Document Scanning and Enhancement

Dropbox launched document scanning on iOS, enabling users to scan documents with their smartphone cameras and store them directly in Dropbox. This feature automatically detects documents, extracts them from the background, fits them to a rectangular shape, removes shadows, adjusts contrast, and saves them as PDF files. For Business users, OCR is also performed for search and copy-pasting. This post details the document detection pipeline, which uses a customized computer vision algorithm based on edge detection and Hough transforms, designed for real-time performance on mobile devices.