Hello. Why do we need to perform roi[0] += (self.resolution[0] - self.resolution[1]) // 2 # x offset for device crop in the code for https://github.com/luxonis/depthai-python/blob/main/examples/ColorCamera/autoexposure_roi.py? Is it required if we use the full resolution ie 12MP on colorCamera?
Hi glitchyordis ,
I believe it's because the preview is 300x300, so 1:1 aspect ratio, while resolution is 16:9 aspect ratio. So you need to update the ROI a bit to match the actual sensor resolution. Thoughts?
Thanks, Erik
Hi erik, sorry but I can't visualize how roi[0] += (self.resolution[0] - self.resolution[1]) // 2 account for aspect ratio difference of 1:1 vs 16:9? Maybe you can provide some simple sketches or resources?
Hi glitchyordis , below is copied from gpt4, I hope it helps.
The code is converting the Region of Interest (ROI) from the 300x300 coordinate space to the actual sensor coordinate space.
The line roi = roi * self.resolution[1] // 300 scales the ROI coordinates to match the sensor's height, maintaining the aspect ratio.
The line roi[0] += (self.resolution[0] - self.resolution[1]) // 2 calculates the x offset for the device crop. This is necessary because the input image is cropped to maintain the aspect ratio, and the resulting cropped image is centered horizontally. By adding half the difference between the sensor's width and height to the x-coordinate, the code accounts for the horizontal offset introduced by the cropping.
