OCR

Optical Character Recognition (OCR) is a real-time mobile Android app that allows users to scan, translate and read aloud text in any major language.

Prerequisites

Google API console account with "APIs and Services" enabled.
Google cloud API credential file in json format.
Android Studio, with a recent version of the Android SDK.

Installation

Download the OCR directory from this repository. Or

git clone https://github.com/DivyaAmirtharaj/OCR.git

In Android Studio, open the OCR directory as an existing Android Studio project.

Install the following libraries by including the following lines in OCR/app/build.gradle

   implementation 'com.android.support:support-v4:24.0.0'
   implementation 'com.google.android.gms:play-services-vision:9.8.0'
   implementation 'com.android.support:design:24.0.0'
   implementation('com.google.cloud:google-cloud-translate:1.16.0')

Compilation

Have minimum SDK Version of 21 to have Translate API work. Have following code in build.grade under android block.

   compileSdkVersion 26
    defaultConfig {
        applicationId "edu.harvard.cs50.divya.amirtharaj.OCR"
        minSdkVersion 21
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        multiDexEnabled true
    }

Setting up Translate API in Google

Translation of OCR text is done through Google API. For that API service for transation needs to be set in Google API console. Follow below step to setup the API service

1. Sign in to Google API Console
2. Use existing project or create "New Project"
3. On the Google Cloud Platform dashboard, select "APIs & Services" on the navigation window at the left side
4. Click on the "Enable APIs and Services" button
5. Search for "Cloud Translation API" and click "Enable" button
6. Click the "Enable billing" and setup the trial service and provide payment information.

Setting up API Credentials

To secure the API service and to restrict the access to authorized apps, use following steps.

1. Click "Create Credentials on the Google API Console
2. Select "Cloud Translation API", check "No, I'm not using them and click on "Which credentials do I need?"
3. Enter your information and select "JSON" as the key type and click "Cotinue"
4. The credentials file will be downloaded in JSON format. Save this file in Android Studio raw folder

Internet Permission for Translate API

Add internet permission to AndroidMaifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="edu.harvard.cs50.divya.amirtharaj.ocr"
          android:installLocation="auto">

    <uses-feature android:name="android.hardware.camera"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.INTERNET"/>

OCR

Following libraries are used for Character Recoginition

import com.google.android.gms.vision.text.TextRecognizer;
import com.google.android.gms.vision.CameraSource;
import com.google.android.gms.vision.text.TextBlock;
import com.google.android.gms.common.images.Size;
import com.google.android.gms.vision.Detector;
import com.google.android.gms.vision.Frame;

Text To Speech TTS

TextToSpeech class used to speak the OCR captured and Translated Text.

Locale

Locale is used to set the language and country of speaker.

Locale locale = new Locale( <<Language>>, <<Country>>);
TextToSpeech.OnInitListener listener =  new TextToSpeech.OnInitListener() {

public void onInit(final int status) {  tts.setLanguage(locale); } };

tts = new TextToSpeech(this.getApplicationContext(), listener);
Locale.setDefault(locale);
Configuration config = new Configuration();
config.setLocale(locale);

Language	Code	Country
English	en	US
Spanish	es	MX
French	fr	FR
Japanese	ja	JP
Chinese	zh	CN
German	de	DE
Italian	it	IT
Korean	ko	KR
Hindi	hi	KR
Russian	ru	RU
Arabic	ar	AE
Greek	el	GR
Hebrew	he	IL
Vietnamese	vi	VN
Tamil	ta	IN

Translation

Following libraries are used for Translation

import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.translate.Translate;
import com.google.cloud.translate.TranslateOptions;
import com.google.cloud.translate.Translation;

Credentials

Credential file generated from the Google API service is stored res/raw folder as cred.json

 try (InputStream is = getResources().openRawResource(R.raw.cred)) {
      final GoogleCredentials myCredentials = GoogleCredentials.fromStream(is);
   } catch (IOException ioe) {
      ioe.printStackTrace();
   }

Starting Translate Service

Using the above credentials to call the API service

TranslateOptions translateOptions = TranslateOptions.newBuilder().setCredentials(myCredentials).build();
OCRSettings.setTranslate( translateOptions.getService());

Translate translate = translateOptions.getService() Translation translation = translate.translate(<>, Translate.TranslateOption.targetLanguage(OCRSettings.getLang()), Translate.TranslateOption.model("base"));