低剂量γ辐射对视频品质的影响及其改善方法

Effect of Low Dose Gamma Radiation on Video Quality and Improvement Methods

利用^(60)Coγ放射源对CMOS图像传感器进行辐照实验,结合其损伤机理分析造成视频画面品质下降的影响因素,并初步提出改善方法.对所采集监控画面的平均亮度及R、G、B三种色彩通道强度的变化进行了分析.实验结果表明,CMOS图像传感器在辐照剂量率为5 Gy/h时随着累积剂量的增大,监控画面的平均亮度增大,噪点增多且发生绿色色偏.可以通过如下方法改善视频品质:将传感器部分与信号处理部分分离并加装外层屏蔽体;采用浅槽隔离结构与耗尽区相隔离且有较低夹断电压的光电二极管结构;通过程序调节色彩平衡.

Irradiation experiments of CMOS image sensor have been presented by ^60 Coγ-ray resource.Influence factors of video quality degradation were analyzed by damage mechanism.And the improvement methods about reduced radiation effect were put forward.The average brightness and color channel intensity of the collected monitoring frame have been analyzed by irradiation experiments.As the results showed,the average brightness and the number of noisy point of monitoring frame increased with the total ionizing dose increasing,also withgreen color cast.Irradiation effect of CMOS image sensor monitoring frame could be improved by the methods as follows： separating sensor part from the signal processing part,adding radiation shielder; using the radiation resistance photodiode with shallow trench isolation and lower pinch off voltage.Color balance could also be adjusted by software program.