多通道时间延迟积分CCD辐射标定和像元实时处理

剖析了时间延迟积分CCD(TDICCD)像元校正对信噪比和调制传递函数测试的影响,设计了基于辐射标定和地面控制的多通道TDICCD像元响应非均匀性实时处理方法以提高星上实时图像的像元响应非均匀性。该方法基于辐射标定去除图像的固定图形噪声,并校正图像奇异点;通过分析星上实时传输图像,处理奇异点像元的图像问题,实现地面控制像元响应非均匀性的实时调整。提出的系统实时处理方式可以不改变硬件结构即有效改善图像的视觉效果,对于坏像元、像元性能降低、像元污染等特定情况有很强的纠错能力。实际成像试验的对比表明,该方法对信噪比、调制传递函数有很好的修正作用,其精确调整能力分别达到0.1db及0.01;在50%饱和值下测试的图像非均匀性指标达到1.25%。该方法结构简单,在工程实践中有很好的应用前景。

Radiometric calibration and pixel data real-time processing of multi-tip TDICCD

The effects of pixel level correction of Time Delay Integration CCD(TDICCD) on the Signal to Noise Ratio(SNR) and Modulation Transfer Function(MTF) are researched.A method to process the Pixel Response Non-uniformity ( PRNU) in a multi-tip TDICCD system is proposed based on radiometric calibration and ground management to improve the PRNU of the TDI-CCD designed. It removes Fixed Pattern Noise(FPN) of the image by the radiation calibration and corrects the strange dot in the image. By analysis of a transmitted image in real time, the pixel in the strange dot is processed and the PRNU can be managed on the ground surface in real time. Without modifying the hardware, the proposed system improves the image quality, and shows stronger correction ability for few bad pixels, low performance pixels or a few dusty pixels. By a comparison of imaging experiments, it concludes that this method corrects the SNR and MTF precisely. The correction precision has been achieved to 0.1 db(SNR) and 0.01(MTF) respectively. The image PRNU can be 1.25% when it is measured at saturation exposure of 50%. For a simpler structure, it has a better foreground in the future projects.