• For regular texts (font size 8-10 points) it is recommended to use 300 dpi resolution for OCR. The reason is that all ABBYY technologies are tuned for that resolution.

• If scans have a smaller resolution, for example 200 dpi, then 10 point font will be too small. To compensate the “missing” pixels, the image will be scaled internally (up to 400 dpi). Low image quality (i.e. resolution) may lead to not only quality but also speed degradation as uncertainty in character picture produces more recognition variants to process.

• For smaller font text sizes (8 points or smaller) we recommend to use A 400-600 dpi resolution.

• ABBYY Technologies use colour information for detecting areas and objects on the image.
• So, if complex layouts have to be processed, it is recommend to use colour or at least, grey scale images.
• The character recognition is always executed on an bi-tonal image, that only contains black & white. But to archive a good OCR result it is important to generate a good, suitable binary image. ABBYY technology is not just using “simple” binarization, but “adaptive binarization.”

See also:

• Improved Binarization in V10 Technologies

• The largest font ABBYY OCR can handle is 5cm or 220pt.

• Currently ABBYY products can open images formats up to 32512*32512 pixels.
• Bigger images have to be cut and the segments have to be processed separately

• ABBYY Technology v.8.x and older were able to open image files up to 2 GB.
• Starting from V9.0 this limit doesn't exist any more.

• Image Resolution Detection

Back to: Inside OCR Overview