The following is an overview of the Auto ROI tab of Capture OEM:

On some cameras models, the auto operations for  exposurewhite balance and  gain  will all use the Auto Roi when it is enabled (this feature is disabled by default). When this feature is enabled and set, the auto operation (for example, Auto Exposure) will be performed over the specified AutoROI, instead of the full ROI. 

The AutoROI can be enabled by clicking the "Enable" box. The AutoROI size can be changed by selecting a preset size from the drop down menu, entering new values into the Width and Height box, or changing the size of the Current Auto-ROI adorner. Location can be determined by dragging/moving the Auto-ROI adorner, or by entering values in the Offset X and Offset Y boxes. 

The One Time buttons for Exposure, Gain and White Balance can then be used to perform an auto operation using the newly set Auto-ROI. 

For API control of this feature, see: Auto ROI