To scan an image, the user can start with a preview scan and then select the part of the scan area to do the final scan on. The preview scan is started by pressing the preview button.
When the preview is scanned the area for the final image can be selected.
To better select the image the user can zoom in, out, to the current selection or zoom to fit the whole preview to the window.
When the image is selected the final image can be acquired by pressing the final scan button.
You will see the progress of the scan.