脉冲序列图像传感器的噪声和误差分析

Noise and Error Analyses of a Pulse Sequence Image Sensor

脉冲序列式图像传感器是一种高速仿生视觉图像传感器,其成像质量受噪声的影响而下降。其中,空间噪声源于比较器等器件的失配,时间噪声源于随机性噪声和同步读出机制下的单码闪烁噪声。本文基于噪声研究和传感器原理建立了噪声模型,仿真预测了不同光电流和积分压降等参数下噪声引起的时间误差率。结果表明:积分压降的增加会减小单码闪烁噪声导致的时间误差率的波动及其他噪声引起的时间误差率;光电流的增加会增大单码闪烁噪声引起的时间误差率的波动;结电容的增加会增大时间噪声引起的时间误差率。最后测试了芯片在脉冲间隔重建方式下的噪声特性,验证了上述分析的正确性。研究结果对于优化脉冲序列传感器的设计、处理噪声和重建出稳定的图像具有指导意义。

The pulse sequence image sensor is a high-speed bionic image sensor, and its image quality deteriorates because of the influence of noise. Spatial noise is attributed to the mismatch of the comparator and other devices, and the temporal noise arises from random noise and single-code flicker noise under the synchronous readout mechanism. This study establishes a noise model based on noise research and the sensor principle, and simulates and predicts the time error caused by noise under different parameters such as photocurrent and integral voltage drop. Results show that increasing the integral voltage drop will reduce the fluctuation of the time error rate caused by single-code flicker noise and the size of the time error rate caused by other noise sources. Further, increasing the photocurrent will increase the fluctuation of the time error rate caused by single-code flicker noise and increasing the junction capacitance will increase the time error rate caused by temporal noise. Finally, the noise characteristics of a chip are evaluated in the pulse interval reconstruction mode and the aforementioned analysis is validated. The findings of this study have guiding significance for optimizing the design of pulse sequence sensors, handling noise, and reconstructing stable images.