QBMFX Perspective correction
Correct the trapezoid shape created when a camera photographs a document from an angle. Identify the top left, top right, bottom right and bottom left corners in that order, then generate a rectangular image. This helps book-center staff prepare readable flat copies from customer phone photos without sending those images to an external service.
Choose your files and review the settings.
Keep originals and inspect the result before printing. File changes clear previous downloads. Heavy image and OCR work can take longer on a phone.
Using Perspective correction
- Choose a photo containing the full document.
- Enter the four normalized corner coordinates in clockwise order, starting at the top left.
- Generate a flattened image and inspect text and edges.
Behind the result
A projective transformation maps the selected four-sided document region onto a rectangle. Coordinates run from 0 to 1 across the input image, so they are independent of its pixel dimensions.
Free tools for everyday work
Book centers, photocopy shops, freelancers and developers can use this workspace without a paid plan or account. Files are processed locally. Prepare website resources from offline setup before disconnecting; Urdu/OCR also needs the separate pack above.
The Windows app currently includes the original four tools. These new Book Center tools are available on the website; app and extension updates will be separate releases.
Answers and practical details
Corner coordinate format
Use an array such as [[0.08,0.06],[0.92,0.10],[0.95,0.94],[0.05,0.90]]. Each pair is horizontal position followed by vertical position, between 0 and 1.
Price and account requirements
This website tool is 100% free. No login, subscription or paid conversion tier is required. Your device supplies the processing memory.
Files and privacy
Input documents and generated results are handled locally. They are not sent to a QBMFX conversion API or stored in a customer database. Website hosting and advertising can still make separate network requests.
Offline preparation
Prepare the website resources from Help while connected, then test the required tool offline. OCR and Urdu text tools also need their optional language or font resources prepared first. Browser storage can be removed by the browser or by you.
Windows app and Edge extension
The existing installed app and extension contain the original four PDF tools. These new Book Center tools belong to the website release; they will need a separate installed-package update.