Scan & OCR
Perspective correction
Straighten any flat thing photographed at an angle (whiteboard, sign, receipt, poster) without changing its colours.
- 1Add your JPG, PNG or WEBP file
- 2Pick options
- 3Click Run
- 4Download result
Limits
- Needs a good contrast between the page and what it lies on (a light page on a darker surface works best). White on white, or a page that fills the whole photo, may not be found; you then get a notice and can set the corners by hand.
- Heavy shadows are reduced but not removed, and curled or folded pages are only straightened as a flat rectangle: they are not unwarped.
- The page is straightened at the photo's own resolution. Photos up to 50 megapixels are accepted (25 on phones) and are handled one at a time; detection runs on a smaller copy (1,000 px), the warp on the full picture.
- Nothing is uploaded. The first use downloads the OpenCV.js image engine (13 MB) from this site and keeps it in your browser.
- No enhancement is applied; colours stay as photographed. The shape is corrected for perspective, but the true proportions are estimated from the corners, so a very small tilt can leave a slightly different aspect than the real object.