Description: This demo clip shows a semi-automatic ROI detection method. In general, touch screen of mobile phone does not provide accurate touch points sensing performance in technical manner. Moreover, most of mobile phone does not provide sufficient processing power for detecting object in an image automatically. In order to detect accurate corner points of the rectangular object by touching inaccurate position, we made Hough-transform-based semi-automatic ROI detection method. It will help following image recognition and tracking techniques by using the detected ROI.