A measurement algorithm based on Point Spread Function (PSF) was proposed to accurately measure radiation characteristics of infrared small targets which are tiny or quite far away from the IR imaging system. With the method, the PSF of the optical system was measured by using the slanted edge method under the premise of given target shapes. Then, the processes of imaging and sampling of the infrared focal plane arrays were modeled and the simulated image of the target on a detector was obtained. Furthermore, the radiance, size and center position of the target were estimated accurately by matching the simulated image and the actual image obtained from the IR imaging system. Finally, experiments were performed to verify this method. The obtained results show when the temperature of a circular target is 70 ℃ and the ideal imaging diameter is greater than 4 pixels, the maximum error of radiance measurement is 2.35% and that of the target size (area) measurement is 1.89%. The experimental results demonstrate that the method is feasible and is suitable for capturing radiation properties of targets or backgrounds, performance measurement of infrared systems, image restoration and small target positioning.

To explore the physical mechanism of sweeping nonlinearity of a Fabry-Perot(F-P) tunable filter based on a PZT and to obtain the optimized scheme for the characteristics of linear wavelength sweeping, a wavelength-swept laser based on the F-P tunable filter was developed. The transmission time domain method was used to research the output nonlinearity of the wavelength-swept laser and the changed sweeping nonlinear characteristics in different sweeping frequencies were obtained. Then, it points out the change is caused by capacitive load characteristics of the PZT from the actuator in the tunable filter. With spectroscopy, the relationship among dynamical sweeping nonlinearity, sweeping range and driving frequency was obtained and it is in good agreement with that of the theoretical analysis. Finally, a new drive scheme based on a voltage follower was proposed to optimize the characteristics of linear wavelength sweeping. The experimental results show that this method promotes the linear responsibility of high-speed wavelength-sweeping. The scheme is applied in FBG interrogation system and obtained demodulation nonlinearity is 0 998 44 at a wavelength-swept speed of 1 000 Hz.

A sensing network was constructed by a Fiber Bragg Grating (FBG) sensor, and a mode identification algorithm for the damage of carbon composite materials was researched by combining the wavelet decomposition and reconstruction, frequency spectrum analysis and support vector classifier algorithm. Firstly, according to the impact test on a composite material structure with different damage modes, the relationship between damage modes and signal characteristics was explored. Then, the wavelet decomposition and reconstruction were used to remove the signal baseline interference, and the identification method of damage mode for composite materials was constructed based on extracting signal amplitude frequency characteristic by Fourier transform analysis. Finally, the extracted signal amplitude frequency characteristic was used as an input and the damage mode as an output, the damage modes of composite materials were identified based on support vector classifiers. An experimental area with 200 mm×200 mm was selected in a 500 mm×500 mm×2 mm carbon fiber reinforced plastic plate center. The 30 damage modes are tested, and the result shows that 29 damage modes are identified accurately with identification accuracy of 96.7%. The research provides a reliable method for the identification of damage modes of composite materials.

Under the action of silver nanoparticles(AgNPs) and emulsifier (OP-10), the complexes generated from oxytetracycline (OTC) and Eu (Ⅲ) produce strong fluorescence intensity. This mechanism of fluorescence enhancement was used to detect the oxytetracycline (OTC) content in duck meat in this paper. Firstly, the fluorescence spectral properties of OTC+Eu+AgNPs+OP-10 system and OTC+Eu+AgNPs+OP-10+duck meat extracting system were analyzed. Then, the effects of the addition amounts of AgNPs, Eu3+, emulsifier OP-10 and the reaction time on the fluorescence intensity of OTC+Eu+AgNPs+OP-10+duck meat extracting system were investigated respectively, and the optimal experimental conditions were determined. Finally, the standard curve for predicting the OTC content in the duck meat was established. The experimental results show that it is a good linear relationship between the OTC concentration in the duck meat extract and the peak area at 617 nm, and the correlation coefficient(r) and the Root Mean Squared Error of Prediction (RMSEP) are 0.996 6 and 0.622 3 mg/L respectively. It is demonstrated that the proposed method is suitable for detecting the OTC contents in the duck meat.

A method to assemble muti-chip CCD devices together for a long focal plane assembly was proposed to meet the need of a space wider format camera for large field of view. By using a long array Time Delay Integration CCD(TDICCD) mosaic apparatus, 17 TDICCD devices were stitched onto the focal plan board with an interleaving assembly method according to the accuracy requirements, and fixed by plugs, then an extra long focal plane with a length of 600 mm, pixels of 69 000 was obtained. The experiments on the completed focal plane assembly were performed by a temperature cycling test, a vacuum thermal test and a vibration test, and the results show that structure design and material selection of the focal plan assembly meet the mechanical and thermal requirements. The accuracy measurment result of focal plane shows that the stitching error is less than 3 μm. The extra long focal plane was applied to a remote sensing camera, and the seamless wider format image was captured. These results testify that the 600 mm long focal plane assembly meets the application needs of wide format remote sensing cameras.

On the basis of multi-spectral multi-angular radiative polarization measurements, a prediction method for atmospheric polarization patterns is investigated. Firstly, the principle of an Aviation Multi-angle Polarimetric Radiometer (AMPR) and the regression algorithm of a Support Vector Machine (SVM) are introduced. Then, according to Vector Radiative Transfer Equation (VRTE), it points out that the atmospheric polarization pattern is primarily dependent on view geometry and surface features when atmosphere condition is invariant. Meanwhile, it introduces the relationship between view geometry and platform attitude and the expressing form of surface features. Finally, how to use the regression algorithm of SVM to predict the detected polarization degree of the APMR and to validate the application process is introduced in the consideration of the surface features and platform attitudes. Furthermore, the predicted degrees of polarization is also compared to that of real measurements. The results indicate that the error of polarization degree predicted is less than 1%. It concludes that the serious factor to affect the model accuracy is not the change of attitude but the variation of underlying surface property caused by the changed attitudes.

A tilt depth-resolved wavenumber-scanning Michelson interferometer was built up to measure and analyze the compression displacement field distributions on the fore, middle and rear surfaces of dual layer epoxy composites. A Distribution Feedback(DFB) diode laser whose wavenumber could be modulated by the temperature was used to perform the wavenumber-scanning interferometric measurement for the dual layer epoxy composites. A Random-Sampling Fourier Transform (RSFT) was designed to evaluate the phase differences of the dual layer epoxy composite samples before and after applying loads. Finally, the unwrapping algorithm was used to unwrap the phase differences for the samples before and after applying loads and the compression displacement field distributions of every surfaces on or inside the epoxy composites were given out. Experimental results indicate that measurement resolutions of the compression displacement field distribution are ±100 nm, and the profile resolution in depth and the maximum measurement depth are 0.41 mm and 52 mm, respectively. This method accurately measures the compression displacement field distribution, and its measurement is independent on the internal plane elastic modulus size of resin matrix composites. It is characterized by higher measuring accuracy, stable system and stronger resisting disturbance.

To overcome the effect of polarization-maintaining fiber delay polarization crosstalk on the measuring accuracy of an all Fiber Optical Current Sensor (FOCS), the polarization error of the FOCS was studied by using the Jones matrix. The error model for the polarization-maintaining fiber delay polarization crosstalk was simplified, and the relation between the polarization crosstalk and the output was deduced based on the simplified model. The influences of the polarization crosstalk on FOCSs normalized scale ratio under a normal temperature and variable temperatures were analyzed respectively by simulation and analysis. The comparison between the experiment results and theory conclusions show that the simplified model is reasonable and the simulation result is correct. The actual temperature characteristic of the polarization-maintaining fiber delay polarization crosstalk was tested. Experimental results indicate that when there is polarization crosstalk in the fiber delay line, the ratio error of the FOCS is proportional to the current;when the current is constant, the higher the polarization crosstalk is, the higher the FOCSs ratio error is. Finally, the fluctuation range of the fiber delay line polarization crosstalk to meet the 0.2S class error of FOCS was put forward.

A preparation method for diffusers with surface disordered submicron structures was proposed, which are characterized by a higher haze property and higher transmittance. By replication method, the diffusers with surface disordered submicron structures were prepared based on silicon-cone molds and anodic aluminum oxide molds for polydimethylsiloxane (PDMS) and polystyrene (PS). It demonstrates that the surface disordered submicron structures significantly enhance the haze properties of polymer films. Moreover, the morphologies and dimensions of the submicron structures have important effects on the diffusing property of the polymer films. The fabricated PDMS films with disordered submicron-holes replicated from a silicon-cone mold with a cone diameter of 650 nm has a haze of 92%, a transmittance of 90.9% and an effective diffusion coefficient of 83.7%. Accordingly, the haze, transmittance and effective diffusion coefficient of PS films obtained from the same silicon-cone mold are 97.9%, 85% and 83.2%, respectively. Both films diffuse light effectively and are used as diffusers properly. The results indicate that using silicon-cone mold based replication method to fabricate the efficient diffusers is simple, low-cost and compatible with different polymers, and is able to be employed for mass production.

By integrating an electrostatic comb drive actuator with a Ⅲ-nitride grating, a Micro-electric-mechanic System (MEMS) tunable Ⅲ-nitride grating was obtianed on a silicon substrate to modulate the grating period. Firstly, the MEMS-tunable Ⅲ-nitride grating was designed on the basis of the Ⅲ-nitride-on-silicon substrate, in which the design values of grating period and the grating width are 1.1 μm and 0.8 μm, respectively. Then the Rigorous Coupled-wave Analysis (RCWA) method was used to analyze the optical responses of the Ⅲ-nitride grating under transverse magnetic modes. It shows that the resonance peak of the Ⅲ-nitride grating has a serious shift by changing the grating period and duty cycle. Finally, the MEMS-tunable Ⅲ-nitride grating was fabricated by combining an electron beam lithography, a Ⅲ-nitride dry etching and a deep silicon etching. Experimental results and rigorous coupled-wave analysis indicate that the fabricated MEMS-tunable Ⅲ-nitride grating has good quality and the shift of the resonant peaks is observed from 1.345 μm to 1 40 μm by applying a voltage on the electrostatic actuator. These results satisfy the requirement of modulating the optical responses of Ⅲ-nitride gratings by using MEMS technology.

To counteract the hysteresis introduced by a harmonic drive and to improve the precision of a Double Gimbal Magnetically Suspended Control Moment Gyroscope (DGMSCMG) gimbal system, a modeling method of hysteresis characteristics of the harmonic drive was proposed. Firtly, the first-order reversal curve method was used to capture the outputting torque of the flexible gear and the torsion angle of the harmonic drive and to obtain the data to establish the hysteresis model of the harmonic drive, in which the outputting torque of the flexible gear was estimated by a system dynamic model instead of a direct measurement from the torque sensor. Then, the Preisach model was used to establish the hysteresis relationship between the outputting torque of the flexible gear and the torsion angle of the harmonic drive. Finally, the modeling was discretized and its weighting function was then well mapped by applying mathematical implementation.Furthermore, a discrete recursive algorithm of the model was also provided for simply programming and further on-line controlling. Results of the carefully designed experiments conducted on the DGMSCMG show that the deviation between calculated and measured torsion angles is limited within a 0.005° range, and the MSE value is under (0.000 83%)°. These results show that the model well predicts the hysteresis of the system.

A method for constructing the models of quartz glass was proposed to improve the processability of quartz glass, and Molecular Dynamics(MD) simulation combined with nano-indentation experiments were performed to research on nano-processing performance of the quartz glass. The accuracy of the model was verified by calculating the density and hardness of the quartz glass. Then the nano-indentation experiment was conducted to obtain indentation curves and to observe the morphology of indentation. Finally, a MD simulation of nano-indentation was performed and the formation and extending mechanism of a damage layer was investigated. According to the calculation of density and nano-hardness, it shows that the density is about 2.28 g/cm3 and nano-hardness is about 9.7—10.7 GPa, which is almost consistent with the experimental results. The experiments indicate that the quartz glass has a stable plastic deformation and a small amount of elastic deformation as well as the indentation size effect. When the indenter is depressed, the atomic dense area is formed. Since it losses the strength of the original covalent bonds, so the damaged layer is formed. Moreover, the surface topography is mainly formed by atoms on both sides squeezed with the indenter and the adhesion of the indenter. The simulation and experimental results show that the quartz glass is suitable for ultra-precision machining.

Conventional design parameters of attitude control fly wheels motor are calculated repeatly based on experiences and the optimal parameters can not be acquired.On the basis of a circuit method and a Finite Element Method(FEM), this paper proposes a design method for the driving motor of an attitude control flywheel, in which the effective ratio of diameter to length is taken as a design core. The computing model for circuit design was established according to the relationship between the ratio of diameter to length and the parameters of the motor, then the air-gap flux density and the inductance were calculated by using FEM based on Laplaces equation. Finally, the calculated results were used for the accurate analysis of the performance of motor. Moreover, a hub driving motor in an attitude control flywheel with angular moment of 5 Nms was designed and its electromagnetics torque ripple and the mechanical characteristic were simulated. The results show that the regulating characteristics of theoretical calculation is in agreement with that of the experimental results well, and the maximum error of electromagnetic structure is 2.9%. It concludes that this method is suitable for the design of attitude control flywheel motors, and is characterized by higher speeds and good precises.

When the Radial Basis Function Neural Network (RBFNN)is used for the temperature compensation of a laser gyro bias, it shows lower computing efficiency and numerical pathology due to incorrecting selection of an initial center randomly. Therefore, this paper proposes a new RBFNN method based on the Kohonen network and Orthogonal Least Squares (OLS) algrithm. It introduces the principle and modeling steps of the method and designs data collection and temperature compensation experiments of the laser gyro under normal temperature and variable temperature environments. As the method combines the pattern classification capability of the Kohonen network and the optimal choice capacity of the OLS, it avoids the effect of drawback mentioned above, and can quickly and accurately identify the laser gyro bias affected by temperatures. The identification and compensation tests for the laser gyro bias effected by a variety of temperature change situations are performed by the stepwise regression method, RBFNN method and the proposed modified methods in this paper. The test results show that the three methods all have the abilities to identify fairly in the situation of normal temperature;with increasing the rate of temperature change, proposed RBFNN method not only saves time, the compensated laser gyro bias is all also less than 5×10-4(°)/h (1σ), and its accuracy is improved more than 86%. The proposed RBFNN method enhances the stability and effectiveness of identification accuracy, and is suitable for laser gyro bias temperature compensation in a variety of temperature change conditions.

As existing Bidirectional Reflectance Distribution Function (BRDF) measuring device is three-axis equipment, and it can not implement the whole angle BRDF measurement in a 2π space on the sample surface. Therefore, a new device was built for BRDF measurement in this paper. A six-axis robot was used as object positioning mechanism to implement three-dimensional rotating for changing the normal direction of the object at the measuring point, and a turntable was used as the detection positioning mechanism to implement one-dimensional rotating for changing the orientation of detector around the measuring point, so that four-dimensional rotation was constructed to form the four-angle geometry of BRDF measurement. The measuring geometry of incident and reflected beams of the device shows its azimuthal angle to be 0—360°, zenith angle to be 0—70°, and the spectral range is 350—2 500 nm.The process of BRDF measurement is controlled by software, and the BRDF measuring geometry is constructed with high-precision, non-blocking, fully automation and speediness. With an average measurement of about 8 s, the device completes the geometry of construction and spectral scanning, transmission, display and the storage. The uncertainty budget of the device is less than 2.5%(k=2).

The site choice and pier foundation of existing ground based large aperture telescopes were analyzed and how to construct a pier for a 2 m aperture telescope was explored. Firstly, the relationship between the astronomical seeing and the pier height of a telescope was discussed and the pier height was determined to be 13 m by measuring the astronomical seeing of the seat of the telescope. Then, according to the requirements of pier construction of the 2 m aperture telescope, a simulation model was established, and the simulation analysis was performed by Ansys. A pier and ground base design scheme with a resonant frequency more than 30 Hz under the load condition of 30 t was proposed to resist a 5 level earthquake and certain wind load. Finally, the spectral analysis and random vibration method were used to research the responses of the pier designed to the earthquake and certain wind loads. The results show that the scheme proposed meets the demands of 2 m aperture telescope for pier foundation and it would provide a reference for construction of a Φ4 m aperture telescope.

The polarization-dependent absorption of the rectangular-block perfect absorber metamaterials in mid-infrared regime was investigated theoretically and numerically. The rectangular-shaped nanostructure absorber consisting of metal-dielectric-metal layers has dual-band resonant absorption spectrum at infrared wavelength of 2.0—5.0 μm and its absorptivity is more than 80%. The simulation results indicate that the dual-band resonance spectra of the materials are attributed to the third order resonance mode and the fundamental mode of the perpendicular polarized incident electronic field. A rectangle array optical absorber was developed and its optical properties were measured. The test results show that equivalent permeability of the absorber in two polarized configurations is satisfied the Lorentz model and the imaginary parts of the permeability agree well with the resonance absorption wavelengths, which indicates that the polarization absorption of the materials is depended on the magnetic resonance induced by the incident wave. These results point out that the dual-band resonant absorption mechanism of the nanostructure absorber is conductive to design of biosensors and photoelectric detectors in special wavelengths.

Lots of lapping experiments were carried out for a single crystal sapphire by using a diamond fixed abrasive (FA) pad. The effects of different kinds of slurries on Material Removal Rate(MRR) and the surface quality of a workpiece were studied. The chemical influences of slurries on the surface of the crystal sapphire were analyzed and the material removal mechanism of the sapphire crystal by fixed abrasives was explored. Experiments show when W14 diamond fixed abrasive plated nickel is used to lap the single crystal sapphire and the deionized water is used as slurry, the MRR is 149.8 nm/min, and the surface roughness (Ra ) is 76.2 nm. However, after adding 2% of ethylene glycol into the slurry, those are 224.1 nm/min and 50.7 nm, respectively. A photoelectron spectrometer (XPS) was used to analyze the surface of the workpiece, and it shows that the solution of ethylene glycol has more chemistry promotion for the sapphire surface. These results indicate that the addition of ethylene glycol is helpful for the formation of softened surface layer on the sapphire surface and increases the activity of sapphire surface. It means that the slurry plays an important role for enhancing lapping efficiency and improving surface quality of workpieces.

A resonant frequency measurement system for a magnetoelastic (ME) sensor based on the impedance response was established and the measuring mechanism, equivalent circuit model and the measuring circuit of the ME sensor were researched. First, the measurement mechanism of resonance frequency was introduced based on the impedance change of the ME sensor. The equivalent model circuit of the ME sensor was established according to the affect of the ME sensor on a coil impedance. Then an impedance measurement circuit based on system-on-chip was designed. Finally, the experiments were performed to verify the feasibility and reliability of the resonant frequency measurement system for the ME sensor. Experimental results indicate that the frequency resolution and the accuracy of the system are less than 0.1 Hz, and 0.5% respectively. Moreover, the deviation between the resonant frequency measurement system and the traditional network analyzer platform is 60 Hz for a same Metglas 2826MB material;the resonance frequency radio of two Metglas 2826MB materials with different lengths is 0.74, similar with the theoretical value of 0.8. The resonant frequency measurement system works well in different media, which means that the system can replace an expensive and large network analyzer and is characterized by higher integration, stronger anti-interference, lower costs and portable measurement.

According to the demands of a Wide Angle Aurora Imager (WAAI) for its optical system in temperature, the thermal design and related test of a high temperature transmission filter in the imager were performed. The optical-mechanical structure of the imager was introduced, especially the transmission filter component. Then, based on establishing a equation set for conducting and radiating thermal resistance, the thermal resistance and its effect factors in the overall heat transfer path from the transmission filter to optical bench were analyzed. Furthermore, the effect factors on the thermal resistance were taken as design variables and the sensitive variables on the barrel temperature were analyzed. Finally, the thermal design of the space optical system was implemented depending on the above analysis result. Experimental results indicate that the filter average temperature reach 105.8 ℃ and 138.2 ℃, respectively, the control temperature accuracy is less than ±2.5 ℃ and the temperature stability is less than 0.75℃/min under the cold and hot extreme cases. The temperature indexes of the mirrors and detector window also satisfy the design demands. It concludes that the design method based on thermal resistance and temperature sensitivity analysis could find the sensitive design variables rapidly, reduce the blindness during thermal design. Moreover, the thermal design of the space high temperature transmission filter satisfies the optical requirement and effectively maintains the temperature difference between transmission filters and mirrors.

To monitor the performance of a Dynamic Tuned Gyro (DTG) on-line under closed-loop working conditions, a closed-loop identification approach was explored for the DTG system. Firstly, the plant model was simplified and discretized to obtain the identification model set and model order based on the complex model structure of DTG closed-loop system. Then, the Instrumental Variable (IV) method was used to the closed-loop identification of the DTG. Aiming at the deficiency of the traditional Ⅳ method, a BJIV method was proposed. The method was applied to BJ model so that the plant model and noise model were not restricted by the identification model. Furthermore, simulations were used to analyze the consistency and asymptotic distribution of the BJIV method. Finally, single and continuous identification experiments were conducted on a DTG closed-loop system. Obtained results indicate that the estimations of BJIV method are unbiased and consistent with different noise levels, and its asymptotic variance is near-optimal. The experiment results on closed-loop identification show that the identification fitting degree is more than 90%. After continuous experiments for two hours, DTG closed-loop system is stable and the identification results are reliable.

According to the technical requirements of precision shafting of inertial navigation test equipment, a comprehensive parameter tester for the rolling bearing is developed. The tester is used to measure the friction torque, bearing stiffness and geometric accuracy in the rotary processing of the rolling bearing and it gives the relations between the friction torque and the axial pre-tightening load, as well as the axial pre-tightening load and the bear axial displacement in the form of a chart or a curve. The system integrates several kinds of sensors and designs hardware control, measuring system and software on a virtual platform. It is characterized by good expandability and lower costs. The system converts control of the best pre-tightening force into control of the bearing bushing height difference, which better solves the best pre-tightening problem in the process of shafting assembly and ensures a stable friction torque for the shafting system. The experiment results show that the system not only finishes all parameter detection successfully, but also can track the variation of frictional torque in bearing running. Under a rotation speed of 8 r/min speed, the rotation friction torque at stable operation is (0.62±0.16) Nm. The experimental data provide theoretical foundation for the control of low rate motion of turntables and the establishment of compensation model for disturbance torques.

A kind of wafer level hermetic packaging based on electroplating Cu-Sn alloy films was developed to reduce the cost and difficulty of traditional hermetic packaging based on anodic bonding。The electroplating parameters of Cu-Sn alloy films were determined by the electroplating experiments, and the structure of alloy film is Cr/Cu/Sn (30 nm/4 μm/4 μm). Then, the hermetic packaging parameter was determined by eutectic experiments. After comparing the hermetic packaging results at different temperatures, the wafer-level packaging was achieved well on a temperature of 280℃, holding time of 20 min and a static pressure of 0.02 MPa. Finally, the quality of hermetic packaging was tested by X-ray Diffractometry(XRD), X-ray analysis, a shear stress analysis and a helium leakage rate test. The XRD experiment shows that the bonding is formed because that there are phase Cu3Sn in bonding layer. The hermetic quality is verified by the X-ray analysis and the helium leak rate test. It is suggested that no obvious holes are occurred around the hermetic ring and most of the cells have good hermetic bond quality. Moreover, the average shear strength is 9.32 MPa by shear stress test. These results demonstrate that the wafer-level hermetic packaging has been achieved well based on electroplating Cu-Sn alloy films.

Humidity sensors are easy to condense and have humidity fluctuation, moreover, their board distributed capacitances affect measurement results under a high altitude environment. Therefore, this paper proposes a sandwich plate capacitive humidity sensor integrated with a snake like platinum resistance heater and its prepared method. Then, it studies the measuring circuit for the sensor. The humidity sensor with heater was designed using Micro-electric-mechanic System(MEMS) technology, the temperature distribution of sensor surface was analyzed and the function relationship between environment temperature, heating power and heating temperature were obtained by using finite element analysis. To suppress the temperature and zero drifts effectively and reduce the influence of parasitic capacitance on measurement, a humidity measurement circuit based on the capacitor charging and comparative law was designed. The ground experimental results on the sensor show that the humidity sensitivity is about 2.3%RH·pF-1, hysteresis is about 0.7%F·S, and the repeatability is about 1.9%. Moreover, it gives the measurement uncertainty about 4%, time constance about 0.5 s. In conclusion, the humidity sensor and measurement circuit have good temperature stability, and is suitable for working at a low temperature correctly.

The mechanisms of frictional chatter of a diamond rulling system and a elastic tool post were researched in mechanical ruling grating processing, and a dynamic model for a mechanical ruling grating was established. Then, the stability of the chatter system was analyzed, and its stability condition and stability threshold were presented. Furthermore, the chatter was researched and analyzed from the energy point of view, and the same stability condition was obtained. A mechanical ruling test were performed with a test device for grating ruling only by changing the ruling speed. After measuring and analyzing the ruling forces, the characteristics of the ruling forces in the vertical direction dropping with the ruling speed were verified, and it satisfied with the precondition for the establishment of frictional chatter. Finally, the surfaces of grooves under four different ruling speeds: 2 mm/s, 6 mm/s, 10 mm/s and 13 mm/s, were measured, which verifies that the chatter will occur when the ruling speed exceeds the critical value (6-10 mm/s). The experiments confirm the effectiveness of the dynamic model of chatter and the existence of the stability threshold. It provides the theoretical foundation for restraining the chatter during grating mechanical ruling process and deep quantitative analysis.

A novel Partial Sensorless Control (PSC) method was proposed to improve the precision positioning capability of multi-DOF (X, Y and θz) motion for a planar motion stage driven by Sawyer motor. For the position estimation, a laser interferometer was used to detect the translational motion and swing in one direction and to construct a closed-loop control;a sliding mode observer-based technique was taken to estimate the translational motion in another direction and to construct a closed-loop control for a corresponding axis. The positioning performance on open-loop control, closed-loop control and PSC was compared by experiments. The experimental results verify that the PSC is an available way to obtain submicron-order positioning accuracy (0.25 μm) with a 300 mm (X)×300 mm (Y) travel range, which is more larger than that of 100 mm (X)×100 mm (Y) travel range from the closed loop control of a multi-DOF (X, Y and θz) location sensing. The result meets the design requirement of positioning accuracy and travel range for planar motion stages.

A fast celestial positioning method based on star identification was proposed to improve positioning accuracy and reduce positioning time. Firstly, the photographic time and angular values were acquired, and the pointing direction of boresight in geocentric inertial coordinate system was calculated by transforming a horizontal coordinate system into a geocentric inertial coordinate system with an astronomical triangle model. Then, all navigation stars and patterns in the area that the boresight pointed were extracted, and the corresponding relationship between stars in images and in the sky was established by a region star match. Finally, the celestial positioning for a space object was completed relatively by reference stars in a background according to pinhole imaging model. The experiment for an image with a FOV of 4°×4°and a resolution of 1 024×1 024 shows that the course of the positioning for the space object has been greatly accelerated due to the introduction of astronomical triangle model and region star match, and the positioning speed is approximately 400 ms. On the other hand, the positing accuracy of a space target is better than 2″ because the relative positioning method eliminates a lot of factors effecting the accuracy.

The performance of MODIS-Aqua Chl-a derived from the standard OC3 band-ratio algorithm and a new band-difference OCI algorithm are compared in the South China Sea(SCS) from the MODIS instrument on the Aqua satellite with nine cruises of chlorophyll measurements collected from 2004 to 2012. Then, the algorithms of OC3 and OCI were corrected by the parameter adjustments based on the satellite, in situ remote sensing reflectance (Rrs(λ)) and corresponding in situ Chl-a pairs respectively. The results show that MODIS-Aqua Chl-a products derived from OC3 and OCI algorithms overestimate the in situ data, with the Average Relative Error(APD) of 59.41% and 44 17%, respectively. However, the algorithm OCI significantly improves the retrieval accuracy for low chlorophyll concentration waters(<0.25 mg·m-3). After regional correction by MODIS-Aqua Rrs(λ) and corresponding Chl-a pairs, the algorithms are likely to fare better, and the modified algorithm NOC3 and NOCI show their APD accuracies are 37.85% and 36.74%, respectively. Moreover, the algorithms NOC3 and NOCI modified by in situ Rrs(λ) and corresponding Chl-a pairs also give a good estimateion with the APD accuracy of 36.61% and 37.79%. Therefore, it suggests that to conduct the regional correction for the operational algorithms is important to improve the accuracy of Chl-a estimation in the SCS.

As phase shift errors will lead to severe ringing artifacts in the restoration results of optical synthetic aperture images, a method to detect and remove the ringing artifacts was proposed based on visual perception. Firstly, the texture region was obtained by calculating the scales of gradient direction randomness and local variance distribution. Then, the whole edges and main edges were separately detected by the Canny operator with different thresholds and whole edges belong to the neighborhood of all edges were considered as the edge ringing candidate. Finally, the ringing region and flat region were respectively derived by combining the texture masking of human visual system. Based on the image classification, the adaptive bilateral filter was applied to removal of the ringing artifacts. Experimental results show that the Peak Signal to Noise Ratio ( PSNR) of a Lena image after processing is improved by 10.8% while the Structural Similarity(SSIM) of resolution board image is improved by 0.057 as well. It condudes that the proposed method classifies the image on pixel scale, so it eliminates the ringing artifacts dramatically while preserving the edges and textures effectively. It is capable of improving the image restoration quality.

In consideration of the lower imaging Signal to Noise Ratio(SNR) and serious mixed noise of a micro-focus X-ray inspector, a denoising method was proposed for the images corrupted with mixed multiplicative noise and additive noise. Firstly, an image model was established to represent the micro-focus X-ray images with mixed multiplicative and additive noises. Then, to remove the mixed noises, the objective functions were proposed based on the principle of total variation and sparse representation. Finally, the multiplicative noise and the additive noise were removed by explicit difference method and gradient projection in steps. Experiment results show that the proposed method enhances the Mean to Standard deviation Ratio(MSR) of the images by 10.9% in smooth areas, the Laplacian Sum(LS) by 15.6% in detail areas as compared with total variation algorithm for the additive noise model. The experiments demonstrate that the proposed method not only removes the mixed noises in X-ray image but also retains the details of the image edge. It meets the requirements of integrated circuit detection for image smoothness and detail definition.

To reduce and eliminate the interstage gain errors caused by capacitor mismatch and finite open-loop gain of an operating amplifier in a pipelined Analog to Digital Converter (ADC), a novel weight-based calibration technique on backend stages was presented. With proposed technique, a weight-based error model was built by merging error factors into a single term and the outputs of backend stages were utilized to calibrate the errors of front stages. To avoid interrupt normal conversion process, two extra stages were used in the calibration process to implement background calibration. During the normal conversion process and calibration process, the first seven stages of every signal path were all calibrated to increase the resolution and to eliminate errors. The improved technique was used in the implementation of 14 b, 80 MS/s pipelined ADC, and the ADC is with Chartered 0.18 μm, 1p6m CMOS process, a consume of 260 mW, and a chip area of 7.161 mm2. The test results show that the calibration technique improves dynamic and static performance and increases the precisions of pipelined ADCs.

As Low-Probability-of-Intercept (LPI) signal detection algorithm based on cyclic spectrum theory has a very large amounts of calculation, this paper proposes an optimized algorithm, Fast Fourier Transform(FFT) accumulation, to update the software program. The signal processing of the original software is analyzed, and the new algorithm based on a parallel signal processing structure is proposed. The new algorithm derives the next FFT sampling signal sequence by the previous FFT sampling signal sequence in a sliding window. By reducing the repeated sampling points, the new algorithm reduces the amount of calculation. In view of the symmetry of the four quadrant of the cyclic spectrum, the quadrant to be calculated is decreased. Moreover, by using one-dimensional search peak detection, the amount of calculation is reduced further. Theoretical derivation demonstrates that the complexity and calculation amounts of the proposed algorithm are reduced obviously. Finally, through verifying the Linear Frequency Modulation (LFM) and Binary Phase Shift Keying(BPSK) signals, it indicates that the calculation time is reduced to about 1/25 that of the original algorithm. In addition, the amplitude values of signals in the optimized algorithm are reduced less than 10%, which not affects the estimation of parameter of a cyclic spectrum.

A pushbroom spectral imaging system based on compressive sampling was established to realize compressive sensing imaging for a hyperspectral image. An image reconstruction algorithm for this system was investigated. In the image acquisition stage, the pixels of ground imaging line were separated along spectral direction by a prism. Then, the linear encoding between the spectral bands was realized by a digital micro-mirror device. Finally, the encoded spectral bands were summed by a cylindrical lens. In the reconstruction of the compressive sampled data, the traditional compressive sensing reconstruction methods which recover hyperspectral data directly were abandoned. The liner spectral library mixed models were used to convert the reconstructed hyperspectral data into reconstructed abundance fraction matrix, the alternating direction method of multipliers was used to solve the optimizing problem of abundance, and the data was recovered by using the reconstructed abundance and spectral library. The comparison experiment between standard compressive sensing reconstruction and our algorithm shows that the reconstructed average peak signal noise rate of our algorithm is improved about 18 dB than that of the standard compressive sensing when the used data are 20% that of total data. The system is suitable for the spaceborne airborne hyperspectral compressive sensing imaging for its simple sampling.

To improve the image reconstruction resolution of ultrasonic tomographic flow field imaging, an iterative Filtered Back Projection (FBP) algorithm was proposed. On the basis of the Simultaneous Iterative Reconstruction Technique (SIRT), the FBP algorithm was integrated into an iterative reconstruction process. With the FBP algorithm, an error image was reconstructed by the residual error of the projection data, then the flow field image was revised and the iterative reconstruction of the image was implemented. By optimizing the iteration step size, the residual error of the projection data for each iteration was minimized to improve the speed of convergence. Finally, according to the flow field characteristics in continuity and compact support, the projection data was interpolated and the flow field image was assigned a value of zero outside the circular domain. Simulation results indicate that the iterative FBP algorithm decreases the image error by 26% and the volume flow rate error decreases from an average of -1.77% to ±0.25% as compared with the FBP algorithm. In addition, the computational time of the iterative FBP algorithm is just 0.63 s, only 0 89% that of SIRT. In actual experiments, the iterative FBP algorithm can reconstruct the flow fields in a straight pipe and downstream of a 90° single bend with high reliability. It concludes that the iterative FBP algorithm implements the reconstruction of flow fields in real-time and higher accurate because of its good reconstruction resolution and high computational efficiency.

According to the requirements of pulse semiconductor lasers for peak powers, pulse widths and rising edges and considering the test behaviors of semiconductor lasers, a driving circuit for the semiconductor lasers with large current outputting, narrower widths and sharp edges was proposed. The circuit used a Metal Oxide Semiconductor Field Effect Transistor(MOSFET) as a switch device and a avalanche transistor as a driver to generate the large current pulse with sharp edge and narrow width. The effect of the pre-trigger pulse width and output load of the avalanche transistor on the amplitude and waveform of MOSFET output pulse was analyzed and how to adjust the coupling resistance to control the pulse “down” and oscillation was discussed. The experimental results show that the circuit generates electric pulses of 10 ns with continuously adjustable attitudes and sharp rising and falling edges, and the amplitude of pulse varies from 0 A to 148 A on a 1 Ω resistor. After adjusting electric parameters, a 124 A current pulse with a pulse width of 8.6 ns is obtained. The circuit meets the needs of driving high power semiconductor lasers as well as laser testing.