In order to search out the shortest path of the 3R manipulator, a path length expression of manipulator’s end-effectors is given first, and then the problem is modeled as a functional extreme problem. For the purpose of simplifying the solving process, the functional extreme problem is translated into a new one with the same solution, and the solution of the latter expressed by a system of differential equations is derived by using variational method. By means of the inverse matrix expression of the upper triangular matrix, the system of differential equations is translated into a new one consisted of normal state equations. The method can avoid complex inverse matrix computing, and make the computation of the transition process simpler when compared with differential geometry method. By using Matlab simulation method, 3 joint angle functions corresponding to the shortest path of the 3R manipulator’s end-effectors is obtained.

In order to keep a lightweight structure, high stiffness, strength and thermal dimensional stability, an 18-strut truss main support structure was designed for large-scale and off-axis Three-mirror Anastigmat (TMA) space camera. The merit and demerit of main support structure of off-axis TMA space camera with overall framework and truss support structure were analyzed. The truss support scheme was confirmed on the basis of optical system and the whole structure size characteristic of the camera. The dynamic and static stiffness single-layer 6-strut and double-layer 18-strut truss structure were analyzed and contrasted. The materials of truss main support structure were selected reasonably. The influence factor of the strut fundamental frequency was analyzed, and then the structure parameters of the strut were optimally designed. The mechanical and thermal characteristics of 18-strut truss support structure were analyzed. Finally, adhesive strength between strut and pipe joint was tested. As shown as the result of finite element analysis, the fundamental frequency of truss main support structure is 78.4 Hz, and the maximum tilt angle of the secondary mirror is 4.6″ around Y axis under the action of gravity in X axis direction. Dynamic and static stiffness index meet the design requirements. The tensile test results show that the strut tensile strength of the adhesive joint is 5.85 MPa, which is satisfied to strength requirements.

According to the structure of large-aperture telescopes azimuth shafting, ANSYS was utilized to establish the two-dimensional model. The contact stiffness, contact algorithm and other contact simulation parameters were analyzed and set. The results show that, compared with the classical Hertz contact theory, the error of maximum contact pressure and elastic approach which were calculated by ANSYS are 4.3% and 0.4%. The results verify the rationality of the model and the parameter setting in ANSYS analysis. Using the ANSYS model, the static analysis of the plane thrust bearing was conducted. A method for the drawing of static bearing capacity curve is established, which provides a reliable theoretical basis for the design of the azimuth shafting of large-aperture telescopes.

To improve the dynamic range of imaging equipment when detecting targets with great intensity differences simultaneously, a pixel-level adjustable telescope based on Digital Micromirror Device (DMD) is designed. The system has an intermediate image plane on DMD. First of all, the micromirrors of the DMD are on and one image of the target is obtained and divided into several little zones according to mean gray level and locality dynamic, and parameters such as time of exposure of each zone are set up. It is effective based on the parameters to modulate the corresponding micromirror’s on-off statement and time, which will improve the dynamic range of the system. The dynamic range of the designed telescope with effective focal length of 223 mm, F-number of 5, field of 3° and wavelength range from 480 nm to 760 nm, can be up to 140 dB. The design results show that, on the image plane of DMD, the modulation transfer functions of each field is greater than 0.70 at Nyquist frequency and the distortion is close to 0, and on the image plane of detector, the modulation transfer function of each field is greater than 0.55 at Nyquist frequency and the distortion is less than 2%.

The microscope is one of the classical optical instruments with long development history. Its performance continues to increase, but the microscopic objective short working distance largely limits its application. As the market demand for long distance microscope, its development has important significance. According to the design requirements, determine objective structure firstly, and then use ZEMAX for design and optimization. A working distance of 150 mm, line 0.8, 5 times of magnification, resolution of 6 μm reflecting and catadioptric microscope objective design results are given. The advantages and disadvantages of the two results are compared.

Optical Coherence Tomography (OCT) has been widely employed as non-invasive 3D imaging diagnostic instrument, particularly in the field of ophthalmology. Although OCT has been approved for use in clinic in USA, Europe and Asia, international standardization of this technology is still in progress. Validation of OCT imaging capabilities is considered extremely important to ensure its effective use in clinical diagnoses. Phantom with appropriate test targets can assist to evaluate and calibrate imaging performance of OCT at both installation and throughout lifetime of the instrument. In this paper, we design and fabricate a physical model eye with 3D resolution test targets to characterize OCT imaging performance. The model eye was fabricated with transparent resin to simulate realistic ophthalmic testing environment, and most key optical elements including cornea, lens and vitreous body were realized. The test targets which mimic USAF 1951 test chart were fabricated on the fundus of the model eye by 3D printing technology. Differing from traditional two dimensional USAF1951 test chart, a group of patterns which have different thickness in depth were fabricated. By measuring the 3D test targets, axial resolution as well as lateral resolution of an OCT system can be evaluated at the same time with this model eye. To investigate this specialized model eye, it was measured by a scientific spectral domain OCT instrument and a clinical OCT system respectively. The results demonstrate that the model eye with 3D resolution test targets have the potential of qualitatively and quantitatively validating the performance of OCT systems.

A new technology of three-dimension visualization of computer tomograms using computer generated holography is proposed. Firstly, information amalgamation of computer tomograms is studied, the three-dimension information extracted from a series of two-dimension computer tomograms is recorded by computer-generated holography, and different Computer-generated Holograms(CGHs) corresponding to different number of computer tomograms are obtained. Then, combining the structural features of Liquid Crystal Spatial Light Modulator (LC-SLM), spatial frequency, angle between object and reference beams as well as sample interval of CGHs is analyzed, and the viewing angle of reconstructed image of CGHs is discussed. On this basis, relevant parameters are properly set making the holographic system and the liquid crystal display system match well. Finally, three-dimensional reconstructed and real-time display system for computer tomograms is build, in which, real-time controlled by computer, different CGHs are output to LC-SLM in sequence, and three-dimensional reconstructed images of computer tomograms changing with the holograms are dynamically displayed on fog screen. The principle and experiment result are given.

Based on the differences between auto-fluorescence spectra of plaque and dental tissue, a quantitative analysis method of plaque using auto-fluorescence imaging was presented. Auto-fluorescence spectrum of tooth samples excited by 405 nm was measured, on the basis of analyzing the correlation between color parameters of fluorescence and dental plaque content, R/B of fluorescence image was proposed as quantitative assessment parameter of dental plaque content, meanwhile long-wavelength pass filter with central wavelength of 490 nm was used to filter fluorescence spectral bands. Finally, experimental setup was built to obtain the auto-fluorescence image. Quantitative analysis results of three different levels of plaque content and distribution was obtained by using R/B value as segmentation thresholds, which confirmed with visual examination results.

To overcome the problem of occlusion in face recognition, the method of extended sparse representation for face recognition based on Gabor Features and Metaface Learning (GMFL) is proposed. Considering the robustness of the Gabor feature to the variation of illumination, expressions and gestures, the method extracts Gabor features of images firstly, and then a new dictionary with stronger sparse representation power can be obtained from the Gabor feature sets by Metaface scheme. Meanwhile, the Gabor occlusion dictionary is employed to encode the occluded part of the image, and a set of over-complete dictionary bases are produced. Finally, the test image can be reconstructed by the over-complete dictionary bases, and the residual between the sample and the reconstructed sample is used for classification by minimizing residual. Experimental results demonstrate that the algorithm proposed is valid and robust on AR database and FERET database.

Recent years have witnessed a growing interest in developing automatic palmprint recognition methods. Most of the previous works have focused on two dimensional (2D) palmprint recognition in the past decade. However, 2D palmprint images could be easily forged or affected by noise, causing potential security risks for practical applications. Therefore, three dimensional (3D) palmprint recognition has been regarded as a promising way to further improve the performance of palmprint recognition systems. In this paper, we have proposed an efficient 3D palmprint recognition method by using local texture feature sets. We first employ shape index representation to demonstrate the geometry characteristics of local regions in 3D palmprint data. Then, we incorporate rich local texture cues from two complementary sources-local ternary pattern (LTP) and Gabor wavelet to extract features from the shape index image-proving that the combination is more accurate than either feature set alone, and finally fuse them at a matching score level. Further experiments on Hong Kong Polytechnic University 3D palmprint database validate that our method outperforms existing state-of-the-art methods in terms of recognition accuracy, showing the effectiveness of our method.

In view of the problems of conventional palmprint recognition algorithms that are susceptible to noise interference, and poor robustness to rotation attacks, a novel palmprint recognition method is presented by using Uniform Local Binary Patterns (ULBP) and sparse representation. This method utilizes ULBP which is good at expressing image texture features and has the good rotation invariance and noise immunity characteristics to extract palmprint features. At the same time, taking into account the phenomenon that the local texture features will be lost if we directly extract palmprint features to the whole image by ULBP, this article blocks the palmprint image first and then statistics each sub-block features by ULBP. On the design of sparse classification algorithm, this article takes ULBP features of the training samples to construct a redundant dictionary, and achieves sparse decomposition of testing samples by solving the optimization problem based on l1 norm, and proposes a sparse representation classification method based on statistical average residuals to achieve recognition and classification result. The experiments demonstrate that the proposed method has the good robustness to rotation and noise, and the overall recognition rate is increased obviously. Compared with the traditional PCA and 2DPCA methods, for the database which contains 50 kinds of palmprint images, the recognition rate is increased by 8.8% and 6.8% respectively.

For the reason of the traditional sparse representation classifier is not sensitive to the changes of characteristics only has enough training samples, a face recognition method based on Shearlet multi-orientation adaptive weighted fusion and sparse representation is proposed. In order to extract the multi-orientation information and reduce the dimension of the features, images are decomposed in multi-scale and multi-direction by using Shearlet, and the subband coefficient matrices are obtained. Then, the directional sub charts on the same scale are sorted in the main direction according to the sizes of the variances of the subband coefficient matrices. Furthermore, using the energy and the mean values of subband coefficient matrices, the face sub charts are weighted fused. Finally, Shearlet multi-orientation feature fusion is applied to construct sparse representation classifiers for sparse representation of coefficient vectors. The experiments taken under the ORL, FERET, and YALE database are used to verify the effectiveness of the proposed method, and the results show that the proposed method can effectively enhance the robustness of the external environment changes and improve the recognition rate.

Local Directional Pattern (LDP) algorithm is a local feature extraction method which is robust to random noise. It has been widely used in face recognition. As LDP algorithm encodes the negative directions convolved by the Kirsch masks, the value of center gradation can’t fully reflect the information in the field of the local features. Thus face recognition performance will be influenced. A new algorithm named CLDP based on LDP algorithm is proposed. The CLDP algorithm encodes the positive directions which are convolved by the Kirsch masks. These directions can fully reflect the information in the field of the local features. And thus face recognition accuracy can be enhanced. To evaluate the performance of the proposed CLDP algorithm, some experiments are conducted in YALE, ORL and JAFFE face databases. Experimental results show that our CLDP algorithm has better recognition performance compared with LDP, LDN and ELDP algorithm.

We investigate a new metric slope Root Mean Square (RMS) for characterizing the performance and for large telescope such as TMT tertiary mirror. The metric can multiply the errors which derived from the low order aberration, such as Zernike polynomials and other frequency composition. It represents the efficiency lose due to mid and high-spatial frequency components in frequency domain. The metric also properly counts for the optic error of the mirror itself such as the deviations from a perfect surface and metrology measurement errors. We also numerically confirm this feature for the TMT M3. We hope the work of this paper will be useful for the metrology of TMT.

The aerosol absorption directly influences the spread of light in the atmosphere, and causes the attenuation of light. With advanced folding Jamin interferometer, the interference system is completely set up. During laser heat and cool process, aerosol absorption can be obtained differently. The parameter of laser exciting power has been determined. It is shown that the system of aerosol absorption coefficient is feasible.

In order to ensure the adjustment range of the optical zoom digital surveillance camera’s zoom and focus stepper motors, a correction method based on zoom tracking curve is designed. First, select a standard curve from the zoom tracking curve manufacturers provided. Second, the real zoom tracking curve with the same distance of the standard curve is collected by the method of automatic focusing. Then, offset of the highest points in two curves is calculated. Finally, with the principle of minimum squared difference, optimal offset value is found in a small area near the offset. This correction method is realized in high-definition digital video camera with 30× lens. Experiments show that this correction method is a good solution for solving the problems of stall phenomenon and out of focusing caused by motor origin error.