In order to adjust the position of the secondary mirror of Cassegrain telescope with large field of view, a computer aided adjustment method of two-step sensitivity matrix model was proposed. Based on the analysis of the shortcomings of the traditional sensitivity matrix method of the two order model, a fine tuning step was added based on the characteristics of the sensitivity matrix and the traditional sensitivity matrix method was improved. For the Cassegrain system, the relationship between the Zernike coefficients and the misalignment was analyzed, and the calibration simulation of Cassegrain system with 300 mm aperture and 0.6° field of view was carried out. The simu-lation results show that after correction by traditional sensitivity matrix method, the mean values of offset along x, y, z axes and tilt around x,y axes are -0.0684 mm, -0.0892 mm, 0.0015 mm, 0.0498° and -0.0444°, respectively, and the full field wavefront aberration RMS is less than 0.1λ(λ=632.8 nm). After correction by two step sensitivity matrix correction method, the mean values are -0.0018 mm, -0.0012 mm, 0.0002 mm, 0.0008° and -0.0012°, respectively, and the full field wavefront aberration RMS is less than 0.03λ, which is obviously superior to the traditional sensitivity matrix method.

The planar compound eye imaging system uses multiple sub-apertures to image the scene. Due to the constraint of the imaging sub-aperture size and spatial sampling rate of the image sensor, the image quality of each sub-aperture is low. How to fuse multiple sub-aperture images for a high-resolution image is an urgent problem. Multi-image super-resolution theory uses multiple images with complementary information to reconstruct high spatial resolution image. However, existing theories usually adopt the oversimplified motion model which is not suitable for planar compound eye imaging. If the existing multi-image super-resolution theory is directly applied to the resolution enhancement of the planar compound eye, the inaccurate motion estimation will reduce the performance of image resolution enhancement. In order to solve these problems, the motion model of the multi-image super-resolution is improved in the variational Bayesian framework, and the derived joint estimation algorithm is used to enhance the resolution of the planar compound eye. The correctness and effectiveness of the proposed method is verified by the simulation data experiments and the real compound eye data experiments.

In view of the problem that 3D-CNN can better extract the spatio-temporalfeatures in video, but it requiresa high amount of computation and memory, this paper designs an efficient 3D convolutional block to replace the 3×3×3 convolutional layer with a high amount of computation, and then proposes a 3D-efficient dense residual networks (3D-EDRNs) integrating 3D convolutional blocks for human action recognition. The efficient 3D convolu-tional block is composed of 1×3×3 convolutional layers for obtaining spatial features of video and 3×1×1 convolu-tional layers for obtaining temporal features of video. Efficient 3D convolutional blocks are combined in multiple lo-cations of dense residual network, which not only takes advantage of the advantages of easy optimization of residual blocks and feature reuse of dense connected network, but also can shorten the training time and improve the effi-ciency and performance of spatial-temporal feature extraction of the network. In the classical data set UCF101, HMDB51 and the dynamic multi-view complicated 3D database of human activity (DMV action3D), it is verified that the 3D-EDRNs combined with 3D convolutional block can significantly reduce the complexity of the model, effec-tively improve the classification performance of the network, and have the advantages of less computational re-source demand, small number of parameters and short training time.

Aiming at the lowoptical efficiencyof Fresnel lens, a high-efficiency non-imaging concentrated optical(NICO) system composed of an aspheric lens and a trumpet lens was designed. The aspheric lens was optimizedinsequential mode of Zemax, and the geometric radius of its image spot was reduced from 42 mm to 1.7 mm by mi-nimizing the spherical aberration. The aspheric lens and trumpet lens were modeled and optimized in non-sequential mode of Zemax, and the NICO system with 87% optical efficiency and 0.9° received angle was achieved by Monte Carlo ray tracing analysis. Finally, the packaging and testing of the high concentrated photovoltaic (HCPV) module were completed based on samples of an aspheric lens array and 48 trumpet lenses. The test results showed that the photoelectric conversion efficiency of the module reached 30.03%, which was significantly improved compared with the HCPV module composed of the Fresnel lens.

Sweep source optical coherence tomographic angiography (SS-OCTA) is a kind of angiography technol-ogies based on split spectrum amplitude deeorrelation angiography (SSADA). It has a great prospect in the early diagnosis of tumors and other diseases. In this paper, skin structure and angiography of melanoma C57BL6 mice were collected on the basis of the SS-OCTA imaging platform with an imaging field of 5.12 mm×5.12 mm and a standard image maximum signal-to-noise ratio of 34.3 dB. The results show that the SS-OCTA system is superior to the structural imaging in early diagnosis of dermatological diseases.

Aiming at the complexity of the traditional gauge detection method, high requirements for the installation and large amount of data analysis, a gauge measurement method based on the relative transverse movement of wheel and rail is designed in this paper. Two sets of laser source and camera combinations are used to dynamically collect the image of the inner straight line part of the rail head in the method. According to the rail parameters, the Hough detection and perspective transformation are used to rectify the image from the same acquisition distance. Compared to datum moment, the variation of vertical displacement of the center point of the laser is computed. And through the geometrical relation of the variation previously described and the lateral relative displacements of the two wheels, the relative transverse displacement of the two wheels is calculated. The relative initial time gauge change is gained by the difference, which realizes the indirect measurement of the track gauge. The experimental results show that the method has the characteristics of simple hardware structure, small data calculation, high measurement precision, and can realize non-contact dynamic measurement of gauge parameters.

In order to measure the transmission wavefront of laser rods and to improve the edge diffraction effect of small-aperture laser rods measured by Tayman or Fizeau interferometer, a variable-inclination Mach-Zehnder inter-ferometer was proposed. The incident angle was changed by adjusting the tilting attitude of the phase shifting ref-lector, then the optical path difference was changed that the phase shift was introduced to the coherent light and the phase shifting interferometry was realized. The transmission wavefront of a laser rod (Nd:YAG) with the diameter of 6 mm and the length of 60 mm was measured by this interferometer, the peak-valley (PV) and root mean square (RMS) of the wavefront were 0.391λ and 0.056λ. The same laser rod was measured by ZYGO GPI XP interferometer, the peak-valley (PV) and root mean square (RMS) were 0.370λ and 0.064λ. The comparison results show that the interferometer can achieve high-precision detection of transmission wavefront of laser robs. The variable-inclination Mach-Zehnder interferometer has high phase-shifting precision and wide phase-shifting range, and the beam in the system can pass through the laser rod only once, which can suppress the multi-beam interference and improve the edge diffraction effect of the small-aperture laser rods.

Aiming at the motion errors of the linear stage, a measurement method for the determination of three-degree-of-freedom (3-DOF) error motions is proposed based on non-diffracting Moiré fringes produced by computer-generated holograms (CGHs). A liquid crystal spatial light modulator (SLM) is used to generate non-diffracting beams, and two non-diffracting beams form Moiré fringes. A 3-DOF measuring optical path of non-diffracting Moiré fringes is designed. Meanwhile, a 3-DOF mathematical model of motion errors is established, and three kinds of motion errors (yaw angle, roll angle and pitch angle) are separated by geometric analysis method. A rotary table is used to simulate the 3-DOF motion errors on different conditions. The NDB and non-diffracting Moiré fringe patterns are obtained by CCD1 and CCD2 respectively. Experimental results show that the motion errors calculated by the positions of the central points agree well with the theoretical value with the error less than 0.0104°, which can verify the feasibility and correctness of the 3-DOF measurement system for non-diffracting Moiré fringes.

The development direction of metal material laser processing is to achieve small roughness, less heat-affected zone and high depth-diameter ratio. Recently, a kind of water-conducting laser processing technology based on laser water-jet coupling technology has been developed. The basic principle of water-conducting laser processing technology and its advantages over traditional laser processing methods are expounded. Based on the principle of laser water-jet coupling technology, a set of water-conducting laser processing equipment is constructed. The experiments of water-conducting laser processing for various metal materials are carried out. The surfaces of work piece are observed and analyzed by Leica DVM6 digital microscope. The edges of blind holes in two kinds of metal materials are regular and smooth, the edges of grooves are straight and without burrs, and there is no heat-affected zone in both materials. The results of experiments show that water-conducting laser processing tech-nology on metal precision machining is practical and has important application value.

In order to solve the problem that the displacement accuracy of linear displacement mechanism is toohigh in traditional white light interferometry, this paper proposes a full-field heterodyne white light interferometry. Thetechnology mainly uses the white light interference signal with difference frequency as the light source to realize thehigh-precision detection of the coherent peak position under the conditions of large push step and low push precision.In this paper, the mathematical model of white light heterodyne interference is established firstly, and then the overallsystem design scheme is proposed according to the light intensity signal characteristics provided by the mathemat-ical model. Then the feasibility of the measurement scheme is verified by experiments. At the end, theoretical anal-ysis and data comparison are carried out for the influence of various errors on the calculation accuracy of the algo-rithm. The results of error analysis show that the white-light heterodyne interferometry technology provides highermeasurement accuracy and better anti-interference performance, effectively reducing the strict dependence of tradi-tional white light interferometry on the accuracy of linear displacement mechanism, and is an optical free-form sur-face detection technology. More solutions are available.

Study of the time characteristics of photomultiplier tube with ultra-fast time characteristics has an impor-tant guiding role for the further development of ultra-fast time response microchannel plate photomultiplier tube (FPMT). Based on the VME test system in high-energy physics and picosecond laser with single-photon pulse mode,this manuscript designs a device to test the FPMT with 25 ps system error. The time characteristics of various FPMTs were tested by optimizing the FPMT signal readout anode, the voltage divider structure and voltage division ratio. The intrinsic time lower limit value of the FPMT in the non-single-photon working mode, is proposed to compare and analyze the time resolution of different FPMTs in different working states. After completing various optimized readout anode structural design for the FPMTs, it can be find that the best FPMT prototype in our Lab has the best intrinsic time resolution lower limit of 30 ps.