PaddleTextRecognizer

Import

import { PaddleTextRecognizer } from '@stabrise/scaledp/ocr'

Group

Recognise

Reads

image

Writes

document

Needs

ppu-paddle-ocr

The default OCR engine, and the best all-rounder: about 6 MB of weights, WebGPU capable, and thirteen language presets.

import { Pipeline } from '@stabrise/scaledp'
import { PdfToImage } from '@stabrise/scaledp/pdf'
import { PaddleTextRecognizer } from '@stabrise/scaledp/ocr'

const rows = await new Pipeline([
    new PdfToImage({ resolution: 300 }),
    new PaddleTextRecognizer({ preset: 'v6-small', keepFormatting: true }),
]).transform(file)

rows[0].text.text      // the recognised text
rows[0].text.bboxes    // one box per detected region

Document.type is 'ocr'.

Strategy

• 'per-box' (default) — the regions as detected.
• 'per-line' — merge boxes that share a line.
• 'cross-line' — merge across line breaks too.

This changes how the result is cut up, not what was read.

Keeping the layout

keepFormatting: true rebuilds the page's layout in the text: indents from the left edge of each line, blank lines where vertical gaps are large, spacing derived from the modal character width. lineTolerance controls line grouping in pixels, and 0 derives it from the measured character height — which is almost always better than a fixed number, because it scales with the render DPI.

The reconstruction is a port of ScaleDP's box_to_formatted_text and is verified against Python goldens.

Language presets

v6-small is the default and covers Latin and CJK. No single model covers every script, so this is a real choice.

import { PADDLE_OCR_PRESETS, detectScript, presetsForScript } from '@stabrise/scaledp/ocr'

const script = await detectScript(canvas)          // needs tesseract.js
const options = await presetsForScript(script.script)

detectScript() reports what a page contains and presetsForScript() lists what can read it — useful for offering the user a sensible default rather than guessing.

An unknown preset throws RangeError from the constructor.

Switching presets mid-session

Handled internally: the call into ppu-paddle-ocr passes noCache: true, without which changing the preset returns the previous model's result. Worth knowing if you are debugging why a language change did nothing.

Parameters