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Fang Y.-Q.,State Key Laboratory of Pulsed Power Laser Technology | Fang Y.-Q.,Electronical Engineering Institute of Hefei | Cheng Z.-D.,Electronical Engineering Institute of Hefei | Fan X.,Electronical Engineering Institute of Hefei | And 3 more authors.
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2015

The morphology algorithm has proved to have good performance in IR small target detection, an analysis for the process of the algorithm was done firstly, and combined with the real IR small target images, the factor that much unnecessary calculation in the process of the algorithm was found. So, aimed at promoting the real-time demand, a morphology method that based on variance-mark was proposed. The local variance of every pixel in the image was firstly calculated according to this method, and then the image was marked by the variance and the threshold qualification. After marking the image, the Top-hat operation was carried on the marked pixels by morphology algorithm. The theory analysis and the simulation demonstrated that the detection efficiency was promoted remarkably through the proposed algorithm; furthermore, the detection performance of the algorithm was also improved. ©, 2015, Chinese Institute of Electronics. All right reserved. Source


Fang Y.,State Key Laboratory of Pulsed Power Laser Technology | Fang Y.,Electronical Engineering Institute of Hefei | Chen W.,Electronical Engineering Institute of Hefei | Sun X.,State Key Laboratory of Pulsed Power Laser Technology | And 5 more authors.
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2015

Cloud is an important factor for the difficulty in air target detection and recognition. Based on the IR radiation of target and cloud, the effects of cloud on the target IR detection were analyzed. Firstly, according to the 4 different position relationships of target and cloud, the models for calculating the radiation difference of target and cloud that received by the detector were established, and then the calculations of the parameters in the model were discussed. Lastly, the simulation calculation was done as an example based on the model, and the results were analyzed. The results show that; in the band of 8-14 μm, the radiation difference of target and cloud has bigger value near the wavelength of 9 μm and direction angle of 50°, and smaller value appears at the longer wavelength and larger direction angle. The conclusion can provide the basis for the design of IR detection system. ©, 2015, Chinese Society of Astronautics. All right reserved. Source


Fang Y.,State Key Laboratory of Pulsed Power Laser Technology | Fang Y.,Electronical Engineering Institute of Hefei | Fan X.,State Key Laboratory of Pulsed Power Laser Technology | Fan X.,Electronical Engineering Institute of Hefei | And 6 more authors.
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2014

When to detect an air target in infrared, bird is a potential source of false alarms, its IR characteristics are similar to the target's. The way to calculate the signal of the bird and target on the detector was firstly discussed, and the effects of the IR system's focus position were specially considered. Secondly, the influences that the flight altitude, area and focus position of system have on the bird's signal on the detector were analyzed according to the obtained formula. The signal of the target was also analyzed through the same way. The results show that the bird and the target can not be discriminated by the signal characteristics. Lastly, the way to discriminate the bird and the target was proposed based on the velocity, and the formula of probability that the bird would be treated as a false alarm was deduced and the calculation examples were done. From the results, it can be seen that the bird can be eliminated largely by the differences in velocity. Source

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