smart_document_capture_tesseract 0.1.0

Offline Tesseract OCR engine for smart_document_capture, with Persian and English support, word boxes and per-word confidence from hOCR output.

smart_document_capture_tesseract

Offline Tesseract engine for smart_document_capture, built on flutter_tesseract_ocr.

• Works without internet, on Android and iOS.
• Supports Persian (fas), English (eng) and every other Tesseract language.
• Reads Tesseract's hOCR output, so every word has a box and a confidence — used by the core package for field scores and for drawing boxes in the review widget.

Setup

1. Add the packages:

   dependencies:
     smart_document_capture: ^0.1.0
     smart_document_capture_tesseract: ^0.1.0
   

2. Download the trained data of your languages (for example fas.traineddata and eng.traineddata from tessdata_fast or the more accurate tessdata_best) into assets/tessdata/, and list them in assets/tessdata_config.json:

   { "files": ["fas.traineddata", "eng.traineddata"] }
   

3. Declare the assets in your app's pubspec.yaml:

   flutter:
     assets:
       - assets/tessdata_config.json
       - assets/tessdata/
   

Usage

final capture = DocumentCapture(
  engine: TesseractOcrEngine(),
  options: const OcrOptions(languages: ['fas', 'eng']),
);

final result = await capture.process(
  DocumentImage.file(photo.path),
  ReceiptSchema.persian,
);

TesseractOcrEngine(args: {...}) sets Tesseract variables. The default page segmentation mode psm: 4 suits receipts; use 3 for full pages. Per-call variables can be passed in OcrOptions.extra.

Only DocumentImage.file is supported; save in-memory images to a file first.

Tips for better results

• Photograph the document flat, well lit and filling the frame.
• Crop and straighten the image before OCR (for example with a document scanner package).
• tessdata_best is slower but noticeably better for Persian.

Parsing hOCR yourself

HocrParser.parse(hocr) turns any Tesseract hOCR output into an OcrResult, for example from a server-side Tesseract.

License

MIT