To measure the quality of optical surfaces, one of the most used methods is the deflectometry. To implement this technique, a screen is used to choose some incident rays on the surface under test. Subsequently, the intersection of the rays is measured, after having passed through the surface, in a detection plane perpendicular to the optical axis. With the coordinates of the points in the detection plane, the normal vectors are determined in each point of the surface under test. The process is simple if the incident rays are chosen in a configuration called null, that is, in the detection plane the measured points will be distributed in a uniform configuration, rectangular, circular, radial, etc. In this work we present the numerical simulations, considering an incident spherical wavefront in the null screen that is placed at an arbitrary position between the source and the flat surface of an aspheric lens that was used in the experimental arrangement. In the simulations it is expected to obtain a uniformly distributed arrangement of spots, which will be compared with the experimental results.
There are a variety of techniques to determine the quality of optical surfaces, which provide quantitative information of the deformation of the shape of the surface under test. This work proposes to use the deflectometry technique using a Hartmann screen to test a spherical surface with a local deformation. In order to perform the theoretical analysis, a model of experimental setup in which the input parameters: the position of the Hartmann type screen and the location for each of its holes, the distance of the observation plane and the positions of the reflected rays, are known. With this model, based on the diameter of the deformation and deviation of the incident and reflected rays in the observation plane, we determine the theoretical sensitivity of the technique proposed.
The use of zinc oxide (ZnO) for its application as gas sensor is frequent in the industry. One important element for the
characterization of this kind of structure is the measurement of the material thickness deposited on a substrate. In this
work, an optical method for determining the measure of the ZnO material thickness, in this case a point diffraction
interferometer (PDI) is used. The PDI uses few optical elements in the arrangement and its low cost represents an easy
implementation. Also, the ZnO sample does not require any chemical treatment to be measure; consequently it does not
need an extra step in the measurement process. The purpose of this arrangement is to implement it as a measuring tool
for the laboratory of sensor films of the Autonomous University of the State of Hidalgo. For early results, it is proposed
to measure the thickness of a ZnO film larger than one micron of the ZnO film, and the results are compared with the
traditional method using a talkstep.
In the podiatry field, many of the foot dysfunctions are mainly generated due to: Congenital malformations, accidents or
misuse of footwear. For the treatment or prevention of foot disorders, the podiatrist diagnoses prosthesis or specific
adapted footwear, according to the real dimension of foot. Therefore, it is necessary to acquire 3D information of foot
with 360 degrees of observation. As alternative solution, it was developed and implemented an optical system of threedimensional
reconstruction based in the principle of laser triangulation. The system is constituted by an illumination unit
that project a laser plane into the foot surface, an acquisition unit with 4 CCD cameras placed around of axial foot axis,
an axial moving unit that displaces the illumination and acquisition units in the axial axis direction and a processing and
exploration unit. The exploration software allows the extraction of distances on three-dimensional image, taking into
account the topography of foot. The optical system was tested and their metrological performances were evaluated in
experimental conditions. The optical system was developed to acquire 3D information in order to design and make more
appropriate footwear.
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