react-native-ocr-package

React Native OCR Component

A React component for scanning National Identity cards using a device's camera. This package integrates OCR technology to extract the text data from scanned cards by making API calls.

Features

• Opens the camera directly in your React application.
• Scans National Identity cards in real-time.
• Calls a backend API for OCR processing.
• Returns parsed data for further use.
• Provides base64 encoded images of the front and back of the document, as well as the selfie.
• Supports liveness detection on Android devices.

Installation

Install the package via npm:

npm install react-native-ocr-package

Additionally, install the required dependency:

npm install react-native-document-scanner-plugin

Usage

Here is how to use the component in your React application:

Basic Example

import React, {useState} from 'react';
import { View, Image } from 'react-native';
import {CameraComponent} from 'react-native-ocr-package';

const App = () => {
  const [documentImages, setDocumentImages] = useState(null);

  const handleOCRResult = ocrResult => {
    console.log('OCR Result:', ocrResult);
    
    // Access the base64 images from the response
    if (ocrResult.DocumentImages) {
      setDocumentImages(ocrResult.DocumentImages);
    }
  };

  return (
    <View style={{flex: 1}}>
        <CameraComponent
          ocrApiUrl="https://your-api-endpoint.com/"
          onScanComplete={handleOCRResult}
        />
        
        {/* Display the images if available */}
        {documentImages && (
          <View style={{flexDirection: 'row'}}>
            <Image 
              source={{uri: `data:image/jpeg;base64,${documentImages.frontImageBase64}`}}
              style={{width: 100, height: 100}}
            />
            <Image 
              source={{uri: `data:image/jpeg;base64,${documentImages.backImageBase64}`}}
              style={{width: 100, height: 100}}
            />
            <Image 
              source={{uri: `data:image/jpeg;base64,${documentImages.selfieImageBase64}`}}
              style={{width: 100, height: 100}}
            />
          </View>
        )}
    </View>
  );
};

export default App;

Integrating Liveness Detection with Document Scanning

To prevent crashes when transitioning from liveness detection to document scanning, use the VerificationWorkflow utility:

import React, { useState } from 'react';
import { View, Button, Text, Image } from 'react-native';
import { CameraComponent, LivenessDetection, VerificationWorkflow } from 'react-native-ocr-package';

const VerificationScreen = () => {
  const [currentStep, setCurrentStep] = useState('start'); // 'start', 'document', 'complete'
  const [livenessResult, setLivenessResult] = useState(null);
  const [finalResult, setFinalResult] = useState(null);
  const [error, setError] = useState(null);
  
  const startVerification = () => {
    setCurrentStep('processing');
    setError(null);
    
    // Use the workflow utility to handle the transition
    VerificationWorkflow.startVerification({
      ocrApiUrl: 'https://your-api-endpoint.com/',
      onError: (err) => {
        setError(err.message);
        setCurrentStep('start');
      },
      onReadyForDocumentScan: (result) => {
        // Store liveness result and move to document scanning step
        setLivenessResult(result);
        setCurrentStep('document');
      }
    });
  };
  
  const handleDocumentScanComplete = (ocrResult) => {
    // Combine liveness and OCR results
    const combinedResult = VerificationWorkflow.combineResults(livenessResult, ocrResult);
    setFinalResult(combinedResult);
    setCurrentStep('complete');
  };
  
  // Render based on current step
  return (
    <View style={{ flex: 1 }}>
      {currentStep === 'start' && (
        <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center', padding: 20 }}>
          <Text style={{ fontSize: 24, marginBottom: 20 }}>Identity Verification</Text>
          {error && <Text style={{ color: 'red', marginBottom: 20 }}>{error}</Text>}
          <Button title="Start Verification" onPress={startVerification} />
        </View>
      )}
      
      {currentStep === 'processing' && (
        <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
          <Text>Processing liveness detection...</Text>
        </View>
      )}
      
      {currentStep === 'document' && (
        <CameraComponent
          ocrApiUrl="https://your-api-endpoint.com/"
          onScanComplete={handleDocumentScanComplete}
        />
      )}
      
      {currentStep === 'complete' && finalResult && (
        <View style={{ flex: 1, padding: 20 }}>
          <Text style={{ fontSize: 20, marginBottom: 20 }}>Verification Complete</Text>
          
          {/* Display liveness selfie */}
          {finalResult.liveness?.selfieImageBase64 && (
            <View style={{ alignItems: 'center', marginBottom: 20 }}>
              <Text>Liveness Selfie:</Text>
              <Image 
                source={{ uri: `data:image/jpeg;base64,${finalResult.liveness.selfieImageBase64}` }}
                style={{ width: 150, height: 150, marginTop: 10 }}
              />
            </View>
          )}
          
          {/* Display document images */}
          {finalResult.ocr?.DocumentImages && (
            <View>
              <Text>Document Images:</Text>
              <View style={{ flexDirection: 'row', justifyContent: 'space-between', marginTop: 10 }}>
                <Image 
                  source={{ uri: `data:image/jpeg;base64,${finalResult.ocr.DocumentImages.frontImageBase64}` }}
                  style={{ width: 100, height: 100 }}
                />
                <Image 
                  source={{ uri: `data:image/jpeg;base64,${finalResult.ocr.DocumentImages.backImageBase64}` }}
                  style={{ width: 100, height: 100 }}
                />
              </View>
            </View>
          )}
          
          <Button title="Start Over" onPress={() => {
            setCurrentStep('start');
            setLivenessResult(null);
            setFinalResult(null);
          }} />
        </View>
      )}
    </View>
  );
};

export default VerificationScreen;

Props

The CameraComponent accepts the following props:

Prop Name	Type	Required	Description
ocrApiUrl	string	Yes	The API endpoint to call for OCR processing of the scanned image.
onScanComplete	func	Yes	Callback function invoked with the scanned OCR result.

Sample Output

Here is an example of the JSON output returned by the API when the scan is successful:

{
  "Code": 200,
  "Message": "Success",
  "Data": {
    "OCR": {
      "Code": 100,
      "Message": "Success",
      "CNIC_MATCHED": true,
      "DOI": "10.06.2014",
      "DOB": "12.03.2000",
      "DOE": "10.06.2024",
      "CNum": "12345-1234567-1",
      "Name": "ABC",
      "FName": "XYZ"
    },
    "Image_Comparison": {
      "Code": 100,
      "Message": "Selfie and CNIC Matched",
      "confidence_score": 100.0
    }
  },
  "DocumentImages": {
    "frontImageBase64": "base64_encoded_string_of_front_image...",
    "backImageBase64": "base64_encoded_string_of_back_image...",
    "selfieImageBase64": "base64_encoded_string_of_selfie_image..."
  }
}

The DocumentImages field contains base64 encoded strings of the captured images, which can be used directly with React Native's Image component or sent to your backend for storage or further processing.

Combined Verification Result

When using the VerificationWorkflow to combine liveness and document scanning, the result will have this structure:

{
  "liveness": {
    "isLive": true,
    "selfieImageBase64": "base64_encoded_string_of_liveness_selfie...",
    "faceDetails": {
      "blinkDetected": true,
      "smileDetected": true,
      "faceAligned": true,
      "headEulerAngleX": 1.2,
      "headEulerAngleY": 0.5,
      "headEulerAngleZ": 0.3
    }
  },
  "ocr": {
    "Code": 200,
    "Message": "Success",
    "Data": {
      "OCR": {
        "Code": 100,
        "Message": "Success",
        "CNIC_MATCHED": true,
        "DOI": "10.06.2014",
        "DOB": "12.03.2000",
        "DOE": "10.06.2024",
        "CNum": "12345-1234567-1",
        "Name": "ABC",
        "FName": "XYZ"
      },
      "Image_Comparison": {
        "Code": 100,
        "Message": "Selfie and CNIC Matched",
        "confidence_score": 100.0
      }
    },
    "DocumentImages": {
      "frontImageBase64": "base64_encoded_string_of_front_image...",
      "backImageBase64": "base64_encoded_string_of_back_image...",
      "selfieImageBase64": "base64_encoded_string_of_selfie_image..."
    }
  },
  "combinedAt": "2023-07-15T12:34:56.789Z"
}