PaddleRecognizer

Import

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

Group

Recognise

Reads

image, boxes

Writes

document

Needs

ppu-paddle-ocr

PaddleTextRecognizer detects and recognises in a single pass, so boxes from a separate detector never reach it. This stage does the opposite: it reads exactly the boxes it is handed, cropping and straightening each one — the PaddleOCR counterpart to TesseractRecognizer.

import { Pipeline } from '@stabrise/scaledp'
import { PdfToImage } from '@stabrise/scaledp/pdf'
import { DbnetOnnxDetector, PaddleRecognizer } from '@stabrise/scaledp/ocr'

const rows = await new Pipeline([
    new PdfToImage(),
    new DbnetOnnxDetector({ outputCol: 'boxes' }),
    new PaddleRecognizer({ inputCols: ['image', 'boxes'] }),
]).transform(file)

Document.type is 'paddle-recognizer'. A missing box column produces a helpful OcrError in exception rather than an empty result.

Only the recognition model is downloaded

A preset pairs a detection model, a recognition model and a character dictionary. This stage never detects, so it fetches only the last two. The cache keys are shared with PaddleTextDetector and PaddleTextRecognizer, so a pipeline that also uses one of those pays for each file once.

The preset is still what picks the script: the same list, and the same choice as everywhere else in the library.

One box in, one box out

There is no strategy parameter, unlike PaddleTextRecognizer. PaddleOCR's 'per-line' and 'cross-line' strategies merge boxes together before reading them; the contract here is one result per box you hand in, which only 'per-box' can honour. The box that comes back is the detector's own — angle included — carrying the recognised text and its score.

Straightening

The crop is a perspective warp onto the box's own axes, which is what makes a skewed line readable at all — PaddleOCR's own cropping is axis-aligned, so handing it a rotated box would read that box's envelope instead.

padding defaults to 5, which is what ScaleDP hardcodes. scaleFactor resizes the page before cropping and scales the box to index into it — useful for small text. The boxes reported back are the originals, in the space they arrived in.

detectLineOrientation defaults off here

TesseractRecognizer defaults it to true; this stage defaults it to false. PaddleOCR already turns a crop that is markedly taller than it is wide, so only the 180° case is missing — and catching it costs a separate ~9 MB model that an ordinary page never needs.

Turn it on for scans that come in upside down. It uses the same model as LineOrientationDetector, so putting that stage in front as well would run it twice.

Parameters