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针对时间延迟积分(TDI)电荷耦合器件(CCD)成像系统多通道间存在响应非均匀问题,开展了基于辐射定标的校正方法研究。结合成像系统的信号处理流程,推导了响应非均匀性校正的理论模型,提出了一种基于加权最小二乘的定标校正方法,分别在1/4、1/2和3/4饱和响应处采集三组图像数据,并利用高斯加权函数对三组通道间的校正参数进行加权最小二乘拟合,从而获得优化的校正参数。利用TDI CCD成像系统进行实验验证,结果表明,系统的响应非均匀性(1/2饱和响应处)由原来的4.09%降低至0.85%,并优于两点校正法的1.93%,同时该方法在宽响应域内均获得了良好的校正效果,具有精度高、实用性强等特点,可应用于机载、星载等相机载荷,为获取高质量的遥感图像数据奠定技术基础。
Aiming at the problem of non-uniform response in time-delay integration (TDI) charge-coupled device (CCD) imaging system with multiple channels, a calibration method based on radiation calibration was developed. Combined with the signal processing flow of the imaging system, a theoretical model of response nonuniformity correction was deduced, and a calibration method based on weighted least squares was proposed, which was respectively at 1/4, 1/2 and 3/4 saturation response Acquisition of three sets of image data, and use of Gaussian weighting function for the three groups of channels between the calibration parameters weighted least squares fitting to obtain the optimal calibration parameters. Experimental results using TDI CCD imaging system show that the system response inhomogeneity (1/2 saturation response) is reduced from 4.09% to 0.85%, which is better than 1.93% of the two-point calibration method. Meanwhile, this method It achieves a good correction effect in a wide response area. It has the characteristics of high precision and practicality. It can be applied to the camera loads such as airborne and spaceborne, and lays the technical foundation for obtaining high quality remote sensing image data.