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长波红外探测器经常被用于机载红外预警系统中,常受严重的非均匀性噪声干扰。为了校正探测器的非均匀性,补偿辐射响应非线性,提出了一种基于梯度场景的非均匀性校正方法。给出了探测器辐射响应非均匀性的观测模型;以标准黑体和梯度场景作为参考源,在理论上推导出校正系数表达式;利用原理样机进行了外场实验,并探测民航客机目标。实验结果表明:与基于黑体的两点校正方法相比,利用本文方法进行非均匀性校正后的图像,局部标准差峰值由8.57降低到2.39;对于相距50.64km的空中客车A319型客机,目标的信杂比由4.87提高到11.22。本文算法可以有效降低图像局部标准差,适用于机载红外预警系统。
Long-wave infrared detectors are often used in airborne infrared warning systems, often subject to severe inhomogeneous noise. In order to correct the non-uniformity of detector and compensate the non-linearity of radiation response, a non-uniformity correction method based on gradient scene is proposed. The observation model of detector radiation response inhomogeneity is given. The standard blackbody and gradient scenes are taken as reference sources, and the correction coefficient expressions are deduced in theory. The outfield experiments are carried out by using principle prototype and the target of civil aircraft is probed. The experimental results show that compared with the two-point correction method based on blackbody, the peak value of local standard deviation is reduced from 8.57 to 2.39 for non-uniformity corrected images by this method. For Airbus A319 passenger aircraft with 50.64km distance, Signal to noise ratio increased from 4.87 to 11.22. This algorithm can effectively reduce the local standard deviation of the image, suitable for airborne infrared warning system.