基于焦平面归一化响应特性的红外非均匀性校正

红外焦平面阵列的非均匀性噪音是制约红外成像质量的主要因素,非均匀性校正是红外焦平面器件应用的一个关键技术.本文提出了一种基于焦平面归一化响应特性且易于实现的非均匀性校正算法,并基于像元分布的卡方直方图提出一种新的图像非均匀性评估方法,即校正比例.该方法的校正输出考虑了每个像元的观测值与焦平面的响应信号的平均值,校正参量通过将像元的输出与其理想校正结果之间的偏差用焦平面响应的平均值建立联系而计算得到.提出的校正比例兼顾考虑了焦平面响应的时间与空间特性,比现有的图像非均匀性评估方法更能合理衡量焦平面的非均匀性程度.多种非均匀性校正的评价数据以及实验结果表明,该算法的校正效果优于两点校正法与原值拟合二阶校正法,并对于响应异常的像元具有较强的校正能力.此外其校正准确度高,所需参量少,易于实时处理,具有较强的实用价值.

Nonuniformity Correction Based on Unified Photoresponse Characteristics of Infrared Focal Plane Arrays

The nonuniformity in the infrared focal plane array limits the quality of infrared imaging system.A new nonuniformity correction procedure based on the unified photoresponse characteristics of infrared focal plane arrays and the correction ratio based on the chi-square histogram were presented.The correction output of each detector took both its observed value and the average response of the focal plane array into account.The correction parameters were obtained by establishing the relationship between the difference of the observed value and its ideal response and the average response of the focal plane array.The proposed correction ratio took into account of both spatial and temporal response characteristics of focal plane arrays,thus it gave more reasonable results on the measurement of the degree of nonuniformity.Experimental results show that its performance is better than that of the two-point correction and the quadratic curve fitting correction using the input values,and has excellent correction capability to the pixels with abnormal responses.In addition,the algorithm has the advantages of high correction precision,less correction factors and easy to real-time processing,which enhances its utility value.