurement results. Meanwhile, the value of an image pixel may deviate from the exact value of the ESF on the position of the pixel center since it is the integral of a short segment of the continuous ESF. Besides, the sampling interval is compressed due to inclination, so that the scale in the frequency domain is changed. In this paper, a novel measurement method which samples the ESF via weighting by distance is proposed and the errors exist in the traditional method is compensated. The edge location estimation method is also improved. Simulation experiments on different edge angles and image noise levels are conducted. The results show that the proposed method has an excellent performance on measuring accuracy and robustness.

The degree of linear polarization (DOLP) expressions at any polarizer direction (PD) was deduced based on the Stokes vector and Mueller matrix. The average gray level range of the target units (20x20 pixels material) under triple-waveband and low illumination condition was obtained with 46 kinds of experimental materials. This paper mainly explored that the influence factors of the error and stability of multi-PD DOLP was researched by the numerical analysis, and outdoors experiments were carried out to demonstrate the analysis method. Studies have shown that when detection angle was near specular reflection direction, when interval angle of PD between angle A and angle B, between angle A and angle C were set as the range (40°≤Φ_AB ≤80°, Φ_AC =2.06Φ_AB), the standard deviation of DOLP was lower, but also polarization information obtained under low illumination condition was stable, and the numerical analysis was consistent with the experimental results.

Using laser features of high brightness and good directivity, can undertake directional transmission of energy, laser charging technology transforms the energy supply way with its own carrying to charge at any time. The key to laser alignment is to identify the target of the charging panel and locate the center. Through the control of the servo module, the battery charging plate can be adjusted to the center of the field of view to complete laser alignment charging. Object recognition and center location algorithm are mainly divided into three steps: image preprocessing, rectangle panel identification and center positioning. Through this, the center positioning is realized, and the center positioning of the panel charged by laser is carried out for rotorcraft with different distances and angles, so as to achieve a better effect.

In this paper, the signal model, the noise model and the error theory of the laser ranging system which aims at noncorporative target and capable of performing in daylight condition, is established. Monte Carlo method is applied to simulate the photon incident detection result of the laser ranging system. The simulation result also shows the trajectory of space target which has radial maneuver as well as disturbance. Finally, two parameters, the accumulation pulse number and laser repletion ratio are optimized according to the simulation

Objective: Utilizing the advantages of non-contact , rapid and flexible three-dimensional contour measurement by surface structure light projection, we can solve the problems of difficult, time-consuming and low precision of three-dimensional surface data in the fields such as bone replacement, tooth embryo planting, orthopedic organs and surgical simulation in the current clinical medicine. Methods: Collect the deformation fringes generated by the light projection of the surface structure generated by the digital grating onto the surface of the measured object, and use the Fast Fourier Transform (FFT), spatial filtering, inverse Fourier transform (IFFT) and phase unwrapping techniques to demodulate the three-dimensionality of the measured object. Results: The structure of the light path is simple and easy. Only by acquiring a deformed fringe pattern of an actual object, the three-dimensional contour surface structure and feature shape of the measured object can be quickly and effectively obtained. Conclusion: This technical method has important clinical value and wide application potential in the rapid acquisition of bone organ three-dimensional surface data.

This paper proposes a none-blind deblurring algorithm for noisy images via distributed gradient prior. The proposed image prior is motivated by observing the gradient properties of noisy images. Based on the prior of image noise's low gradient distribution, we propose an effective optimization method to deal with noisy and blurry images. In this paper, an image-gradient-related distributed factor is introduced to balance image deblurring and denoising. The distributed factor is related to image noise and works adaptively according to different noise levels of blurry images. Richardson-Lucy method is also adopted to achieve a better deconvolution result. Experiments show that our proposed method outperforms other deblurring algorithms in both preserving details and removing noise.

Owing to the high temporal coherence and spatial coherence of laser, it has been considered as the perfect source to study light’s interference effect so far. The simulation method of multi-beam interference effect was proposed based on the maturity Gaussian optics in this paper. The simulation result and stripe’s equidistant distribution of the dual-beam interference effect agreed with that of Yang’s double slit interference well. The agreement strongly proved that the simulation method was right and feasible. The simulation results have showed that the triple-beam interference effect was hexagonal arrangement’s lattice distribution; the quadruple-beam interference effect was foursquare arrangement’s lattice distribution; the pentuple-beam interference effect was radially symmetrical lattice distribution; and the hextuple-beam interference effect was regularly hexagonal arrangement’s lattice distribution. Every lattice around the center spot was all circular in the quadruple-beam and hextuple-beam interference effect.

A generative adversarial network denoising algorithm which uses a combination of three kinds of loss functions was proposed to avoid the loss of image details in the denoising process. The mean square error loss function was used to make the denoising results similar to the original images, the perceptual loss function was used to understand the image semantic information, and the adversarial learning loss function was used to make images more realistic. The algorithm used the deep residual network, the densely connected convolutional network and a wide and shallow network as the component in the replaceable module of the network. The results show that the three networks tested can make images more detailed and have better peak signal to noise ratio while removing image noise. Among them, the wide and shallow network which uses fewer layers, larger convolution kernels and more feature maps achieves the best result.

The infrared small spot system is the main equipment to test the crosstalk of the infrared focal plane array device. According to the current test method can’t meet the infrared light spot characteristics of the test problem, the use of infrared imaging device scanning technology to build a small infrared light beam characteristics of the calibration System, to achieve the infrared light spot characteristics of the measurement, and the system of the uncertainty was assessed. Finally, chooses an infrared small spot optical system is used to verify the measurement uncertainty of the system. It can be seen from the data analysis that the method can measure the characteristics of the infrared light beam and meet the measurement of the infrared small spot optical system. Infrared small spot system development and infrared focal plane crosstalk test to play a certain help.

In order to display a high dynamic range (HDR) image on a standard monitor, tone-mapping operators (TMOs) aim to compress HDR images into low dynamic range tone-mapped (TM) images. To accurately evaluate the performance of different TMOs, this paper proposes a no-reference image quality assessment (IQA) method for TM images. Firstly, the image is divided into dark area, middle area and bright area by using clustering algorithm. The entropy and area ratio features are extracted from three areas mentioned above and the saliency area that is detected by the proposed method. Then the natural scene statistics features of the luminance channel and RGB color channels of TMI are used to assess the luminance naturalness and chrominance naturalness, respectively. Finally the support vector regression module is utilized to yield a quality score of the TM images. The experimental results on the tone-mapped image database (TMID) show the effectiveness of the proposed algorithm. Compared with the existing representative IQA methods, the proposed method has better performance.

The related theory of laser ranging technology, design principle of the detector component as well as research status of some key technologies are introduced in this paper. It mainly includes high sensitivity detection technology and large dynamic range detection technology. It provides reference for the selection and design of detector component.

Infrared imaging technology plays an irreplaceable role in early warning detection, intelligence reconnaissance, night vision sighting, fire control guidance, precision strike and electronic confrontation. The optical tomography imaging system, obtaining a plenty of target object information with non-invasive, can realize long-distance and high-resolution imaging. The system has important significance for accurate target recognition and detection. This paper aims to combine the two for the purpose of research for optical guidance of large field of view, high spatial resolution infrared imaging methods. In this paper, the principle of tomography and the commonly used filtered back-projection reconstruction algorithm are introduced firstly. Then the innovative infrared tomography system construction design is proposed. According to this design, a set of infrared tomography imaging device is successfully built. An infrared tomographic image of the target was photographed and reconstructed. It has a great significance to the research of infrared tomography.

Recent years have witnessed a strong renewal of interest in light field cameras, as they can capture rich angular information within one snapshot. As a representative application of light field cameras, refocusing can change the in-focus region of images so that objects lying on a specified plane are in focus, whereas objects lying off this plane are blurred. The existing refocusing methods can only project images onto focal planes. In this paper, we proposed a reprojetion-based method to refocus the images captured by camera arrays onto arbitrary focal surfaces, rather than only planes. Combining the camera imaging model and the equation of the focal surface, we can reproject the images onto arbitrary focal surface. We can change the focal surface by changing the equation of the focal surface. Experiments on real-world scenes (captured by our self-developed light field devices) demonstrate the validity of the proposed method.

In the ultraviolet and visible part of the spectrum, measurements of space-borne grating spectrometers are in general sensitive to the state of polarization of the observed light. Light reflected from the Earth’s atmosphere is polarized because of scattering of unpolarized sunlight by air molecules and aerosols. One common method to overcome polarization bias in optical systems is the insertion of a depolarizer. The sources of linear polarization sensitivity of space-borne grating spectrometers were analyzed and a model was developed using the Mueller Matrices formulating to evaluate the polarization sensitivity. The experimental results verify the correctness of the theoretical model. The theory of the quartz depolarizer operation was also described. The polarization sensitivity of the system is within the specification of 1% with inserting the depolarizer, which meets the requirement of the high precision radiance measurement in space remote sensing.

In order to initially explore the different temporal and spatial distribution characteristics of sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) concentrations in Huainan, the gas concentration detections were carried out at Huainan Academy of Atmospheric Sciences by the differential absorption laser radar system of Anhui Institute of Optics and Fine Mechanics. According to the detected distribution profiles of atmospheric SO₂ and NO₂ concentrations in part of the months from July 2016 to June 2017, in this paper, the typical examples are selected to analyze the distribution characteristics of SO₂ and NO₂ from three aspects: diurnal variations of horizontal concentration, vertical concentration changes and monthly variations of horizontal concentration. According to the SO₂ and NO₂ concentration distribution profiles in the selected examples, the following conclusions can be drawn:(1) The concentrations of SO₂ and NO₂ at night are greater than that of SO₂ and NO₂ in the afternoon on the same day;(2) The vertical concentrations of SO₂ and NO₂ decrease with the increasing height;(3) The monthly variations of SO₂ and NO₂ horizontal concentration are the highest in the winter months, and the lowest in the summer months, followed by the spring and autumn months. The changes in SO₂ and NO₂ concentrations are the result of a combination of population activities and changes in meteorological conditions.

In order to effectively improve the frame of mid-wavelength infrared measuring system, based on a 320×256 cooled staring focal plane array(FPA) detector, pixel size 30μm×30μm, a special optical system combined with time-sharing exposure technology was designed. In this paper, the working wavelength is 3μm~5μm, the temperature range is -30°C~+40°C, this system can realize 200mm focal length, the F-number is 4 and the full field of view is 3.44°. A re-imaging refractive system was adopted in this designed optical system consists of main optics and projection components. First of all, the working principle of the measuring system was introduced in detail. Secondly, on the basis of variety of the distance and temperature, a focusing lens was presented in this system to adjust to produce a clear image. Last but not the least, to improve image quality and environment adaptability, the analysis of temperature change and narcissus effect was described particularly. The design results prove that at the spatial frequency of 17 lp/mm, the MTF of the optical system is greater than 0.58(the axis MTF of the optical is greater than 0.65), the system can offer a high resolution and excellent images. The measuring system implements 400fps measuring system consisting of four 100fps detectors.

A long-wavelength infrared optical system suitable for fast turntables is designed to meet the needs of fast and small target detection and tracking. The optical system consists of a main optical system and a projection lens assembly, it adopts a reflex structure, a secondary imaging technology and a pupil matching technique, reduces the radial size and lateral dimension of the system effectively. The envelope of the shape is within the range of Φ204mm×360mm, compact structure and small volume. Considering that the system's working distance is in the range of 0.2km~1km and the target speed is fast, the object distance has been specially designed to ensure that no focus adjustment is required within the range of action distance. In addition, stray light analysis is performed on the system and a stray light suppression scheme is given. The system is analyzed by stray light analysis software. The design results show that the optical system has excellent imaging quality and stray light suppression effect.

The images captured from environment often suffer from low contrast and visual quality due to the bad imaging conditions like low light or haze weather. Many methods have been proposed based on traditional image enhancement models including dehazing model and Retinex model typically. However, their scopes are limited and specific. In this paper, we propose a simple but effective method to enhance images contrast and keep the good visual quality. By observing the traditional image enhancement models including dehazing model and Retinex model, a general normalized model is proposed. To preserve the image details and control the brightness, we introduce dual boundaries called the dark and bright boundary to handle the low light and high light condition. After getting the dark and bright boundary, the images are enhanced accordingly. Experiments show our method can be applied in many bad imaging conditions and keep good performances.

In this paper, we establish the cat's eye echoes model of the optical imaging system under different damage conditions and analyze the influence of the damage to CCD layers on the cat's eye echo power. Based on this, the corresponding relationship between the echo power of the cat's eye and the damage degree of the CCD was established and verified by experiments. The results show that the field intensity is the strongest in the center of cat's eye echo in the imaging optics system, and the power of the echo increases dramatically and then decrease steeply and decrease slowly. The damaged status of CCD can be judged according to this rule. This study has certain reference value for the actual situation that the degree of the damage to CCD is required to be monitored in real time in the far field.

To resolve the issue of blurred backgrounds and fuzzy targets in using the infrared and visible image fusion algorithm, this paper proposes a new method for image fusion based on target-enhancement. First, average filtering is used to obtain rough estimation of the transmission rate, which is refined by calculating the images’ statistical information. Further, a final target-enhanced infrared image is obtained using the atmospheric scattering model. Then, the edge of the target-enhanced infrared image and the visible image is detected and separated using the improved edge detection. The fusion rule based on binary information is used for the edge part, and the fusion rule based on the ratio weighting analysis is used for the non-edge part. Experimental results show that the image fusion algorithm based on target-enhancement not only highlights the target information of an infrared image, but also retains the detailed information of the visible image as much as possible. Additionally, the fused image has better visual effects and higher objective quality evaluation indexes.

Based on multiple fields of view (FOV) point spread function (PSF) estimation, we propose a novel gradient-constrained image restoration method to solve optical degradation in microscopic imaging. The whole FOV is segmented into several parts. The modulation transfer function (MTF) is measured to obtain the corresponding PSF for each part. L0 gradient constraint is treated as a regularization term, a fast image restoration method is designed to deblur degraded images of each field of view. Finally, gradual weight approach is used to stitch the multiple field of view (m-FOV) restoration images. Several microscopic images are tested and evaluated. Comparing with other methods, the results indicate that our method performs better, and runs fastest of all.

When the optical signal is transmitted in atmospheric channel in the wireless optical communication (WOC) systems, the inter-symbol interference (ISI) will be caused by the atmospheric motion and the fading characteristics of the atmospheric channel. In addition, device noises such as photodetectors noises can also affect the signal in the real communication systems. It is difficult to eliminate both types of interference by the single equalization algorithm at the same time, therefore, a cascaded equalization algorithm is proposed. First of all, we use the MATLAB to simulate the cascaded equalization algorithm, the convergence performance of the algorithm is analyzed, the bit error rate (BER) under different signal-to-noise ratios (SNR) are also compared. Then, the algorithm is verified under laboratory conditions, we calculate the BER of the receiving signal, which is processed by the cascade equalization algorithm. The simulation analysis and experiments results show that, the convergence performance of the cascaded equalization algorithm is improved effectively, the ISI is decrease, the BER can reduce to about 10^-8 , decreased by 4 orders of magnitude than without equalization. It can improve the communication performance of the WOC systems, the validation of the cascaded equalization algorithm is verified.

When taking pictures in low-light scene, due to the insufficient light, we are often posed to the following problem: Using short exposure setting, image tends to be dim and noise, but with a sharp outline. While using longer exposure setting, image captures more color and detail information, but with partly blurred areas. A very common situation, none of those images is good enough. Good brightness and color information are retained in long-exposure images, while sharp outlines are retained in shorter ones. In this paper, we propose a fusion method based on wavelet decomposition for such low-light image pair. In this work, we firstly decompose the original image pair into different frequency subbands. After that, we compute the importance weight maps according to the difference value between corresponding subbands. In order to refuse artifacts and ghost, we compute weight maps in Gauss model. Finally, the coefficients of subbands are blended into a high-quality fusion image. Experimental results show that the proposed method effectively preserves sharp edges of the short-exposure image, and maintains the color, brightness, and details of the long-exposure image.

Structure Function is under investigation to better specify the atmosphere turbulence, which is represented by r0. Its fast calculation algorithm, taking advantage of Fast Fourier Transfer and Power Spectral Density, is presented in this work. The Zernike polynomials in frequency domain were used to release the error characteristics of this algorithm, which also determines the number of averaging. Lastly, the structure function and air correlation length are reached by the algorithm presented here.

In order to solve the evaluation problem of optical system under partially polarized light conditions caused by single ray tracing method, a full-field and full-pupil ray tracing method based on Stokes is proposed. The analytical relationship among the degrees of polarization (DOP) of the incident ray, the angle of the ray and the DOP of the emitting light is analyzed. The analysis results show that when the difference value between the incident angle and the refracted angle is less than 5.7°, the influence of the system on the DOP of the light can be reduced effectively. According to the space target polarization imaging requirements, a polarization imaging optical system with micro-polarizer array detector is designed. The resolution is 0.5m at the distance of 500km. Dynamic data exchange (DDE) is used to trace the full-field and full-pupil rays for the optimized optical system. Due to the DOP of any field of view can be calibrated, the polarization detecting accuracy of the optical system is improved. Therefore, the target can be recognized by matching the DOP of the incident ray and the DOP of any field of view.

Raman spectrum is a scattering spectrum, and its frequency, intensity and polarization can characterize the peculiar properties of materials, thus it has been widely applied in many fields. The Raman signal is so weak that the background interferes it greatly. Polynomial fitting is the simplest method of baseline correction. The order of polynomial is hard to be chosen for the whole data, because if the polynomial order is too high or too low, the accuracy of the baseline fit will be affected. This paper proposes a new approach: piecewise polynomial fitting(PPF). Segment the spectral data, and then the proper order is fitted respectively. Then we employ iterative optimization method eliminate discontinuities between segments. Simulation and experiment results show that this method has a higher accuracy.

In order to study the infrared radiation characteristics of the solid rocket plume at high altitude, a numerical method is used to simulate the infrared spectral radiation intensity of a solid rocket plume at three altitudes, which are 120km, 150km and 180km, and the cause of the phenomenon is produced from the flow and radiation transmission views. It is confirmed that the peak value of infrared radiation intensity of the plume is within the range of 4~5 μm, due to the influence of high altitude diffusion effect. At the high altitude, the infrared radiation intensity of the plume increases rapidly at 4.7μm, which is at the CO absorption band. It can be within the same magnitude as the radiation intensity at the 4.3μm, which is at the CO₂ absorption band. And the radiation intensity varies slowly with height, there is no severe fluctuation.

We design a first-photon 3D Lidar system to solve the problem of reconstructing the target reflectivity and depth maps in low-light-level. The Monte Carlo method was used to simulate the photon counting model, mean value and gated filter algorithm for doubly stochastic Poisson point processes. The influence factors of reflectivity and depth imaging are light intensity, noise and scanning time, we simulated them and use gated filtering to suppress noise. The simulation results showed that the noise ratio, light intensity and scanning time all have impact on the reconstruct reflectivity and depth maps. if the light intensities and scanning time increase, noise ratio decrease, the image quality of target reflectivity and depth maps would improve. And the gated filtering can effectively suppress noise and improve the quality of target reflectivity and depth maps’ reconstruction. we simulate the system in order to verify the feasibility of the system design, provide reference and optimize to the design of system, save time and experimental costs.

It is essential to measure the sensitivity accurately, because sensitivity is an important index of low light level image intensifier for evaluating the photocathode’s responsiveness. In this article, the economic testing equipment has been founded on the method required in the military standards, the way to select parameters of measurement have been shown, and the uncertainty of measurement for testing sensitivity has been analyzed. The expanded uncertainty, which is only below 4.6%, can completely satisfied to the requirement of high precision testing.

A semi-active laser/active radar/infrared imaging tri-mode common aperture compound optical system is proposed, which adopts the compound structure of parabolic antenna and Cassegrain optical system. The three detection methods share a primary mirror ,which implement the separation of the infrared energy and laser energy and microwave energy in the secondary mirror; in order to reduce the blocking of microwave transmission by laser detection, using special design, the laser light spot is split into four parts, using of right-angle reflection optical waveguide, to placed in four separation unit quadrants which are located at the edge of the center of the optical axis at a distance 90° radar feeds are located in front of the optical waveguides which are connected with transmitters and receivers in the electronics bay by microwaveguides. This optical structure has high utilization of aperture and compact structure, and can effectively realize the combination of the three methods of detection and guidance modes.

In this paper, we propose a photon counting ghost imaging scheme based on time-correlated single photon counting, and based on this scheme, Monte Carlo simulation is conduct with doubly Poisson stochastic process model ,the feasibility of traditional ghost imaging and corresponding ghost imaging is verified in this simulation, the influencing factors such as the number of frame M and the number of pulse within a single digital micro-mirror device(DMD) period D is also analyzed in the simulation. The results shows that the corresponding ghost imaging algorithm can effectively reduce the calculation amount when the imaging quality is close between the two algorithms, and the number of frames M has a greater influence on image quality. The model can effectively verify the feasibility of system design and improve the efficiency of the experiment, saving experiment time and costs.

Exhaust plume from the rocket engine produces strong infrared radiation signals, widely used for target diagnosing, detecting and identifying. Exhaust plume flow field have the characteristics of high temperature, high speed and multi-species reacting flow. The radiation mechanism is very complex in the flow field. Infrared spectrum of exhaust plume involving complex gaseous kinetic and thermodynamic processes, which makes the exhaust plume have a complex spectral structure. On the base of a rocket motor, the two-dimensional axisymmetric and Reynolds Averaged Navier-Stokes equations (RANS) coupled with chemical reactions are solved. With the flow field of the exhaust plume, line-by-line method and LOS method are used to calculate the infrared radiation of the exhaust plume. The spectral radiation characteristics of H₂O, CO₂, CO and HCL in 2μm to 8.6μm band are analyzed in detail, and the characteristics of radiance distribution in typical gas emission bands are studied.

In optical test of modern shooting range, the 2D spatial imaging technology is usually used for the identification and tracking of ballistic targets. However, limited by its own mechanism of the conventional imaging system (visible imaging system is easily affected by the meteorological environment, and the infrared imaging system has low resolution), the resulted image often suffered from serious reduction in quality with overshadowed target which cannot be identified. In this paper, aiming at the problem which is susceptible to complex background, shading, blaze and other factors in optical imaging, a characterization and detection method of spectral-polarization information for ballistic target recognition is proposed by employing the consistency of space radiation, spectrum and polarization characteristics of targets. The method combines the three steps of target detection in space, enhancement in polarization vector domain and recognition in spectrum domain to achieve accurate detection, identification and stable tracking of targets in test range.

Extinction ratio is one of important parameters which are characterization of optical properties of Glan-Taylor prism (GTP) .In this paper, we adopt the ray tracing method to deduce the extinction ratio expression of the GTP. By performing the computer simulation, some important relationship curves are obtained as the variations of the extinction ratio on optical axes and the structural angle, the work has great guiding significance in the design and use of Glan-Taylor prism.

Polarization Detection is a new remote sensing technique. There is a huge potential for application in space-based imaging, material recognition and clutter suppression. This article presents a simulation study of polarization characteristics distribution and space-based polarization detection of typical materials. In order to provide technical support for space-based applications of polarization detection technique, the main technical indicators of space-based polarization detection were carded and analyzed.

For the fast touching imaging of the capacitive touch screens (CTS) with a very large size, the conventional methods can only be achieved at the expense of the analog hardware complexity and power consumption. Firstly, the sparse feature of variation within the capacitance of CTS being touched was analyzed. Secondly, the principal for measuring the capacitance of CTS was introduced, and then the scheme of sparse touching imaging was given. Moreover, the hardware implementation for sparse sensing was presented. An algorithm of touching sensing for CTS and its implementation were proposed. The test result indicated the validity of sparse touching imaging for CTS. The proposed method can achieve touching imaging efficiently with lower hardware complexity and lower power consumption.

The imaging tracking systems often face different backgrounds,such as the ground, the sky, the sea, the jungle, the Gobi, tec. This paper is based on the complexity of different backgrounds and the mechanism and method of automatic optimization of the tracking algorithm under different background conditions. The paper presents a comprehensive decision model of background complexity, which combines the statistical characteristics of gray scale, image texture features, edge characteristics and high frequency features of the image. The model can realize the scientific and effective combination of multi algorithm fusion and tracking algorithm of autonomous scheduling. It can improve the adaptive and autonomous decision-making tracking ability when the diversity tasks are carried out.

Infrared radiomentric calibration is of critical importance for information quantification of remote sensing of environment at infrared spectrum. In the quantitative analysis, the calibration of the measured spectra is very important. LWIR Interferometric Hyperspectral Imager Spectrometer Prototype (CHIPED-1) is developed for studying Radiation Calibration. Two-point linear calibration method is carried out for the spectrometer by using blackbody respectively. Firstly, relative intensity is converted to the absolute radiation lightness of the object. Then, radiation intensity of the object is converted the brightness temperature spectrum by the method of brightness temperature. The result indicated that this method of Radiation Calibration calibration was very good. This calibration method is of significance to the further analysis of atmospheric transmission and the retrieval of the concentration of infrared chemical gas in atmosphere.

The basic principle of evaluating the background radiation response of the InGaAs detector is introduced. Based on the structure characteristics of the InGaAs detector, the background radiation response calculation model is established. A background radiation response assessment scheme was designed and a test system was designed. Based on the effect of dark current output of the detector, the background radiation output of the InGaAs detector at different temperatures was measured. The results showed that the theoretical calculations of the background radiation response were consistent with the measured values. It provides data support for setting and parameter evaluation of InGaAs detector conditions.

We propose a single-photon three-dimensional compressive imaging system based on TCSPC. The system uses compressive sensing instead of raster scanning to achieve high spatial resolution, and only two-dimensional reconstructions are required to image a three-dimensional scene. We also propose a system simulation model based on Monte Carlo, which is conduct with double poisson stochastic process model. In the simulation model, we studied the effects of imaging time, optical noise ratio, and gating algorithm on the imaging performance of the system. The results show that the single-photon compressive 3D imaging system based on TCSPC can image in 5 seconds. Noise gating can effectively improve the 3D imaging quality of the system. Our simulation provides a good choice of parameters for subsequent experiments. It has played a theoretical guiding role in the research and application of the actual three-dimensional imaging system.

This article proposes a real-time calibrating(non-uniformity correction) method for the bi-directional scanning infrared TDI imaging load on the aerospace platform. The method is completed through efficient cooperation of a scanning mechanism, a real-time calibration device, and an image preprocessing device, by employing the scanning blanking period for bi-directional calibration. The image preprocessing device uses high-performance FPGA as the core processor, which can perform flexible working sequence control of the detector, accurate detection of calibration synchronization signal, fast acquisition of calibration data and efficient pipelining data processing. Moreover, by using the Micro Blaze IP core, the preprocessing device can calculate the calibration coefficients of two-point correction in real time and also fulfill communication with the host computer. Proven by practice, the calibration method of the bi-directional infrared TDI detector described in this paper has high practical value with the advantages of high processing speed, significant effect, and high system integration.

Low-light image enhancement is a challenging problem in the field of computer vision. In order to obtain more pleasing enhancement results, a low-light image enhancement method via joint convolutional sparse representation is proposed. The method is based on the Retinex theory and improves the problem of insufficient constraints. More concretely, when estimating illumination, the joint convolution sparse representation is proposed as structure and texture constraints to obtain a structural image severed as illumination. Then, the adaptive gradient constraint is used to enhance the details of the reflection image. Experiments on a number of challenging low-light images are present to reveal the efficacy of our method and show its superiority over several state-of-the-arts on both subjective and objective assessments.

A visual localization method based on roadside landmarks is proposed in this paper. This method uses a single image obtained by a high-speed camera fixed on the top of the vehicle to accomplish real-time positioning. The information and characteristics of roadside landmarks is extracted and recognized from the image obtained. The distance between landmark and camera optical center is calculated according to the shape of the landmark. Finally, the vehicle position is calculated with the distance and the landmark database, which contains the characteristics and position of the landmark. Static and dynamic experiments are carried out and the results demonstrate that the proposed method can achieve vehicle positioning. Under the condition of an actual distance is below 40 m, the average positioning error is below 1m.

With the increase in the lens aperture and widen in the spectrum, the dispersion range of diffractive optic image spectrometer (DOIS) is also growing. Large scale axial scanning increases the difficulty of system design and manufacturing of the GEO spectrometer. In this Letter, an efficient method and system for hyperspectral imaging of GEO orbit is realized by fusing diffractive optic and light field imaging technology. The emergence of the light field imaging technology provides a perfect solution for DOIS. Our system is a snapshot spectrometer that projects the spectral and spatial information simultaneously onto a CCD detector. Here a spectrometer system that operates in the 500-650nm band is designed and the performance of the system is analyzed and evaluated. Experiments are shown to illustrate the performance improvement attained by the new model. Our analysis shows that the novel snapshot hyperspectral diffractive computational image spectrometer is no-slit, high throughout, feasible and usable imager that can be widely built for many fields.

Based on the high-resolution imaging property of the products of optical fiber material, a novel imaging system is proposed. The prototype of the system is made by coupling CCD chip(CMOS) and a large-scale optical fiber faceplate together. Firstly, the working principle and manufacturing process of large-scale optical fiber faceplate is described. Secondly, the effectiveness and practicability of the prototype of the system is verified by experiment. Finally, the potential application prospect of the imaging system is discussed. The theoretical analysis and experimental result show that the prototype works perfectly under high temperature and pressure condition and the resolution of the image that obtained by the imaging system is larger than 70 lp/mm, which can satisfy the basic imaging requirements in the research fields such as medical diagnosis, industrial detection and monitoring. Further, the novel imaging system provides a new approach for the application of optical fiber product in scientific research.

Polarization imaging focuses on degrees of linear polarization (DoLP) and angles of polarization (AoP). This paper introduces a polarization imaging set which employs a LWIR polarization imaging system along with a set of cooperative self-made target panels to acquire polarized radiation. The sampling flowchart is given and the process of polarization acquisition demonstrated. The experiment shows that larger the observation angle, stronger DoLP signal and weaker radiance lowers the contrast of polarization image.

The light field imaging system can record the azimuth information of the light. With exposure, the views of different viewpoints can be obtained by calculation. In order to get those views, the traditional algorithm usually uses a periodical method. However, this kind of algorithm ignores the angle-relationship between the viewpoint and the center of each microlens. In this cases, it leads to distortion views. The reconstructed image has a low resolution and poor quality. In order to solve these problems, we studied the principle of light field sampling based on microlens array. According to geometrical optics, we proposed an efficient algorithm to acquire non-periodically the views. Firstly, we calculated the offset of each microlens center by analyzing the optical path of the light field. Then, we analyzed the range of visual angle. We calculated the projection region of the synthetic viewpoint, and extract non-periodically those pixels to form the view. It can improve the resolution of views. Finally, we smoothed and sharpened the result image to further improve the quality of the views, which can preserve the detail information and eliminate the noise at the same time. Experimental results showed that the image quality of the perspective views reconstructed by the proposed algorithm was much better than the conventional method. It had no image superposition and no distortion phenomenon. And the image resolution was much higher and the visual effect was also much better compared to the conventional one.

With the development of electronic displays becoming flat and portable, field emission displays (FED) get the widespread attention because they have the advantages of flat-panel displays and CRT displays together. At present, as one of the core components in FED, the screen is still the short board in the application of FED. With thin film phosphor as the phosphor layer, the screen will be very beneficial to the application of FED because of many advantages of extremely high resolution, strong adhesion, good smoothness, low release of gas, good conductivity and so on. That highlights the important application value and research significance of thin film phosphor in FED. In this review, we summarize the recent advances in the thin film phosphors for FED with emphasis on the film materials, preparation technology, and the main problems in the film. And the further study of thin film phosphors in FED is also presented.

To detect the quality of jujube in outdoor with hyperspectral, part of the polarized light is formed by the absorption and scattering of atmospheric and jujube. Polarization dimension contains red jujube of fine quality information, by increasing the polarization spectrum detection, further improve the detection accuracy, research methods, the characteristics of high spectral band orthogonal polarization imaging technology, to obtain samples of jujube different orthogonal polarization direction of hyperspectral images. Texture features were extracted by PCA wavelength ratio. The basic processing methods of spectral region correction and spectral smoothing were used to compare the characteristic absorption peak of 992.65nm, 1188.96nm, 1449.96nm, 1107.68 nm and 1294.68nm in both indoor and outdoor southern xinjiang jujube. Results, comparative indoor and outdoor nearly hyperspectral images found on the ground, jujube and reflection spectral absorption peak position unchanged, spectrum waveform similar, affected by different band size is different, characteristic peak place have obvious difference, the longer the wavelength, the greater the difference. The hyperspectral images of parallel and vertical components of the target were obtained, and the orthogonal differential polarization spectrum information was obtained. The preliminary results were obtained by fine remote sensing of quality of jujube. The results show that the quality information of jujube can be obtained by using the orthogonal polarization imaging technology of high spectral characteristic band. It provides an important reference for monitoring the quality change information of large area jujube.

As the core component of lidar, APD detector is used to realize photoelectric conversion of laser echo signal. The detector needs to work at a stable temperature to ensure its application performance. A high gain amplifier circuit is designed. The temperature signal is collected by the MCU and the semiconductor refrigerator is controlled. The precision control of the temperature is realized through the PID algorithm. The adjustable high voltage module is integrated, and the APD bias voltage and temperature can be controlled through the serial port of the MCU. Reducing the volume of the APD detector, ensuring the wide temperature range of the detector and improving the integration degree of the lidar.