OCRModule

TypeScript API implementation of the useOCR hook.

Reference

import {
  OCRModule,
  DETECTOR_CRAFT_800,
  RECOGNIZER_EN_CRNN_512,
  RECOGNIZER_EN_CRNN_256,
  RECOGNIZER_EN_CRNN_128,
} from 'react-native-executorch';
const imageUri = 'path/to/image.png';

// Loading the model
await OCRModule.load({
  detectorSource: DETECTOR_CRAFT_800,
  recognizerSources: {
    recognizerLarge: RECOGNIZER_EN_CRNN_512,
    recognizerMedium: RECOGNIZER_EN_CRNN_256,
    recognizerSmall: RECOGNIZER_EN_CRNN_128,
  },
  language: 'en',
});

// Running the model
const ocrDetections = await OCRModule.forward(imageUri);

Methods

Method	Type	Description
load	(detectorSource: string, recognizerSources: RecognizerSources, language: OCRLanguage): Promise<void>	Loads the detector and recognizers, which sources are represented by RecognizerSources.
forward	(input: string): Promise<OCRDetections[]>	Executes the model's forward pass, where input can be a fetchable resource or a Base64-encoded string.
onDownloadProgress	(callback: (downloadProgress: number) => void): any	Subscribe to the download progress event.

Type definitions

interface RecognizerSources {
  recognizerLarge: string | number;
  recognizerMedium: string | number;
  recognizerSmall: string | number;
}

type OCRLanguage =
  | 'abq'
  | 'ady'
  | 'af'
  | 'ava'
  | 'az'
  | 'be'
  | 'bg'
  | 'bs'
  | 'chSim'
  | 'che'
  | 'cs'
  | 'cy'
  | 'da'
  | 'dar'
  | 'de'
  | 'en'
  | 'es'
  | 'et'
  | 'fr'
  | 'ga'
  | 'hr'
  | 'hu'
  | 'id'
  | 'inh'
  | 'ic'
  | 'it'
  | 'ja'
  | 'kbd'
  | 'kn'
  | 'ko'
  | 'ku'
  | 'la'
  | 'lbe'
  | 'lez'
  | 'lt'
  | 'lv'
  | 'mi'
  | 'mn'
  | 'ms'
  | 'mt'
  | 'nl'
  | 'no'
  | 'oc'
  | 'pi'
  | 'pl'
  | 'pt'
  | 'ro'
  | 'ru'
  | 'rsCyrillic'
  | 'rsLatin'
  | 'sk'
  | 'sl'
  | 'sq'
  | 'sv'
  | 'sw'
  | 'tab'
  | 'te'
  | 'th'
  | 'tjk'
  | 'tl'
  | 'tr'
  | 'uk'
  | 'uz'
  | 'vi';

interface Point {
  x: number;
  y: number;
}

interface OCRDetection {
  bbox: Point[];
  text: string;
  score: number;
}

Loading the model

To load the model, use the load method. It accepts:

detectorSource - A string that specifies the location of the detector binary. For more information, take a look at loading models section.

recognizerSources - An object that specifies locations of the recognizers binary files. Each recognizer is composed of three models tailored to process images of varying widths.

• recognizerLarge - A string that specifies the location of the recognizer binary file which accepts input images with a width of 512 pixels.
• recognizerMedium - A string that specifies the location of the recognizer binary file which accepts input images with a width of 256 pixels.
• recognizerSmall - A string that specifies the location of the recognizer binary file which accepts input images with a width of 128 pixels.

For more information, take a look at loading models section.

language - A parameter that specifies the language of the text to be recognized by the OCR.

This method returns a promise, which can resolve to an error or void.

Listening for download progress

To subscribe to the download progress event, you can use the onDownloadProgress method. It accepts a callback function that will be called whenever the download progress changes.

Running the model

To run the model, you can use the forward method. It accepts one argument, which is the image. The image can be a remote URL, a local file URI, or a base64-encoded image. The method returns a promise, which can resolve either to an error or an array of OCRDetection objects. Each object contains coordinates of the bounding box, the label of the detected object, and the confidence score.