The whole performance of an electro-optical imaging system consisting of optical systems and array detectors was explored and optimizing design of the system was discussed. As array detectors were developed and updated in a higher speed, how to improve the optical system to optimize the whole performance of electro-optical imaging system was researched. According to the sampling theory of the sampled electro-optical imaging system, the Modulation Transfer Function(MTF) characteristics of the electro-optical imaging system were studied and the MTF phase average concept for the sampled electro-optical imaging system was discussed. Then, the effect of fabrication and use errors of the electro-optical imaging system on the MTF was analyzed and the calculation formulas of the signal-to-noise ratio of the electro-optical imaging system were given. For a remote sensing electro-optical imaging system, it suggests that the optical system MTF normalized spatial frequency should be set to be 0.5 for matching with the Nyquist frequency of the array detector. By which the system satisfies the demand of the signal-to-noise ratio, the MTF at Nyqust frequency reaches 0.1, and the resolution power is close to Nyquist frequency without the spectrum aliasing.

The film system structures of Co/Ti multilayer film were designed optimally at the L-absorption edge of Ti(452.5 eV) to meet the requirements of a multilayer mirror at the ‘water window’ energy region between 280 eV and 540 eV. The reflectivity of the multilayer film was calculated at different interface roughness conditions and it shows that the interface roughness has greater effect on the reflectivity of the multilayer film. Co/Ti multilayer films were deposited on a Si substrate by DC magnetron sputtering method and the quality of these films was improved by adding nitrogen gas into original argon gas in magnetron sputtering. Finally, the multilayer film structure was measured by a Grazing Incident X-ray Reflection (GIXRR) method and a Transmission Electron Microscope(TEM), and the reflectivities in different nitrogen concentrations were measured by Soft X-ray Reflectivity(SXR) at Beijing Synchrotron Radiation Facility(BSRF). The results show that the reflectivity of the Co/Ti multilayer with nitrogen gas fraction of 5% is the highest among the samples, by which the reflectivity has been improved from 9.5% to 12.0%. The results demonstrate that the reaction sputtering with nitrogen gas improves the quality of Co/Ti multilayer films effectively.

According to the requirements of an airborne imaging spectrometer for the wide angle and large relative-aperture, an optical system for the airborne imaging spectrometer was designed using an off-axis Schwarzschild telescopic system and a double-Schwarzschild spectral imaging system. The imaging spectrometer has specifications by a field of view of 28°, a relative-aperture of 1/2.5, and working waveband from 04 μm to 1 μm. Based on the astigmatism-correction condition of double-Schwarzschild spectral imaging system, the initial parameters were calculated. Then, the ray tracing and optimization design were performed by ZEMAX software. The analysis and evaluation on the design show that 88% of the encircled energy for centric and edge wavelengths is within one pixel;both smile and keystone are less than 5% of the size of one pixel, so it is easy for spectral and radiation calibrations. Moreover, the MTF of imaging spectrometer is more than 0.59 for different wavelengths, which satisfies the requirements of specifications. As the spectrometer has a smaller volume and lower mass, it is suitable for airborne remote sensing.

To measure accurately the spatial and temporal distribution of laser intensity in a far-field for a mid-infrared high energy laser system, two thermal issues existing in laser parameter measurement for an uncooled photoconductive HgCdTe detector were discussed, including environmental temperature variation and the laser induced temperature rise of a sensor chip. Then, two solution schemes were presented respectively. On the basis of empirical formulas for electrical properties of n-type HgCdTe materials and device physics of the photoconductor, the temperature dependences on dark resistance and responsivity were analyzed. A thermal analysis model of the photoconductive HgCdTe detector was established and verified by experimental data. Thermal contact resistance and natural convection were considered in this model. After the time characteristics of thermal equilibrium between sensor chip and environment were investigated, an environmental temperature calibration model for continuous wave laser parameter measurement was presented. Finally, dynamic responses of the HgCdTe detector under fixed and variational laser irradiations were analyzed, and a correcting method for the effect of laser heating on sensor chip was presented. The results show that the measurement uncertainty of a single unit in the beam detector array is reduced by 2% or more under a typical implementing condition. The proposed methods have been successfully used in different mid-infrared high energy laser quantificational measurement systems.

As the method to get the removal function by traditional Ion Beam Figuring (IBF) has complicated operation and higher costs, this paper proposes a new method to calculate the removal function. The method uses the Faraday cup scan to measure and calibrate the temporal distribution of ion beams and to obtain the different working parameters of ion sources which corresponds to removal functions. Firstly, the material removal theory of IBF was studied based on the Sigmund sputtering theory, and the influence of ion beam distribution on the removal function was researched. A simplified IBF removal function model was proposed. Then, an experiment was conducted to obtain the relationship between the temporal distribution of ion beam and the related parameter of removal function, and the different removal functions of various working parameters were calculated with the combination of the basic removal experiment and Faraday cup scan results. Experiments were performed on silicon and fused silica, and the experimental results show that the peak value of the removal function for the same material is proportional to the that of the scan result. A mirror with a Φ800 mm silicon flat modification layer was polished, obtained the Root Mean Square(RMS) of surface error is 57866 nm. After polishing for two times, the RMS is 11.837 nm, and the convergence rate is up to 4.89. These results meet the requirements of optical fabrication for polishing accuracy and improve the determining efficiency for removal functions.

A new method to improve the measuring resolution of a Frequency Modulated Continuous Wave (FMCW) laser ranging system was presented by splicing the sampling signals at an equal frequency interval. The principle of FMCW laser ranging was explored and a fiber FMCW laser ranging system based on dual-interferometric systems was built. In which, the auxiliary interferometric system was used to generate time clock pulses to sample the measured signals at equally spaced optical frequencies and then to splice the sampling signals. By using LabVIEW graphical programming software, a signal processing system was design to detect signal errors, sample and splice signals. The experiments on the ranging system proposed were performed. The results show that the proposed method for sampling and splicing measured signals at equally spaced optical frequencies breaks though the laser scanning limitation and reduces the effect of tuning nonlinearity of the laser source, so it improves the ranging resolution. In the experiments, it offers the range resolution of 70 μm at 8.7 m and the standard deviation of 30 group results is 35 μm.

The basic theory and design method of a broad-band spatial heterodyne interferometric spectrometer was researched based on the multi-order diffraction of echelle grating. The characteristics of the heterodyne interferometric spectrometer was described and the relationships between the instrument performance parameters (such as spectral resolution, spectral range, signal-to-noise ratio, field of view, and diffraction order) and the initial optical and electronic parameters (such as echelle grating, field prism, imaging system and detector) were discussed. Then, an experimental platform for the broad-band spatial heterodyne spectrometer was settled to demonstrate the above discussions. The designed spectral resolution is 0.173 cm-1@16 950 cm-1, and the spectral range is 500 nm to 700 nm. The broad-band results were given with a laser source (543.5 nm, 632.8 nm), a sodium lamb (589 nm, 589.6 nm) and a mercury lamb (576.96 nm、579.07 nm). It shows that the average wavenumber sampling interval of recovered spectra is 0.17 cm-1.When the triangle apodization is used in the process of spectral recovery, the measured spectral resolution is 0.39 cm-1.The obtained results conform to theoretical results and the relationship among orders of recovered spectrum accords with the theory results decided by grating function.

In structured light measurement, the current phase error compensation algorithms always lead to phase error overcompensation or under-compensation as the ambient light is varied. Therefore, a new correction method for the phase compensation errors was proposed. Based on analyzing the impact of ambient light on phase errors of four-step phase-shifting method, the reasons of phase error overcompensation and under-compensation were illuminated, the expression of the phase errors was deduced and a method to correct the phase compensation error was proposed. To compensate phase error accurately, a group of four-step phase-shifting images, sixteen-step phase-shifting images, black and white images were projected to the calibration plane, then the operation was repeated in eight different ambient light conditions to obtain several groups of coefficients. Subsequently, the analytical expression was obtained by a curve fitting. Experimental results show that the accuracy of phase error compensation is 0.002 rad no matter under dark or light environments when the method is applied, which is about 9.6 times higher than that without phase error compensation and about 3.5 times higher than that with Look-Up-Table(LUT) compensation only. This method is characterized by higher accuracy and reliability and can be used to compensate the phase errors in varied ambient lights accurately.

When the quartz(SiO2) is used as the piezoelectric actuator of a photoelastic modulator(PEM), it has shortcomings of smaller electromechanical coupling coefficient, high driving voltage required, and serious frequency drifting with a temperature. Therefore, this paper designs an optimized PEM. In consideration of the special crystal structure of lithium niobate (LiNbO3), the feasibility of LiNbO3 crystal to be a piezoelectric actuator was verified and its cut shape was set as zyw/35°cut. Based on the finite element analysis software COMSOL4.3a simulation, the chip size and the resonant frequency were determined. Then, a LiNbO3 piezoelectric actuator was designed. The piezoelectric performance of the piezoelectric actuator was tested and compared with SiO2 piezoelectric actuator. Finally the LiNbO3 piezoelectric actuator was combined with a ZnSe crystal to construct a PEM, and it was performed a photoelastic experiment by a 671 nm laser. The experiment for achieving the same displacement show that the drive voltage for the SiO2 based piezoelectric actuator is 100 times that of LiNbO3 based piezoelectric actuator, and the unity and stability of lateral length stretching vibration mode for the latter is better than that for the former. Moreover, when the drive voltage is 3.76 V, the optical path difference of 671 nm laser will be modulated to 3.7 μm through the LiNbO3 piezoelectric actuator based PEM. These results demonstrate that proposed LiNbO3 piezoelectric actuator based PEM is easy to drive and control and the modulation performance is better than that of previous PEMs.

According to the requirements of a coronagraph for suppressing the stray light in Solar Polar Orbit Radio Telescope Mission, a toothed occulter for the coronagraph was designed to suppress the diffracted light in a higher level. The diffracted light distribution from the toothed occulter was calculated by using the semi-infinite rectangle method, and an optimized shape with the lowest diffracted light was obtained. Meanwhile, the stray light level of the optimized toothed occulter was measured experimentally, and the obtained result was compared with the diffraction intensity of a round disk occulter. It verifies that the toothed occulter has an advantage over the round disk in diffracted light reduction. The measured data show that the suppression of diffracted light of the proposed toothed occulter has been up to 10-7 level after optimization, higher than internationally 10-6 level in the lab. The suppression level has been met the demands of large view coronagraphs.

The single tube receiver consisting of a vacuum tube and a Compound Parabolic Concentrator(CPC)has special requirements for the mirror field arrangement of a linear Fresnel reflector system. According to the characteristics of the single tube receiver, a method of mirror field arrangement without shading was successfully presented by using CPC maximum acceptance angle to control the aspect ratio of mirror field. Practical mathematical expressions of the mirror field arrangement without shading were derived by geometric method, and concrete numerical method was given. The mirror field arrangement was optimized through combining the distance between the reflector and the center of mirror field with the ratio of ground coverage. The experiment results for the CPC with 45° maximum acceptance angle and a mirror field with 21-mirrors and 380 mm width show that when the working time of the system without shading is set to 6 hours, the relative reasonable maximum spacing between two mirrors will be 537 nm and the corresponding ground coverage is 73.28%. For the linear Fresnel reflector system with a single tube receiver, the method of mirror field arrangement has universality and guiding significances.

An improved experiment method in a laboratory for intensity correlation imaging was designed to simplify the experiment processing of the intensity correlation imaging and to obtain measured data close to the actual observation. Firstly, the theory of intensity correlation imaging and its influencing factors on imaging quality were analyzed. Then,the existing intensity correlation imaging method and its disadvantages were discussed. A new experiment of intensity correlation imaging was designed and implemented by using a pseudothermal light and a CCD array, and the theories and characteristics to simulate the intensity correlation imaging by proposed method were introduced. Finally, the data analysis and imaging experiments were performed to verify the feasibility of the method. Experimental results indicate that the proposed method measures well the spatial power spectra of the objects, and the measurement noise mainly distributes in the high frequency region. Moreover, the intensity image of the object can be reconstructed by a phase retrieval algorithm when the signal-to-noise ratio is higher than 20.It concludes that this method preferably realizes the simulation of intensity correlation imaging. In the experiment, the adjustment of the intensity random fluctuation and the parameter of observing baseline are more convenient, so that the object with a small angular diameter is easy to be imaged.

To implement the in-line self-calibration of a time grating angular displacement sensor in practical applications, a self-calibration method called Fixed Angle Shift (FAS) was presented and a self-calibration system was designed. Firstly, circle-closed natural base was shifted to a fixed angle base to be as the self-calibration base of time grating. According to properties of Fourier series, the relations between differences of measured values and errors were established by shifting the fixed angle base to amplitudes and phases in the Fourier transfer. Then, the error function was reconstructed based on the Fourier analysis for differences of measured values. Finally, the error sources effect on the calibration accuracy were discussed and a zero point correction algorithm was designed. To verify the results of self-calibration, self-calibration experiments were performed and compared with the proposed FAS system and a laser interferometer. Experimental results indicate that the accuracy of self-calibration with FAS method is 1.9″, which is well consistent with that of the theoretic calculation (1.5±0.5)″. The method solves the self-calibration base of the time grating angular displacement sensor and satisfies, the requirements of precise measurement systems for high precise and high reliability.

A miniature intestinal anchoring mechanism is designed to realize the effective anchor of a gastrointestinal robotic endoscope in the special environment of human intestine. The mechanism explores a kind of expansion method through protruding three sets of legs radially, which lowers the risk of intestinal clamping because the three sets of legs show a enclosed structure after expansion. At the terminal of every legs, a curved plate is fixed to enlarge the contacting area between legs and intestine, which reduces the damage to intestinal tract. The interaction between anchoring mechanism and intestinal tract is modeled. The anchoring force is divided into two parts, Coulomb friction and marginal resistance, and its mechanism is analyzed. The expanding force and anchoring force are tested through experiments. The experimental results show that the expanding force of the anchoring mechanism is close to the theoretical analysis, and the anchoring force is related to intestinal diameters, the expanding diameters of anchoring legs and the speed of the anchoring mechanism. When the diameters of the anchoring legs are 20—26 mm, the anchoring force is 0.15—0.4 N;when the diameters of anchoring legs are greater than 26 mm, the anchoring force increases rapidly between 0.5 N and 1.8 N. The anchoring mechanism proposed in this paper is characterized by safe and a smaller volume and is suitable for the physical environment of the intestine. It provides a new idea for design of the intestinal anchoring mechanism for micro robots in gastro intestinal tract diagnosis.

The exciting Bouc-Wen model with fixed-parameters can not characterize the frequency-dependent and time-varying properties from the hysteresis of piezoelectric actuators and easy to generate simulation errors. In order to accurately describe these characteristics, the Bouc-Wen model was established and a recursive least square online identification method was proposed to identify the parameters of the Bouc-Wen model in real-time. Meanwhile, the limited memory method was used to limit the data sets to avoid the data saturation phenomenon. To verify the availability of the identification method, an experimental system was set up and the performance of the identification method was experimentally verified. Experimental results show that the limited memory recursive least square identification method makes the Bouc-Wen model show the frequency shift and time-varying characteristics. When the drive voltage is set to be 100 Hz, the largest absolute simulation error decreases from 1.38 μm to 0.51 μm, and reduced by 63.7%. Compared with the traditional off line parameter identification, the online identification effectively improves the modeling accuracy of the Bouc-Wen model.

An error evaluation method for the opto-mechanical system of a large aperture telescope was proposed based on structure function. The error transfer property of the structure function was analyzed, and the numerical simulation of the atmosphere disturbance was obtained by inverting the Power Spectral Density(PSD). Then, the error allocation of opto-mechanical system was built with the structure function consequently. The method was proved to be correct and feasible with the application in the 1.23 m telescope in the Changchun Institute of Optics, Fine Mechanics and Physics. Finally, the method was used in the tertiary mirror system of 30 m telescope(TMT), and the print through effect of the system in the atmosphere disturbance was researched. The experiment show that the resolution ability of the system for print through peaks does not weaken at different seeings. The method proposed has important significant for reducing the cost efficient of the large aperture telescope and lowering its risk in developing and use processing.

For the unbalance vibration of an active-passive hybrid magnetically suspended rotor caused by high speed rotation, an adaptive control method based on a sliding mode observer and a notch filter was proposed to improve the pointing accuracy and stability of attitude control for a spacecraft. The sliding mode observer was adapted to eliminate the effects of rigidity parameter perturbation and magnetic force coupling of the magnetic bearing on the synchronous vibrations and the sliding mode observer combining with the notch filter was used to eliminate adaptively the unbalance vibration of the rotor and to ensure the method without distinguishing the displacement stiffness force and the current stiffness force, and also not need to design an algorithm to compensate the influences caused by a power amplifier. The simulation and experiments were performed. Simulation results demonstrate that this method reduces the synchronous bearing force significantly;Experiment results demonstrate that this method reduces the synchronous vibrations from 0.053g to 0.012g, reduced by 77% even if the passive magnetic bearings cannot be controlled. Moreover, the method is not only suitable for the active-passive hybrid magnetically suspended rotors but also for the all-active magnetically suspended rotors.

A three degrees of freedom modeling method for a long-stroke wafer stage in lithography was proposed to solve the X-Y coupling problem of the long-stroke wafer stage and to achieve ultra-precision tracking with micron accuracy. In the modeling method, the rotation angle of X linear motor was considered as one of the controlled objects and the coupling effect on the moving in X direction was involved in the model. Then an adaptive neural network control method was presented based on the proposed model. The Radial Basis Function (RBF) neural network was used to estimate the model information and external nonlinear disturbances real-time online and to reduce the influences of unmodeled dynamics, cogging forces, end effect and friction on the control system. With the theoretical derivation and stability analysis, the convergence of the closed-loop system was guaranteed. Finally, the effectiveness of the modeling and the control method were verified by a S-curve tracking experiment on the actual long-stroke wafer stage of the lithography. The experiment results show that the tracking errors of the X and Y linear motors are less than 3 μm and the rotation angle of X motor is less than 1 μrad. The tracking errors meet the design requirements.

An adaptive feed-forward control method combining with feedback control was proposed to improve the command tracking performance of control circuit in an inertial stabilized platform. On the basis of subspace system identification, the input-output data were used to identify a state space of the stabilized platform model and the frequency-domain loop shaping technique was used to design the feedback loop controller to reject the external disturbance. Furthermore, a Recursive Least Square (RLS) adaptive filter was taken to build the inverse model of the feedback control loop and to construct the all-pass transfer function for increasing tracking performance. Several tracking experiments were conducted on different command inputs to verify the validity of the adaptive feed-forward controller. Experimental results show that this method responses quickly to step commands and the overshoot has decreased from 30% to 4.5% as compared with that of the feedback control. For a sinusoidal signal at the frequency of 30 Hz, the adaptive feed-forward controller can obtain an amplitude response without attenuation and the phase lag is reduced to 54° from 90° as compared with that of the feedback control. This method significantly improves the transient performance and is superior to the feedback control alone.

For the collapse and adhesion of photoresist with nano-structures due to the surface tension of deionized water in electron beam lithography, a drying method based on microwave heating is proposed to improve the quality of the photoresist with nano-structures. The method makes use of the microwave penetrate the photoresist to heat the water stored between resist patterns directly, and the water will evaporate with absorbing energy of microwave. Thus the collapse and adhesion of the photoresist with nano-structures can be avoided. The proposed method is used for drying photoresist lines with a height of 260 nm, width of 16 nm and photoresist pillars with the diameter of 20 nm in electron beam lithography and development. The results show that the lines and the array containing of 15 625 pillars are no collapse and adhesion, which demonstrates that the microwave with an alternating electric field can reduce the sizes of water clusters and the tension of deionized water dramatically.

A novel testing method for the protection effect of locking device on a magnetic bearing flywheel was proposed by consideration of the performance of existing locking devices and magnetic bearing flywheels. By taking a repeated clamping locking device as an example, its protection effect for magnetic bearing flywheels was evaluated from the performance of magnetic bearing flywheel, vibration macroscopic response and microscopic wear. With comparative analysis on the performance data of the magnetic bearing flywheel and the locking device before and after environmental mechanics tests, they could run normally or not were judged. In the mechanics tests, an acceleration mechanics sensor and an eddy current displacement sensor were respectively used for measuring online response spectra of flywheel system and the vibration displacement between stator and rotor, and for evaluating the macroscopic protection function of the locking device for the flywheel. After mechanics tests, a Scanning Electron Microscopy (SEM) and an Energy Dispersive Spectroscopy (EDS) were applied to analyzing the wear morphology and the spectra of locking surface, and the microscopic protection function was obtained. This testing method provides important significance for detecting of similar aerospace products.

A method to prepare nanostructures based on injection molding was proposed by taking Anodic Aluminum Oxide (AAO) templates as the mold inserts. Mold temperatures, hydrophobic properties and service life of the mold inserts were studied. Firstly, the replication quality of the nanostructures under different mold temperatures was studied by comparing the morphologies and aspect ratios of three different AAO templates. Then, according to the hydrophobic property of a nano-array structure, the influences of structural characteristics and mold temperatures on the static contact angle were analyzed to explore the hydrophobicity in different regions of PC products. Finally, the macro/micro quality and service life of AAO templates were analyzed after injection molding process. The results indicate that the mold temperatures significantly affect the replication quality of nanostructures, which focuses on the molding heights of nanostructures. There are slight hydrophobic differences at different regions of injection molded parts. Compared to the PC products without nanostructures, the maximum contact angle increases by 31.5%, reaching to 108.2°. After 500 molding cycles or more, the AAO templates with low aspect ratios show good quality, while the defects in high aspect ratio AAO templates are quite obvious.

An auto-focusing system based on a step motor (without position detection sensor) and image quality feedback for an astronomical telescope was introduced, which consists of a step motor position open-loop control subsystem and an image definition evaluation subsystem. Based on the characteristics of astronomical images, the Ful Width at Half Maximum( FWHM)of point source images of stars was used as image definition evaluation parameters. In order to achieve high efficiency of focusing process, the error of the position control system was analyzed. Then, the focusing equivalent, focal depth, system backlash and the step pulse equivalence were measured to correct the system position errors effectively. By analyzing and measuring the correlation between temperature change and image quality change, the qualitative relationship between focusing direction and temperature change was obtained. Moreover, the focal depth edge positioning policy of the focal plane was designed and a fast process focusing was achieved. The system has fault-tolerant function and self learning ability, so it shows higher levels on automation and intelligence. The design above mentioned was applied to a Ground-based Wide-Angle Camera(GWAC) array of SVOM astronomy satellite. Measurement results and astronomical observations show that positioning accuracy of the auto-focusing system is ±3.0 μm and the focusing accuracy is 0.05 pixel. As it can obtain the best image quality only by one focusing process, it has higher focusing efficiency while containing stable running.

A linear lever-type piezoelectric inchworm actuator is designed to implement the high precision positioning of optical field. The actuator adopts the displacement amplification mechanism of symmetric lever, which offers enough clamping force while obtains a larger driving displacement. The working principle of piezoelectric inchworm actuator is presented. And the displacement loss of the flexible amplification mechanism, the coupling characteristics between piezoelectric ceramics and flexible mechanism, and the stiffness and driving mechanism of the clamping mechanism are analyzed. The finite element method is used to simulate the clamping mechanism and the driving mechanism, then the deformation, stress, output displacement and natural frequency are all analyzed. An experimental platform is set up to test the performance of the actuator. The results on the actuator are shown that the travel range, clamping force and the bearing capacity for the actuator are 25 mm, 17 N, and 11 N, respectively. Moreover, the maximum step is 55 μm, and the minimum step is 60 nm, respectively. By applying a driving voltage of 150 V, it offers the highest driving speed of 1.259 mm/s. these data meet the demands of the precision positioning in the optical field.

To improve the performance of a micrometer inductive sensor, a design method of solenoid coils was put forward based on the theory of Helmholtz coils to improve the uniformity of the axial magnetic field of a solenoid coil. Firstly, the model of the solenoid coil was analyzed and the generalized function model between the parameter of solenoid coil and the axial magnetic field intensity distribution was established. Then, the system function model for axial magnetic field intensity distribution was determined based on the parameters of the core and coil sizes, the minimum error objective function of the uniformity for the magnetic field was set from the core moving range, and the best parameters of solenoid coil by objective function optimization were obtained. Finally, a test system for the micrometer inductive sensor was established to get its detection performance. The test results show that modified solenoid coil improves the linearity from 0.42% to 0.25% in 100 μm measurement range as compared with the original solenoid coil. It concludes that the modified solenoid coil uniforms the intensity distribution of the axial magnetic field and enhances the measurement accuracy.

A measuring error separation method was proposed on the basis of self-calibration algorithm for an imaging instrument. A self-calibration model was established and verified by the imaging instrument. A regular grid plate was used to replace the standard, and the grid plate was put on the image instrument stage in three different positions to get three sets of measurement data. The data were put into the self-calibration model through the developed transformation model in advance. Then, the system error contained in the measurement results was separated, and self-calibration was implemented. As measurement data transformation model was established, the problem of misalignment between grid plate and stage coordinate system was solves effectively during the process of experiment and the measuring accuracy of the imaging instrument was improved. Experiments show that the error of the measurement point is or millimeter scale without the self-calibration algorithm, but the maximum and minimum errors of the measurement point after self-calibration are 0.49 μm and 0.00 μm respectively. The results mean that it is feasible to apply the self-calibration algorithm to error separation of measurement results for the image measuring instrument.

Deep-notch elliptical flexure hinges are more suitable for a flexible mechanism with large stroke requirements as compared with other common flexure hinges, so this paper optimizes their design. The stiffness model of deep-notch elliptical flexure hinges was established firstly, and the impact of structural parameters on the rotational stiffness was also discussed in detail. Then, the flexibility matrix was analyzed by using Newton-cotes quadrature formula to simplify the calculation of flexibility coefficients, and each structural parameter was optimized by fuzzy optimization method based on the multi-objective optimization model. The results of optimization show that the angular displacement rotated with the Z axis is improved by 16.72%, while that rotated with the Y axis is decreased by 16.01%, and the linear displacements along the axes X, Y, Z are decreased by 10%, 2933% and 51.84%, respectively. After optimization, the rotation capacity of Z axis has been improved and the transmission capacities in other directions are both inhibited, so that the movement accuracy and structural flexibility are enhanced. The test results demonstrate that the optimized deep-notch elliptical flexure hinges meet the requirements of high-precision and large travel of waveguide package positioning platforms.

Space Heat Switches (SHSs) have wider and important applications in thermal control fields of deep space detectors, space coolers and some spacecrafts. This paper overviews heat transfer mechanisms of SHSs and their structures, key techniques and the advantages and disadvantages of every kind SHSs. Then it reports research progress of the SHSs in recent years, summarizes existing researching work and points out the developing directions of the SHSs. Finally, the authors suggest that those SHSs with high switch ratios and high reliability will be the research emphasis in future because they work at different conditions and require different thermal conductivities, also because the field of space exploration has been extended continuously. Moreover, some component manufacturing and material preparing technologies related to the SHSs will receive much attention, such as the development of new type of drivers, new thermal control coatings and their treatment processes as well as the precision machining and assembly technologies of components.

An improved Fast Fourier Transform(FFT) method was proposed to solve the lack of information resulted from frequency resolution limitation of the FFT. Firstly, a frequency component fmax which is corresponding to the maximum value of amplitude F(fmax) was searched with FFT method, and the frequency scope around fmax was reduced by the dichotomy. Then, the inverse Fourier transform was used to seek a larger value of amplitude in the extent scope including the f′max as the center. The frequency scope will be bisected every iteration until smaller than the target uncertainty. To prove the validity of the improved FFT method, a measured object (TGD01)was simulated with software Matlab. The data from the different acquisition ranges were evaluated by FFT and improved FFT respectively, meanwhile the evaluating progress was illustrated. Moreover, the topography of grating within 20 μm×2 μm was scanned with a metrological atomic force microscope. The results of two kinds of data evaluation were compared with each other. It shows that the pitch of the grating under the improved FFT is (277.84±0.39)nm, which is consistent to the nominal value (278±1)nm very well. The simulation and experiment both prove the validity of improved FFT method in analyzing pitches of gratings.

In automatic camera calibration with traditional black and white chessboard patterns, the corner sorting results are usually influenced by the rotation angle of the calibration pattern. Therefore, this paper designs an improved chessboard pattern and corresponding automatic corner detection and sorting algorithm. In the new pattern, four rectangular boundaries were added to filter the complex background, and a double-triangle mark was used to determine the original point of the corners so as to adapt to the rotation of the pattern. A corner detection algorithm based on cross entropy of the symmetrical quadrant was proposed to implement the corner position with the accuracy of pixel level by local non-maximum suppression and rectangular selection. Then, the Frostner operator was used to calculate the sub-pixel coordinates of the corners. According to the detected corner, the curve fitting method was employed to realize the automatic corner sorting with the distance information between the corners and the origin. Experiment results show that the corner detection results are correct and the sub-pixel coordinate error between the new method and Matlab Calibration Toolbox is less than 0.8 pixel unit. Moreover, the sorting results show an invariance to the pattern rotation, which verifies that the method is suitable for online auto camera calibration.

When the improved Laplace algorithm is used to forecast the satellites orbit, the extrapolate accuracy of the algorithm is usually relatively lower at a high elevation angle for the satellite, especially at the time of passing zenith. To meet the requirements of high-precision orbit forecast, this paper proposes a new orbit forecast method based on time-correction by analysis of extrapolating data and measured data. Firstly, the method performs a coordinate rotation for the extrapolating data and measured data, Then, it uses the measured data to correct extrapolation data on the time to obtain high-precision forecast data of satellite orbit. An experiment is carried out by using a horizontal photoelectric device with high-precision automatic tracking data more than 60 s length. By fitting the equations of motion and time correction, over 20 s duration precision forecast data are extrapolated, and the forecast error has be maintained at about 3″ on the time of passing zenith. Experimental results show that this method effectively improves the orbit forecast accuracy and the time ensuring tracking accuracy when the satellite is at the time of high evelation angle.

An algorithm was proposed to deal with the phase-shifting error and contrast variation in a Phase-shifting Interferometry (PSI) under vibration. The algorithm detected phase shifts and contrast variation by analyzing the spectra of spatial-carrier interferograms firstly. Then the phase shifts were used as priori information to retrieve the wavefront phase from least-square equation with contrast compensation. To deal with interferograms with non-rectangular aperture, a mask with soft border was constructed and data extrapolation was avoided. The effectiveness of the proposed algorithm was validated by simulations and experiments. The simulation results show the proposed method can detect the phase shifts and contrast variation in high accuracy and can compensate effectively phase retrieval errors caused by contrast variation. The practicability of the algorithm was verified under a simple harmonic vibration with a frequency of 9 Hz and an amplitude of 0.5 μm. The measurement under vibration demonstrates that the retrieval error of a flat surface is less than 0.015 waves (PV value). The algorithm provides a low-cost approach to application of PSI to field measurement under vibration without modification of the hardware of interferometers.

To solve the error-drift problem and improve the robustness of state-of-the-art open-loop video watermarking algorithms performed in H.264/AVC compressed domain, the characteristics of error-drift of open-loop watermarking method was deeply investigated. A new robust video watermarking algorithm without error-drift was proposed. Firstly, the error-drift mechanism of the open-loop watermarking method was analyzed in detail to derive the independent reconstruction error of watermarking information during the process of video reconstruction. Then, four watermarking patterns enabling to avoid the error-drift problem were proposed by the linear combination of reconstruction errors caused by watermarking. Finally, the watermark was embed into 4×4 subblocks with more non-zero coefficients by modulating the positive/negative correlation between residual coefficients and corresponding watermarking pattern, rather than previous algorithm directly adding watermark on the residual coefficients. Experimental results indicate that the proposed algorithm decreases the average structural similarity(SSIM) values within 0.005, increases the bitrates by about 1.00%;and the bit error ratio (BER) is below 0.15 in face of the attacks such as requantization transcoding, additive white Gaussian noise and brightness adjustment. The results satisfy the requirements of video watermarking in compressed domain for transparency, bitrate stability, robustness and real-time performance.

To simplify computation and to achieve higher positioning accuracy, a Sum and Difference of Neighborhoods along Axis(SDNAA)algorithm was proposed to implement the edge detection of a microscopic image with a lower signal-to-noise ratio and lower transition. Firstly, characteristics of gray profile of the line microscopic image was analyzed and the inadequacy of derivative based edge detection was analyzed according to the configuration of the microscope imaging system. Then, the computation was defined for the SDNAA algorithm based on the orientation information measure, and the SDNAA edge detection algorithm was derived according to the moment invariant theory. Experimental results indicate that the SDNAA algorithm adapts to different resolution images. It has strong anti-noise ability and high positioning accuracy, which is superior to that of the derivative based edge detection algorithm. Using the algorithm for microscopic images with low signal-to-noise ratio and low contrast, the variance of located edge coordinates is 0.57 pixel, and the measurement result of micro line width deviates from that of SEM (1.35 μm) by 0.17 μm, which reaches the expected precision.

To reconstruct the image of a deep space target by using non-uniform sparse launch array of a Fourier Telescopy(FT), a new method based on the least square fitting was proposed to estimate the lack of Fourier component of the target. Firstly, the T-sparse emitter array of laser transmitter system was used as transmitter configuration of FT, and the returned time-domain signal was processed by a DC filter. According to the basic principle of FT, the signal was demodulated to obtain a triple product by the phase closure. The least square fitting method was used to estimate and fit the absent Fourier components and to take it for the information recovery basis. Finally, the image was reconstructed with inverse non-uniform Fourier transform. Four targets were simulated with different SNRs. As compared with the original method, the new method resolutes the details of targets and the Strehl Ratios are improved by a maximum value of 0.074 2 and the minimum value of 0.009 8 at a SNR of 200 db and seven rank fitting. Obtain data in a field experiment show that the new method overcomes the distortion of reconstructed image come from frequency spectral deviation and provides a reference for practical engineering.

According to compressive sensing theory, a compressive sensing based normalized ghost imaging method was proposed. Firstly, the measurements of a bucket detector were normalized, and the measurement matrix was constructed with speckle fields.Then, the object image was reconstructed with a low number of measurements by adopting orthogonal matching pursuit method. Several experiments were performed by using gray-scale images and binary images respectively as the imaging targets and the Peak Signal to Noise Ratio(PSNR) as the yardstick. The reconstruction effects were quantized and compared for traditional Ghost Imaging(GI), Normalized Ghost Imaging(NGI) and Compressive Sensing based Normalized Ghost Imaging(CSNGI) respectively. The simulation results indicate that the PSNR of CSNGI is about 6 dB and 2 dB higher than those of GI and NGI on gray-scale images with more details, and 3.4-4.3 dB and 5.2-6.5 dB higher than those of NGI and GI for binary images with less details, respectively. Finally, the actual speckle field measured by Charge Coupled Devices(CCDs) was used to construct the measurement matrix, and the experiment results also further indicate that the CSNGI improves the reconstruction quality greatly.

As Scale Invariant Feature Transform(SIFT)describes local characteristics of images only and ignores the color information of the images, it has higher match errors when a lot of similar regions in the images are matched. This paper improves the SIFT algorithm and proposes a novel method as an extension of the SIFT, called a Shape-color Alliance Robust Feature (SCARF) descriptor, to resolve the problems mentioned above. The proposed approach SCARF uses the SIFT descriptor to extract the feature point set of the images. Then, by building a concentric-ring model, it integrates a color invariant space and a shape context with the SIFT to construct the SCARF descriptor, and uses the Euclidean distance as cost function to match the descriptor. A comparative evaluation for different descriptors is carried out by the INRIA database, which verifies that the SCARF approach provides better results than other four state-of-the-art related methods in many cases, such as viewpoint change, zoom+rotation, image blur and illumination change. It concludes that the SCARF reduces the probability of mismatch and improves the stability and robustness of matching process greatly.

An improved shape context algorithm is proposed to overcome the shortcoming of traditional shape context algorithm in lacking of rotation invariance ability. The algorithm looks for the direction where the most sampling points are included to change the image angle. Then it compares the corresponding regions in the image and calculates the match cost to add the rotation invariance ability into the algorithm. To improve the calculation speed, the pruning is induced in the algorithm to address the problem of traversing sample points in calculating the histogram distance. The experiment in the case of the same recall rate shows that the Precision Racall Line(PR) curve of proposed algorithm is closed to that of the Zheng, but the calculating speed is double that of above mentioned. Moreover, the PR curve of this algorithm is obviously better than that of traditional shape context algorithm, and the retrieval speed is increased greatly. Therefore, the overall performance of the algorithm is improved, and it is more suitable for the binary image retrieval.

On the basis of characteristic of differential “curl to straight” and disperse calculation method, an extraction method using local reconstruction and differential calculation was proposed for valley-ridge features from point clouds. First, the dispersed Laplacian operator was used to enhance the point data and an appropriate threshold was set to obtain potential valley-ridge points. Then, a triangle mesh attached on the potential surface was constructed in every valley-ridge points to effectively reflect the local geometry feature information. Finally, according to Weingarten mapping, principal curvatures and principal directions of potential valley-ridge points were calculated. A simple differential calculation method and a linear interpolation method were used to decide if the point is an extreme value point in principle direction and to extract the valley-ridge features based on the multi-scaling idea. The experimental results indicate that when the number of vertexes and the number of valley-ridge features are 10 375 and 1 129,respectively, the execute time is just 97.39 ms. And when those are 327 853 and 105 482, the execute time is 3 956.12 ms. The method proposed in this paper is simply, stable, and avoids higher time cost due to fitting surface to approximate the differential quantities in the traditional method, so it extracts valley-ridge features from point clouds fast and efficiently.