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ClearScan is a free, 100% browser-based utility that flattens and restores shadowed, unevenly-lit smartphone photos of documents, receipts, or whiteboards. Using a powerful, client-side local adaptive binarization algorithm, it cancels out glare and shadows to transform muddy photos into perfect, high-contrast black-and-white documents ready for archiving, printing, or OCR. Since all image math runs directly in your browser's canvas memory, your data is kept completely private — no uploads, no cloud, no account required.
ClearScan uses a specialized local adaptive binarization algorithm (Bradley-Roth). Instead of comparing every pixel to a single global threshold, it calculates a sliding-window moving average of the local neighborhood surrounding each pixel. If a pixel is significantly darker than its local neighbors, it is classified as text (black); otherwise, it becomes background (white). This dynamically balances out dark corner shadows and glare.
Yes, 100% safe. Unlike traditional scanning apps that upload your images to third-party cloud servers for processing, ClearScan executes all image thresholding and flattening mathematical operations entirely inside your web browser. No document data is ever sent over the network. You can even run the tool completely offline.
Place your document on a flat surface with high background contrast. Photograph it as straight-on as possible to minimize perspective distortion. Avoid using the phone flash as it creates harsh circular reflections; standard flat room lighting is best, as ClearScan's adaptive threshold will easily cancel out any ambient shadows.
The Shadow Removal slider adjusts the local binarization tolerance. Increasing it pushes more shaded, greyish mid-tones into pure paper white, which is ideal for clearing out dark folds or corner shadows. The Contrast slider enhances the sharpness of the text boundaries, ensuring thin pen strokes or pencil marks are recovered clearly as dark ink without becoming pixelated.
Yes. After ClearScan processes the image, click 'Download Image' to save it as a high-resolution PNG. To save or share as a PDF, simply use your system's built-in Print option (Ctrl+P or Cmd+P) and select 'Save as PDF'. Alternatively, look out for the upcoming native PDF export module in our Phase 1 updates.
No. ClearScan processes images using standard HTML5 canvas memory. For performance optimization, ultra-high-resolution images (above 1920px) are scaled proportionally so the sliding-window math runs smoothly in real-time, keeping the process instantaneous while preserving legibility.