Basic Barcode Recognition

Read Barcode from Image File

Overview

Aspose.BarCode for Java provides powerful barcode recognition capabilities that can read barcodes from various image formats. This guide shows you how to quickly recognize barcodes from image files.

Basic Barcode Recognition

Here’s the simplest way to read a barcode from an image:

import com.aspose.barcode.barcoderecognition.*;

public class BasicRecognitionExample {
    public static void main(String[] args) {
        // Create barcode reader instance
        BarCodeReader reader = new BarCodeReader("barcode.png");
        
        // Read all barcodes
        for (BarCodeResult result : reader.readBarCodes()) {
            System.out.println("Barcode Type: " + result.getCodeTypeName());
            System.out.println("Barcode Text: " + result.getCodeText());
        }
    }
}

Specifying Barcode Types

For better performance, specify which barcode types to recognize:

import com.aspose.barcode.barcoderecognition.*;

public class SpecificTypeRecognition {
    public static void main(String[] args) {
        // Read only QR codes
        BarCodeReader reader = new BarCodeReader(
            "image.png", 
            DecodeType.QR
        );
        
        for (BarCodeResult result : reader.readBarCodes()) {
            System.out.println("QR Code: " + result.getCodeText());
        }
    }
}

Multiple Barcode Types

// Read multiple specific types
BarCodeReader reader = new BarCodeReader(
    "image.png", 
    DecodeType.CODE_128, 
    DecodeType.QR, 
    DecodeType.DATA_MATRIX
);

for (BarCodeResult result : reader.readBarCodes()) {
    System.out.println(result.getCodeTypeName() + ": " + result.getCodeText());
}

All 1D Barcodes

// Read all 1D barcode types
BarCodeReader reader = new BarCodeReader(
    "image.png", 
    DecodeType.ALL_SUPPORTED_TYPES.Types1D
);

All 2D Barcodes

// Read all 2D barcode types
BarCodeReader reader = new BarCodeReader(
    "image.png", 
    DecodeType.ALL_SUPPORTED_TYPES.Types2D
);

Reading from Different Sources

From File Path

BarCodeReader reader = new BarCodeReader("/path/to/barcode.png", DecodeType.CODE_128);

From Stream

import java.io.FileInputStream;

try (FileInputStream stream = new FileInputStream("barcode.png")) {
    BarCodeReader reader = new BarCodeReader(stream, DecodeType.QR);
    
    for (BarCodeResult result : reader.readBarCodes()) {
        System.out.println(result.getCodeText());
    }
} catch (Exception e) {
    e.printStackTrace();
}

From Byte Array

import java.nio.file.Files;
import java.nio.file.Paths;

byte[] imageBytes = Files.readAllBytes(Paths.get("barcode.png"));
BarCodeReader reader = new BarCodeReader(imageBytes, DecodeType.CODE_128);

Accessing Barcode Details

The BarCodeResult object provides detailed information about recognized barcodes:

BarCodeReader reader = new BarCodeReader("barcode.png", DecodeType.QR);

for (BarCodeResult result : reader.readBarCodes()) {
    // Basic information
    System.out.println("Type: " + result.getCodeTypeName());
    System.out.println("Text: " + result.getCodeText());
    
    // Barcode region coordinates
    System.out.println("Region: " + result.getRegion().toString());
    
    // Confidence level (0-100%)
    System.out.println("Confidence: " + result.getConfidence() + "%");
    
    // Barcode angle
    System.out.println("Angle: " + result.getRegion().getAngle() + " degrees");
    
    // Raw bytes
    byte[] bytes = result.getCodeBytes();
    System.out.println("Raw bytes length: " + bytes.length);
}

Setting Recognition Region (ROI)

To improve performance, you can specify a region of interest:

import com.aspose.barcode.barcoderecognition.*;
import java.awt.Rectangle;

BarCodeReader reader = new BarCodeReader("image.png", DecodeType.CODE_128);

// Set recognition area (x, y, width, height)
reader.setBarCodeImage(new Rectangle(100, 100, 400, 300));

for (BarCodeResult result : reader.readBarCodes()) {
    System.out.println(result.getCodeText());
}

Complete Recognition Example

import com.aspose.barcode.barcoderecognition.*;
import java.io.File;

public class CompleteRecognitionExample {
    public static void main(String[] args) {
        try {
            String imagePath = "barcode_image.png";
            
            // Check if file exists
            if (!new File(imagePath).exists()) {
                System.err.println("Image file not found!");
                return;
            }
            
            // Create reader for multiple barcode types
            BarCodeReader reader = new BarCodeReader(
                imagePath,
                DecodeType.CODE_128,
                DecodeType.QR,
                DecodeType.DATA_MATRIX,
                DecodeType.PDF_417
            );
            
            // Configure recognition quality
            reader.setQualitySettings(QualitySettings.getHighPerformance());
            
            // Read all barcodes
            BarCodeResult[] results = reader.readBarCodes();
            
            if (results.length == 0) {
                System.out.println("No barcodes found in the image.");
                return;
            }
            
            System.out.println("Found " + results.length + " barcode(s):");
            System.out.println("-----------------------------------");
            
            for (int i = 0; i < results.length; i++) {
                BarCodeResult result = results[i];
                
                System.out.println("\nBarcode #" + (i + 1));
                System.out.println("Type: " + result.getCodeTypeName());
                System.out.println("Text: " + result.getCodeText());
                System.out.println("Confidence: " + result.getConfidence() + "%");
                
                // Get coordinates
                java.awt.Point[] points = result.getRegion().getPoints();
                System.out.println("Position: (" + 
                    points[0].x + ", " + points[0].y + ")");
                
                // Rotation angle
                System.out.println("Angle: " + 
                    result.getRegion().getAngle() + "°");
            }
            
            System.out.println("\nRecognition completed successfully!");
            
        } catch (Exception e) {
            System.err.println("Error during recognition: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

Performance Optimization

High Performance Mode

For fast recognition when image quality is good:

BarCodeReader reader = new BarCodeReader("image.png", DecodeType.CODE_128);
reader.setQualitySettings(QualitySettings.getHighPerformance());

High Quality Mode

For difficult images or damaged barcodes:

BarCodeReader reader = new BarCodeReader("image.png", DecodeType.QR);
reader.setQualitySettings(QualitySettings.getHighQuality());

Maximum Barcodes

Set expected number of barcodes for optimization:

BarCodeReader reader = new BarCodeReader("image.png", DecodeType.CODE_128);
reader.setQualitySettings(QualitySettings.getHighPerformance());

// Expect exactly 1 barcode
reader.getQualitySettings().setExpectSingleBarcode(true);

Handling Multiple Barcodes

BarCodeReader reader = new BarCodeReader("multiple_barcodes.png");

int barcodeCount = 0;
for (BarCodeResult result : reader.readBarCodes()) {
    barcodeCount++;
    System.out.println("Barcode " + barcodeCount + ": " + result.getCodeText());
}

System.out.println("Total barcodes found: " + barcodeCount);

Supported Image Formats

Aspose.BarCode supports reading barcodes from:

• Raster formats: PNG, JPEG, BMP, GIF, TIFF, EXIF
• Multi-page formats: Multi-page TIFF
• Other formats: EMF, WMF

// Example with different formats
BarCodeReader pngReader = new BarCodeReader("barcode.png", DecodeType.QR);
BarCodeReader jpgReader = new BarCodeReader("barcode.jpg", DecodeType.CODE_128);
BarCodeReader tiffReader = new BarCodeReader("barcode.tiff", DecodeType.DATA_MATRIX);

Error Handling

Always handle potential exceptions:

try {
    BarCodeReader reader = new BarCodeReader("barcode.png", DecodeType.CODE_128);
    BarCodeResult[] results = reader.readBarCodes();
    
    if (results.length == 0) {
        System.out.println("No barcodes detected");
    } else {
        for (BarCodeResult result : results) {
            System.out.println(result.getCodeText());
        }
    }
    
} catch (java.io.FileNotFoundException e) {
    System.err.println("Image file not found: " + e.getMessage());
} catch (Exception e) {
    System.err.println("Recognition error: " + e.getMessage());
    e.printStackTrace();
}

Best Practices

1. Specify barcode types: Always specify expected types for better performance
2. Use appropriate quality settings: Balance speed vs accuracy based on your needs
3. Handle no results: Always check if any barcodes were found
4. Set recognition region: Use ROI when you know where barcodes are located
5. Check confidence levels: Validate results with low confidence scores
6. Optimize image quality: Use high-resolution, clear images for best results

Next Steps

• Learn about Advanced Recognition Settings
• Explore Image Preprocessing
• Read about Recognition Quality Optimization
• See Multi-Page TIFF Recognition