# Scan a document with your camera or from a photo

> Scan documents with your camera or a photo: Nibbo finds the page, straightens it and removes shadows. Colour, grey or B&W, save a multi-page PDF. No upload.

URL: https://nibbo.org/en/scan-document/

## How it works

1. The edges of the sheet are found with a Hough transform on the photo: the four strongest lines that form a page-shaped quadrilateral. Drag any corner if the guess is off, or use the whole photo.
2. The sheet is straightened with a perspective transform (homography), so a page shot at an angle comes out rectangular with straight text lines.
3. Shadows and yellow light are removed by estimating the paper tone with a wide blur and dividing it out; black-and-white mode then applies a local (Sauvola) threshold for crisp text that compresses small.
4. Pages are saved as JPG, or placed into an A4, Letter or page-sized PDF, one page per photo, in the order of the strip above.

## Questions

### Are my documents uploaded?

No. The camera stream, the photos and the PDF stay in this browser tab. Nothing is sent anywhere.

### Why does the camera not start?

The browser asks for camera permission the first time; allow it. On a desktop without a camera, drop photos instead. The page must be opened over HTTPS for the camera to be available.

### Can I scan several pages into one PDF?

Yes. Capture or drop as many pages as you like, reorder or remove them in the strip, and save as PDF.

### Which mode should I use?

Colour keeps stamps and highlights. Grey is smaller and good for text. Black-and-white gives the crispest text and the smallest files, like a fax.

### Does it recognise the text?

Not here. Save the scan and open it in Image to Text or OCR PDF to get searchable text.

## Guides for this tool

- [How to compress a PDF to 300 KB (and what to do if it won't fit)](https://nibbo.org/en/guides/how-to-compress-pdf-to-300kb/)

## Why Nibbo

- Runs on your device, nothing is uploaded
- No sign-up, no watermark
- No queue and no daily limit
- Works offline once opened
- Free for files up to 3 GB
- [Nibbo vs Canva, iLovePDF, Smallpdf](https://nibbo.org/en/guides/nibbo-vs-canva/)