
The algorithm of spatial heterodyne interferogram matching on finite impulse response and multiple linear regression analysis is proposed based on the radiation transfer model and Beer-Lambert law. For object identification, we extracted the characteristic of potassium double resonance from analyze interferogram directly. Traditional finite impulse response digital filter processing method was adopted to eliminate background information and other interfered information which except from interference frequency information of effective target. By multiple linear regression analysis processing interference data of time-domain of before and after filtering, the optimal coefficients of time-domain filtering had been obtained. So that, interferograms of target signals and background signals were filtered directly. Finally, the signal of potassium double resonance was identified by the interferogram matching. In this algorithm, it’s not required measuring the spectrum and interference pattern of background, neither Fourier transforming of interferogram to access spectrum, and improved efficiency and increased inverting capacity of spatial heterodyne spectroscopy analysis remote sensing data simultaneously.
Aiming at several problems occurred in multi-target tracking, such as the moving targets interleaving or overlapping, and the target losing momentarily, an improved discrete continuous optimization for multi-target tracking algorithm is proposed. The method according to the principle of discrete continuous optimization for multiple target tracking, added speed constraints and ameliorated the original energy function, so as to achieve the purpose of constraint the trajectories form. Clustering strategies after global optimization is used to achieve the purpose of distinguishing different trajectories. The experimental results show that the algorithm has better robustness and can well realize multi-target tracking in complex image sequences.
To achieve robust target tracking in a highly dynamic scene, a single target tracking algorithm with multi-feature fusion in multi-scale models is proposed. The proposed models can adaptively fuse multiple features to achieve real time tracking in complex scenes. To tackle the problems of target significant deformation and occlusion, the proposed algorithm computes the confidence of the observation and uses it to update the reference models adaptively. The tracker is tested on ten representative sequences in a standard tracking benchmark. Compared with some other state-of-the-art algorithms, the results demonstrate that the tracking precision has been improved in the highly dynamic scenes with target significant deformation.
In order to deal with the problem of modal analysis of the single-link manipulator with end-effector payload, an integral equation is used to express the bending moment of the single-link manipulator with end-effector payload by using the method of materials mechanics. Then the integral equation is transformed into a partial differential equation that has the same expression and different boundary conditions as Euler-Bernoulli equation. The mode functions can be obtained by solving the partial differential equation. As the parameter of the mode functions, natural frequency of the single-link manipulator with end-effector payload is expressed by an equation. An iterative method to solve the natural frequency from the equation and an approximate expression of the natural frequency are given. The comparison result of real values and approximate values of the natural frequencies shows that the errors do not exceed 10-4 except the first natural frequency, and the errors are close to zero with the increase of the natural frequency ordinal.
Active Disturbance Rejection Controller (ADRC) is used in the current loop of a miniaturized electro-optical stabilized system. In addition to current loop, the method uses an improved auto disturbances rejection. The method uses classical adjust elements series connected with non-linear feedback adjustment to design control system. The frequency response data of a miniaturized electro-optical stabilized system show that the method can be applied in engineering field and the method is more adaptive than classical ADRC.
For reducing the effect of flexibility, backlash and friction, which are brought by the harmonic gear, a kind of multiple loops’ control method is proposed based on double speed loops. Double speed loops consist of speed loop in motor side and speed loop in load side. The speed loop in motor side is the inner loop and the speed loop in load side is the outer loop. The paper separately analyses the control performance of single speed loop and double speed loops in theory. Finally, the experiment results are used to validate the effectiveness of the control method based on double speed loops for inhibiting the nonlinear deadzone in the harmonic drive system.
In order to improve the static and dynamic characteristics of hanging-back box, the effect of different stiffeners distribution modes was researched. Combined with engineering practice of a hanging box with photoelectric load, ANSYS model was set up and eight kinds of suggestions were presented based on the static and modal analysis results. PROE was applied to set up the parametric model, which can achieve models with different distribution forms of stiffeners in a shorter time. ANSYS was applied to analyze the box with different stiffeners, and a compromise evaluation function was presented to help select the best way of strengthening. At last, considering the practical application of the box, the size of stiffeners was changed and a longitudinal stiffener was added. In conclusion, the static maximum displacement of the optimized box reduced from 0.029 mm to 0.013 mm, meeting the accuracy requirement and the fundamental frequency increased from 88 Hz to140 Hz avoiding the vibration frequency points including 80 Hz, 85 Hz and 100 Hz. The box has been used in a photoelectric device.
A kind of method of topology optimization design for the supporting structure was presented, which aimed at decreasing the acceleration response RMS value of the space cameras. Firstly, after analyzing the common various forms of the space camera supporting structure, a supporting pattern with the secondary mirror and the folding mirror fixed separately was determined according to the characteristics of this optical system. Secondly, a trussed supporting structure met the requirements on the acceleration response was designed, which directed by objective function of acceleration response RMS and in the meanwhile restricted by the volume fraction, the displacements of the secondary mirror with the influence of axial gravity and the first-order frequency of the supporting structure. Finally, the finite element analysis and vibration experiments show that the supporting structure could satisfy the requirements on the whole mechanics performance index of this camera. The fundamental frequency reaches 291.4 Hz, and the acceleration response RMS value is 5.08 g with 2 g RMS random load under the condition that the mass of this trussed supporting structure is not more than 4 kg. The design scheme of this trussed supporting structure could provide some reference to the other light-small space camera with the same type.
In order to achieve the deployable and segmented telescope’s coarse co-phase of the focus, this paper will take three segment mirrors to adjust the primary mirror surface. Firstly, a stepper motor and a linear motor implement to deploy the dynamic mirror within macro scale, i.e. μm magnitude. Secondly, piezoelectric actuator achieves the micro adjustment, i.e. nm magnitude. A three-degree of freedom platform made of three piezoelectric actuators can precisely adjust the segment mirrors’ tilt error and piston error. The test result shows that the flat mirror’s surface error is less than 0.5″by the three-degree of freedom platform adjustment. Testing the three segment mirrors optical system by the ZYGO interferometer, the result showed that it realized the confocal adjustment. This method for the segmented telescope’s coarse co-phase of the focus adjustment can be used for further surface error compensation to achieve fine co-phase of the focus.
Aiming at the problem of camera calibration of the linear array CCD camera vertical target, a filed self camera calibration method was presented. Firstly, the model of self camera calibration based on the principle of system measurement and the principle of optical imaging was built. And then, a kind of sub-pixel detection algorithm based on partial area effect was used to detect the target characteristic edge’s location in linear image. Finally, the least square was adopted to build the connection between image edge’s pixel coordinate and the corresponding edge’s real coordinate based on the function form of the self camera calibration model. Neither camera’s intrinsic and extrinsic parameters need to be evaluated nor the camera need to be separated from the system through the camera calibration process, so this method has high efficiency with reducing the complexity of calibration. Experimental results show that the proposed cameral calibration method has high precision to meet the demand for project application.
Workspace Measuring and Positioning System (wMPS) is a kind of large-scale system, which depends on the multi-station synergy to achieve the coordinate measuring, so the station layout optimization is a common but important problem. Station optimal topological geometry based on simulated annealing particle swarm algorithm was proposed. Firstly, the positioning accuracy, coverage area and cost were taken as objectives to establish the multi-objective optimization function. Secondly, particle swarm algorithm and simulated annealing algorithm were cooperated to find the best solution, and simulated annealing particle swarm algorithm optimization process was established according to multi-objective function. Finally, simulation analysis for layout optimization algorithm of 2~4 stations was performed. The results show that the proposed method has reliable stability and is able to quickly converge to optimal solutions.
Scattered light will cause the loss of system, damage the imaging quality of optical system and cause other hazards. According to the impact of scattered light of high reflective mirror in the optical system, the total integrated scattering method is put forward for measuring the total integrated scattering optic to get the ratio of the scattered light to the total reflected light. This method applies the theory of the total integrated scattered, considering about the photometric characteristic of integrating sphere. According to the principle of the method, a set of scatterometer is built, and the scattering of high reflective mirror is measured. After experimental verification, the result obtained by this scatterometer is very close to the consequence obtained by the scatterometer produced by Germany Laser Zentrum Hannover e.v. The values of Total Integrated Scattering (TIS) are both between 300 ppm and 500 ppm, which proves the feasibility of the self-made device.
Since rare multi-primary white LED, traditional Wavelength Division Multiplexing (WDM) visible light communication (VLC) system only has R, G, B three channels. In view of the WDM technology restricted by white LED device in VLC, a method of multispectral mixed light optical communication is proposed. According to the color characteristic of LED light, feature of multi-pulse position modulation (MPPM) and the approach of mixing light, a MPPM dimming modulation is designed for each channel, which uniforms the color and time domain that can realize communication and white light output in the meantime. A multispectral mixed light optical communication system is built using four single-color LEDs. The experimental results show that a white color, 5500K color temperature, is obtained when four channels parallel communication, and chromatic aberration is indecipherable for human eyes (CIE 1976 Δu′v′<0.005). Multispectral mixed light optical communication is feasible.
Aiming at refractive index homogeneity of space flexible optical polyimide membrane, it can be measured through reflected wavefront of the substrate for preparation of polyimide optical membrane, reflected wavefront of up-surface of the membrane before being released from substrate and the transmission wavefront after the membrane released from substrate. Compared with data measured by the prism coupling, the results show that the proposed method is efficient and reliable for refractive index homogeneity measurement of flexible membrane in fully-aperture.
To improve the laser induced damage threshold of dual-wavelength antireflection coatings which were deposited by ion beam sputtered for 1 064 nm and 532 nm, a certain thickness of the silica layer was deposited near the substrate and the air respectively to investigate the effect of the buffer layer and the protective layer on antireflection coatings for laser induced damage threshold. The laser induced damage threshold of different antireflection coatings was tested by a 1 064 nm laser system according to ISO 21254-2 standard. The experiment results show that compared with the coatings without buffer layer and protective layer, the laser induced damage threshold of the coatings with buffer layer, the coatings with protective layer and the coatings with buffer layer and protective layer are 65.4%, 66.7%, 119% higher respectively.