Click or drag & drop an image
Supports JPG/PNG/GIF/WebP/BMP
Upload Image: Click or drag & drop an image. Supports JPG, PNG, GIF, WebP, BMP.
Adjust Threshold: Drag the slider (0-255) for real-time binarization preview. Higher threshold = more white; lower = more black.
Auto Threshold: Click "Otsu Auto" to calculate the optimal threshold using Otsu's method (maximizes between-class variance).
Download: Click "Download" to save the result as a PNG image.
OCR Preprocessing: Binarizing scanned documents significantly improves OCR accuracy.
Image Analysis: Thresholding is a fundamental step in image segmentation and edge detection.
Document Digitization: Convert color/grayscale documents to black-and-white to reduce file size.
Image thresholding (binarization) converts color or grayscale images to pure black and white. It compares each pixel's brightness against a threshold (0-255): pixels brighter than the threshold become white, darker become black. It's commonly used for document scanning, OCR preprocessing, and image segmentation.
The optimal threshold depends on your image content and purpose. For text/document images, try 120-150. For QR codes/barcodes, ~128 works well. For photos, adjust based on visual results. The Otsu algorithm typically suggests values between 120-180. Use real-time preview to find the best setting.
No. Processing happens entirely in browser memory. Your original file is never modified. Only click 'Download' to save the processed result. Your images are never uploaded to any server.
Supported formats: JPG/JPEG, PNG, GIF, WebP, BMP. Output is always PNG format for optimal binarization clarity.
Yes, significantly. Binarizing document images as an OCR preprocessing step can dramatically improve recognition accuracy. The standard OCR pipeline is: grayscale → binarization → denoise → deskew. Our adjustable threshold helps you find the optimal parameters for your OCR workflow.