To reduce the stray light effect of Xing Long 1-meter optical telescope, an objective lens was developed,and simulations and observations were undertaken to evaluate the lens.The Point Source Normalized Irradiance Transmission(PSNIT) for“dome-telescope”and “dome-telescope-lens” systems was calculated with the code Tracepro and observations were carried out at a moon night.The calculation results indicate that for the stray light sources located at off-axis angle within 30°, the PSNITs of the observational system, including dome,1 m telescope and the lens, have been lower than 10-10.Furthermore,the observation results for stars located at 22°and 25°off-axis angles away from the moon in May 26th 2008 indicate that the observational SNR of the system has been increased by a factor about 1.4 with the lens.These results show that for the 1-meter optical telescope the stray light is reduced and the photometric accuracy and limiting magnitude are improved by the lens effectively.

In order to realize rapid imaging of Fourier telescopy, an approach of image reconstruction via sparse sampling is proposed and the accurate image reconstruction by using sparse Fourier samples is investigated.Firstly, based on compressed sensing theory and the sparsity or compressiveness of object images in transformation domains, the optimization model of image reconstruction via sparse sampling is established.Then, appropriate masks for random and sparse sampling are constructed to sample Fourier components of object images.Finally, object images are reconstructed accurately through nonlinear optimization by using the random and sparse samples.Experimental results indicate that the RMS errors of reconstructed images between 20%~30% sampling and full sampling are only 4%~6%, which shows that the proposed approach can realize accurate image reconstruction by using random and sparse Fourier samples and can reduce the amount of measurement samples greatly.The method lowers the requirements of costs and complexity to Fourier telescopy systems for rapid imaging effectively.

As the design of phase mask in wavefront coding imaging systems is complex and the aberration of original optics cannot be taken into consideration, two new design methods are proposed based on the popular optical software ZEMAX.By using ZPL macros, the user defined operands are written to optimize the energy concentration and consistency of the point spread function, and the depth of focus of the optimized rotationally symmetric phase mask is 5.5 times as large as that of traditional imaging systems at the criterion of Strehl ratio larger than 0.8.By using an externally defined and compiled C program, the user defined operands are written to optimize the defocus invariance of modulation transfer function, and the depth of focus of the optimized odd symmetric phase mask is 12.5 times as large as that of traditional imaging systems.However,the depth of focus of the cubic phase mask is only 10.1 times as large as that of traditional one in the same condition.These results show that the design methods proposed are practical and effective.

In order to extend the depth of focus of optical systems, an optical-digital system using wave-front coding technology was established.By adding a phase mask at the aperture stop of a general optical system combined with post-digital processing, this system extended its depth of focus greatly.Firstly, the proposal, development and theoretical basis of wave-front coding were briefly introduced; then, a triplet system with a cubic-phase-plate was designed, and the imaging characteristics of the traditional system and wave-front coding system were analyzed using CODEV.Furthermore, the three-dimensional contour maps of Point Spread Function (PSF) and the Modulation Transfer Function(MTF) curves within defocus of ±40 times were obtained.Finally, the imaging experiment of manufactured system was carried out, and the images of a traditional system and a wave-front coding system before and after decoding were compared.The results show that the wave-front coding system can extend the depth of focus by 40 times compared with the traditional system while maintaining the light flux and image plane resolution.

A one-dimensional position-sensitive ionization chamber has been designed and fabricated.The cathode of this ionization chamber consists of two selfsame units that are insulated from each other and each unit is divided into two-way cleft plates.From current output signals, it can offer the intensity and position of X-ray beam.The ionization chamber was installed on a SSRF macromolecular crystallography beamline and its performance was tested.In the test,a standard ionization chamber was used for the comparison of beam intensity measurement.The one-dimensional position-sensitive ionization chamber was fixed on a high precision linear motor stage and was driven on horizontal direction to scan the beam position step by step, In which the beam energy was set to be 8 keV and the scanning range to be 10 mm.The position scan was repeated 12 times.The tested specifications were plateau curves, linearity, position resolution and the intensity of beam.The results indicate that the 1-D position-sensitive ionization chamber has a good linearity and its position resolution is better than 20 μm and linear measuring range is 6 mm.Moreover,it will be installed on the beamline of SSRF for monitoring the stability of beam.

To reduce the smile effect caused by the thermal stress and to improve the beam quality of laser diode arrays, a set of optical system is designed for measuring the smile effect.By using an image amplification method, the smile effect of a laser diode array is accurately measured, and the measurement error is about ±0.1 μm.The quantitative characterization of the smile effect is a key technology to compare objectively the different measuring methods for smile effect and to reduce or eliminate the smile effect.According to analysis of the measurement results,the diode laser array package technique about reflow soldering is optimized, and the smile effect has been controlled within ±0.5 μm.As the smile effect values of the laser diode array is decreased and the beam quality of the laser diode array is improved significantly,the proposed method provides a technological fundation for development of small fiber diameters and high beam quality diode lasers.

In order to realize a high flattening C+L-band fiber source by C band matching L band closely, a superfluorescent light source structure with three-stage two-pumping is presented.Firstly, the experimental equipment is composed of three erbium-doped fibers, two 980 nm LDs,a Wavelength Division Multiplexer (WDM),an isolater(ISO)and a 3 dB coupler.Then, a high flattening C+L-band fiber source is achieved by optimizing the lengths of three erbium-doped fibers and adjusting the powers of two pumps, and the mechanism of production is also analyzed.Experimental results indicate that when the lengths of three fibers are 11.5 m, 53 m, 6.5 m and the powers of the two pumps are 65 mW, 115 mW respectively, the light source can offer a linewidth in 75.68 nm with a power ripple of 3 dB, and the flatness of the spectra from 1 543 nm to 1 603 nm is less than ±1.3 dB without any external spectral filters.The high flattening C+L-band superfluorescent light source can satisfy the requirements of the optical fiber sensing and optical fiber communication systems.

A co-focus experiment system of segmented-mirror active optics is built to realize the co-focus fine-tuning of a segmented-mirror.In this system, the segmented-mirror consists of three hexagonal submirrors with 300 mm side to side, and the shape of each submirror is spherical with 2 000 mm radius.A Shack-Hartmann sensor is used for co-focus measurement, and six micro-displacement translation stages in this system are used for adjusting the co-focus and tilt of the two sub mirrors.Each sub-mirror corresponds to 36 sub-apertures of the Shack-Hartmann sensor,and the co-focus errors can be calculated by the position deviation of the spots formed by the sub-apertures.After fine-tuning for micro-displacement translation stages, the rms de-focus error in the optical axis direction and the rms tilt errors in two orthogonal dimentions of the sub mirror can be controlled to less than 1 μm and 0.02″,respectivelly.The experiment shows that the method used in this system is also compatible to the co-focus calibration and real time adjustment of the large segmented mirror telescope.

In order to study correcting capabilities for figure errors of ultra-thin mirrors with active supports, a 0.5 m demonstration mirror is designed and tested.Firstly, the relevant relations between actuator forces and figure forms are analyzed, and some lower-order figure errors, such as primary spherical aberration, coma, astigmatism and distortion due to gravity, are introduced.Then, the optimization objective is set up, and the Sequential Quadratic Programming (SQP) method for nonlinear constraint problem is applied to calculating optimum actuator forces.The residual figure errors of the ultra-thin mirror are given.Simulation analysis shows that by using the actuator arrangement proposed in this paper,the normalized primary spherical aberration, coma, astigmatism as well as their summation can be corrected to be less than λ/24 rms,and the correcting capability for astigmatism is the strongest and for spherical aberration and coma are less; moreover,the deformation due to gravity combined with the summation of above three lower-order aberrations can also be corrected to be less than λ/24 rms.After the actual surface errors from the interferometry based on the 0.5 m demonstration mirror are given, the optimum actuator forces and form errors are solved.The results show that the surface quality is about λ/7 rms ,which is in accord with the test data.The causes that the figure error can not meet the desired objective are analyzed,then an improved method is proposed.By the method, the figure error of the 0.5 m ultra-thin mirror with active supports satisfies the requirements equal to or less than λ/20 rms.

By making the best of the spectral information of medium and long infrareds, a harmonic diffractive/refractive optical system in middle and long infrareds is established, the hyper-spectral imaging system has obtained more than 200 spectral images in medium-wave infrared band of 3.7~4.8 μm and long-wave infrared band of 8.5~12 μm based on the special large dispersion capability of harmonic diffractive elements.The design results show that the optical modulation transfer function is greater than 0.52 at 18 lp/mm in medium-wave infrared band; and greater than 0.51 at 13 lp/mm in long-wave infrared band.Furthermore, the RMS spot diameter is less than 27 μm in medium-wave infrared band and is less than 34 μm in long-wave infrared band.Obtained data indicate that the optical modulation transfer functions at all wavelengths are close to the diffraction limit; and the RMS diameter of points can match with the pixel size of existing detectors.

The quantification model of zinc rapid analysis in the soils was established by using near-infrared diffuse reflectance spectroscopy and a Partial Least Square (PLS) method, and the optimal measured wave band was also selected.All the samples were divided into calibration set and prediction set based on the prediction effect of single wavelength model, and then the spectra were pretreated by Multiplicative Scatter Correction (MSC) and Savitzky-Golay (SG) smoothing methods.The following five wave bands, the whole region 400-2 500 nm,400-1 100 nm,1 100-1 900 nm,1 900-2 500 nm,580-900 nm were selected, and 15 calibration models were constructed for each band selected by the original spectra, the first derivative spectra and the second derivative spectra respectively.By simultaneous adjusting the numbers of SG smoothing points and PLS factors，the PLS computational experiments for each model were carried out and the best model was selected according to the prediction effect.The results indicate that the prediction effect of the model using the first derivative spectra in 1 900-2 500 nm is the best, and its prediction correlation coefficient (RP), RMSEP and RRMSEP are 0.806, 31.0 mg/kg, and 19.96% respectively.Obtained results show that 1 900-2 500 nm can replace the whole band to get a better calibration effect, and can provide a basis for the design of special soil near-infrared spectroscopy instruments.

In order to improve the environmental adaptability of airborne infrared optical systems, the effects of ambiance temperature upon an IR optical system was analyzed, and several typical athermal compensation methods were compared.The optical layout and athermal compensation of the optical system were studied.Firstly, the active athermal compensation method was proposed based on the nonlinear speciality of the lens athermal compensation.Then, it pointed out that the normal cam-potentiometer method could not meet the demands, so the stepper motor with 0.006 mm was selected as a driver.Aim at the disadvantage of proposed method, a linear Hall sensor was introduced to be a position feedback component,and precision athermal compensation was realized by a partial fit method.Finally, the zoom and athermal compensation mechanical structures were discussed.Experimental results indicate that the method proposed can get 0.02 mm compensation precision, and the MTF attenuation of IR optical system is within 0.05,which satisfies the system requirement of athermal compensation in the full temperature range.

In the laser aiming process at far-field atmosphere,the atmospheric turbulent will result in beam spreading and wandering and the pointing accuracy of a laser is dropped seriously.Based on the modified Von Karman turbulence spectrum and the theory of partially coherent beam propagating, a light field simulation software of Gaussian beam propagating though atmospheric turbulence was developed, and the transmission characteristics of beam propagating through far-field strong atmospheric turbulence were investigated in a certain meteorological condition.A test system with a laser optical axis in beam diameter less than 9 mm and a large-calibre receiving lens in 120 mm was designed for measuring the dynamic aiming deviation.At the same time, the relationship between the beam spreading and the variation of gravity center of laser spot was investigated in the range of 3 km and the influence of the beam spreading on laser aiming accuracy was analysed.Based on above results,the compensation scheme for aiming deviation can improve the laser aiming accuracy in an atmospherical visible range of 10 km.When the laser transmission distance is less than 3 km and the angles of elevation are 0~45°,the deviation error of a laser spot is equal to or less than 0.1 mrad.

In order to obtain the high resolution human retinal images in vivo, an adaptive optical (AO) system for retinal imaging was designed to correct the dynamic human eye wavefront aberrations, especially high order ones.On the basis of an open-loop and two-wavelength mode, the system adopted a Shark-Hartmann wavefront sensor (SHWS) and a liquid crystal spatial light modulator to detect and correct the wavefront aberrations respectively and used a 790 nm near infrared luminescent diode and a 570 nm visible laser for the wavefront detection and retinal imaging.Furthermove,a reflective off-axis system was adopted to enhance the energy-utilizing rate and to avoid the chromatic aberrations and stray light.The optical system was simulated and analyzed with ZEMAX and results show that the optical system can achieve the diffractive limit, and MTF@30 lp/mm is 0.4(4 μm at retina)，MTF@50 lp/mm is 0.16(2.5 μm at retina).Compared with the close-loop refractive AO system,the system has doubled the energy-utilizing rate at least,and shows its some merits in high energy-utilizing rate,low stray light and little disturbing effect caused by chromatic aberrations.

A high-precision satellite attitude simulation system for ground-based optical communication experiment was established.For the features of satellite trajectory, an improved auto-disturbance-rejection control algorithm was designed.The characteristics and principle of auto disturbance rejection control technology were introduced.Then, the improved servo algorithm was proposed and an selective integration item was added for ADRC algorithm.To achieve the dynamic error of ± 10″ for the system, a multi-threshold nonlinear function was designed, and a state determine module was added to change nonlinear function parameters in real time.At the same time, the setting principle of algorithm parameters was given, and the realized method and process for improved ADRC algorithm were presented based on the open servo functions of controller.The experimental results show that the system has a good capacity for acceleration and deceleration and the dynamics following error of tracking ramp signal is ± 6″.By contrast, the auto-disturbance-rejection control of anti-interference ability is superior to PID in the satellite attitude trajectory tracking, and the following error is ± 7″.These results meet the requirements of high-precision attitude simulation and also have stability and strong anti-interference ability.

A test system for dynamical images of Time Delay and Integration Charge Coupled Device(TDICCD) cameras in space was designed to simulate the ground image motion related to the space aerocraft and to validate the capability of image speed matching and the quality of dynamical imaging of TDICCD cameras.The design adopted a precision table and a drift table to simulate the aerocraft motion around the earth and its drift motion in different latitudes caused by the earth rotation.The precision table drived by a permanent magnet torgue motor was controlled by a phase locked loop serve-control strategy and its steady speed error reaches 0.029 7%.The drift table was drived by a stepping motor and its average rotation speed is 0.02 (°)/s and trace precision of draft angle is better than ±5′.The experimental results show that the precision of designed system meets the test requirement for the dynamical images of TDICCD cameras,and has been applied to the development of a certain space visible light camera.

In order to develop ultra precision master gears, this paper takes the Y7125 grinder as an example to analyze the effect of the cone-shaped error of grinding face on the helix deviations.It establishes a geometric model and derives the numeric expression of the effect.The theoretical results show that the minimum effective bearing width has a little effect on the form deviation of gear helix.However, as the increase of gear width, the effect of the cone-shaped error on the form deviation of gear helix will significantly increase.Moreover, the cone-shaped error can make the curve of gear helix deviation to be an arc-shape and the crowns of arc vary from the dedendum to the addendum.Finally, the error measurement, gear-grinding experiment and deviation analysis are conducted by an example.The results show that the ultra-precision gear can achieve the quality of 1 helix deviation by controlling the cone-shaped error of grinding face of flat faced wheel under 2.7′.

To reduce the ellipticity of the steel pipes processed by JCO forming,a precise bending technology was presented based on plastic bending engineering theory and machine vision technology.In the first bending step,the prescribing two-bend was used to obtain the springback law,then using the springback law and considering the aimed bend angle, the exact punch displacement to determine the forming angle in each bending step was predicted.In the succedent bending steps, the bending process was carried out with the exact punch displacement predicted above.The angle error in each bending step was calculated by comparing the actual forming angle with the aimed bend angle, and each precise bending process was realized by compensating for the last angle error in the next bending step.Furthermore, the image processing and line detecting algorithms suitable for the image of the steel pipe end plane were proposed by a machine vision system.A calibration method was presented to calculate the exterior parameters of the CCD camera, which employed a equilateral triangle as the calibration board and only needs to capture one image.A mathematical model was derived to convert the angle in the image into the actual forming angle.Experimental results show that the measuring error of the forming angle is less than 0.2° and the ellipticity of the formed pipe is less than 1.5%.Employing the precise bending technology, the high-quality pipes can be manufactured without depending on worker’s operating experiences.

A vibration isolation platform is designed for keeping the precise optical instrument to work accurately.By taking displacement sensors with an accuracy of 10 nm as measuring devices, the platform calculates the changed force of the supporting spring by measuring the length change of the spring with the displacement sensor, then it adjusts the force of electromagnet actuator according to the changed force of spring to balance the precise optical instrument to isolate the vibration of base.According to the analysis of theory and simulation, it can satisfy the request of vibration isolation.Furthermore,this method is propitious to the multilevel reduce vibration, for each vibration isolation platform is independent.Experimental results indicate that when the vibration amplitudes of foundation are 0.22,0.20,0.18 and 0.15 mm, the vibration amplitudes of isolation vibration platform is 1.6,1.4,1.2 and 1.0 μm, respectively, which shows proposed method can satisfy the requirement of isolation vibration.

In order to improve the inspection efficiency of Ultrasound Lock-in Thermography (ULT) and to obtain optimal results, the ultrasound modulation, thermal sequence image processing and the optimal parameter selection were investigated.The principle of ULT was analyzed theoretically,then an inspection system was developed,and several experiments were carried out on the steel plane with surface (subsurface) microcracks and Al alloy with defects at different depths.In inspection, the modulated ultrasonic square signals were used to excite the samples and an infrared camera to collect the transient sequences,then the lock-in processing was taken to obtain phase images and amplitude images.Experimental results indicate that, for given A3 steel samples, the modulation frequency of 0.5 Hz and the pressure between sample and ultrasonic transducer about 0.25 kN is a good choice.Furthermore, the distance between the injection position and the crack has a few effects on the inspection and appropriate injection position should be depended on the specific structure of samples.As deeper defect can be detected with decreasing modulation frequency, the defect at 4 mm depth on the Al alloy sample is detected at modulation frequency of 0.3.Moreover, the method can also be used for detecting the skin unbond on a honeycomb sandwich structure.Using the inspection system, reliable detection of contacting interface-type defects can be done for a few seconds.

To measure precisely the discharge state and overcome the shortcomings of the distortion of discharge signals and the instability of discharge state,the principle and method of successive mapping detection were proposed combined with the system identification and fuzzy control after analysis on traditional discharge state detection methods in micro Electrical Discharge Machining(EDM).For real-time collected gap voltage and current signals in the process,the fuzzy operation was used to identify the discharge state of a sampling point and then to map the sampling point discharge state value into sampling point discharge state vector.Furthermore,the vector was counted to obtain the“Short rate” and “spark/arc rate” and the fuzzy reasoning was used to identify the discharge state of each cycle.Test results show that the presented detection method has highly accuracy and is able to identify data and operate fast.Compared with that of the average voltage detection method, the efficiency has been increased by 22.2%.Detection results can provide feed back inputs of the system discharge states for the real-time control of the discharge process, which ensures the stability and accuracy of the processing control system.

UV-LIGA technology was investigated to fabricate the ultra-high micro electrode array, and the micro electrochemical machining was used as an aided method to remove the SU-8 resist.During the lithography process,a SU-8 mold up to 1 mm thick was fabricated on the substrate by methods of single coating,increasing soft bake temperature and decreasing post bake temperature.Before the electroforming process, a reverse polarity procedure was carried out to make the micro roots on the substrate, which could enhance the adhesion of the electroformed micro copper electrode array to the substrate.Using the optimized parameters: single coating; soft bake 110 ℃/12 h; post bake 50 ℃/5 min, 70 ℃/10 min, 90 ℃/30 min; electrochemcial machining 10 V/15 min et al., the micro electrode arrays with a heigh of 900 μm and a linewidth of 300 μm were fabricated.The result indicates that UV-LIGA is an excellent method for fabricating ultra-high metal micro electrode arrays.

Considering the drawback of checking method indoor for the dynamic characteristics of tracking systems of photoelectric theodolites, a novel approach is proposed to evaluate the tracking performance of photoelectric theodolites in this paper.The equivalent mathematical model of tracking error of a photoelectric theodolite is established.On the basis of identification theory,the equivalent sine signal is inputted to the equivalent model, and then the output signals are processed to evaluate the tracking performance.The principle of the equivalent model of tracking error and the identification method of equivalent model order are introduced, and the design approach of equivalent sine signal is given according to the checking and testing desires of theodolites.Because the dynamic characteristics of the theodolite need to be inspirited fully by input signals to obtain accurate parameters of equivalent model, the frequency of dynamic target is modulated continuously.The proposed equivalent model is verified by simulation and experiments, obtained results indicate that the estimate errors of equivalent model including average error, maximum error and standard error are (2.587 2×10-6)°≈0°, 1.8″ and 1.1″,respectively,which shows that the equivalent model meets the needs of evaluating the tracking performance of theodolites, and achieves the accurate evaluation of tracking performance.

In order to solve the duality problem in pose estimation of a single circle in machine vision, an approach based on Euclidean angular constraint is presented to identify the unique pose result.The accuracy of pose estimation is analyzed, which provides constructive suggestions on achieving accurate pose estimation of circles based on experimental results.The pose of single circle is recovered from its projection in an image with a calibrated camera, though the result is ambiguous, only two possible results exist.Then, the unique pose is identified based on the Euclidean angular invariant.Finally, the accuracy of pose estimation is analyzed based on the theory of error propagation.Experimental results indicate that the absolute error of pose angle of the circle plane and the relative error of position determination are within 0.2°and 0.5% m respectively,and the absolute error of reconstructed distance between the two lines is within 0.8%.These results show that the approach can identify correctively poses and positions of circle planes and can offer a high measuring accuracy and reliable results by a simple computing process.

Matching-area suitability for Synthetic Aperture Radar(SAR) images, one of the key technologies of scene matching aided navigation, was studied in this paper.The problem of SAR matching-area suitability was described combined with SAR imaging process, integrated navigation course and SAR image characters.Then, for decreasing geometric distortion and improving matching probability, several effect factors on matching-area suitability were analyzed, including constraint conditions in application, construction of feature criterions and predicting functions.Furthermore, a multi-objective genetic optimizing model based on SAR matching-area selection was proposed to decrease geometric distortion and optimize image features.Experimental result shows that the matching probability of the best matching area selected is 94%, which proves the rationality of the analysis and model.The proposed method can provide a reference for choosing good SAR matching areas.

To solve the “soft-field” effect and ill-posed problem in electrical capacitance tomography, an image reconstruction algorithm based on weighted Singular Value Decomposition(SVD) truncation conjugate gradient is presented for electrical capacitance tomography.The working principle of electrical capacitance tomography is introduced and a measurement method for ECT system with 12 electrodes is proposed.On analysis of the sensitive matrix based on the SVD theory, a weighted conjugate gradient truncated SVD mathematical model is derived,and it is weighted normally by Tikhonov regularization method.Finally, the convergence of the algorithm is analyzed and applied to the image reconstruction for electrical capacitance tomography.Experimental results and simulation data indicate that for laminar flow, the average error can reach 27.54%, and the average number of iterative steps for all flow regimes can achieve 13 by the proposed algorithm.Compared with LBP,Landweber and CG algorithms, the algorithm has advantages in good image quality,high image speed and is a feasible and effective method for image reconstruction.

A fusion method of infrared and visible light images based on Pulse Coupled Neural Network (PCNN) and wavelet transform is studied.Firstly, the two original images are decomposed by wavelet transform, then, a fusion rule in the wavelet domain is given based on the PCNN.This algorithm uses the local entropy of wavelet coefficient in each frequency domain as the linking strength, then its value can be chosen adaptively.After processing PCNN with the adaptive linking strength, new fire mapping images are obtained.According to the fire mapping images, the firing time gradient maps are calculated and the fusion coefficients are decided by the compare-selection operator with firing time gradient maps.Finally, the fusion images are reconstructed by wavelet inverse transform.Two groups of experiments are undertaken for the fusion of visible and infrared images,results indicate that when the numbers of iterations are 50 times, the entropy has increased by 1.1% and 0.7%; the average grads by 8.3% and 3.7%; the spatial frequencies by 2.5% and 1.5%; the standard deviation by 1.9% and 0.6%, respectively; and the cross-entropy has reduced by 5.6% and 4.9%, respectively as comparing with that of classical wavelet method.These results show that proposed method has improved the details of fused images and is suitable for fusing visible and infrared images.

Kernel Particle Filter (KPF) is an effective method for target tracking of a dynamic system with small noises, in which the selection of the kernel bandwidth is a critical step of Kernel Density Estimation(KDE) in KPF.In this paper, a Variable Bandwidth Kernel Particle Filter (VBKPF) based on covariance matrix is proposed.Firstly, the covariance matrix of particle sets is used to compute the coarse bandwidth and the coarse posterior Probability Density Functions (PDFs).Then, each particle can acquire its own accurate bandwidth by adjusting the global kernel bandwidth to improve the precision of the KDE.Finally, to get a more effective particle allocation, the variable bandwidth KDE in the VBKPF is used to approximate the PDFs by moving particles toward the posterior, which gives a closed-form expression of the true distribution.Experimental results show that the proposed VBKPF performs better than the standard particle filter(PF), Unscented Particle Filter(UPF) and the Kernel Particle Filter(KPF) both in efficiency(20% particle number of PF)and estimation precision for optoelectronic target tracking systems.

For improving the accuracy of automatic target detection in complex ground scenes,the statistical property between the Rényi entropy and its occurrence probability of images calculated through the Pseudo Wigner-Ville Distribution (PWVD) with a two dimension window was analyzed based on exponential function.Then the change of the statistical property caused by the appearing of man-made targets is investigated.The methods of saliency map generation and target detection based on Rényi entropy are proposed.Firstly, the image of Rényi entropy is smoothed by the average filter.Then, the image of residual Rényi entropy is obtained by the subtraction of fore-and-aft filter images, and the saliency map is obtained by Gaussian filter.Finally,the target detection is completed by segmenting the saliency map with a simple and convenient threshold method.Experimental results demonstrate that the detection probability and false alarm probability of the method are 100% and less than 7.1% respectively for 14 targets in 8 images.In comparison with traditional methods, the proposed method can detect the military targets from complex ground scenes effectively.

In order to optimize the transmission performance of 1553B bus and to reduce the transmission delay time of messages on the bus, a scheduling strategy for the mixed periodic and aperiodic messages on the bus was proposed.Firstly, a model for the periodic messages was established according to the scheduling model of periodic tasks, and an improved rate-monotonic scheduling algorithm was presented.Then, the M/M/1 queuing model for aperiodic messages was established based on the queue theory, and the time performance parameters of the 1553B bus were quantitatively analyzed, including average response time, bus utilization, and so on.Furthermore, the delay time for aperiodic messages was optimized.The formulas for optimal bus service rate and minimal average delay time were derived; and the scheduling algorithm of aperiodic messages was presented.Finally, the scheduling characteristic of the mixed messages for above algorithm was validated.The experimental results indicate that the average response time of the mixed messages is only 0.713 ms when the utilization of 1553B bus is up to 96%.The deviation of the average response time between aperiodic messages and M/M/1 queuing model is less than 10% under the condition of transmitting mixed messages.Obtained results show that the algorithm has good response characteristics, and can ensure the real-time scheduling of the periodic and aperiodic messages on the 1553B bus.

To overcome the shortcomes of large energy distraction, slow detection speed and low detection probability in target detection using the technique of energy accumulation based on traditional Dynamic Programming Algorithm (DPA), an energy accumulation method of IR point target detection based on DPA is proposed.The Weighted Information Entropy (WIE) attenuation factor and directional weights are imported into the DPA recursive formula.Research results indicate that the WIE can reflect the targets’ moving information.When a target exists in the searching window, accumulated energy shows a little attenution, which guarantees the larger energy accumulation and less energy distraction in the area of target track.Moreover,directional weights can reflect the moving direction of a target and make the energy accumulation toward the moving direction with a large probability.An experiment is carried out for 12 frames of image sequences with the average SNR of 2.172 5.Results show that the accumulated energy reaches the detecting threshold in the 5th frame with the detection probability of 0.915 by using the proposed method, while the energy reaches the threshold in the 9th frame with the detection probability of 0.956 by using the traditional method.It is concluded that the method is able to reduce the area of energy distraction tremendously and can increase the detecting probability and speed obviously.

4f system has the characters of noise and low-pass.In order to remove the image noise and to protect the image texture of its outputs,an image denoising method based on Nonsubsampled Contourlet Transform(NSCT) is proposed combined with the continuity of image texture.Based on the classic hard threshold denoise method in NSCT domain, it adopts a smaller threshold to remove the small amplitude noise to protect the image detail better and protrude the remanent big amplitude noise, then uses the continuity of image texture to remove the large amplitude isolated noise from the consecutive image detail in the high-frequency sub-band images.Eventually the noise is removed and the image detail is protected in the same time.Experiments show that the method can reach the same denoising and can better protect image details for that its Peak Signal Noise Ratio(PSNR) and Structure Similarity(SSIM) have been improved by 0.5~1 dB and 3%~5% respectively as compared with those of traditional methods.

In order to improve the quality of Magnetic Resonance (MR) images, a denoising algorithm for a MR image using Dual-Tree Contourlet (DT-Contourlet) transform is proposed.The distribution model of noise of the MR image is investigated, and a method to estimate the noise parameters of the squared magnitude MR image is derived based on the assumption that such noise obeys Rician distribution.Then, the pyramidal dual-tree directional filter bank of DT-Contourlet is analyzed to show that DT-Contourlet maintains the flexibility direction selectivity of the Contourlet transform, and overcomes the shortcomes of the Contourlet in lack of shift invariance.After that, the locally adaptive window is used to compute the shrinkage factor to shrink the DT-Contourlet coefficients of the squared magnitude MR image in the DT-Contourlet domain by calculating the Variance Homogeneity Measurement (VHM).Finally, the denoising algorithm to MR image is implemented via the inverse DT-Contourlet transform.Experimental results show that the Peak Signal-Noise Ratio (PSNR) of simulated MR images by proposed algorithm is superior to that by traditional algorithms.With different noise variances, the PSNR of new algorithm is high 2.13 dB and 0.91 dB than those of wavelet-based and contourlet-based algorithms averagely.For visual quality, the proposed algorithm can reduce the noise in MR images effectively and retain more details simultaneously.

An improved IR target tracking algorithm based on Mean Shift is proposed combined the mean-shift based gradient matched searching strategy with the feature-classification based tracking algorithm.An improved target representing model is set up by taking the likelihood ratio of gray level features of a target and a local background as a weighted value of the original kernel histogram of target area.The expression of mean-shift vector in this target model is deduced,when Bhattacharyya coefficients are regarded as the similarity measures.Meanwhile, the criterion of model updating based on tracking complexity estimation under target occlusion is presented.The experimental result indicates that the algorithm can improve the shift weight of target pixel gray level and can suppress the background interference, therefore the tracking performance of the low contrast IR target is robust and the average Bhattacharyya coefficients can keep above 0.97 in a correct tracking case.