This tool is to set the sensor area used for imaging.
The first row is the horizontal starting point and width.
The second row is the vertical starting point and height.
You can set the values with the mouse on a preview exposure. Press the Shift key and the mouse left button to draw the frame.
A list of predefined ROI can be set in the Camera preferences. When the list is not empty it is show here for selection. Be sure to always click the Set button after changing the selection.
Click the Set button to send the values to the camera.
Click the Reset button to reset to full frame.