According to the characteristic of high concentration of red pixels in pentagram area, a new method of circular seal imprint extraction based on smoothing convolution location is proposed. Firstly, the colorful bill image is converted to grayscale image. Secondly, a pixel in pentagram area is located by smoothing convolution, and then the grayscale image is converted to binary image using the average of grayscale value of the neighborhood of the pixel as the threshold. Finally, the seal imprint is extracted after calculating the coordinate of the center and the radius of the circular seal imprint by searching its outmost frame. Meanwhile, in order to improve the extraction speed, the algorithm of smoothing convolution, with the highest time complexity in the whole extraction process, is optimized by reducing the image resolution appropriately during convolution. Experiments show that the method can effectively extract the circular seal imprint from complex background. And the computation speed increases by nearly 12 times after algorithm optimization.

An extraction method in sub-pixel level was proposed to solve the high accuracy center point extraction problem of the light-spot image of the spacial light-emitting-spot. The gray level distribution mathematical model of the light-spot image of the spacial light-emitting-spot with Gauss energy distribution was established, as well as the proof was given for the perspective projection invariability of the spacial light-emitting-spot. Based on the analysis of the second-order directional derivatives and the self-correlation function of the light-spot image, the Hessian matrix was obtained which was used to derive the determinant terms for the pixel level center point. Furthermore, the Taylor expansion was performed on the image gray level within the sub-pixel neighborhood of the pixel level center point, and the maximum of the gray level curved surface of the light-spot image was taken as the wanted sub-pixel center point. Compared with the existing classical methods, the experiment results show that the proposed method has higher accuracy and better robustness which can be widely used in camera calibration and 3D shape measurement, etc.

The figure evaluation method is put forward which is the fast evaluation method of interpolation errors of the encoder with high precision. Wavy generator is formed on photoelectrical signal of the encoder. The criteria for judging the quality of a fitting curve is also established. High-precision encoder moiré fringe photoelectrical signal is analyzed by using figures evaluation method, and the curve of interpolation errors is gotten. Compared with interpolation errors which are received from traditional detect method, the experimental result indicates: the figure fitting method can be applied to evaluate interpolation errors of high-precision encoder, the equipments is convenient and the examination method is efficient and feasible. Data processing can be realized by valuation analysis software in short time. The system can be used in the working field to avoid the influence of the speed，and has important meaning to the research of high-precision encoder’s dynamic precision characteristics.

In order to solve the lower measurement efficiency in traditional modulation profilometry, a fast modulation profilometry is proposed based on double color projections. Two sine gratings through the different projections form color fringe on measured object surface, and pictures are gotten by color CCD. Own to arrangement in layers’ quality of color CCD, we separate fringes into two signals, and acquire the modulation distributions. Because the modulation ratio is one-to-one correspondence to the height of object, the object is reconstructed. The design method for project of experiment, the method for acquiring modulation, the result of experiment and the deviation analysis are proposed. Several factors are discussed which affect the measurement accuracy. The result proves that this method in measuring complex objects, such as the object with deep holes, is highly efficient, simple and greatly accurate.

The Gauss width of focal spot which is too small results in the sampling error while using CCD as the centroid detecting device of Shack-Hartmann Wavefront Sensor (SHWS) in Adaptive Optics (AO) system. In order to solve the problem of sampling error, the reason of sampling error of CCD is analyzed in detail. The math model of sampling error, displacement sensitivity and open loop dynamic range are established. The results show that the optimal position during sensor calibration is the center of the four pixels of sub-aperture, where centroid detection possesses that sampling error is 0 and the displacement sensitivity and the open loop dynamic range are maximum as well. It provides theoretical basis for research of SHWS calibration method in AO system.

Based on the geometry optical theory and the diffraction optical theory, the variety of wavefront error with the propagation distance in free space is analyzed, so the spatial conjugation request of deformable mirrors, wavefront sensors and the corrected pupil in the Adaptive Optics (AO) system are presented. The results show that the propagation distance, the aperture of beam and the magnitude of the aberration affect wavefront error together. The wavefront variety is not distinct for small aberrations near propagating with a big aperture. Generally, the system’s compensation capability doesn’t decrease when the wavefront sensors and deformable mirrors depart from the conjugation position in some range whose Fresnel number is more than 1000. The positions of wavefront sensors and deformable mirrors should be designed and the 4F optical system is selected according to the character of the aberrations. This paper will provide some theoretical reference for the optical design of the AO system.

In order to satisfy the strict requirement of surface-shape and realize the ultra-lightweight design of the space mirror, the topology method was introduced into the design of a Ф500 mm round space mirror. According to the density method, the SIMP model was established. In the condition of axial-oriented gravity, taking general flexibility as design constraint, minimum volume as design objective, after iterations, better structure was gotten, whose RMS was less than 5nm and lightweight ratio reached 75.83%. In the same weight, the conventional triangular lightweight structure had the RMS of 8.17nm and lightweight ratio of 67.39%. The surface-shape contrast between topology structure and conventional structure was made in the condition of radial-oriented gravity. The computational result meets the requirements of design. The method of topology optimization is better than the conventional method in both the surface-shape and lightweight ratio.

Considering azimuth angle and elevation angle of star sensor, a new method about images simulation of star sensor was presented. Firstly, exact speed and position of star sensor platform and target were computed by NORAD TLE data and the SGP4/SDP4 model. Secondly, the relations of sensor coordinate system, spacecraft body coordinate system and J2000 geocentric inertial coordinate system were considered. Then the precise position and gray value of stars and targets in CCD images were computed, and sequence images were generated by accumulating stars image and target image. Finally, according to simulation result, movement characteristics of stars and targets in images were analyzed. The method is more reliable than traditional methods. The movement characteristic analysis is effective for dim target and helpful to detect target in star sensor images.

Speckle patterns will arise on the screen of the laser projection display while a laser beam is scattered by the elements, which is once scattering speckle. Twice scattering speckle patterns will arise on the retinas of the audience’s eyes after the laser beam is scattered by a screen again. Both the speckle patterns could be suppressed by a random phase plate modulating the laser beam in illuminator of the laser projection display. A simplified model was built. It was deduced in theory that the contrast of twice scattering speckle patterns decreased while the random phase plate was rotating. It shows that the contrasts of once scattering speckle patterns and twice scattering speckle patterns obey the same rule for a certain system. Simulations were carried out, which confirmed the result. The contrasts of once scattering speckle patterns are 0.009 6 and the contrasts of twice scattering patterns are 0.019. It shows that once scattering speckle patterns and twice scattering speckle patterns could be suppressed while the laser beam is modulated with a random phase plate. A confirmation experiment was performed.

Aiming at the structure and stability problems of the single axis Interferometric Fiber Optic Gyroscopes (IFOG), fiber Lyot depolarizer was introduced in the light path system. Due to the new structure of the light path system, the very low polarization natural light was obtained in the gyroscope to ensure the accuracy and stability of the gyroscope. Using Jones matrix and coherence matrix, the model of interferometric fiber optic gyroscope system was established for the simulation analysis of the zero bias, and the result was verified by experiment. It was obvious that the light path system could maintain high accuracy and stability of the gyroscope system with the lower requirements of the polarization of the light.

The idea and method for designing aspherical Intraocular Lens (IOL) were proposed. First, the wavefrontaberration was calculated according to the corneal topography, and then, based on the wavefront aberration expressed asZernike polynomial Z40, the aspherical IOL was designed. The imaging quality of two practicable eyes implanted with aspherical and spherical IOLs of power 9.5D and 20.5D was analyzed. The results show the Modulation Transfer Function (MTF), contrast sensitivity and defocusing MTF of eye implanted with aspherical IOL are better than those with spherical IOL. The aspherical IOL displays more excellent optical performance than traditional spherical IOL, and the method is feasible to design aspherical IOL. The results provide theoretical bases for the clinical application of aspherical IOL.

One of the most important stages in the later period of zoom system design is to optimize the cam curve. We can not guarantee the final image surface stable unless the variable parts of the zoom system move along the accurate cam curve. A new method based on ZEMAX is presented in this article. By utilizing ZEMAX Programming Language (ZPL) to create a program, we can obtain the accurate relationship of displacements between the zooming group and the compensating group. Meanwhile, the program can figure out the continuous change of the spot size in the image surface during the whole zooming process, which helps us know the synthetical image quality and provides strong evidence to the reasonableness of the cam curve.

Laser communication system needs evaluation and quantitative analysis and it has multiple criteria. In consideration of the fuzziness, diversity and relativity of evaluation criteria, the grey cluster method in grey system theory was introduced to evaluate laser communication system quantitatively. Firstly, the evaluation criteria with fuzziness and relativity were whitened, and then all the laser communication systems were clustered by clustering criteria and the integrated clustering effects of all the criteria of each laser communication system were computed. Finally, the performance evaluation was done through determination of systems’ clustering type. This method can convert a Multiple Criteria Decision Making (MCDM) problem into a Single Criterion Decision Making (SCDM) problem and it is a new method to evaluate laser communication system quantitatively.

A simplified engineering model is built by analyzing the flow field of cruise missile. It can calculate the distribution of temperature and pressure if the temperature and pressure of tail pipe are known. The model is basically consistent with the simulation which is used by hydromechanics. The luminance is calculated by the C-G approximate model of spectral bands. The results indicate that the character of luminance on core area of plume is apparent and the luminance on vertical direction is brighter than other orientations. 3~5 μm spectrum band can be main spectrum band for detection for plume of cruise missile. The analysis and results provide the basis for the detection of cruise missile and selection to spectral band for spatial camera.

Since the measuring signal obtained from Brillouin distributed sensing system, which is disturbed by the external environment, degrades the measuring accuracy in field applications, a wavelet signal processing method is used to denoise the measured signal based on Brillouin distributed optical fiber sensing technology, and verified by the measured strain data of a smart cable based on the Brillouin sensing technology. The results of wavelet denoising method shows that this method can effectively denoise measured strain of the smart cable polluted by noise, and improve the measuring accuracy of cable force. The maximum relative errors between the control cable force and the whole average cable force before and after noise filtering are 8.8% and 5.1%, respectively, which hints that the wavelet denosing method is suitable for the measured signal obtained from the Brillouin optical sensing system.

A theoretical model of high power multimode fiber amplifier is built based on rate equations of the multimode rare earth doped fiber considering the launching condition of the seed light and improvement of the mode coupling in the core. The theoretical study on the effect of rare earth dopant profiles in the core on the output characteristics is carried out. The output characteristics of the high power multimode fiber amplifier with flat and parabolic dopant profiles fibers in different launching conditions are described respectively. The results indicate that the different rare earth dopant profiles may have different impacts on the output characteristics. Besides, the high order modes in the large core fiber can be suppressed and the output beam quality can be improved by designing and controlling the rare earth dopant profiles.

In-line digital holography is presented for the particles analysis in 3-D. Since the effects of zero order waves, conjugate image and defocused particle images degrade the reconstructed image quality of the focused particles during the reconstruction of in-line digital holography containing small particles at different depths, a numerical method for reducing these effects was proposed. A new subtraction method of reconstructed wave fields was presented for particles analysis. The effects of zero order term, conjugate image and the defocused particle images were simultaneously minimized. Therefore, the contrast of reconstructed amplitude images was improved. This method is useful to slice in-line digital holograms to display only in-focus particles at any particular plane. Furthermore, this process is accomplished from a single hologram without additionally required pre or post processing. The theory, simulation results and experimental examples were also given.

Dynamic fringe pattern can be observed throughout the testing by real-time holographic interferometry, while the traditional method is only suitable for static fringe pattern in phase extracting. Based on the characteristics of real-time holographic interferometry fringe pattern and Hilbert transform, the method of phase extracting with Hilbert transform is presented for real-time holographic interferometry fringe pattern. High-Pass filter method is used to reduce the influence of the bias intensity, and the fringe pattern phase change has been obtained in the experiment of aluminum deformation. The experiment results show that the Hilbert transform method can be applied to dynamic fringe pattern in phase extraction and extract the phase difference between any two moments at any point in the field of real-time holographic interferometry. Moreover, the automatic measurement results are consistent with man-made results.

The Precipitation Radar (PR) onboard Tropical Rainfall Measuring Mission (TRMM) is the first rain radar in space. Research on PR retrieval algorithms is important in data application as well as algorithm development. This paper first introduces the PR’s standard algorithms of radar reflectivity factor retrieval used by NASA and JAXA, and then presents an improved retrieval method. Equivalent raindrop diameter is computed for each radar resolution cell according to its rain rate. If a cell doesn’t obey Rayleigh scattering condition, the corresponding radar reflectivity factor will be corrected before rain attenuation correction. Qualitative and quantitative comparisons are made on 5 km×5 km×1.5 km grids among ground radar data, PR standard results and the improved results. Results show that the method improves retrieval accuracy at the cost of a small increase in calculation.

The effect of spatial resolution ratio on the quality of optical remote sensing image fusion was discussed. By simulating images with continuous resolution ratio from IKONOS-2 panchromatic and multispectral images, experiments were carried out on Gram-Schmidt pan-sharpening method provided by ENVI V4.4, which could be seen as a complement of existing achievements. Results show that fusion quality deteriorates as the spatial resolution ratio decreases so that the spatial resolution of multispectral should be as high as possible in applications, and that the panchromatic image will need to be down-sampled to perform better fusion quality if the spatial resolution ratio is too small. Furthermore, fusion results have better quality than their original multispectral images even at the situation of a very small spatial resolution ratio.

The features and shortcomings of Toeplitz method for realizing image restoration are discussed. To overcome the disadvantage of traditional Toeplitz deblurring method, a simplified deblurring method for linear symmetric real kernel applied in image restoration is provided, accompanied with relevant algorithms. With new means, finite sized inverse kernel is gotten through rationally corresponding projecting and truncated processing. Among several topics concerned, the format of project matrix and the size of truncated inverse kernel are explained and discussed in detail. Simulation results show that the simplified algorithm is significantly better than the traditional Toeplitz method.

Input signal power of GPS receivers changes with time. If fixed threshold is used to determine completion of the acquisition stage, two problems will arise, namely, decreasing in detection probability or increasing in false alarm probability. Therefore, it is proposed to apply a decision method for adaptive acquisition threshold in signal acquisition. Specifically, maximum likelihood estimation method is used on the sample data for decision statistic to obtain the maximum likelihood estimation value for noise variance. Afterwards, adaptive acquisition threshold can be obtained based on the Constant False Alarm Rate (CFAR). As the average acquisition time is one of the most important indexes of GPS receivers, calculation methods for the average acquisition time are analyzed for the case when both carrier frequency and PN code phase are uncertain. Furthermore, constraint relationship among acquisition time, Signal-to-noise Ratio (SNR) and threshold are derived. Analysis results show that adaptive acquisition threshold method can reduce acquisition time effectively, thus accomplish faster acquisition.

To improve the segmentation performance, a novel approach for shadow detection integrating multiple features was proposed, which considers information of color, shading, texture, neighborhoods and temporal consistency to detect shadows in a scene. Firstly, illumination logarithm invariability of neighborhood shadow pixel was proposed to detect shadow. Then, integrating the shadow feature of HSV color space and the statistical feature in a region with the combined blocks based on a gradient algorithm, the shadow was detected efficiently and reliably. Finally, an improved quantitative method was introduced to evaluate the algorithm on a bench mark suite of different illumination and environment video sequences. The experimental results show the effective performance of the algorithm. The method can be applied to moving target segmentation in intelligent video surveillance.

A novel texture image segmentation method is proposed to segment the wire rope in complex background. Firstly, the Local Binary Pattern (LBP) operator is used to extract local texture feature histogram of sub windows in an image. Then, these histograms are measured statistically by the first-order entropy and second-order entropy to reduce the dimension of LBP characteristic. At the same time, edge density is combined to describe the texture feature. Based on the three features, the Fuzzy C-Mean clustering algorithm is adopted to realize non-supervised texture images segmentation. In the experiment, the results of texture image segmentation by the proposed method are compared with the results of Gray Level Co-occurrence Matrix (GLCM) and typical LBP operator respectively. The results show that the proposed method can realize wire rope image segmentation effectively, and its performance is batter than the GLCM’s and LBP’s.

Texture is an important image feature. A novel texture feature extraction technique is proposed based on coefficient co-occurrence matrix of discrete wavelet frame transformed image, which captures the information about relationship between each high frequency subband and low frequency subband of the decomposed image at the corresponding level. It is not independent to extract the information of each subband coefficient. Considering that the Support Vector Machine (SVM) has advantages of resolving the small-sample statistics and generalizing ability, the classification performance is analyzed by using the SVM classifier. The experimental results demonstrate the effectiveness of our proposed texture feature in achieving the improved classification performance.

A new iris pre-processing method was proposed, which breaks the traditional localizing principle. The process of noise detection was achieved by converting the spatial domain into the frequency domain. The detailed steps were as follows: Firstly, the light spot within the pupil was filled in the original image. And then the image was unfolded into a rectangle, the circle detection was substituted by the point and line detection in the rectangle image to find the inner and outer edge, and the normalization was also performed. Finally, eyelash and eyelid were detected and disturbed region was marked as well by taking advantage of the direction selectivity of 2D-Gabor filter in the normalized iris image. The results prove that this method not only solves the problem of pupil carry-over or the texture loss caused by the inner edge which is not an ideal circle, but also sharply reduces the location time and enhances the accuracy of iris recognition.

A complete combinatorial pre-processing algorithm based on the characteristic of capacitance sensor fingerprint image was pointed out. The problems were considered in this algorithm such as fingerprint image’s quality and area and so on, and the filter was increased twice based on the original algorithm to enhance fingerprint ridge and eliminate noises effectively for better preprocessing result. Firstly, the fingerprint image was filtered by edge keep filter. Then, the image was enhanced by the algorithm based on the lines of directional of Gabor filter, which could reduce the effect of the rotation and shift of the images on the fingerprint recognition. Finally, the thinning image was received in the morphological thinning method after dynamic threshold method and the second filter were used to receive a binary image. The experimental result proves that this algorithm is effective to fingerprint image and helpful to the fingerprint feature extraction and matching.

The properties of Electrowetting–on–dielectric (EWOD) on the core-surface of optofluidic lens-array with specific “conductive silicon rubber /insulation film” material are one of the important research topics in optofluidics. In this work, the effect of insulation thickness and relative dielectric constant of insulating layer on the contact angle of conductive droplets were analyzed in detail. Then, the characteristics of electrowetting–on–dielectric with different insulating layer materials were also tested. The experimental results show that contact angle increases as the voltage increases. The contact angle varies inversely when changing the thickness of the insulating layer. At a given thickness, it was also observed that the dielectric constant of conductive silicon rubber is of better performance than Parylene. These conclusions are valuable in the field of the design and development of new types of optofluidic zoom lens array devices.