OCRModule

TypeScript API implementation of the useOCR hook.

Reference

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

// Creating an instance
const ocrModule = new OCRModule();

// Loading the model
await ocrModule.load(OCR_ENGLISH);

// Running the model
const detections = await ocrModule.forward(imageUri);

Methods

Method	Type	Description
load	(model: { detectorSource: ResourceSource; recognizerLarge: ResourceSource; recognizerMedium: ResourceSource; recognizerSmall: ResourceSource; language: OCRLanguage }, onDownloadProgressCallback?: (progress: number) => void): Promise<void>	Loads the model, where detectorSource is a string that specifies the location of the detector binary, recognizerLarge is a string that specifies the location of the recognizer binary file which accepts input images with a width of 512 pixels, recognizerMedium is a string that specifies the location of the recognizer binary file which accepts input images with a width of 256 pixels, recognizerSmall is a string that specifies the location of the recognizer binary file which accepts input images with a width of 128 pixels, and language is a parameter that specifies the language of the text to be recognized by the OCR.
forward	(input: string): Promise<OCRDetections[]>	Executes the model's forward pass, where input can be a fetchable resource or a Base64-encoded string.
delete	(): void	Release the memory held by the module. Calling forward afterwards is invalid. Note that you cannot delete model while it's generating.

Type definitions

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 an object:

model - Object containing the detector source, recognizer sources, and language.

• detectorSource - A string that specifies the location of the detector binary.
• 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.
• language - A parameter that specifies the language of the text to be recognized by the OCR.

onDownloadProgressCallback - (Optional) Function called on download progress.

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

For more information on loading resources, take a look at loading models page.

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.