According to the adjustability of the gain multiplier of Electron Multiplying CCD , an image gain adjustment method
based on dynamic gray-level is proposed. Compared to a fixed value adjustment algorithm, the automatic gain
algorithm here is more adaptive,even in low-light conditions , it can achieve better gain values. Experimental results
show that the automatic gain algorithm which combines mean values with the dynamic range of histograms meets the
requirements. Whether it is during the day or at night , the brightness of image can quickly converge to the optimum
range of gray histogram distribution, gray-level dynamic range is also accounted for more than 90% . Judging from the
images obtained: the brightness is moderate, details are clear .