SnapOtter/apps/docs/tools/image/ocr.md

description

description
Extract text from images using AI-powered optical character recognition.

OCR / Text Extraction

Extract text from images using AI-powered optical character recognition. Supports multiple languages and quality tiers.

API Endpoint

POST /api/v1/tools/image/ocr

Processing: Synchronous JSON response. If clientJobId is provided, progress is also reported through SSE.

Model bundle: ocr (5-6 GB)

Parameters

Parameter	Type	Required	Default	Description
file	file	Yes	-	Image file (multipart)
quality	string	No	"balanced"	Quality tier: fast (Tesseract), balanced (PaddleOCR v5), best (PaddleOCR VL)
language	string	No	"auto"	Language hint: auto, en, de, fr, es, zh, ja, ko
enhance	boolean	No	true	Pre-process image for better OCR accuracy
engine	string	No	-	Deprecated. Use quality instead. Maps tesseract to fast, paddleocr to balanced

Example Request

curl -X POST http://localhost:1349/api/v1/tools/image/ocr \
  -F "file=@document.png" \
  -F 'settings={"quality":"best","language":"en","enhance":true}'

Response (200 OK)

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "filename": "document.png",
  "text": "Extracted text content from the image...",
  "engine": "paddleocr-vl"
}

Progress (SSE, optional)

If a clientJobId form field is provided, progress events are streamed:

event: progress
data: {"phase":"processing","stage":"Recognizing text...","percent":50}

Notes

• Requires the ocr model bundle to be installed (5-6 GB).
• OCR returns extracted text directly rather than an image download URL.
• Uses a fallback chain: if a higher-quality tier crashes (e.g., PaddleOCR segfault), it automatically retries with the next lower tier.
• If a tier returns empty text without crashing, it also falls back to the next tier.
• Quality tiers map to engines: fast = Tesseract, balanced = PaddleOCR v5, best = PaddleOCR VL.
• Supports HEIC/HEIF, RAW, TGA, PSD, EXR, and HDR input formats via automatic decoding.