According to the working principle of the binocular photoelectric instrument optical axis parallelism digital calibration instrument, and in view of all components of the instrument, the various factors affect the system precision is analyzed, and then precision analysis model is established. Based on the error distribution, Monte Carlo method is used to analyze the relationship between the comprehensive error and the change of the center coordinate of the circle target image. The method can further guide the error distribution, optimize control the factors which have greater influence on the comprehensive error, and improve the measurement accuracy of the optical axis parallelism digital calibration instrument.
As the developing appliance range of high-resolution optical design, the requirement on the aberration of system design is becoming higher and higher, but the installation and adjustment error of optical components is an important element which influences the aberration. The decentration and tilt of optical components result not only the image lateral displacement but also the aberration enlargement of the optical system, the research on image quality of plane symmetric optical system is becoming more and more popular. The Gaussian correction methods on lens decentration already exist, but it is short of theoretical research to guide the correction on the lens tilt, which leads to the effect of image lateral displacement. This thesis analyzes theoretically a mathematical model between the lens tilt degree and wave aberration, and deduces mathematically the correction equation of zero aberration increment under the aberration constraint condition. Taking an example of some type optical sight, the ZEMAX simulation is carried out to validate this method, and the results show that: This method can effectively guide the correction of lens tilt, and reduce the influence of lens position change on the optical imaging quality. It has important practical significance to guide high-resolution optical design.
The beam expander is a device used for extending the action radius of the optical system by removing the optical axis parallel. It is usually composed by a pair of plane mirror or two total reflection prism which is installed parallel. However, limited by manufacturing and installation progress, optical axis parallelism errors can be generated while it is hardly to guarantee the two plane mirror or the two total reflection prism installed completely parallel to each other. To detect the optical axis parallelism error of the beam expander quantitatively, a digital optical axis parallelism error detection method for the beam expander is designed taking advantage of the CCD technology and the Image processing technology. In this method, the reticule of the collimator is regarded as the target at infinity. Firstly, the reticule of the collimator images on the CCD camera directly. Keep the pose of the CCD camera unchanged. Then the parallel optical beam is shifted into the beam expander detected by removing of the pentaprism, and the reticule of the collimator images on the same CCD camera again. The location of the collimator reticule center image on the CCD camera is determined respectively through the corresponding image processing. The error of the beam expander is calculated by comparing the coordinate of the collimator reticule center image. An experiment platform is set up based on and the feasibility of this method is verified that the accuracy of the detection method is less than 3’’; this method has the advantage of simple operation, high practicality and high accuracy.
With the wide application of laser beams in the atmosphere, such as optical communications, the propagation of
high-power laser beams and laser ranging, the propagation of laser beams in turbulent atmosphere has been studied
extensively for many years. The atmospheric turbulence severely influences the beam quality and therefore the efficiency
of the technology. Up to now, there have been many studies in random effects on laser beams propagation through
atmosphere. Typically, M2 factor which is a very important parameter for characterizing the laser beam quality is
widely investigated. In this paper, energy Strehl ratio was utilized to characterize the laser beam quality. The propagation
of a collimated Gaussian beam through atmospheric paths was numerically simulated using phase screens by the FFT
method. And the effects of various factors such as atmosphere turbulent parameter C2n, the inner scale, the outer scale
and meteorological parameters on energy Strehl ratio were analyzed by means of probability statistics. The results show
that the mean of energy Strehl ratio decreases with the transmission distance increasing, and it is the same with strong
refractive index fluctuation. However, the beam quality may be improved in shorter distance when energy Strehl ratio is
larger than 1. The energy density of the laser beam after propagating through turbulent atmosphere in the radius of that in vacuum can be calculated by energy Strehl ratio. It may represent the accepting states of the laser beam in a short
Image intensifier is the kernel of the low-light-level image device. Output signal-to-noise ratio is one of its important parameters which can reflect the image intensifier’s imaging quality. Traditionally the test of image intensifier’s output signal-to-noise raito is realized by using a multiplier phototube, which method only gets the output signal-to-noise ratio of temporal field and can not evaluate the effect of the space structure’s nonhomogeneity of the fluorescence screen in the round. In view of these defects, the traditional method is replaced by a new one based on the three-dimensional noise theory. In this paper, a set of test formulas of output signal-to-noise ratio in spatio-temporal field which can roundly evaluate the image intensifier’s imaging quality are deduced, a test system based on the planar CCD image gathering and processing system with high sensitivity and low noise is designed. By using digital image processing technology based on Visual C++ and Matlab, a part of tested data of some home image intensifiers are given and subsequently some 3-D graphs of noise which can describe the spatical-temporal field’s imaging character in different brightness gain are drawn. The practical results can show that the new test method is rounded, accurate and visualized.
A new method to deal with images by computer is put forward, which is more convenient for the eyes to identify and much easier to understand. As the image edge is a basic character of image, checking it is one of the most important parts in processing the image. The traditional technique is to use the edge detection algorithm, which is to detect the gray level changes of every pixel of image in some epsilon, and to detect the image edge by using the changing regular of directional derivative. But sometimes there is uncertainty of image edge, and man can't distinguish it is the edge or not. Diagram algorithm can't solute this pivotal problem. In order to turn the fuzzy edge to be in focus and solve the problem above, this paper mentions fuzzy enhancing technique to realize image edge's being detected. Fuzzy technology is a newly rising technology used in many fields, especially in the image domain, and fuzzy enhancing technique is one important portion of the fuzzy technology. Based on this technology, this paper firstly sets the image fuzzy characteristic plane of original image, secondly proceeds the fuzzy enhancement, and then detects the edge by Sobel differential arithmetic. At the end of the paper, it realizes the histogram algorithms and the fuzzy enhancing algorithm by Visual C++. Results of the experiment show that fuzzy enhancing algorithm is a superior one in image procession.