To evaluate quantitatively the uniformity of image illumination for an On-line Visual Ferrograph (OLVF)imaging system, a new mathematical model of image illumination was presented. The view field of an object space was represented by image space parameters and optical magnification, then it was discretized into a micro area. By taking Lambert-cosine law as reference, the image illumination model based on the aperture of entrance pupil was established, the image illumination distribution was calculated reliably and the uniformity of image illumination was evaluated successfully. On the basis of Matlab simulation analysis, the number of single Light Emission Diodes(LEDs) in the circular ring array source of the OLVF imaging system was obtained and the optimized values of focal length and optical magnification were determined. The light loss of imaging system and the illumination distribution of wear debris deposition region were analyzed and calculated under the condition of the oil cavity filled with lubricant oil. The relationship between the absorptivity of lubricant oil and the peak value of CCD image illumination was investigated. The experimental results show when the luminous intensity of LED arrays is known, the imaging plane illumination non-uniformity is more than 5.60% by simulating calculation and that is from 8% to 9% by a practical test, which satisfies the demand by indicator less than 10%. Finally, this imaging system was practically used to capture the reflected ferrograph. The results show that the characteristics of wear debris has been clearly distinguished from the reflected ferrograph, and it is favorable to the ferrograph segmentation and image extraction. It concludes that the proposed model evaluates quantitatively the uniformity of image illumination, optimizes systematical structure and improves the imaging performance of the system.

In synchrotron radiation field, the apertures of optical components increase gradually and their surface figure precisions have been demanded to be a nano-radian level. This paper researches the modern surface figure measurement methods in this field, stitching interferometry, to realize the high resolution two-dimensional measurement of optical components. The basic principles of the stitching interferometry are introduced. Then, a series of common optical surface shape measurement instruments in the synchrotron radiation field are overviewed, such as long trace profilers based on laser beams, high precision and auto-collimation measuring machines for nanometer optical components and stitching interferometers. It describes their development history and working characteristics and compares their shortcomings and advantages. Finally, this paper analyzes the main error sources involved in the stitching interferometry, and points out that the application and development trends of the technology are mainly the innovation of the stitching algorithm, the improvement of measuring speeds of interferometers, the commercialization of interferometers and the integration of the interferometry and other science technologies.

As the non-equivalence of absolute radiometers has complex sources and it is difficult to be measured, this paper proposes the finite element method to correct the non-equivalence of a Solar Irradiance Absolute Radiometer (SIAR).On the basis of the measuring method the SIAR, the nonlinear thermal dynamic response of the cavity in vacuum was tested. A finite element model with a relative error of 0.14% for an experimental cavity was established based on the finite element method to test the temperature response of the receiving cavity. The experimental results show that the temperature difference between the receiving cavity and the heat sink is approximately 0.85 K and the time constant is 29.8 s when input optical power is 73.8 mW. The finite element method was employed to estimate and correct the non- equivalence of the absolute radiometer. It indicates that the source of non-equivalence of SIAR mainly comes from the drifts driven by different heating paths and areas, and the correctional factor of non-equivalence for the SIAR is 0.999 621±0.000 004. The finite element correct model completes the correctional system of SIAR and significantly increases the accuracy of the SIAR. It is helpful to improve the future design of absolute radiometers.

Based on Giant Magnetostritive Materials(GMMs), a novel GMM-FBG (Fiber Brager Grating) current sensor with automatic temperature compensation is proposed by combing a sensing fiber Bragg grating (S-FBG) and an auxiliary fiber Bragg grating (A-FBG). The sensor cascades the S-FBG and the A-FBG and pasts them crossly on the GMM bars, then puts them into a magnetic circuit consisted of the ferrites. The radial direction of S-FBG is controlled the same as the direction of magnetic field, and that of the A-FBG is opposite with the former. Finally, the center wavelength of S-FBG is placed in the side-band of A-FBG spectrum, and current measurement and temperature compensation are implemented by detecting the optical intensity variation of cascaded gratings. The experiments are performed by the A-FBG and S-FBG with the 3 dB band width of 0.23 nm and 0.08 nm. The experimental results show that when the ampere-turns-current varies from 1 A to 138.2 A, the sensor can realize the linear measurement, and the goodness of fit is 0.996 3, the sensing sensitivity in the linear range is 16.0 mV/A and the minimum effective ampere-turn is 1.0 A.

To improve the weak correcting capacity of a wide band Czerny-Turner structure, the influence factors on the astigmatism correction of an optical system were analyzed. The Matlab software was used to simulate and analyze the reasons that the astigmatism was produced and the traditional method could not suppress the astigmatism. Then, the dependence of the angle difference α between the off-axis angle of collimator mirror and the off-axis angle of focusing mirror on the astigmatism S of the optical system was discussed. The astigmatism correction of wide band Czerny-Turner structure was simulated at different α values. To verify the validity of the theoretical analysis, an astigmatic Czerny-Turner system ranging from 900 to 1 700 nm was designed, the Zemax was used to perform the ray tracing and optimal design and the design results were processed and analyzed. The simulation results demonstrate that the shortwave band astigmatism correction ability is getting stronger with increasing the difference angle, which may achieve about 1.6 times on increase. However, long wave band astigmatism correction ability is more and more weak, which may reduce about 1.27 times on average. It suggests that the reasonable selection of the difference angle can provide the theoretical guidance for correcting the astigmatism of wide band Czerny-Turner structures.

The principle and composition of terahertz time-domain spectrum systems were described, and a terahertz time-domain spectrum system ranged from 0.1 THz to 3 THz was developed. The characters and predominance of terahertz time-domain spectrum technology on explosive identification were introduced and a mathematical model and a method for the explosive identification were proposed. The terahertz time-domain spectrum system was used to test the character absorbing spectra of explosives and main absorbing spectra were regarded as standard templates. Then, four kinds explosives(RDX,CL-20,LLM-105 and FOX-1) were put behind the barriers (soil, cement and plastic),and the terahertz time-domain spectrum system was used to obtain the character absorbing spectra of explosives penetrating through the barriers. The results were compared with standard templates to implement the explosive identification. The character absorbing spectra of RDX were obtained, and their character frequencies are 0.82, 1.70 and 2.40 THz. Furthermore, these explosives were tested through different barriers with different thicknesses. The results show that character absorbing spectra of explosives penetrating through the barriers match the standard templates perfectly, which verifies that it is feasible to use the terahertz time-domain spectrum system to realize explosive identification according to character absorbing spectra. Moreover, the terahertz time-domain spectrum system can be used to identify the residual trace of explosives and explore the imaging technology for penetrating through barriers.

As the characteristic parameters of a multi-sensing keyhole reflect effectively the welding quality of high power lasers, this paper researches the extraction method of keyhole characteristic information and establishes a prediction model for welding formation. By taking a high power disk laser to weld 304 austenitic stainless steel plates for an example, a near-infrared high-speed camera and an X-ray vision imaging system were used to capture the molten images in welding processing and to obtain the keyhole region by image processing. The invariant moment characteristics were extracted from near-infrared visual images by the moment method, meanwhile the keyhole area and ordinate value of the keyhole forefront were calculated as the characteristic parameters. Depth and entropy of the keyhole were extracted from X-ray visual images. In different laser powers, the keyhole characteristics were obtained and three BP (Back Propagation) neural network models were set up through feature fusion of all the characteristic parameters. The relationship between the keyhole formation, welding condition and welding state was explored and the on-line monitoring for welding process was implemented. Experimental results show that the average absolute value of relative errors between predictive and measured values of weld width and penetration are 0.18 mm and 0.57 mm, respectively through fusion analysis and principal component analysis on characteristic parameters of two sensors, and they have been reduced by about 0.03 mm and 0.31 mm as compared with that of a single sensor. The proposed method can be applied to monitoring high-power disk laser welding quality in real time.

To measure the Refractive Index (RI) of transparent liquid and translucence liquid in industrial process in real-time, in situ and non-contact, a simple method for measuring liquid RI was proposed based on the optical property of glass pipe wall is presented in this paper. By coating a transmission-scattering layer on the outer wall surface of a glass pipe, the incident laser beam was transformed into a wide-angle distributed transmitted scattering light in the glass wall. After the scattered light reached the interface between the pipe wall and the liquid, the scattered light satisfying the condition of total internal reflection was reflected to the transmission-scattering layer to form automatically an oval dark pattern related to the RI of the liquid in the pipe. The method to measure the RI of the liquid in the glass pipe in situ and non-contact could be implemented according to the analytic relation between the long axis length of the oval dark pattern and the liquid RI in the glass pipe. Several RIs of transparent liquid and translucency liquid were measured. The experimental results show that the accuracy of this apparatus is the same as that of an Abbe refractometer(±2×10-4 RIU(refractive index unit)). It concludes that the method is characterized by simple configuration, lower cost, anti-interference and higher robustness. It is suitable for the optical images relative to liquid refractive indexes, and is expected to monitor the liquid RIs of a closed pipe at an abnormal temperature and an abnormal pressure in real-time, in situ and non-contact.

Because traditional positioning methods can not satisfy its requirements for high accuracy, high integration, multi-task and real-time, an indoor positioning method by using laser ranging technology is proposed for industrial manufacturing fields. This method transmits rotation scanning plane laser signals and ultrasonic pulse signals through a measurement base station. It uses rotation scanning plane infrared laser to form a multi-plane constraint, and uses high precision ultrasonic ranging to form a distance constraints. Then the plane constraint and distance constraint are fused to obtain a nonlinear constraint equation set. Finally, the nonlinear optimal algorithm is used to calculate and obtain the accurate 3D coordinates of the target bar. The method achieves omnidirectional, multi-task and real-time positioning by using a total station. A laser tracker is taken as standard to verify the measuring accuracy and reliability of the proposed method. The experiment results show that the positioning measurement error of the method is less than 0.3 mm within a 5 m range, which meets the most industrial fields. As compared with that of the traditional indoor positioning methods, the proposed method improves the integration level and measuring efficiency and provides a new way for whole station positioning methods.

To control precisely the 2D rotation stable of a laser communication terminal unit on the satellite platform, a special optical angle encoder was designed to measure the rotary angle of the 2D rotation stable to realize the close control of the terminal unit. The grating disk, index grating and a signal pick-up method were designed and chosen respectively on the basis of design requirements of angle measurement device in the laser communication terminal. An absolute type binary coding was combined with a high quality electronics dividing to implement 24 bit absolute angle measurement of the encoder, and a four quadrant matrix encoding was used to effectively reduce the radial size of encoder. Moreover, the parted reading head type indicating gratings were employed in the encoder to allow its volume and weight to be smaller and lighter than that of the whole glass grating disk. The angle measurement precision of an optical angle encoder mounted on the satellite borne laser communication terminal unit was tested and analyzed after finely manufacturing, assembling and adjusting at a indoor temperature. The results show that precision of the designed encoder is about 0.7″(is superior to 1.0″). The laser communication terminal unit on the satellite platform operates normally in orbit and completes capturing, tracking and communication of the signals, which verifies that the designed encoder is characterized by high precision, high resistance to radiation and high working reliability.

As the output moments of reaction wheels for micro-satellites and nano-satellites are the same as the disturbance moment of an Air Bearing Table (ABT), the attitude dynamic simulation and ground test of the micro-satellites and nano-satellites can not be implemented directly by the ABT. To solve the problems, an active compensation ABT with a supper low disturbance moment was designed and developed. The disturbance moment of the ABT was analyzed and three kinds of methods to reduce the disturbance moment were proposed. Firstly, the viscous damping moment was reduced by optimizing design; Then, the vertex moment was reduced by setting sloping slant orifices to generate an active vertex to balance the inherent vertex of the air bearing, and to reduce the inherent vertex moment. Finally, the swing characteristics of air bearing was used to implement high precise balance adjustment and to reduce the gravity induced moment. A measuring device of micro-moment was designed and the remaining vertex moment was measured and the measuring results were used to direct the compensation of the vertex moment and gravity induced moment. Experimental results indicate that the disturbance moment of the ABT is smaller than 5×10-5 Nm, which is less than the minimum output moment(1×10-4 Nm) of the reaction wheel. Obtained results satisfy the requirements of the ground simulation of attitude dynamics and the control of micro-satellites and nano-satellites.

To improve the heat-dissipation regulation capability and thermal environment adaptability of space thermal control subsystem, a micro-expansion type heat switch with micron stroke was designed. The structural components and operating principle of the switch were introduced, and the key thermal properties of heat switch, including OFF resistance, ON resistance and ON/OFF ratio, were evaluated by combination of theory, simulation and experiments. Theoretical thermal properties of heat switch is calculated based on the series-parallel relationship of thermal resistances, the OFF resistance and ON resistance are 301.71 K/W and 1.06 K/W, respectively, the ON/OFF ratio is about 283.6. Transient thermal properties of the OFF/ON process was analyzed by the finite element model, when the heating power of hot end is 18 W, the turn-ON response time and triggering temperature are 340 s and 35.5 ℃, and the ON resistance is about 2.3 K/W. Moreover, in the twice property experiments,the ON resistance and ON/OFF ratio are 1.08 K/W, 279.4 and 1.67 K/W, 180.7 respectively,and experimental data is in agreement with the theoretical calculations well. The experimental results point out that the uncertainty of assembly-regulation process would cause small interval fluctuations of macro thermal properties of the heat switch, The conclusions cloud provide references for structural optimization design, machining refinement and assembly-regulation improvement of subsequent micro-expansion type heat switches.

According to the characteristics of Micro Heat Pipe(MHP) in an integrated Light Emitting Diode (LED) on small sizes, fast temperature rising and temperature change,as well temperature gradient, a non-contact infrared temperature measurement system was conducted to measure the temperature of different feature regions of th MHP integrated with LED chips. The signal acquisition and conversion, error analysis and compensation, characteristic indexes of temperature measuring and heat performance experiments of the MHP were investigated. Electrical signal acquisition and temperature conversion were implemented through LabVIEW programming. Then, the heating blocks with different temperatures were considered as isothermal reference bodies, and the measuring results of the infrared sensors and the thermocouples were compared and analyzed for static and dynamic temperature measurement characteristics. The drift error resulting from LED radiant heat was corrected by environment temperature compensation, and infrared sensors were calibrated by linear fitting. Finally, the heat performance of MHP under different heat loads were measured by proposed measuring system. Experimental results indicate that the accuracy, repeatability and the linearity of the system are 1.2-1.5 ℃, 1% and 0.2%, respectively, while the time constant and the response time are 15 ms and 30 ms, respectively. The Infrared measuring reduces the effects of sensor elements on temperature distribution of feature areas, and is characterized by high temperature measurement precision and small thermal inertia. It provides a new measuring method for the evaluation of heat performance of MHPs.

To achieve long-term data storage on a sapphire optical disk, this paper researches how to record data on the sapphire optical disk surface in a digital form. On the basis of Eyring equation, the time-to-failure of data recording on the substrates made of inorganic materials was estimated. The data recording process on the sapphire optical disk with the substrate made of sapphire in digital form was introduced. Dry etching techniques as well as an ion beam etching system were emphasized. Experimental results show that the width and depth of a pit on the optical disk are 0.6 μm and 0.2 μm, respectively, the track pitch is 1.6 μm, and those parameters of the pits on the surface of sapphire optical disk are in compliance with that of CD-ROM form defined by ISO/IEC 10149:1995 standard. These results demonstrate that the proposed method is feasible to realize data recording in digital form on sapphire optical disks. The method is not only suitable for the sapphire optical disk , but also for other optical disks with substrates made of high stable materials(such as quartz glass).

For a 1.2 m Zerodur primary mirror, an effective primary mirror support system was proposed. A lateral support based on 6 sets of flexible tangent link structures and an axial support based on 18 sets of semi-flexible Whiffletree structures were combined to ensure the primary mirror to maintain good surface figure accuracy and system stiffness at a larger temperature range and different elevation angles. The working principle of the system was analyzed and the surface figure accuracy of the primary mirror and modal of the support were tested. The analysis for system structure indicates that the support system ensures the positioning accuracy and surface figure accuracy of the primary mirror and its thermal decoupling ability is verified by support principle deduction. The finite element analysis (FEA)on the statics distortion and thermal distortion of the mirror surface shows that the system has excellent structural rigidity. The surface figure accuracy tests indicate that the RMS values of mirror optical surface distortion at the optical axis in vertical and horizontal states are 15.25nm and 20.75 nm respectively. Furthermore, the first natural frequency of support system is measured to be 60.3 Hz at modal tests. As comparing FEA simulation results with measurement results.It shows that relative errors of the mirror optical surface distortion are 14.0% and 17.8% separately at different elevation angles, and that of the first natural frequency is 10.8%. Due to the approximate results between simulations and measurements, it demonstrates that the design scheme and principle deduction of primary mirror support system are reasonable, and the FEA modeling is creditable.

To solve the contradiction between speed and precision for a high speed mechanism, the flexible problem of a 3-RR-P parallel measuring machine was researched. On the basis of the elastic beam kinematics theory and Galerkin modal truncation method, a kinematics deformation model of one-dimensional elastic beam was established. Then, a flexible rod was assumed to be Euler-Bernoulli beam, the flexible structure coupling dynamics model considering the deformation of midline was built based on Hamilton principle. Finally, the measuring error generated by vibration of elastic beam was tested at different speeds based on midline coupling dynamics model. A method to reduce vibration coupling error by adjusting reasonably the viscous friction coefficient was proposed to improve the test accuracy. Experiment results show that the max lateral one-order coupling error is 28.6 μm when angular velocity comes to 300 rad/s in ignoring structure errors. Moreover, when viscous friction coefficient is adjusted to be 0.4-0.5, the vibration coupling error is reduced to less than 15 μm, reducing by 13.6 μm as compared to that of the previous adjustment. These data have been verified to be effective and feasible for solving the contradiction between high speed and high precision. It offers a foundation for research on the coupling principle between high order elastic vibration and accuracy.

When the time series algorithm is used to establish a thermal error compensation model for a Computer Numerical Controlled (CNC) Machine, it shows a shortcoming of forecasting robustness caused by the severe multiple collinearity. This paper proposes a method for improving the forecasting robustness of the time series algorithm. This algorithm combines the time series algorithm with the modeling algorithms which are able to suppress multiple collinearity. Thus, it not only provides more comprehensive temperature information by adding the temperature lag values in the thermal error model, but also deals with the severe multiple collinearity brought by the added temperature lag values. The Distribution Lag (DL) algorithm that belongs to time series algorithms and Principal Component Regression (PCR) algorithm that can suppress the multiple collinearity are selected as the examples, and a modeling method for establishing the thermal error compensation model of the machine tool is proposed by the Principal Component Distribution Lag (PCDL) algorithm. The forecasting accuracy and robustness of PCDL algorithm are compared with that of DL algorithm. The results show that the PCDL algorithm suppress the impact of multiple collinearity, so, its model′s forecasting accuracy and robustness are far better than that of DL model, and the forecasting accuracy is improved about 9 μm. The proposed method provides a good reference for the application of time series data modeling in different fields.

A kind of fixed-abrasive pad by using nano-aggregate silica was proposed to overcome the shortcomings of the pads using conventional silica abrasives on its surface scratch and low removal efficiency. The nano-aggregate silica particles were added into the fixed-silica pad,and the polishing experiments of Si wafer were performed using this pad with D.I.water of pH=10.5 instead of conventional nanosilica polishing slurry. Several investigations were performed by comparing with fixed-silica pads using conventional irregular natural silica abrasive and spherical fused silica, the polishing performance the fixed- abrasive pad using nano-aggregate silica were obtained and some factors affecting the pad′s polishing performance also were investigated. The material removal rate same as the exiting polishing nanosilica slurry (concentration 3wt%，pH=10.5) was obtained, and polished surface roughness was decreased by about 1/3 . Compared with the pad with fixed-conventional natural silica, the proposed fixed-aggregate silica pad is not easy to scratch Si wafer, because the nano-aggregate silica is not only a spherical shape but also has a elastic coefficient down to its 1.4%-60%. As compared with the pad with spherical fused silica, the proposed fixed-aggregate silica pad improves its adsorb ［-OH］ ion by 25 times in D.I.water of pH=10.5, and allows the removal of material mainly came from chemical removing to be more than 70%. Moreover, nanoscale polished surface roughness is almost no changed with increasing the sizes of fixed-aggregate silica particles, but the polishing ability of pre-polishing surface roughness has been increased, which shows a micron particle size effect.

It has complex process and lower efficiency when traditional electrospinning preparation method is used to prepare the poly (vinylidene fluoride) (PVDF) piezoelectric fibers, so this paper proposes a new method for the PVDFs by using a rotation drum to collect aligned PVDF nanofibers. Aligned fiber membranes with different alignment degrees were collected by changing the rotating speed. Then, the Fourier Transform Infrared (FTIR) spectroscopy was used to analyze the content of β phase of the fiber membranes and a data acquisition card of National Instrument (NI) was used to research the piezoelectric property of piezoelectric fiber membrane under the same pressing force. The results show that the order of fiber alignment and the content of β phase are both improved as the rotating speed increasing, and the output voltage of piezoelectric also increases, which indicates that the change of rotating speed has the same influence on the content of β phase and the output voltage. Based on the aligned PVDF fiber membrane, a pressure sensor was designed and its dynamic responses under different air pressures were obtained with a lab-made testing system. In the pressure range of 0.145-0.165 MPa, the piezoelectric output of the sensor increases linearly with the increment of air pressure, showing excellent linearity and high sensitivity up to 179 mV/kPa. The preparing method for PVDF nanofibers has wide application prospects，especially in the field of high accuracy dynamic pressure tests.

An optical control servo system for micro displacement was proposed based on the photodeformation effect of PLZT(Lead Lanthanum Zirconate Titanate) ceramic and its closed-loop servo control characteristic was researched via an experiment method. The control equations of servo system were derived based on the mathematical model of PLZT with coupled multi-physics fields. Then, parameters in photodeformation expression of PLZT ceramic during light on/off phases were identified through the static experiment. An experimental platform for closed-loop servo control of photo-induced micro displacement of PLZT ceramic was set up and corresponding control experiments were carried out based on on-off control strategy under different light intensities. The experimental results show that the output displacement of PLZT ceramic is controlled with simple on-off method by applying ultraviolet light. After the output displacement curve of PLZT ceramic actuator reaches the target value, some different degrees of overshoot are presented, and the output displacement of PLZT ceramic actuator fluctuates around the target value. The response speed, overshoot and fluctuation height increase with the increasing light intensity. The time of the output displacement of PLZT ceramic reaching the target value under the illumination of 400 mW/cm2 is only about 20 percent of that under the illuminated of 100 mW/cm2 by the UV light. The results lay foundation for application of the PLZT ceramic in micro actuator engineering.

To explore the influence of micro-vibration of flywheel components on the imaging quality of a high resolution optical satellite, a flywheel component disturbance model and a whole structure dynamic model of the satellite were established. The ground disturbance of flywheel components was tested, the analysis of the measured data shows that there is series of first harmonics at the first order frequency 50 Hz, and a series of peaks independent on rotation speeds around the 190 Hz and 280 Hz. Then, the unit sine excitation was performed on the satellite, the angular displacement response of the optical axis was obtained. The integration of the angular displacement response and the flywheel measured disturbance data was analyzed. The results show that there are a lot of angular displacement harmonic response frequencies in 50 Hz-80 Hz and 230 Hz-280 Hz, the maximum angular displacement resonance amplitudes are 2.718″ and 2.739″ along the optical axis direction and the vertical direction, and 0.5″ magnitude harmonic amplitude is around 245 Hz. It concludes that the flywheel micro vibration has a great influence on the imaging quality of high resolution optical satellites and the results provide important references for system optimum design and vibration isolation.

To improve the measurement accuracy of a parasitic time grating sensor, the working principle and dynamic error composition of the sensor were analyzed deeply and the main error components including constant error, periodic error and random error were obtained. According to the error characteristics of parasitic time grating, a high precise prediction model for dynamic error of the parasitic time grating was established and the modeling method was compared with other modeling methods. The Bayesian prediction model interpolated with standard values was chosen to build the error prediction model based on the actually measured dynamic error data of first pole in the sensor. Then, a part of actual measurement error data were inserted in the specific location of subsequent pole to establish the error prediction model to predict the dynamic error of 83 poles of the sensor. The modeling method of cubic spline interpolation and BP neural network were used to build the whole circle dynamic error model of parasitic time grating sensor and compared with the above Bayesian model. The modeling verification experiment results show that the modeling time of cubic spline interpolation method is the shortest (0.62 s), but the modeling accuracy is not high(16.050 0″). The modeling time of Bayesian prediction model is slightly longer than that of the cubic spline interpolation(0.86s), but the modeling accuracy is the highest one(0.415 3″). The modeling time of BP neural network method is the longest one (32 min), and the modeling accuracy is the lowest one (19.680 2″). Moreover, the modeling data points of Bayesian prediction model interpolated with standard value(69395) is far less than that of cubic spline interpolation and BP neural network(235526). Therefore, Bayesian prediction model interpolated with standard values saves a lot of calibration time and modeling data points, and can be used for high precision modeling and dynamic measurement error correction of parasitic time grating sensors.

To evaluate the imaging quality of a CCD camera rapidly, the Signal to Noise Ratio(SNR) was selected as the evaluation factors, a measurement system was constructed and methods to measure the camera′s noise based on the output images of the camera were researched. The noise from the linear CCD camera was analyzed, a model for computing the SNR was established based on the fix pattern noise sources and temporal noise sources and the impact of Correlated Double Sample(CDS)processing on the power supply noise source was analyzed. A rapid measurement system for the SNR of camera in industry applications was designed, and a scheme to measure various noise sources was proposed by analyzing the theoretical model,practical tested data and 8 bit output images. Finally, the non-uniformity of the light source in the measurement system was discussed and it demonstrates that the light source meets the requirements of EVM1288 industry-standard. Experiment results indicate that the SNR of the camera reaches to 44 dB when the AD gain is set to be 8.7 dB, and it reaches to 46 dB if the interference of the non-uniformity from light source are eliminated. It concludes that the proposed scheme has higher measuring speeds, and satisfies the system requirements of SNR measurement for industry applications.

When a photoelectric device can not track the satellite due to the changed intersection angle of the sun or the orbit blocking, the satellite orbits have to be predicted. Because the traditional orbit prediction method based on orbit elements can not meet the requirements of real-time and precision measurement simultaneously, this paper proposes a new satellite orbit prediction method based on orbit elements. The movement rule of satellite orbits was analyzed, then the elliptic curves were used to predict the satellite orbits and to process approximately the orbit equation based on the characteristics of a low orbit satellite. Some redundancy variable quantities were induced to simplify the calculation model for satellite orbit, so that the orbit prediction accuracy is greatly increased in guaranteeing a good real-time calculation. The experiments show that when the linear extrapolation is used to predict the satellite orbit, its prediction deviation will increase to 10″ after 5 s forecasting. However, if the method presented in this paper based on the orbit elements is used in the prediction, the maximum deviation is not more than 2″after 50 s prediction. The method has greatly promoted the prediction precision of satellite orbit, and makes the photoelectric device implement the 'blind tracking' for satellites when the automatic tracking is become to be invalid.

A small target detection algorithm working at a compressed domain was proposed for parallel compressive imaging systems to reduce the computational complexity by eliminating the process of image reconstruction. A mathematical model of the parallel compressive imaging system was used to capture measuring values of background and current frames. Then, the background measurements were updated according to a compressive sensing-mixture of Gaussians model (CS-MoG) to obtain the measurement values of the foreground. The cosine similarities between the measurements of current frame and the compressed target-location templates were calculated. And the local threshold and target area in the compressed domain were adopted to screen candidate targets. Finally, the effects of down-sampling rate, number of measurements, projection error and noise on the detection results were studied by simulation experiments. Experimental results show that large down-sampling rate and noise would decrease the detection performance, but the number of measurements to detection results has limited contribution. When 2 or 3 measurements are set, the operation time could be controlled while ensuring the detection performance. It suggests that the noise in the system should be controlled strictly because the noise effects the detection ability greatly. Furthermore, the proposed algorithm can achieve real-time target detection without any image reconstruction.

By analyzing the textural features and local key points of the built-up area in a plain from high resolution remote sensing images, a method to extract the built-up area in the plain was proposed based on multi-core learning, multi-scale segmentation and multi-hypothesis voting. With the proposed method, MR8 texture characteristics and Scale Invariant Feature Transform (SIFT) algorithmwere used to extract the built-up area, and multi-characteristics was fused to implement the learning and classification to improve the robustness and stability of classifiers and to enhance the detection accuracy. Then, based on the pixel segmentation and multi-hypothesis voting, the discriminant result based on image blocks was translated into test result based on pixels to completely eliminate the block effect and to make the target area showing precise edges and shapes. The proposed method has been validated in GF-1 satellite images. The results show that the average detection precision, average recall rate and the average F-measure of the method have been achieved above 80%, 85% , and 80%, respectively. Moreover, its comprehensive performance is better than that of other methods. These results demonstrate the feasibility and accuracy of this method. As extraction precision of the built-up area has been to be the pixel level and the leak detection and error detection have been avoided, the built up area images extracted are very accurate.

For calibration of the phase shifter in a phase-shifting interferometer, an iterative algorithm was proposed to extract phase shift from a set of interference patterns. In each iteration cycle, the wavefront phase and phase shifts were calculated in two individual steps.Firsly, the phase shifts were assumed knowns and the calibration wavefront phase was retrieved from tri-variate equations. Then, the wavefront phase was assumed knowns and the phase shifts were extracted from bi-variate equations. Meanwhile, an error estimator to indicate the maximum calculation error of phase shifts was established based on the basic trigonometry and ergodic principles. The proposed algorithm was verified with computer simulations and experiments. The simulation results indicate that the proposed algorithm achieves higher accuracy, lightens the calculation burden, and the deviation between the error estimator and actual error is less than 15%. Validation experiments were carried out on a Fizeau interferometer. Two capacitive displacement sensors were employed in experiment to measure the actual phase increment. The results show that the extracted phase shifts are identical that from the proposed algorithm well and the maximum deviation is 0.7 nm. Moreover, the error estimator is 0.52 nm, which covers the deviation between calculation and measurement. It concludes that the proposed algorithm achieves higher accuracy and is more advantageous on that the calculation error can be given simultaneously, showing a convenient and reliable way to calibrate the phase shift for phase-shifting interferometers.

As captured images for surface defect detection of a steel strip is vulnerable to lighting conditions, weaker defect characteristics and other factors, this paper proposes a new algorithm based on spectral residual visual attention mode to complete the strip surface defect detection in real time. Firstly, the homomorphic filtering method was proposed to preprocess the image to remove the influence of uneven illumination and to perfect the subsequent segmentation results. Then, a visual-attention model was constructed to obtain the defect saliency map by applying the subtraction to the logarithmic spectrum curve. Finally, the weighted Mahalanobis distance method was proposed to significantly enhance the saliency image thresholding. These locations of the defects in the original strip defect images were marked by using the connected-component labeling method. The proposed algorithm was verified by experiments. Experimental results show that the algorithm has a fast detection speed, and takes only 37.6 ms in the single image detection, meeting the requirements of the real-time detection. The comparative experiment with the gray projection method, multi-scale Gabor edge detection method and Markortree model was carried out in the same defect database, and the results show that average detection rate of the proposed algorithm reaches to 95.3% for 8 common types of defects. In the meantime,the missing rate and false positive rate are still low. These results validate the effectiveness of the algorithm.

A novel method was proposed to estimate the normal for a scattered point cloud with sharp features to overcome the shortcomings that existing methods are unable to reliably estimate the normal of point cloud model and lead to the smoothed sharp features. With proposed method, the normal of point cloud was estimated with principal component analysis method. Then, different values were weighted on neighborhood normals according to spatial distance and normal distance of current points of the neighborhood, and the revised or current normals were updated by the sum of weighted neighborhood normal. Finally, the average deviation between standard normal and estimated normal was measured and the accuracy of estimated normal was evaluated. The estimated normal was applied to point cloud processing to verify the feature-preserving property. The proposed method was validated. The results demonstrate that proposed method accurately estimates the normal for data with noise and the least average deviation is close to 0. Moreover, the method has good robustness to the niose, and it keeps the original geometry well when the normal is used as input of the point cloud processing. Comparing with other sharp feature preserving normal estimation methods, the proposed method shows smaller average deviation, higher processing speeds and less computation time.

To overcome the weak edges and large noise of flotation froth image, and to solve the weakness of traditional valley detection algorithm on different kinds of bubble segmentation sizes, a froth image segmentation method was proposed based on Contourlet transform multi-scale edge enhancement and adaptive valley detection. Firstly, the froth image was decomposed by using the Contourlet transfom to obtain multi-scale and multi-direction sub-band coefficients. Then, thresholds of the nonlinear enhancement function were determined according to the coefficients of each scale to enhance edges and suppress the noise. Furthermore, the optimal position adjustment strategy and parameter setting of HS were improved to find the optimal parameters of valley detection algorithm and to detect the different kinds edges of bubble image size. Finally, segmentation experiment was performed and obtained result was further improved by morphological processing. Experiments show that the proposed method effectively detects the edges of different type of bubbles adaptively, and the average detection efficiency (DER) is 91.2% and the average accuracy (ACR) is 90.6%, which is much better than that of traditional methods. This method has high precision, good adaptive ability, and does not need to adjust parameters manually.

On the basis of characteristics of Passive Millimeter Wave (PMMW) imaging, an Improved Sparse Representation-Circle-Surround Center Difference(ISR-CSCD) algorithm is proposed to improve the weaker distinction between dim small target and background and the smaller target features to be extracted. The algorithm firstly improves the sparse representation to complete the background suppression and target enhancement. Then, according to the features and prior knowledge of the target and the surrounding background, the background suppression algorithm of circle-surround center difference is used to suppress the background of the image. The results by two methods mentioned above are fused to get the final enhanced target image. Finally, the Constant False Alarm Rate (CFAR) is used to complete dim small target extraction. The millimeter wave images in different scenes are detected. The results show that as compared with the mainstream algorithms, Sparse representation (SR), Newton methods for Robust Regularized Kernel Regression(NRRKR), Spatio-temporal Classification Sparse Representation(STCSR) and Accumulated Center-surround Difference Measurement(ACSDM), the ISR-CSCD algorithm has a lower false alarm rate, higher detection accuracy and stronger robustness. For all kinds of false alarm rates and the signal to noise ratios of the millimeter wave small target detection results in statistics, the detection rate of ISR-CSCD is increased by about 15% as compared with other algorithms.