激光辐照面阵CCD探测器的杂散光斑现象

为了研究短脉冲强激光辐照下同轴数字全息图像中的杂散光斑,进行了短脉冲强激光辐照和停止激光辐照情况下CCD图像采集的实验,采用粒子衍射原理和CCD输出电信号的过程分析了CCD图像灰度的变化,得到了像素上灰尘的衍射及CCD吸收激光能量导致复位电平失常是杂散光斑及阴影产生的原因,受热效应和记忆效应的影响,激光辐照停止后CCD图像采集失常。结果表明,激光辐照停止后随着热量的消散,杂散光斑逐渐消失,去除灰尘并延长CCD的图像采集时间间隔,避免CCD产生热积累能有效消除杂散光斑。

Study on stray facula of array CCD detector irradiated by laser pulse

In order to investigate the stray facula in the in-line digital hologram with an array CCD detector irradiated by short intense laser pulse,variable images were gathered with CCD under laser irradiation or not.Different image grey was analyzed based on the diffraction fringes of the particles and the output electrical signal of the pixel.The stray facula was induced by diffracting dust in the pixels and the abnormal behavior of the reset level due to laser absorption of CCD.Without laser irradiation,the image gathered by CCD was quite abnormal due to the thermal effect and memory effect of CCD.The results showed that the stray facula vanished slowly with the elimination of heat during a long time.Finally,the image gathered by CCD can recover normally and the stray facula vanished completely when the dirty was removed and the time interval of the gathering image was prolonged.