光學(xué)方法抑制攝像機AGC 變動幅度研究

針對自動增益控制A GC 引起固態(tài)攝像器件感光靈敏度大幅度變動的缺陷, 引入穩(wěn)定的強光束單獨照射CCD 或CMO S局部區(qū)域上的像素, 由視頻信號延時、平均產(chǎn)生的A GC 可抑制器件自身靈敏度。選擇適度的預(yù)照射面積以產(chǎn)生足夠的預(yù)置光通量, 可使被測對象引起器件上的總光通量變化減小, 對應(yīng)的A GC 輸出變化幅度變小, 并鈍化靈敏度。模擬計算以5 倍測量平均光強照射抑制區(qū)、攝像器件的光通量變化中值為基準(zhǔn)的相對變化范圍: 抑制30% 像素為81%～ 119%; 抑制50% 像素后為91%～ 109%。強光抑制少量感光元能產(chǎn)生超過多數(shù)感光元測量時的光通量。用單板CCD、CMO S 測量細光束, 光學(xué)抑制法可防止出現(xiàn)感光元下電荷溢出、圖像亮區(qū)飽和及面積擴大等不良現(xiàn)象, 提高被測物體邊緣的清晰度和亮度信號的穩(wěn)定性。
Put t ing a fixed stable ligh t beam on part CCD? 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.