--deskew

Automatically apply correction to acquired pages that may be skewed (slanted to the left or right of the acquired area). The device must support automatic deskewing for this command to have effect.

For example, if the paper is not placed correctly on the flatbed portion of the scanner, without deskewing, the image will be acquired with the page slanted to either the left or right. Deskewing will correct the slanted page.

Please note that TwainSave does not do the actual deskewing of the acquired image -- TwainSave is relying solely on your device's internal deskewing processing to detect and deskew the image.