Enhance
Detect page corners and flatten the perspective so a photographed document looks like a flatbed scan. Adjust the corners by hand any time.
There is no upload endpoint — your files are processed in this browser tab. Open your network tab and check. See how it stays private.
How to crop and de-warp a scanned document
- Add a page. Use a camera scan or an imported photo.
- Auto-detect corners. The page boundary is found automatically.
- Adjust. Drag any corner to fix the detected edges.
- De-warp. The perspective is flattened into a clean rectangular page.
The difference between a photo of a document and a scan of one is geometry: a scan is flat and rectangular, a photo is tilted and keystoned. Auto-crop finds the page in the frame and de-warp corrects the perspective, turning the snapshot into something that reads and prints like a real scan.
Automatic detection handles clean cases; the manual corner handles are there for the rest — a page on a busy desk, or one that blends into its background.
After cropping, straighten small tilts with Deskew, boost legibility with Scan filters, and assemble the result with Build PDF.
Frequently asked questions
What does de-warping actually do?
It applies a perspective transform that maps the four page corners to a rectangle, removing the keystoning you get when a photo is taken at an angle.
What if the corners are detected wrong?
Just drag them. Auto-detection gives a starting point; manual corner adjustment lets you get it exact even on low-contrast or cluttered backgrounds.
Will it crop out my content?
No — it crops to the page you set, keeping everything inside the corners. Widen the corners if part of the page falls outside the detected box.
Is the image uploaded to process it?
No. Corner detection and the perspective transform run on a canvas in your browser, so the page image stays local.
Related tools
- DeskewAuto-detect the skew angle of a scan and straighten every page without clipping content — pure canvas, runs on your device.
- Scan filtersApply flatbed-quality scan filters — grayscale, high-contrast black & white, or a color boost — plus brightness and contrast, all in your browser.
- Build PDFAssemble your captured pages into a single PDF with your choice of page size and margins — built locally with pdf-lib, never uploaded.
- Camera scanTurn your camera into a document scanner — live edge detection, multi-page capture, and a private review strip. Frames never leave this device.