The integration time refers to the time for the infrared focal plane array (IRFPA) imaging system detector pixel that accumulate radiation signals to generate electrical signals. For the infrared seeker, in order to accurately capture the target, the integration time seriously affects the overall performance of the detection system, such as the output voltage, responsivity, noise equivalent temperature difference (NETD), and so on. This paper introduces the traditional method of setting the integration time, which is based on user’s experience and subjective judgment. This method often cannot give full play to the best performance of the detector. Moreover, because it’s highly subjective, different people may come up with different results. In order to make full use of the performance of the detector and obtain a consistent calibration effect, this paper proposes an integration time calibration method based on histogram and the response characteristics of the detector. And it is applied to the HgCdTe 640×512/15μm pitch MWIR. By comparison, after adopting the new method, the Residual fixed pattern noise (RFPN) and NETD of the device have been greatly improved after NUC. Compared with the traditional method, the new method can form a standardized process, and then provide guidance for the automatic calibration of IRFPA.
In this paper, we propose a dynamic model of an asymmetric passive walker with the knee joint. The stable initial conditions of the dynamic model are obtained by the cell mapping method. We analyze how the length ratio of the left and right legs of the walker (the left and right leg mass and the moment of inertia change along with the length of the leg) and the angle of the ramp influence the gait characteristics of the walker, such as the length of step, gait cycle, and walking speed of the model. Based on the existing researches, if there is a very small asymmetry difference, the walker will have a double-step gait. When the leg length difference reaches a certain level, a four-level gait will appear, and as the leg length ratio continues to change, eight times and sixteen times will continue to be shown out, which in turn evolves into a chaotic gait.. If the proportion of leg length exceeds an upper bound, a stable passive walking gait will no longer be found. According to the study on the asymmetric passive walker, this research can not only guide the design and manufacture of a driven biped robot but also be used for clinical-pathological asymmetric gait treatment, exoskeleton assist device development, prosthetic design, and prosthetic adaptability training to provide theoretical guidance.
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