In consideration of the crosstalk between reconstructed image and zero-order image existed in the digital reconstruction for off-axis digital holography, this paper presents a method to suppress the zero-order image. Based on the principle that the pixel gray-scale of the image is decided both by the image illumination and surface reflectance, the hologram is considered as a product of the incident and reflected components. The incident components which change slowly are mainly concentrated in the low-frequency region, and the reflected components which determine the detail of the image are concentrated in the high-frequency region. A reasonable homomorphic filter with the upper and lower limits of 0.001 and 1 respectively and a diameter of 300 pixel is designed and processed into the hologram. The results show that the zero-order image can be suppressed with only one Fresnel digital hologram at a distance of 34 cm. Meanwhile, the contrast and the details of reconstructed image at the same distance are improved.

A large frame and framing camera with a continuous rotating mirror is developed under the coaxial imaging theory and a controlling defocusing range. With the frame size of 30 mm×18 mm, it shows a large relative aperture and higher resolution. Moreover, its big stops are 1/15 for the spatial direction and 1/35 for the scanning direction. The static visual resolution and dynamic visual resolution of the camera are 46 lp/mm and 35 lp/mm, respectively, and it can offer the number of frames of 80 and framing rate from 1×104 frame/s to 5×105 frame/s. Furthermore, the high speed rotation mirror in the camera uses a fiber sensor system to produce and transfer the rotation signals, which eliminates the influence of the electromagnetic disturbance from a high speed rotating electromotor on the rotation signals and ensures the measurement accuracy. The camera has been applied to the detonation and shock wave physics experiments and the experimental processing has been recorded at a framing rate of 2×105 frame/s. Obtained results demonstrate that the camera has larger frames and higher resolution and is suitable for the various experiments of shocking, detonation, projectile attitude and target photography.

To eliminate the difference between data bits and pixel bits of the processors in a Ternary Optical Computer(TOC) in the logic operation, a new typical optical structure, Double Rotator Structure(DRS), was proposed to improve the reconfiguration speeds of the optical processors and reduce the difficulty of managing a large number of data bits. The operation unit based on the DRS was used to achieve one lines function of the truth table in the logic operation, and it was called Line Calculator(LC). The reconfigurable features, circuit implementations, and reconfigurable commands for the LC were discussed in detail. Then, the DRS Ternary Optical Processor(TOP) was designed and achieved to reduce the complexity of the processor management software. Finally, a verified experiment of reconfigurable LC was performed, which shows that the principles of DRS TOP are correct, and all 81 commands for the reconfiguration are effective. Moreover, each of the two input, three-valued logic operations with thousands of data bits can be concurrently achieved in the DRS TOP with three partitions.

To control the lasing of Surface Plasmon Polaritons (SPPs) more effectively, an integrated device of lasing SPPs based on a coupling grating was researched and the propagation and lasing of the SPPs in passive metal layers were realized by electron beam exciting and grating coupling. The characteristics of wave vector for the SPPs propagation were analyzed and the general characteristics of the device were obtained through the analysis of lasing condition and light wavelength under a special condition. Results indicate that the device to complete the SPPs lasing based on the coupling grating has an obvious strong local characteristics, and it can control the lasing SPPs effectively by adjusting the intensity of injecting electron beam. The device can propagate the SPPs well when it is in the range of visible light wavelength. The device has a positive significance for researching the construction of plasmon cell circuit, the detection of nano-wire structure and the explosion of nano-optical field.

A simulation equation of surface etching for amorphous materials during ion beam etching was worked out based on the characteristic curve method, and a simulation program named BLAZING for the ion etching process was established according to the holographic grating.Then, the relation between the etching rate of amorphous materials and ion beam incidence was analyzed and optimized. Finally, an experiment was carried out to verify the simulation program with the ion beam etching. By adjusting the etching rate ratio from 2∶1 to 1∶2 for a mask and substrate materials, four 1 200 l/mm blazed gratings with the right angle between 34°and 98°and the blazed angle about 8.6° were fabricated, and the simulation error between the experimental data and the simulation data is less than 5%. By controlling the etching time from 6 min to 14 min, six 1 200 l/mm blazed gratings with the ridge between 0 nm and 211 nm and the same blazed angle of 8.6° were fabricated, and the error mentioned above is less than 1%. The contrast results illustrate that the error of contour line between simulation and experimentation is less than 5%, and the error of etching ending time between simulation and experimentation is less than 1%. It concludes that the simulation program BLAZING can simulate the effect of different etching processes and different parameters on the etching results, and can predict and control the ion beam etching process.

On the basis of the requirements of cavity adjustment completed by measurement ellipticity, an ellipticity measurement system with double beam paths was researched for adjusting the cavity of a ring gyro laser. The frequency response characteristics of a square ring resonator to the S line polarized light and P line polarized light were analyzed, and the S line polarized light was chosen to stabilize the frequency of a positive resonant cavity. By inputting the S polarized beam to improve the frequency stability accurately, a frequency stabilization system and a ellipticity measurement system with double beam paths were established. By utilizing the new frequency-stabilization system and measurement methods, the frequency stabilization of the system can be realized in 10 s and the stabilization accuracy is better than 1.8%. Furthermore, the fluctuation of ellipticity has been 0.65% by the proposed method, which reduces the effect of light fluctuation on the measurement accuracy. In conclusion, the proposed system meets the needs of ellipticity measurement.

As the support accuracy of primary mirror of a large caliber optical telescope directly influences the overall unit of opto-electrical detecting equipment, this paper presents a support structure combined an axial support and a radial support for the primary mirror with a diameter of 1 000 mm according to the requirements of an optical system for support accuracy. Furthermore, the finite element method is used to analyze and calculate the support positions theoretically. Experiments show that when a 18-point floating support is used in the axial support and a 3-point resilient mounting in the radial support, the higher surface figure accuracy for the primary mirror can be reached. As traditional assembling and adjusting techniques can not reach the ideal surface figure accuracy, it explores a new assembling and adjusting approach to the primary mirror. An interferometer is applied to the measurement of the primary mirror with a support in real-time, then it is grinded again to obtain the higher accuracy. After the primary mirror is assembled, its surface figure accuracy reaches λ/18. The results not only meet the index requirements of the project, but also offer a new way to assemble and adjust larger caliber primary mirrors.

In order to obtain the movement data of an aircraft, including trajectory, attitude, displacement, deformation and other kinds of movement data of the aircraft structural parts in the flight accurately, an optical and dynamic measurement method is proposed and implemented based on the theory of close-range photogrammetry and stereo vision technology. The main contents of the method are multi-camera self-calibration technique based on close-range photogrammetry, camera dynamic positioning and jitter eliminating in flight technology, rapid acquisition for the trajectory and attitude of rigid structure, precise matching of non-coding landmark array by multi-camera (≥3) collaboration. The simulation results show that the reprojection error of the camera is less than 0.03 pixel, the trajectory and attitude measurement accuracy of the system can be up to 0.01 mm/1 m, and the measurement accuracy of key point displacement and deformation is 0.05 mm/1 m. It demonstrates that the system have met the standards of accuracy and reliability for aircraft testing industry.

A focusing mechanism with a tilt of focusing plane assembly less than 7 ", positioning accuracy better than 0.01 mm in the ±2 mm focusing range was designed to ensure the best image quality for a wide field space camera with a focal plane length more than 600 mm. To meet the requirements of the focusing mechanism for focusing accuracy, mechanical environments and the vacuum environments, the dual-cam drive technology was used to complete the accurate focusing, and the loss of power brake self-locking technology allowed the camera to be a stable image plane position under the impact of mechanical environments. Furthermore, the high stiffness rail and bearings were used in the focusing mechanism to obtain a high dynamic stiffness. The design analysis and experimental results show that the dual focal plane cam-driven focusing mechanism has high focusing precision and high reliability and is able to complete the focuing and improve the image quality of space cameras in the complex space environments.

For mars exploration, a novel prototype of imaging spectrometer consisting of an optomechanical subsystem and an electronic subsystem was designed based on an Acousto-optic Tunable Filter(AOTF). An achromatic telescopic optical system was used in the spectrometer and its spectral range was between 550 nm and 1 000 nm, while the spectral resolution was 0.9-4 nm. In electronic subsystem, a system-on-a-programmable-chip was introduced and data transmission was implemented by employing a novel bus technology of SpaceWire. On the basis of laboratory calibration, the prototype was installed in the stimulant mars explorer, and a hyperspectral imaging experiment was performed. Experimental results indicate that the prototype of imaging spectrometer can offer good imaging quality and the measurement identify between the prototype and an ASD spectrometer is over 96%. Furthermore, the SpaceWire bus can transport data at a rate of 100 Mbps continuously, which satisfies the technique requirement of 25 Mbps. The development of the prototype provides technical foundation for applications of AOTF imaging spectral technique to mars-based remote sensing in future.

A self-collimating optical measurement system was set up to measure the deflection angles of three-dimensional objects, in which the values of the deflection angles were obtained by extracting the coordinate of a turntable cross wire. First, Sobel operator was used to detect the image edge of the cross wire taken by a CCD camera, then lines of the cross wire were extracted through self-adaptive threshold division. Because of other turntable scratches, the partial least square method was used to extract the cross wire, and the weighted total least squares was adapted to fit the cross-wire lines. Thus two equations were set up, and the intersection coordinate was obtained through solving the two equations. Experimental results show that the precision of the two line-slope product is within ±1%, very close to the true value (theoretical true value is -1). By taking the angle from Leica theodolite (the accuracy is 0.5″) as the true value to calibrate the precision, the measured precision angles for α and β are 3.59″ and 3.76″, respectively, which satisfies the requirements of deflection angle measurement.

A two-dimensional self-calibration algorithm was developed to extract the stage systematic measurement error from a stage position measurement error. On the basis of the stage measurement error model, the algorithm got the iterative self-calibration model and the initial value by measuring five different views of an artifact on the stage, and then it established a complete iterative 2D self-calibration model. The algorithm was used to simulate a 2D stage with an accuracy of 0.2 μm. The results show that the calibration error is 0.33 nm without random measurement noises and is the same order of magnitude with random measurement noises. The actual self-calibration experiment on a stage with the given measuring accuracies of 2.98 μm and 3.22 μm in x and y directions was performed, and obtained measuring accuracies are 2.59 μm and 3.14 μm in x and y directions, respectively. All results demonstrate that the proposed algorithm has a good robustness for the random measurement noises, and it is suitable for the calibrations for precision stages or ultra-precision stages.

According to the requirements of a coaxial space remote sensors, a high-precision truss made of carbon fiber composites was developed to be as the supporting structure between primary and secondary mirrors, and its engineering applications were analyzed. In the manufacturing process, the relevant technological process was explored and the high-precision machining of the structure was realized. Finally, the vibration test, mechanical test and temperature stability test were performed. Based on the optical measurement method, an automatic testing platform was set up and the measurement precision was improved by rapidly repeated measurement and the elimination of artificial factors. The analysis and test results indicate that the high-precision truss only weights 13 kg, the first natural frequency is 119 Hz, and the deformations are less than 4″ under the conditions of gravity, 10 ℃ temperature rise and 4℃ temperature difference. Furthermore, the flatness of mounting interfaces for each component is less than 8 μm in the high lightweight and high stability. The truss has been successfully applied in a space remote sensor, and the design scheme, test scheme and the manufacturing process discussed in this paper can be used as a reference for other coaxial space remote sensors with the same type.

A 3-DOF mechanical leg with compact structure, strong carrying capacity and the rotational motion in decoupled was proposed. To analyze the drive parameters of the 3-DOF parallel mechanical leg, a dynamic model was established and the peak of a servo motor was predicted based on the dynamic model. Firstly, by analyzing the motion parameters of the leg mechanism, the dynamic model was established based on the Lagrange equation, and the drive force acted on the mechanism was given. Then, based on the dynamic model, a peak prediction model of the servo motor for the drive speed and torque was defined. Finally, for a given motion equation and a set of structural parameters, the time curves of drive speed and torque were obtained, the dynamics of the mechanism was given and the peak prediction model was proved to be correct. Calculations show that the peaks of the drive speeds from three driving motors are 19, 17, 27 r/s for Nx , Ny and Nw , and the peaks of the drive torque are 5.8, 3.1, 4.4 N·m for εx, εy and εw respectively.

In order to improve the thermal conductivity of materials and decrease the temperature gradient of a space optical remote sensor, the carbon-carbon composites were pasted on the metal surface. The characteristics of carbon-carbon composites were introduced and the heat transfer models of one bare steel plate and two pasted plates with carbon-carbon composites in the thicknesses of 0.5 mm and 2 mm respectively were established. The three heat transfer states of the steel plates were calculated and experimented, and their equivalent thermal conductivities were obtained. The models were simulated by using the finite element model IDEAS-TMG and the heat transfer properties of three kinds of plates mentioned above were compared. Results is shown that the carbon-carbon composites could improve the temperature uniformity of the plates. Finally, the carbon-carbon composites were applied to a TC4 star-tracker bracket of a star sensor, and the temperature difference between the assembly area and the radiator was tested. The tested results indicate that it is 28 ℃ and 5 ℃, respectively, for the bare bracket and the one with 0.5 mm-thick carbon-carbon composites on the inner and outer sides. The tested result illuminates that the thermal conductivity of the bracket of the star-tracker is improved and its temperature gradient is reduced effectively. This method could give some guidances and references for the thermal design of other space optical instruments with great temperature gradients.

A 5 DOF magnetically suspended flywheel with vernier gimballing capacity which is composed of a conoid reluctive bearing and a Lorentz magnetic bear was investigated and its rotor rim was designed optimally. Based on the structure of the rotor and the goal to minimize the mass of the rim, the mass, inertial moment and resonance frequency of the rim were analyzed theoretically to confirm the optimal variables. Consequently, an optimal design was achieved through iSIGHT and ANSYS , and by taking the number of spokes into account, the variables were optimized by the sequential quadratic programming algorithm in the restrain cases of the resonance frequency, inertial moment, maximum equivalent stress, and the ratio of polar inertia moment to equinoctial inertial moment. Those results of optimization indicate that the mass of the rim is decreased from 2.226 kg to 2.036 kg (namely reduced by 8.54%) when the number of spokes is 3 and other design variables are optimal. The proposed optimal design method can improve the rationality and efficiency of rotor design, and will be an important part in the optimal design of flywheel systems.

The impact of pneumatic pressure for a supersonic conformal dome on optical and structure characteristics was studied. The elliptical dome with a diameter of 203 mm and the ratio of length to diameter of 1∶1 was designed. Wind tunnel experiments in an attack angle 0′ were accomplished by speeds of 2.0, 2.5 and 3.0 Ma and the pressure was obtained on the surface of dome. The displacement distribution and the stress distribution of a hot-press MgF2 dome were obtained by the fluid-structure coupled analysis on the finite element model based on different thicknesses. According to the data, the figure curves of these dome models were fitted renewedly. Imaging quality was compared based on the optical system designed and the results illuminate that the maximum stress is 37.5 MPa when the thickness of the dome is 2 mm and the speed is 3.0 Ma. At the same time, by contrast with the initial optics of the dome, the relative error of spot radius is 0.26%, and figure relative error is -1.03%, which meets the requirements of structure strength and imaging quality under the dynamic pressure.

Ultrasonic treatment was originally introduced into UV-LIGA technology in this paper. The effect of ultrasonic treatment on SU-8 swelling was researched, and ultrasonic mechanism of SU-8 swelling was explored. Then, a novel method to reduce SU-8 swelling and improve the dimensional precision of an electroformed microstructure was obtained. In experiments, the effect of ultrasonic treatment on the SU-8 swelling during the development and electroforming process was respectively studied, the surface hydrophilicity of SU-8 photoresist in different ultrasonic time was analyzed, and the SU-8 swelling removal ratio in different ultrasonic time was calculated. Furthermore, the effect of ultrasonic treatment on the dimensional precisions of different micro devices was discussed. The experimental results indicate that the SU-8 mould swelling in development process is not obvious, and the ultrasonic treatment has a little effect on the SU-8 mould swelling during development process. The effect of ultrasonic treatment on the SU-8 mould swelling mainly occurs in the electroforming process, and the SU-8 swelling and its surface hydrophilicity both decrease first and increase afterwards with increasing the ultrasonic time. By 10 min ultrasonic treatment, the SU-8 swelling removal ratio is up to 70%, and the dimensional error of electroformed microstructure is independent on the structure of SU-8 mould. Moreover, the reason that SU-8 swelling behavior varies with increasing ultrasonic time was explained based on the ultrasonic mechanical scission of polymer chain and water absorbing mechanism. In conclusion, the presented method to reduce the swelling of SU-8 resist mould does not depend on the process parameters and not increase the complexities of mask layouts, and is a practical method.

To determine the emissivity of the primary mirror in a space camera and to analyze the thermal control effort for a subsystem, a method for measuring emissivity by using two kinds of materials with known emissivity as references was proposed based on the analysis of temperature measurement principle of a thermal imager. According to the emissivity measurement experiment, the primary mirror emissivity was calculated to be 0.565. To determine the influence of different measuring factors on the measurement accuracy, an error analysis was carried out. Analysis results prove that when the materials to be measured have almost the same emissivity with the objects, the temperature measurement errors of the thermal imager and emissivity standard error of the material will have greater impacts on the measurement accuracy. The measurement error caused by temperature measurement error and emissivity error is ±0.028 in the proposed experiment. Finally, the thermal model of the camera was modified by using a thermal equilibrium test, the results demonstrate that the emissivity measured by proposed method reflects the actual state of the primary mirror, and the method is useful and feasibility for measuring the emissivity of primary mirrors.

For improving the machining precision and surface integrity of hard and brittle materials in rotary ultrasonic grinding, the influence of bond patterns of tools on working performance was analyzed. First, the bonding patterns between diamond particles and bonds in ceramics-bonded, iron-bonded and bronze-bonded tools were investigated by energy spectral analysis, and bonding strength was confirmed according to the tool wear of the same process parameters. Based on results above and the characteristics of ultrasonic vibration tool, the relationship between bond patterns and cutting force, tool wear, surfaces integrity was studied by rotary ultrasonic grinding machining experiments. Experimental results indicate that average cutting force in Z axis is 46.8 N and the tool wear of after removing 18 000 mm3 is 0.1 mm by iron-bonded ultrasonic vibration tool, they are smaller than those of ceramics-bonded and bronze-bonded tools. However, the ceramics-bonded ultrasonic vibration tool is the best one, and its surface roughness is 21.79 μm. These results prove that the iron-bonded ultrasonic vibration tool is suitable for rough maching and the ceramics-bonded ultrasonic vibration tool is favourable to finish maching.

To get fatigue properties of the small and hard brittle components working at conditions of little amplitudes and high frequency forces, this paper presents a novel kind of resonance and high frequency fatigue testing machine driven by a piezoelectric vibrator (PZT、PLZT or PMN). First, the working principle of the piezoelectric resonance and high frequency fatigue testing machine was introduced, and the dynamic model of the machine was established and its systemic dynamic characteristics were obtained. Then, a prototype was designed and produced. Finally, the dynamic load on the specimen was measured by the prototype. The results indicate that the dynamic load on the specimen is 24.7-99.2 N by changing the AC voltage amplitude (100-250 V) and the thickness of the plate spring (1.1-0.6 mm). The prototype designed in this paper is suitable for the tensile and bending fatigue testing under conditions of little amplitudes and high frequency forces with the dynamic load mentioned above.

A micro-arrayed multichannel optical filter is proposed to allow the colposcopy to have an ability of multispectral imaging. The micro-arrayed filter is fabricated by micro-lithographic procedures and vacuum multilayer thin film coatings, and the wavelengths of light passing through the filter correspond to the characteristic peaks of the biomarkers in the reflectance or fluorescence spectra. After integrating the filter with an image sensor on colposcopy, multiple spectral images centered at different wavelengths can be obtained to provide the information about morphological changes on cervical surface and the quantitative variation of the biomarkers in cervical tissues. The micro-arrayed filter with four kinds of filter cells (λ1=630 nm, λ2=460 nm, λ3=515 nm, λ4=577 nm) has been fabricated successfully with an area of 10 μm×10 μm for each filter cell. The bandwidth of each filter cell is about 40 nm, and the transmittance is between 30% and 40%. Experiments demonstrate that the optical properties of micro-arrayed filter satisfy the basic requirements of multispectral imaging. After integrating with a colposcope, the sensitivity and specificity of colposcope diagnosis is improved significantly, which can reduce the biopsy frequencies for patients.

With the aim to locate singular points (core point and delta point) precisely and to complete fingerprint classification and matching, the Radon transform was introduced firstly to extract the directional filed characteristic of a fingerprint image and to implement the image segmentation. The concept of directional entropy was proposed to describe the distribution of directional filed characteristic and the singular point area search method based on directional entropy was given. Furthermore, a directional density function was established to evaluate effectiveness of singular point location, which can guide the inspecting system to achieve optimal directional entropy threshold. After singular points were detected, the performance of similar algorithms was compared by taking accuracy and efficiency into consideration. Experiments show that the algorithm proposed in this paper is more advantageous, and it not only achieves high inspecting accuracy by 83%, but also has better adaptability and robustness fitted for practical application.

To improve the measurement accuracy of a cantilever vibration gyroscope in an inertial measurement system, the sensitive structure of the cantilever vibration gyroscope was modified and a measurement system was developed based on the gyroscope. The structural and temperature characteristics of the improved gyroscope were analyzed and the zero drift and linearity were researched in detail. Firstly, the reasons that affect the gyroscope measurement accuracy were analyzed base on the working principle of the cantilever vibration gyroscope. According to the insignificance of the piezoelectric film coupling structure of the original cantilever vibration gyroscope, a new piezoelectric film coupling structure was proposed. Then, the new structure was simulated by ANSYS software combined with 50, 60, 100 mmcantilevers to prove its engineering feasibility. Finally, a prototype of the gyroscope based on the new structure and test performance was produced in a laboratory. Simulation and prototype experiments show that the average sensitivity of the new structure gyroscope increases by 8.73%, and the average zero drift and temperatare drift decrease by 30.5% and 10%, respectively when the temperature is 25℃. These results prove that the improved cantilever vibration gyroscope can be used in engnieering practices.

The Wiener filtering principle and characteristics of a Pulse Couple Neural Network(PCNN) model were analyzed and a wavelet adaptive denoising method based on the PCNN(W-PCNN-WD)was proposed according to a statistical model of speckle noise combined with a wavelet transform to improve the quality of ultrasound image. Firstly, the ultrasound image was performed a log conversion to transform the speckle noise to an additive noise. Then, the Wiener filtering was used to process the medical image to get the variance of the additive noise as the threshold of wavelet. Furthermore, the image was preprocessed by the wavelet transform and wavelet coefficients were recomposed appropriately by using the PCNN. Finally, the image was processed again by the wavelet inverter and the exponential transforms to get a denoising image. The result shows that the proposed filtering method is better than the other filtering methods, and the Peak Signal to Noise Ratio( PSNR) from the proposed method is higher 9 dB than that from the Wiener filtering when the noise variance is 0.01. The method can keep the edge details of the information on the basis of removing speckle noise, which improves the visual quality of images greatly.

An improved Iterative Closest Point (ICP) method based on the boundary feature points of the point cloud is proposed to improve the efficiency and accuracy of point cloud data registration in reverse engineering fields. First, an initial registration method based on the boundary feature points of point cloud is proposed. The method partitions the minimum bounding box of point cloud with grids in a 3D space, and sets up the space grid model. Then, it applies boundary seed grid recognition and growth algorithms to extract feature points from the boundary of point cloud, and works out the transformation matrix using Singular Value Decomposition (SVD) method to get the results of initial registration. Furthermore, an improved ICP accurate registration method is presented. It weighs the corresponding points of the point cloud, eliminates the points whose weight is larger than the threshold, and introduces M-estimation to the objective function to eliminate the abnormal points. Finally, the point cloud is accurately registered by the improved ICP method on the basis of initial registration. Compared with original ICP method, the improved ICP method increases the efficiency by more than 70 percent and reduces the error to 0.02 percent. The experiment results indicate that the method proposed in this paper improves the efficiency and accuracy of point cloud registration greatly.

To overcome disadvantages of the original Non-negativity and Support constraint Recursive Inverse Filtering (NAS-RIF) algorithm, an adaptive algorithm for the blind image restoration based on NAS-RIF algorithm was proposed. Firstly, regularization terms and space weights were added to the cost function of the original NAS-RIF algorithm. Through adaptively modulating the regularization parameters and space weights, not only the noise resistance ability could be improved, but the restored image could be smoothed. Then, image segmentation technique was employed in each iteration to find the precise object support region, meanwhile, the non-uniform background was replaced by the average background. Finally, the N-step-restart conjugate gradient routine was applied to optimization of the cost function, and then the convergence rate was enhanced. The experiments on degraded images derived from two kinds of blur operators were performed under different SNR (Signal Noise Ratio) conditions, and the ΔSNRs by proposed algorithm are 6.315 3 dB and 8.910 6 dB, respectively. The experiment results demonstrate that the proposed algorithm has a positive improvement in both reducing noises and preserving edges. Particularly, the proposed algorithm can obtain a better restoration result under a low SNR condition.

For the effect of hysteretic linearity of a piezoceramic actuator on nano-positioning system, a modeling method based on Hammerstein model was proposed. The Hammerstein-based model for the piezoceramic actuator was established and its frequency dependence was described.By using the Hammerstein model, the piezoceramic actuator was taken as a static hysteretic model couple with a dyamic second-order system, and the former was described by the Preisach model and the latter was identified by the genetic algorithm. The experimental results show that the frequency dependence of the Hammerstein-based model is improved after adding the second order system, correspondingly, the error is decreased greatly. In 800 Hz, the absolute average tracking error of the Hammerstein-based model is 0.339 2 μm, which is less than that of the Preisach model in 0.888 1 μm.

An image sequence compressed sensing algorithm by minimizing prediction errors was proposed for high speed camera image compression in real-time. First, an original image was compressed only by a projection matrix on the encoder side. The observed vector obtained by compressing was transferred to the decoder through a channel. Then, motion estimation and motion compensation were performed on correlated images on the decoder side, and a prediction image was generated in this way. Furthermore, the prediction error image which is the difference between original image and prediction image was reconstructed by compressed sensing. Finally, the reconstruction of prediction error image was improved by an iterative procedure, until the difference between two consecutive reconstruction results was smaller than a predetermined threshold. Therefore, the original image was reconstructed by the prediction error image. Experiments by CR-GEN0-H6400 camera from DALSA indicate that the proposd algorithm can compress 1 000 frame/s images in real-time, and image reconstruction result is improved by 2-6 dB at least as compared with that of independent reconstruction. The proposed algorithm can compress high speed camera images in real-time, and can reconstruct the images in high quality.

When machine vision technology is used to detect the inner surface quality of a pipeline, the geometric center of an original image will deviate the center of a pipe wall panoramic annular image in the original ones fore ground area. However, it will lead to serious deviation in the image unwrapped with the geometric center. In order to reduce the measuring errors of the geometry characters, a fast unwrapping algorithm for the panoramic annular image with center deviation was proposed. Firstly, the least square fitting circle method was used to find a fitting circle representing a cross-section of the wall on the image and to obtain the center parameters of panoramic annular image. Then, by unwrapping the panoramic annular image with a quarter circle scanning method and by correcting the frame aspect ratio of the unwrapping image, the panoramic image was completely restored. Experimental results indicate that it takes 0.868 s to unwrap the annular detection area of a panoramic image into a rectangular one with the resolution of 2 044 pixel ×199 pixel, and the relative errors in outline dimensions of the tested targets are less than 1.54%. It is shown that the method could satisfy the real time and accuracy requirements in the image processing.

A Double-semicircle Cantilever Beam(DSCB) accelerometer based on a fiber Bragg grating (FBG) was proposed to measure the acceleration signals. Firstly, the model of FBG accelerometer based on the two-dot coating was established, and the linear response between acceleration and displacements of sensitive elements was analyzed theoretically. Then, the natural vibration of the FBG based two-dot coating was described, and the effects of the length and prestress of the coated fiber on natural vibration frequency were discussed. Finally, according to the natural vibration of FBG, the FBG accelerometer was designed, and the linear response, amplitude-frequency characteristics, and direction anti-interference of the FBG accelerometer were researched experimentally. Experimental results indicate that the sensor has good flat response from 10-250 Hz, and the sensitivity of the accelerometer is 41.2 pm/G. Furthermore, the sensor can offer a good linear response in a linear fitting of 99.8% and a good cross-axis anti-interference ability in the cross-axis sensitivity less than 4.8%.