I expect the autoExposure over ROI would automatically adjust the overall exposure such that the ROI (person) has optimal exposure level while the background level goes up or down opposite to the illumination level on the ROI. For example, when I am away from my desk where the camera sits, I am not well illuminated from the desk lamp, thus the overall exposure should be adjusted higher. As I approach the desk, I become better illuminated, thus the background level should be dialed down. But this is not the case. The video in Example 23_autoexposure_roi.py shows similarly, as if the exposure level is never adjusted according to the light level in ROI.