Abstract:A new method for outdoor direct measurement of the effect of sun stray light on a camera is presented. When the method is used, the lowest threshold of Point Source Transmittance (PST) can be up to 10-5 which is suitable for the stray light test of large aperture optical systems. The cost of the test equipment is far lower than that of a professional laboratory PST test equipment. The stray light test equipment includes a top opening plant, shutters, adjustable angle tooling, a baffle, a mechanical arm and a camera to be tested. The camera to be tested is placed on the adjustable angle tooling and the shutters are placed on the camera hood. During the test, the sun is shining directly into the camera. According to the response of the detector in the camera, the effect level and distribution of sun stray light on the camera can be evaluated.

Abstract:In the development process of a spaceborne laser range finder, how to test the performance indexes of the range finder on the ground is critical. According to the operation principle of a pulse laser range finder, a high precision dynamic testing system based on the photoelectric time delay method is designed. The system error which may affects system precision is analyzed. Finally, the measurement of the ranging accuracy of the laser range finder is realized. Compared with the traditional testing method, this method has the features of large dynamic range and high precision. The experimental results show that the testing system has its simulation range of 15 m to 30 km and its simulation accuracy better than 0.15 m. Because of easy operation and strong practicability, the system can meet the testing needs of all kinds of current laser range finders.

Abstract:Dynamic infrared scene simulation technologies play important roles in the performance evaluation of infrared imaging, tracking and guided weapon systems. The infrared scene simulation technology based on Digital Micromirror Device (DMD) is of most research value among infrared scene generation schemes. The gray modulation principle and operation mode of DMD are presented. On this basis, the DMD driver based on TI's 0.7 XGA DMD driver development platform is designed. The contrast of the infrared image is improved by magnifying the original image. Finally, a scheme for improving DMD projection frequency is proposed according to the integration time of detector output signals and the frame synchronization signals. The contrast of the gray level image projected by using this scheme is improved. The infrared imager can collect distinct gray images. Moreover, the display time of each gray image is reduced to 1.12 ms which is improved greatly compared with the 7.87 ms of conventional ways.

Abstract:The logic design of timing driving, video acquisition and temperature acquisition is realized for an uncooled infrared focal plane by using a CyconeIV FPGA from Altera Corporation. The logic module is packaged into two peripheral controllers which are connected to the Avalon bus as the peripherals of a Nios II processor. This logic design has been used in actual products. It has the advantages of less logical resource, lower power consumption, stable time sequence and easy portability for different focal planes.

Abstract:To detect dim and small infrared targets in real time, a real-time infrared target detection system based on DSP and FPGA high speed ping-pang cache structure is proposed. Taking a high speed cache structure as the core, the hardware system uses a region growing algorithm based on target characteristics to detect dim and small infrared targets. The experimental results show that the system has good detection effectiveness and high real-time performance for dim and small infrared targets. It can implement the real-time detection of dim and small infrared targets.

Abstract:Since high spatial resolution thermal infrared images can provide more details of target scenes, they are widely used in the fields of computer vision, medicine and remote sensing etc. Because it is usually more expensive to improve the performance of a thermal infrared camera, the super-resolution reconstruction algorithm is selected to improve the spatial resolution of thermal infrared images. The thermal infrared images to be reconstructed are obtained in the flight test over Zhoushan. The thermal infrared camera used is designed and equipped independently. The thermal infrared images are reconstructed by using the iterative back-projecting algorithm and the Projection onto Convex Sets Approach algorithm respectively. The experimental results show that both algorithms can improve the spatial resolution of thermal infrared images effectively.

Abstract:The images of remote infrared targets acquired by a phototheodolite in the background of sea and sky have the disadvantages of low contrast, nonuniform gray level and a large number of noises etc. This may affect the interpretation of the target in the image severely. For this reason, an infrared image enhancement method based on bit-plane slicing and adaptive rainbow pseudo-dolor transform is proposed. The experimental result shows that the pseudo-dolor image enhanced by this method is more colorful and saturated. The details and edges of the target are clearer. Particularly, different color gradations can be identified from the edges of the target. So, it is more fit for human's visual habit.

Abstract:The performance of β-FeSi2(n)/a-Si(i)/c-Si(p)/μc-Si(p ) HIT heterojunction solar cell is simulated and the parameters of each layer of the solar cell are optimized. The simulation results show that the performance of the solar cell can be improved remarkably by adding an intrinsic thin-layer and BSF to the FeSi2(n) /c-Si(p) solar cell structure. When defects are introduced and the parameters are optimized, the ultimate parameters of the solar cell are: VOC=647.7 mV, JSC=42.29 mA·cm-2, FF=75.32%, EFF=20.63%. The efficiency of the FeSi2(n)/c-Si(p) solar cell is improved by 2.3%.

Abstract:The original Near Infrared (NIR) spectral data inevitably contain a large amount of noise signals and data. So, before spectral analysis, it is necessary to preprocess the spectral data. The preprocessing of NIR spectral data mainly includes two tasks. One task is to de-noise so as to improve the robustness of the model and the accuracy of the prediction result. Another task is to compress the data for storage and modeling speed improvement. Traditional spectral preprocessing methods have their own limitations in these two aspects. The wavelet analysis method is used to preprocess the NIR data of apples. The Peak Signal to Noise Ratio (PSNR) and Normalized Correlation (NC) coefficient are selected as the evaluation index. Compared with the common Savitzky-Golay smoothing and multiple scattering correction, the wavelet method not only can compress spectral data effectively, but also has its superiority in noise removal and spectral detail preserving.