To reduce the material porosity in Laser Metal Deposition (LMD) processing, the Inconel 718 (IN718) was used as powder additive in this study, and the influences of main process parameters on the material porosity in a high deposition-rate LMD were investigated. Then, the methods to reduce the material porosity were researched by adjusting these process parameters. Based on the newly developed target with a high deposition rate by 2 kg/h in the LMD process, a coating experiment was performed by parameter solidification and parameter separation and the effects of laser power, scanning speed and powder mass flow on the material porosity were designed and carried out. Furthermore, the cross-sectional porosity and track porosity of tracks deposited by different process parameters were analyzed. The results show that as the laser power increases from 1 440 W to 4 214 W, the porosity of the longitudinal track decreases from about 1.5% to about 0.02%. When the scanning speed varies in the range of 500 mm/min to 5 000 mm/min, the range of track porosity is approx. 0.07% to 0.18%. Moreover, when the powder mass flow increases from 0.64 kg/h to 6.48 kg/h, the porosity increases from approx. 0.01% to 0.84%. It is shown that in high deposition-rate LMD, the scanning speed has no obvious influence on the porosity; and increasing laser power and reducing powder mass flow rate significantly reduce material porosity and increase the consistency of cross-sectional porosity.

An Acoustic Emission (AE) detection system based on a Fiber Bragg Grating(FBG) network was constructed and an AE location system by using Minimum Variance Distortionless Response (MVDR) algorithm was designed. In this system, linear FBG array constituted by seven FBGs was used to detect AE signals, and the edge filter technology using an unflatted Amplified Spontaneous Emission(ASE) source was applied to signal demodulation. Shannon wavelet transform was employed in extracting narrow signals of AE signals with complex frequency dispersion and the spatial spectrum could be obtained by canning over the monitoring area with the MVDR algorithm. The spatial spectrum function was used to calculate output values and the values were used as pixels. Finally, the AE source location was determined by the peak of spatial spectrum of MVDR. The system was verified on a LY12 aluminum alloy plate. The result shows that the maximum error and average error are 11.4 mm and 8.2 mm in a 400 mm ×400 mm monitoring area, respectively, and the average consumed time is less than 3 s. The system has higher real time ability and location accuracy, and is a new AE location technology.

The performance of multi-aperture superposition compound eye imaging systems was introduced. The FOV (field of view) modeling for a multi-aperture partial superposition compound eye imaging system based on a micro-surface fiber faceplate was established. The effects of some device parameters such as the FOV, the overlapping rate of different sub-FOVs and the minimal FOV overlap distance between top sub-surface and side sub-surface on the system performance were analyzed. Then, the feasibility of the FOV modeling was verified by measurement of compound eye FOV and FOV overlap rates in an experimental system. Experimental results indicate that the FOV modeling is in accordance with the real imaging system. The deviations of side and corner FOV angles of the system are 3.58% and 12%, respectively, the deviation of overlapping fields between top surface and side surface is 3.33%, and the deviation of overlapping fields between top surface and corner surface is 5.17%. The artificial compound eye FOV modeling establishes a theoretical basis for further study of the target detection and tracking theory of compound eye imaging and has a guiding significance for the designing of multi-aperture FOV artificial superposition compound eye systems.

A measuring method for liquid diffusion coefficients(D) was proposed by an asymmetric liquid-core cylindrical lens combined with an feature extracting method of optical images in real time automatically. Based on the Software Development Kit provided by a CMOS camera used, the application codes were programmed to extract and analyze the features of the brightness and width of a diffusion image. On the image features, the focal position corresponding to a specific liquid layer with a certain refractive index was found out, and the curve of focal positions varied with diffusion time was recorded automatically. Finally, the diffusion coefficient was calculated by using Ficks second law on the acquired experimental data. With the proposed method, the diffusion process of ethylene glycol with pure water was researched at the room temperature (25 ℃) and the measured diffusion coefficient (D) is 1.164×10-5 cm2/s, the relative error is only 0.34% that of the literature value. As compared with traditional direction observation method, the obtained results demonstrate that the method avoids the error caused by reading focal position with human eye, implements measurement automation and is characterized by higher measuring speeds and accuracy, shorter computing time and stable measuring results.

To control and compensate the thermal aberration of objective lens accurately, a special three lens integrated experiment optical system was designed, and the calculation method for the thermal aberration was verified based on the designed system. Firstly, thermal aberration simulation method and corresponding verified experiment were introduced. Then, a series of experiments were carried out in different thermal load conditions and comparison of experimental and simulated results were also presented. Finally, combining experimental and simulated results, asymmetric aberrations and focus drift trends of the optical system under a certain thermal load were analyzed, and transient properties of thermal aberration were obtained. The results show that the ratios of RMS(Root Mean Square) values of thermal aberration from the experiments and simulations are 1∶3.75∶9.00 and 1∶4.01∶9.01 when the thermal load ratio of the optical system is 1∶4∶9. The data suggests that the thermal aberration is proportional to a heat load it suffers. For transient thermal aberration, simulation results show that stable time of the best focus position is less than 450 min whereas the stable time of Z4 and Z11 are 48 min and 9 min respectively. The stable time of best focus is much longer than that of asymmetrical aberration. Thermal aberration properties obtained through the three lens integrated optical system provide references for thermal aberration reduction and calibration strategies both for lithography objective lenses and other similar optical systems.

A cross-referenced image quality assessment method for laser stripes was proposed to detect image quality in laser-aided stereo vision measurement. The intensity profile of laser stripes in a single image and the correlation of the same laser stripes acquired in left and right images were analyzed. Then, the definition of the images was characterized by grayscale profile gradients and a model of cross-referenced image quality assessment was proposed by taking both the single image quality and the correlation quality of left and right images into account. To determine thresholds of quality coefficients, the effect of noise on laser stripes extraction error was analyzed and simulated, and the quality coefficients of single image QL, QR belongs to ［0.2, 1) with the extraction error of less than 1 pixel were determined. By projecting the lasers onto different surfaces, the correlation quality coefficients of left and right images QLR were determined to be ［0.8, 1). Finally, experiments were performed in a forge workshop, and the reconstructed results of forgings heights are 1 747.0 mm and 491.3 mm. Experimental results show that the image quality coefficients of clear laser stripes conform to the thresholds, while the image quality coefficients of the laser stripes interfered by noise are deviated from the threshold. It concludes that the proposed method of image quality assessment reflects the defects in images of laser stripes very well.

When machine vision technology is used to detect the surface defects of parts with omnidirectional curved surface characteristics such as ‘O’ sealing rings, it shows a poor consistency of surface imaging. To achieve the full-automatic and reliable detection of surface defects of ‘O’ rings used in aerospace systems, the curved surface imaging theory and the surface defect detecting methods of ‘O’ rings were investigated. Firstly, the surface of ‘O’ ring was divided into small pieces like small grids. Based on the bidirectional reflectance distribution function of surface pieces, the radiation strength calculation formula of surface pieces was derived under the condition of point light irradiation. Then, the radiation strength calculation method of surface pieces suitable for the space continuous light irradiation was obtained through a hemisphere integral. Finally, combining with the ‘O’ ring surface equation, the imaging theory of ‘O’ ring surface was established and the imaging and detecting methods for ‘O’ ring surface defects based on three lens & camera units were proposed. The imaging experiment results of the segmental arc surfaces of ‘O’ rings indicate that the theoretical brightness distribution is consistent with the actual brightness. The average brightness error corresponding to the vertical lens & camera unit is 6.8 and its standard deviation is 12.6. The maximum average brightness error corresponding to the gradient lens & camera units is 19.4 and its standard deviation is 10.3. The defect detecting experiment results show that the proposed method detects reliably the defects in any location of the surface of ‘O’ rings and the proposed detecting system implements the automatic detection of the sealing rings in aerospace systems.

For the higher time consumption, complex constructs and lower detecting accuracy of microbia detection, this research presents a fast, simple microbial detection system with a low detection limit. Combining fluorescence marker, filter membrane, laser scanning and fluorescence imaging technologies, a rapid scanning system for the trace microbia detection was designed. On the basis of the scanning lens with a large field of view, a large depth of field, and a longer focal length, the fast detection for a microbial sample was implemented by combined with a 2D scanning galvanometer. Basic principles of the detection system were described and the optical system was designed and optimized. The collected signals were analyzed, and the performance of the detection system was demonstrated and tested. Experimental results show the detection system accurately detects microbial samples ranged from 10 cfu/mL to 2.5×103 cfu/mL in 10 min, and the detection limit is 10 cfu/mL. The system meets the demands of real-time detection of medical high-purity water and other sensitive detection situations.

A novel fiber-optic sensor with dual Fabry-Perot(F-P) cavities was reported to detect the Acoustic Emission(AE) signals induced by the damage in composite and metal materials. A sensing model for detecting the AE signals of the fiber-optic sensor was established based on the multi-beam interference principle of the low finesse F-P cavity. The operating mechanism for stabilizing the quadrature-point of the dual F-P cavity sensor was analyzed, and then the fiber-optic sensor with a dual F-P probes was designed and manufactured to maintain the stability of the quadrature-point. The operating performance of the designed sensor was verified by two types of experiments on simulating AE signal detection and thermal stress interference experiments. In the first experiment, two kinds of AE signals were generated by shock vibration and breaking pencil leads and they were detected and compared with a piezoelectric sensor and a optical fiber sensor. The test results show that the optical sensor successfully measures the simulated two kinds of AE signals and it possesses a sensitivity of 12.9 nm and a frequency response of 30 kHz. In the second experiment, the stability of operating points of the sensor was detected, and the results indicate that control mechanism of the dual F-P cavities ensures the sensor to operate at the quadrature-point, and overcomes the signal attenuation of the sensor outputs.

To measure the sound field distribution accurately, a direct sound field measurement method based on a laser vibrometer is researched. Based on the fact that the air refractive index is changed periodically when the sound wave propagates in the air, the vibration velocity caused by the periodically changed refractive index occurred in laser passed through a sound field can be measured by the laser vibrometer. As the projection of the sound field in the direction of the laser is the vibration velocity, the direct measurement of sound field can be completed by measuring the projection of the sound field in different directions and reconstructing the complex amplitude distribution of the sound field using inverse Radon transform. The amplitude distribution and phase distribution of the vibration velocity caused by a 2 kHz sound field are measured experimentally, and the sound pressure amplitude distribution and the instantaneous sound pressure distribution are reconstructed. The measurement shows that the spatial resolution is 2 cm, the measured maximum sound pressure amplitude is 0.026 Pa, and corresponding sound pressure level is 62.3 dB. Experimental results indicate that the direct sound field measurement based on the laser vibrometer is feasible, and it solves the problem existing in the sound field measurement by using microphone arrays.

On the basis of carbon fiber composites with advantages of high specific strength and high modulus, a structural design scheme of the carbon fiber composite primary force-taking structure combined with several layer element modules was proposed for a principle bearing cylinder in satellite and rocket structures. A primary force-taking structure was designed based on composite laminate structure theories and section beam theories. The designed primary force-taking structure was molded in layering by carbon fiber composite material piles to remove the couple stiffness between the layers and was formed with a thin skin+“几”stringers +”T”-shaped cross-rib truss structure to improve its loading abilities. The primary force-taking structure was simulated numerically. The results indicate that the strength and stiffness of the designed structure meet design requirements. Finally, the primary force-taking structure was assessed by experiments. The verified results show that both the experimental results and simulation results are consistent. As compared to the same type of aluminum structure, the deadweight of the designed structure has reduced by 30%, which means that the proposed lightweight design method is effective.

There are axis errors in orientation processing of a digital zenith camera. This paper focuses on how to compensate the axis errors among optical axis, rotation axis and vertical axis. To calculate the astronomical coordinate of the vertical axis in a measuring station position, two star images in an opposite direction were used to calculate the coordinate of the rotation axis. Thus, the compensation between optical axis and rotation axis was avoided. A two-axis tilt sensor was used to measure the inclination between rotation axis and vertical axis and the position coordinate of the vertical axis could be obtained by compensating the angle error of the rotation axis. As the turntable error could impact on the coordinate of rotation axis and tilt compensation, the influences of turntable error on the calculation of rotation axis and tilt compensation were analyzed, respectively and the range of turntable error was gained. The experimental data demonstrate that when the absolute value of the latitude of the measuring station is below 88.3°, the turntable should be below 35″. Otherwise, the turntable error should be below |1 166.8cosδ|″. The precision of rotation angle should be improved to eliminate the influence of turntable error when the coordinate of the measuring station is calculated in the opposite direction.

A beam combination method based on the optical coating was proposed for three light paths to design a high power infrared laser multi-band beam combination system. As the ZnSe used as substrate materials of a beam combination mirror was easy to be susceptible to thermal effects, the optical-mechanical-thermal coupling analysis was used to research the influence of coupled thermal effect caused by laser irradiation in different wave bands on laser wavefront distortion of each band under the fixed temperature boundary conditions. Meanwhile, the thermal effect caused by beam biased was analyzed qualitatively. Simulation results show that the wavefront distortion (Root Mean Square, RMS) of each band laser is able to satisfy the design requirements(the wavefront distortion needs to be less than λ/8). The high-frequency component increases the distortion of a long wave laser, but it still meets the system requirement. The axial temperature difference reaches the equilibrium after 35 s, so the main factor of wavefront distortion is the surface distortion of every mirror. An experimental testbed was set up based on the analysis results, and the experiments were carried out on a 400 W short wavelength laser. The surface data were obtained and compared with that of the simulation, and the results validate the feasibility of the proposed analytical method.

An over-sized monolithic holographic lens with a micron plane precision of 0.4 μm is fabricated on a quartz substrate well polished by Micro-electro-mechanical system(MEMs) process. Some improved methods are used in this series process, such as the stepper projection exposure with a resolution of 0.2 μm and the stitching method, the improved ICP ( Inductively Coupled Plasma)dry etching technology for a quartz, the physical cleaning method designed especially and a lot of other supporting processes. The ideal surface shape curve of cross section for the hologram lens is a piecewise parabola. A single lens is horizontally arrayed by 23 column cell structures with a width about 2.966 mm. Because of the difficulty in practice, the 4-step structure with an equal depth and an unequal width is used to fit it. At last, single piece square hologram lenses with the area more than 68 mm×68 mm are obtained at a 4 in(10.16 cm)circle piece. The step profiler, scanning electron microscope, high-powered and resolution optical microscope are used to measure lens accuracy at different stages. The results indicate that the lens has a plane precision of 0.4 μm, vertical precision of 30 nm, and shows a good vertical wall shape and etching uniformity. This process technology can be used for small batch production, and the cost is moderate. It is suitable for processing the same grade lenses with the size of 6 in(15.24 cm), and also for processing the sapphire substrates.

To describe the behavior characterization of a MEMS(Micro-electro-mechanical System) resonator with a large amplitude accurately, a lumped parameter model of the nonlinear stiffness MEMS resonator was established and an innovative method to measure and characterize the nonlinear coefficient of the resonator was presented. A closed loop control circuit was designed and manufactured based on a Phase Locked Loop (PLL) and an Automatic Gain Controller (AGC) and the quantity relationship between the vibration amplitude, vibration frequency, and the nonlinearity coefficient was given. Finally, according to the the given relationship, the natural resonant frequency and the stiffness nonlinear coefficient were measured by curve fitting in both of decaying mode and stable mode. The results indicate that the repeatabilities of the two measured results are 18.6×10-6 and 1.5%, respectively. With the measured amplitude self-decaying curve, the residuals were measured by an ideal second-order system resonator model and a stiffness nonlinear resonator model, and the results show that residuals from the latter is less 9.5% than that of the former. The results demonstrate that the stiffness nonlinear resonator model is more close to the actual situation and verify the validity of the measured nonlinearity characteristics by the proposed method. Moreover, the temperature characteristics of nonlinear coefficient and natural resonating frequency were also investigated. The temperature coefficient of the natural resonant frequency is -0.487 Hz/℃, and the goodness of linear fitting is up to 99.964%.

A 3D semi-automatic assembly and adhesive dispensing system was designed and constructed for assembling and bonding the trans-scale parts of micro-tube and micro-sphere together in a three-dimensional space. The system mainly consists of a stereo microscope, two zoom microscopes, a Light Emitting Diode(LED) backlight, a pL class glue dispenser, three micromanipulators and three micro-part grippers. A method to transform the magnification of the zoom microscopes was adopted to detect the trans-scale features of the micro parts from several millimeters to several micrometers. An assembly and adhesive dispensing strategy based on people guiding and micro visual servo technology was proposed and used to align, insert and glud the trans-scale micro parts together fast and accurately. The assembly experiment was carried out by the developed system to validate the method and assembly accuracy. The experimental results show that the position alignment error is less than 1 μm and the pose alignment error is less than 0.5°。The system assemblies and bonds the micro-tube without diameter of 10 μm and the micro-sphere with a hole diameter of 12 μm together and meets the requirements of assembly accuracy and success rates.

The dynamics equation of a space parallel mechanism was established on the basis of Newton-Euler approach to explore the rigid-body dynamic modeling of the 4-UPS-UPU 5-DOF parallel mechanism. The forces of driving limbs and a moving platform for the parallel mechanism were analyzed, and the rigid-body dynamics equation of 4-UPS-UPU parallel mechanism was derived by Newton-Euler approach. Then, Matlab was used to calculate numerically the driving forces for the moving platform with or without loads, and the driving forces of five driving limbs were obtained respectively. Finally, the ADAMS was taken to perform the dynamic simulation for a virtual prototype of the parallel mechanism. Research results indicate that when the parallel mechanism moves a circle with a radius of 0.01 m in the Z axis at a 0.95 m plane, the driving force of the limb 1 is the maximum, the maximum value without the load is -760.6 N, and that with the load is -889.7 N. The theoretical calculation results are greatly consistent with that of virtual prototype simulation, which verifies that the rigid-body dynamics analysis is correct. The research not only provides a theoretical basis for manufacture of 4-UPS-UPU parallel mechanism, but also suggests a way to the rigid body dynamics modeling for other spatial parallel mechanisms.

A control scheme for the electromechanical actuator systems in air-to-air missiles was propose based on main modal of a transmission mechanism. and a double-loop control system was designed by matching mechanism dynamic characteristics and main modal method. Firstly, a connecting rod from crank slider mechanism was analyzed and the high order multi-degree-of-freedom dynamic model was simplified into two-degree-of-freedom free rotor model by matching mechanism dynamic characteristics and the main modal method. Then, the two-degree-of-freedom model and control system were modeled jointly to analyze the influence of main resonator model on the cutoff frequency of open-loop system with or without damping states. By which it makes sure that it is more reliable when the system is analyzed at the undamped state. Finally, a modal test was performed for the transmission mechanism and the feasibility of modal dynamic characteristic matching method was confirmed. A performance verification test was done for the electromechanical actuator system containing main model on a whole trajectory flying platform according to the data from wind tunnel measurement. The results show that the first order torsional frequency of clamped support control surface is 1 210.47 rad/s, and that of the transmission modal(consist of the control surface) is 1 148.17 rad/s, which is consistent with the theoretical result of 1 180.0 rad/s. The external loading verification of whole trajectory flying platform indicates that the actuator system meets the demand of performance index when the maximum hinge moment is 6.8 Nm, the elastic angle of control surface is 1.1°and the actuator maximum error of instruction from a tracking autopilot is ±0.1°.

As the robot based on a directly serial leg mechanism has great walking inertia and a larger weight/load ratio, a novel series-parallel hybrid quadruped walking robot is presented. The robot consists of a load platform and four serial-parallel legs. The kinematics characters of serial-parallel legs for the robot are analyzed. Each leg is connected by a hip, a thigh, a calf sequentially and the hip joint is a 3-RRR parallel mechanism. By considering the least energy-consuming posture as the optimal posture, the forward kinematics and inverse kinematics are derived based on vector method and they are verified by ADAMS and MATLAB softwares. The velocity Jacobian matrix and acceleration matrix of the serial-parallel hybrid leg are obtained based on vector method and differential transform method and their singularity is analyzed, then the workspace of the hybrid leg is figured out by MATLAB software. Calculations show that when the linkage diameters of the hip and thigh are 22 mm and 50 mm and the angle of knee θ4 is within ［105°, 155°］, the workspace of the hybrid leg is part of a sphere, whose radius of the inscribed circle R is 400 mm and altitude H is within［500 mm, 900 mm］. This research has great significance to a series of further studies on stiffness analysis, dynamic properties, mechanism optimal design and system control of the novel series-parallel quadruped walking robots.

To accurately analyze dynamic characteristics of pointing mechanism of a CO2 space spectrometer, a bearing finite element contact analysis model was established according to the bearing structural parameters in this paper. The displacements with different loads for an axis were calculated, and the nonlinear stiffness curve for the bearing was obtained by the polynomial fitting for calculated results. In finite element dynamic analysis model of pointing mechanism, a spring unit with corresponding stiffness was used to replace the bearing structure, and the dynamic characteristics of the pointing mechanism were obtained by analysis of infinite element frequency response. The simulation experiment shows that the surface shape of mirror is 19.23 nm and 19.27 nm in optics axis and meridian direction at a static condition, which satisfy the design requirement of λ/30(RMS, λ=632.8 nm) and all base frequencies in 3 directions are over 100 Hz. Moreover, mechanical vibration experiments also verify that all base frequencies in 3 directions are over 100 Hz and the surface shape accuracy of the mirror is λ/35. The calculation results agree well with the experimental results. It concludes that the analysis method with nonlinear contact solves the bearing stiffness accurately, and the static/dynamic performance of pointing mechanism meets design requirements.

A new diamond micro-displacement magnifying mechanism using eight cross-spring flexural pivots was presented for light beam acquisition, tracking and pointing in space optical communication. The piezoelectric ceramic was taken as the actuator, and the cross-spring flexural pivots as the centralized flexural elements. Every two pivots were set in one axis, and the coaxial set of two pivots on each corner of the diamond configure could reduce the axis draft and improve the rigidity and stability of the mechanism. Through analyzing the operation principle, the magnifying ratio and the sensitivity of the mechanism were derived. According to the stiffness model of the cross pivots, the theoretical stiffness of the displacement mechanism was deduced. Finally the displacement mechanism was modeled by finite element method and its kinematics, statics and dynamics were simulated. A prototype was established and tested. Some characteristic parameters were derived, such as the structure stiffness and the eigen frequency of the mechanism. The test results show that the magnifying ratio is 1.905 with the error of 2.2%, the stiffness is 18.21 N/mm with the error of 0.2% and the eigen frequencies is 8.8 Hz with the error of 5%. The experimental data verify the feasibility and effectiveness of proposed design and show that the mechanism is suitable for high precise spatial micro-displacement fields.

To improve the compensation accuracy and robustness of a thermal error compensation model for Computer Numerical Control(CNC) machine center in practical engineering applications, a selection method for the optimal speed of CNC machine center was presented. For the Z-axis of Leaderway V-450 CNC machining center, several batches of experiments were carried out at a variable speed spectrum and a constant speed by controlling the spindle in an idling condition. Then, fuzzy clustering method combined with the gray correlation was used to select the temperature sensitive point and establish multiple linear regression models. Finally, by analysis of the model predictive effect in different type speeds and comparison of the model predictive effect in the same speed type, a selection method for the optimum spindle speed of CNC center in modeling of thermal error compensation was given. The research results show that thermal error compensation models established by different spindle speed regimes based on the international standard have great differences in the thermal error predictive effect of machine tools. It suggests that the compensation model based on optimum spindle speeds selected by practical engineering application will provide a good prediction effect.

To decrease the single installation point acceleration response RMS(Root Mean Square) of a micro-satellite for earth observation, this paper presents a topology optimization method for satellite primary load bearing structure to minimize the acceleration response RMS. Firstly, the design scheme of the entire satellite is analyzed by finite element simulation. The results suggest that the acceleration response RMSs of some component installation points are too large and failed to meet the design requirements. By sensitivity analysis, it points out that the backplane is a key element for the acceleration response RMS of Gaussian random vibration. By adopting the method of topology optimization for a continuous body, the satellite model is optimized and a new model that fully meets the design requirements is obtained by taking the acceleration response RMS as an objective function and the volume as a restrict condition. Finally, both the finite element simulation and Gaussian random vibration are performed. It indicates that the parameters of new satellite primary load bearing structure meet design requirements, and among them, the acceleration response RMSs of some key component installation points like star sensors, storage battery and source controllers have reduced at least 23.3%, 10.6%, 11.3%, respectively. These results verify the feasibility and effectiveness of the proposed optimized topology.

To obtain the error of gear characterized curves from gear topographic inspection, a method of gear profile orthogonal distance regression was proposed. Some algorithms involved in the method were researched, such as the matching of a real gear profile with a theoretical gear profile, the calculation and decomposition of topographic error and the evaluation of profile character line error. Firstly, topographic points were obtained by coordinate measurement, and the nonlinear equation including parameters of theoretic profile was established. Then, the nonlinear equation was solved to get the optimal parameters of the regression gear profile and to obtain the theoretical gear profile matching with the real gear profile. Here, the orthogonal distances from measuring points to the theoretical gear surface were calculated as the topographic errors. Finally, based on the multi-degrees of freedom theory for gear deviation, the gear profile error and the helix error were evaluated by local degree regression and holistic degree regression. The coordinate measuring points on a cylindrical gear were used as an example for error calculation. The results are well consistent with the characterized curves measurement using a coordinate measuring machine, and the difference is within 0.5 μm. These results show that the proposed gear profile orthogonal distance regression is reasonable and effective, and it can be applied to the gear inspection using coordinate measuring machines.

For investigating on the surface morphology variation of structure ceramic materials and its effect on the friction characteristics during friction, the relationships between contact and mechanical were analyzed in friction process. Meanwhile, the friction characteristics of Si3N4 ceramic samples machined by rotary ultrasonic grinding, such as friction surface morphology and friction coefficient were studied with experiments. First, according to the contact characteristics and material properties, the calculation formula of the total load was deduced based on fractal theory. The friction coefficient fractal model was also established on the basis of above. The analysis results shows that the relationship between friction coefficient and surface profile fractal dimension after friction is similar to the normal distribution curve, when the initial surface profile fractal dimension is 1.4, 1 45, 1.5 and 1.55 respectively. Then with surface to surface contact friction experiments of Si3N4 ceramic sample machined by rotary ultrasonic grinding, surface topography and friction coefficient variation after friction were investigated. And the influence factors on the friction coefficient were also analyzed. The results indicate that micro-cracks are the notable feature of the surface morphology for Si3N4 ceramic friction. The temperature of 160℃ is the inflection points of fall and rise for Si3N4 ceramic friction coefficient. The friction coefficient is the maximum when the applied load is 360 N and reciprocating frequency is 80 Hz. It concludes that the machining surface morphology control improves the wear resistance of structure ceramics.

To monitor the image quality in real-time, a binary spatial dependence model of pixel wavelet coefficients was established, and the model was used to realize the image quality assessment by the no-reference image method. Firstly, the RGB image was mapped into a HSV(Hue, Saturation, Value) space and was processed by wavelet decomposition. A binary space dependent relationship model of wavelet coefficients was established, in which the generalized Gaussian distribution was used to fit the binary joint distribution of wavelet coefficients. Then, the correlation between the binary spatial interdependence relationship and the image quality was analyzed, and the no-reference image quality assesment index was obtained. Finally, the proposed image quality assessment indexes were studied and tested comparatively based on the TID2013, LIVE and CSIQ databases. The results show that the image quality assesment index based on the spatial dependency can be used to classify the image distortion degree accurately, and the classification accuracy rate reaches above 96%. It concludes that proposed no-reference image method based on the spatial dependency achieves accurate image quality classification.

The electronics system in a remote sensing camera will generate V/Q nonlinearity and DN/V nonlinearity in signal conversion processing and both of them effect the Modulation Transform Function(MTF) of the sub-imaging system. This paper focuses on the generation mechanism of two kinds of electronic nonlinearities and the effects of the nonlinearities on the MTF and proposes a discriminant method for the electronic nonlinearities. On the basis of the generation mechanism, the V/Q and DN/V nonlinearity theoretical models are established, their effects on the MTF of the camera are researched and a simulation experiment is performed. Experimentl results show that the MTF falls with electronic nonlinearity from 0.55 under a normal state to 0.47, and it also changes with illumination. Finally, a method based on combination of a video response curve and a Photo-response Non-uniformity (PRNU) noise curve is proposed to distinguish the V/Q nonlinearity and DN/V nonlinearity. The simulation is put forward and the feasibility of the proposed method is verified。 The research provides strong supports for the design, improvement and nonlinearity compensation of remote sensing cameras.

As traditional sliding window detectors need to search the whole image by exhaustive method, a visual attention mechanism-aided target detection model by the particle window is proposed to reduce the calculational load while containing high detection accuracy. This model takes the target saliency as prior information of searching process, and then extracts the region of interest containing true target position by the “Image Signature” saliency map generator and entropy threshold. By uniformly drawing particle windows in an image range corresponding to the saliency targets with Monte Carlo sampling, the local region is treated as candidate detection points, thus resampling is carried out according to corresponding particle windows response. This strategy only focuses on the areas where the objects are potentially present and avoiding the tradeoff between accuracy and efficiency resulting from searching steps. A multi-stage classifier with Adaboost+HLF and SVM+ HOG is established, the former is applied to once-over and the latter is used to locate precisely. The target detection model proposed is compared with the traditional sliding window method and particle window method, and the results show that the Receiver Operating Characteristic(ROC) curve by proposed method contains the area to be larger than that of the other methods and the time consuming is only 1/3 to 1/4 that of the sliding window method and 1/2 that of the particle window method. It increases significantly detection speeds at maintaining high precision detection speed and achieves fast and accurate target detection.

To effectively extract the line features of an industrial CT(ICT) image, a feature extraction method based on second order Wedgelet decomposition was presented. Firstly, the definition of the Wedgelet decomposition was introduced. According to the different constitutions of second-order Wedgelet basis functions, they were divided into three kinds(same side type, neighbouring type and apart type). Depending on the spatial relationships of different kinds of second order Wedgelet basis functions, the second order Wedgelet rapid decomposition algorithm was designed. Then, based on the proposed algorithm, candidate line features at different mono-scales were extracted respectively. Finally, considering the multiscale quadtree structure, the line features were fused to get the final extraction result. The actual ICT images were used to an experiment, comparative test results show the feasibility and advance of the line features extraction method based on second order Wedgelet rapid decomposition. For applying to the ICT images, the method not only extracts effectively interest line features, but also lays a solid foundation for the feature description of the other types images.

A novel independent component feature separation based on Spatial Down Sample(SDS) was presented for solving the long run-time defection of traditional Independent Component Analysis(ICA). Small windows were obtained by gridding the two-dimensional spatial space of a hyperspectral image. In each window, the distance between the central pixel and around pixels was measured by spectral similarity and the around pixels whose distances were smaller than the threshold value were discarded. The projection matrix was calculated by FastICA with the central and the around pixels whose distances were larger than the threshold value. The feature separation ICA components were achieved by projecting the original hyperspectral image using a project matrix. The performance of traditional ICA and SDS~~ICA were compared. The influences of threshold values, window size values and the initial projecting matrix on the feature separation performance and run-time of SDS~~ICA were studied. Experiment results show that SDS~~ICA has the similar feature separation performance with the traditional ICA and its run-time has reduced above 30% under moderate threshold values and insensitivity window sizes. The novel method can be widely applied in the fields of hyperspectral feature extraction, data reduction, target detection etc.

As human eye perception for the brightness accords with the Webers law, this paper uses the log Gabor filter to simulate the human eye perception for an image and proposes a new log Gabor Weber characteristics to keep the structural information interested by human for different scales. To assess the image quality more effectively, a new image quality assessment method was proposed by using log-Gabor Weber feature. The log-Gabor filter and Webers law were used to obtain a new feature named log-Gabor Weber feature (LGW). Firstly, the distorted image and reference image were transformed from the RGB color space into a YIQ color space to separate the luminance component and the chromatic component. Then, the LGW feature and gradient feature were used to calculate the distortion of luminance component. Furthermore, the distortion of chromatic component was integrated to get the local similarity map between distorted image and reference image. Finally, a modified CSF pooling strategy was applied to the overall local similarity map to obtain the final image quality index. The experimental results on three benchmark image databases, LIVE, CSIQ and IVC, indicate that the proposed method owns a good consistency with human subjective perception and it has a more stable performance as compared with other state-of-the-art methods. The weighted Spearman Rank Order Correlation Coefficient(SROCC), Kendallrank-order Correlation Coefficient (KROCC) and the Pearsonlinear Correlation Coefficient, PLCC) values on three databases by the proposed method are 0.949 8, 0.802 6 and 0.943 8, respectively, which notably outperform other methods.

The general pipeline architecture units and corresponding structures were proposed. It overcomes the problems that the hardware architectures consisting of delayers, selectors and multiplying units based on 3D DCT/IDCT(Discrete Cosine Transform and Inverse Discrete Cosine Transform) should use a lot of devices independently and their different blocks are not easy to be integrated. Firstly, based on the theory of 3D DCT, universal pipeline algorithm architectures compatible with positive and negative transformations were proposed. The delayer-group models by reusing delayers and selectors were set up to allow the models to be integrative and nested. Then, unit device-saving pipeline architectures and the corresponding whole pipeline architecture of 3D DCT were proposed. Finally, video signals with different formats and size blocks were processed by using this device-saving 3D DCT/IDCT pipeline architectures proposed. The experimental results indicate that the reduce ratio of number of delayers and selectors increases obviously as block size increasing by using our device-saving algorithm. When the block size reaches 64×64×64, the used number of delayers and selectors reduce by 54.7% and 44.5% respectively. It shows that the proposed method reduces the used number of delayers and selectors, meets the demand of the hardware requirements for reducing costs, improves the energy efficiency, and facilitates the integration of different block sizes.

For a panoramic sea image with complex backgrounds and the sea-sky-line shows as a nearly circle, this paper proposes a panoramic sea-sky-line extraction algorithm based on fractal dimensions and improved Hough circle transform. It firstly calculates the fractal dimensions of the panoramic sea image by blanket-covering method, then extracts the images of panoramic acquisition devices and other equipment to eliminate their adverse effects on sea-sky-line detection based on these fractal dimensions. As the traditional gradient Hough circle transform can not give out a correct solution when it is used to extract the panoramic sea-sky-line, an improved Hough circle transform algorithm is put forward. 400 frame panoramic sea images extracted in different conditions are processed. Experimental results show that this proposed algorithm effectively extracts the circle panoramic sea-sky-lines under conditions of ideal background, lower contrasts images and the sea-sky-line with partial loss or severe breaking and its detection accuracy reaches 95.75%. The applicability and robustness of the proposed algorithm are excellent.