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为抑制CCD相机信号处理电路中由温度等原因引起的偏置漂移对图像质量造成的影响,提出了一种基于反馈的近实时偏置漂移校正方法。为了获得偏置在整个链路中的变化情况,对整个信号处理链路进行了分析;设计了两种数字低通滤波器,分别对获得的暗像元数据进行滤波;根据工程经验并辅以计算给出校正算法的有关参数;校正图像偏置漂移并对输出的图像进行比较分析。实验结果表明,在可变增益放大器增益为1.8的条件下,使用12 bit精度的模/数转换器时偏置稳定在10个码值以下,基本满足精度高、稳定性好及抗干扰的要求。
In order to suppress the influence of bias drift caused by temperature and other factors on the image quality of CCD camera signal processing circuit, a near real-time offset drift correction method based on feedback is proposed. In order to obtain the variation of the bias in the entire link, the entire signal processing chain was analyzed. Two kinds of digital low-pass filters were designed to filter the obtained dark pixel data separately. Based on the engineering experience and supplemented by Calculate the relevant parameters of the calibration algorithm; correct the image offset drift and compare the output images. The experimental results show that when the gain of the variable gain amplifier is 1.8, the bias is stable below 10 codes when the 12-bit A / D converter is used, basically meeting the requirements of high precision, good stability and anti-interference .