基于LED的CCD光强响应特性测定

Measurement of CCD light intensity response characteristics based on LED

针对电荷耦合器件(charge-coupled device,CCD)的光强响应曲线的测量,提出采用大功率LED作为线性光源,设计基于成像方式的光强响应信号的测量装置。通过控制恒流激励电流大小来调节LED的辐射输出并测量CCD的响应数据。根据CCD响应信号拟合出对应的光强响应曲线,并建立光电响应模型分析CCD饱和与非饱和的响应特性。实验结果表明:CCD的光强响应受到LED发光角和辐射模式的影响,当采用LED作为CCD光强响应测量的线性可调光源时,不能忽视LED光强分布的近朗伯特性;同时,H694C-II相机输出灰度值大于61713时CCD ICX694AL的光强响应曲线出现较明显的饱和非线性,但在非饱和区域CCD具有优良的线性响应特性。

To measure the light intensity response curve of the charge-coupled device （CCD）, an LED with high power was proposed as a linear light source for the design of a light intensity response signal measuring device based on imaging technology. The intensity response data of CCD were obtained by regulating the LED rediation output via controlling the constant excitation current of LED. Corresponding light intensity response curves were fitted according to the response signals of CCD intensity response and also, a photoelectric response model was built to analyze the saturated and unsaturated response characteristics of CCD. Test results show that the light intensity response of CCD is influenced by the radiation angle and radiation pattern of LED. When LED is used as an adjustable linear light source for measurement of light intensity response of CCD, the near Lambert characteristics of the distribution of LED light intensity should not be ignored. Meanwhile, if the output grey level of H694C-II camera is greater than 61713, the light intensity response curve of CCD ICX694AL will have obvious saturation nonlinearity, but CCD has excellent linear response characteristics in the unsaturated region.