How JPG Lossy Compression Affects OCR Accuracy
JPG files use lossy compression, meaning each save cycle removes a small amount of image data. This reduction introduces compression artifacts — blocky distortions around text edges. High compression (low quality settings like 30-50%) causes visible blurring on character boundaries, reducing OCR accuracy by 5-15%.
Convert JPG to Word compensates for JPG compression artifacts by running a pre-processing sharpening filter before OCR. The system detects JPEG block boundaries (8×8 pixel grids) and applies edge-aware smoothing to restore character outlines. This pre-processing step recovers 8-12% of accuracy lost to compression.
When to Use JPG for Document Scanning
Use JPG for document scanning when storage space is limited and the original document uses standard printed text. A single A4 scanned page at 300 DPI produces a 2.5 MB (megabyte) JPG file at 85% quality, compared to 8.5 MB for the same scan in PNG format.
- Printed Text Documents: JPG at 85% quality preserves enough detail for OCR engines to extract characters at 97% accuracy.
- Color Photographs with Text: Use JPG at 90%+ quality for receipts, product labels, or signage where color context matters.
- Avoid JPG for Fine Print: Legal contracts or medical documents with sub-8pt fonts should be scanned as PNG to preserve thin stroke details.
JPG Metadata and EXIF Data Handling
JPG files contain EXIF (Exchangeable Image File Format) metadata — camera model, GPS coordinates, timestamps, and orientation tags. Convert JPG to Word reads the EXIF orientation tag to auto-rotate images before OCR processing. Without this correction, sideways or upside-down photos produce garbled text output.