The Influence of the non-uniformity of sensitivity of the photodetector in evaluating the detection characteristics of optoelectronic systems
In optical-electronic systems (OES) of visual observation, the non-uniformity of the output signal is compensated quite well. At the same time, the non-uniformity of the sensitivity of the photodetector (NUSP) degrades the threshold sensitivity of the photodetector devices. At the same time, compensation does not lead to an increase in the characteristics of the OES. Thus, assessing the impact of NUSP on the characteristics of detection of the OES is an urgent task. The calculation of the estimation of the mathematical expectation of the signal shows that it is biased and the displacement is proportional to the sensitivity of the corresponding element. Compensation for NUSP eliminates this bias, but the effectiveness of the assessment changes and the NUSP is transferred from the mathematical expectation to the variance. The presence of NUSP results in a corresponding the non-uniformity of the probability of correct detection and a threshold signal. Performing compensation does not change the probability of correct detection and the threshold signal. It is shown that for each element of the photodetector the detection range is determined by its sensitivity. The ratio of the maximum range to the minimum is related to the ratio of the maximum sensitivity of the photodetector element to the minimum. The presence of NUSP leads to a corresponding uneven detection range. It is shown that the compensation of NUSP does not change the value of the detection limit. At NUSP of 40%, the minimum detection range will be 1.5 times less than the maximum detection range.