光学方法抑制摄像机AGC 变动幅度研究

光学方法抑制摄像机AGC 变动幅度研究

针对自动增益控制A GC 引起固态摄像器件感光灵敏度大幅度变动的缺陷, 引入稳定的强光束单独照射CCD 或CMO S局部区域上的像素, 由视频信号延时、平均产生的A GC 可抑制器件自身灵敏度。选择适度的预照射面积以产生足够的预置光通量, 可使被测对象引起器件上的总光通量变化减小, 对应的A GC 输出变化幅度变小, 并钝化灵敏度。模拟计算以5 倍测量平均光强照射抑制区、摄像器件的光通量变化中值为基准的相对变化范围: 抑制30% 像素为81%～ 119%; 抑制50% 像素后为91%～ 109%。强光抑制少量感光元能产生超过多数感光元测量时的光通量。用单板CCD、CMO S 测量细光束, 光学抑制法可防止出现感光元下电荷溢出、图像亮区饱和及面积扩大等不良现象, 提高被测物体边缘的清晰度和亮度信号的稳定性。
Put t ing a fixed stable ligh t beam on part CCDö CMOS camera element s, it w ill rest rain A GC funct ion against it s big changes and sensibility. St ronger rest raining2beam than measured object s’ go t mo re efficiency, stability. The relat ive flux change ranges are 02200% w ithout rest rained beam, 81%～ 119% w ith 30% rest rained element s o r 91%～ 109% w ith half ones, under 5 t imes measurement mean ligh t intensity and m iddle value standard by calculat ion. So that to tal flux change and A GC becomes less by object in full p re2flux condi2
t ions under available illum inated area, and camera becomes insensit ive. It consist s of 2 main regions, measure2 ment and rest rained, and a small separated area between the two fo r p revent ing charges under element s sp ill over the rest rained region. By using brigh tness rest raining A GC on oneboard camera, it get s good linear output w ith object brigh tness, p revent s charge overflow under measurement element s, video2signal disto rt ion, and p icture’s brigh t component expansion o r sp ill.