ing at the three-dimensional inversion problem of high power laser multi-pass amplification, we propose two inversion methods. The first method is a modified gain iterative algorithm based on the curve fitting method of input-output integral energy. The second method is a forward iterative algorithm based on the modified input pulse. In the four-pass amplification with gain distribution, the two methods are verified by numerical simulation. The results show that the two iterative algorithms are effective and feasible, and the three-dimensional intensity distribution of spatio-temporal separation of input pulse can be obtained. The calculated output pulse is basically the same as the demanded value. The relative deviation of the output energy is less than 10 -7. The relative deviation of the power waveform obtained by the first method is less than 1%, and this value is less than 10 -6 for the second method. The spatio-temporal evolution distortion caused by the saturation effect is solved. The first method relies mainly on the consistency of the forward and inverse model, which is relatively straightforward. The second iterative algorithm introduces a feedback factor, and has high precision and strong expansibility.
.ing at the problem of the ship detection with a low accuracy in the offshore and inland river scenes, a method based on shortwave infrared multispectral remote sensing images is proposed to realize water segmentation and automatic detection of ship. Based on the low reflectance characteristic of water area in the shortwave infrared frequency range, the water area is rapidly and accurately extracted from the images by using the threshold segmentation and morphological processing. Then, the image chips of candidate targets are extracted by using the visual saliency model for searching the targets in the water areas. As for the possible existence of phony targets, the gray-scale distribution histogram is proposed to describe the characteristics of gray-scale distribution of the target chips, which are combined with the gradient direction information to eliminate phony targets by the method of threshold constraint. The results show that the proposed method can efficiently detect the ship targets with different sizes in offshore and inland rivers. 279 candidate targets are obtained after the saliency detection and 138 of 142 true targets are detected after the target discrimination step. The false discovery rate is less than 6% and the recall rate is higher than 97%.
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