Search code examples
javaandroidbarcodegoogle-mlkit

ML Kit Barcode scanner picks up wrong scans sometimes

I am trying to make a barcode scanner using ML Kit and CameraX. My program would pick up the wrong scan once in a while and I have download several apps using ML Kit from google play and they have the same issue, I tested on other phones too. On the other hand, the ML Kit quick start app I pulled from Github works correctly so it has to be my code. Can anyone help me to find the issue ? I cannot upload img yet you can use online barcode generator (code 128) and create barcode for PAN/230954 my app will read as PAN/2 30954☒. Here is the barcode

Code 128 barcode

MainActivity.java


import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.AspectRatio;
import androidx.camera.core.CameraSelector;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageProxy;
import androidx.camera.core.Preview;
import androidx.camera.lifecycle.ProcessCameraProvider;
import androidx.camera.view.PreviewView;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.media.Image;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.mlkit.vision.barcode.Barcode;
import com.google.mlkit.vision.barcode.BarcodeScanner;
import com.google.mlkit.vision.barcode.BarcodeScannerOptions;
import com.google.mlkit.vision.barcode.BarcodeScanning;
import com.google.mlkit.vision.common.InputImage;

import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executors;

public class MainActivity extends AppCompatActivity {
    private static final String[] CAMERA_PERMISSION = new String[]{Manifest.permission.CAMERA};
    private static final int CAMERA_REQUEST_CODE = 10;
    private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;
    PreviewView previewView;
    ImageAnalysis imageAnalysis;
    ProcessCameraProvider cameraProvider;
    String barcodeText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        previewView = findViewById(R.id.previewView);
        if (!hasCameraPermission()) {
            requestPermission();
        }
        cameraProviderFuture = ProcessCameraProvider.getInstance(this);
        cameraProviderFuture.addListener(() -> {
            try {
                cameraProvider = cameraProviderFuture.get();
                bindPreview(cameraProvider);
            } catch (ExecutionException | InterruptedException e) {
                // No errors need to be handled for this Future.
                // This should never be reached.
            }
        }, ContextCompat.getMainExecutor(this));
    }

    void bindPreview(@NonNull ProcessCameraProvider cameraProvider) {
        Preview preview = new Preview.Builder()
                .setTargetAspectRatio(AspectRatio.RATIO_4_3)
                .build();

        CameraSelector cameraSelector = new CameraSelector.Builder()
                .requireLensFacing(CameraSelector.LENS_FACING_BACK)
                .build();

        preview.setSurfaceProvider(previewView.getSurfaceProvider());

        imageAnalysis =
                new ImageAnalysis.Builder()
                        //.setTargetAspectRatio(AspectRatio.RATIO_4_3)
                        //.setTargetResolution(new Size(1280, 720))
                        .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)//keep the latest
                        //to prevent bottleneck
                        .build();

        BarcodeScannerOptions barcodeScannerOptions = new BarcodeScannerOptions.Builder()
                .setBarcodeFormats(// input all desired code formats to be scanned
                        Barcode.FORMAT_CODE_128
                        //Barcode.FORMAT_CODE_39
                ).build();
        BarcodeScanner scanner = BarcodeScanning.getClient(barcodeScannerOptions);

        imageAnalysis.setAnalyzer(Executors.newSingleThreadExecutor(), new ImageAnalysis.Analyzer() {
            @Override
            public void analyze(@NonNull ImageProxy imageProxy) {
                @SuppressLint({"UnsafeExperimentalUsageError", "UnsafeOptInUsageError"}) Image mediaImage = imageProxy.getImage();
                if (mediaImage != null) {
                    InputImage image = InputImage.fromMediaImage(mediaImage, imageProxy.getImageInfo().getRotationDegrees());

                    Task<List<Barcode>> result = scanner.process(image);// get a list of barcode
                    result.addOnSuccessListener(new OnSuccessListener<List<Barcode>>() {
                        @Override
                        public void onSuccess(List<Barcode> barcodes) {
                            processBarcode(barcodes);

                        }
                    }).addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            Toast.makeText(getApplicationContext(), "Could not detect barcode!", Toast.LENGTH_SHORT).show();

                        }
                    }).addOnCompleteListener(new OnCompleteListener<List<Barcode>>() {
                        @Override
                        public void onComplete(@NonNull Task<List<Barcode>> task) {
                            mediaImage.close();
                            imageProxy.close();
                        }
                    });
                }
            }
        });


        cameraProvider.unbindAll();
        // Toast.makeText(this, String.valueOf(cameraProviderFuture.isDone()), Toast.LENGTH_SHORT).show();
         cameraProvider.bindToLifecycle(this, cameraSelector, imageAnalysis, preview);
        // Toast.makeText(this, String.valueOf(cameraProviderFuture.isDone()), Toast.LENGTH_SHORT).show();


    }

    private void processBarcode(List<Barcode> barcodes){
        Log.e("barcodes:",String.valueOf(barcodes));
        for(Barcode barcode: barcodes){
            barcodeText=barcode.getRawValue();
            Toast.makeText(getApplicationContext(),barcodeText,Toast.LENGTH_SHORT).show();
        }
    }
    /////handle camera permission////////////
    private boolean hasCameraPermission() {
        return ContextCompat.checkSelfPermission(
                this,
                Manifest.permission.CAMERA
        ) == PackageManager.PERMISSION_GRANTED;
    }

    private void requestPermission() {
        ActivityCompat.requestPermissions(
                this,
                CAMERA_PERMISSION,
                CAMERA_REQUEST_CODE
        );
    }
    //////////////////////
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <FrameLayout
        android:id="@+id/frameLayout"
        android:layout_width="415dp"
        android:layout_height="587dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <androidx.camera.view.PreviewView
            android:id="@+id/previewView"
            android:layout_width="match_parent"
            android:layout_height="588dp">

        </androidx.camera.view.PreviewView>

    </FrameLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

build.grade(app)

plugins {
    id 'com.android.application'
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.3"

    defaultConfig {
        applicationId "com.sunrise.barcodescantest"
        minSdkVersion 26
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.3.1'
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.1'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    def camerax_version = "1.1.0-alpha08"
    // The following line is optional, as the core library is included indirectly by camera-camera2
    implementation "androidx.camera:camera-core:${camerax_version}"
    implementation "androidx.camera:camera-camera2:${camerax_version}"
    // If you want to additionally use the CameraX Lifecycle library
    implementation "androidx.camera:camera-lifecycle:${camerax_version}"
    // If you want to additionally use the CameraX View class
    implementation "androidx.camera:camera-view:1.0.0-alpha28"
    // If you want to additionally use the CameraX Extensions library
    implementation "androidx.camera:camera-extensions:1.0.0-alpha28"
    //BUNDLED MODE ML KIT
    implementation 'com.google.mlkit:barcode-scanning:17.0.0'
    //Apache common library
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.sunrise.barcodescantest">

    <uses-permission android:name="android.permission.CAMERA" />


    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.BarcodeScanTest">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>
Solution

  • I found the issue. I used barcode.getRawValue() which return the raw value. For the barcode I tried to scan the checksum is 29 so the raw value is the barcode text + char with acii code 29. So I used barcode.getDisplayValue() instead