How to read datamatrix embedded in document? - zxing

Question

I try to read a datamatrix which is embedded into a document.
This is for an opensource project which helps to create and read 2DCODE standard.
I try with this code :
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.Hashtable;
import javax.imageio.ImageIO;
import org.junit.Test;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
public class ZxingTest {
#Test
public void test() {
readQRCode("sfr-facture-1048469311-1.jpg");
readQRCode("sfr-facture-1048469311-1.png");
}
public static void readQRCode(String fileName) {
System.out.println("Try reading " + fileName);
File file = new File(fileName);
BufferedImage image = null;
try {
image = ImageIO.read(file);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (image == null)
return;
Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>();
// hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
hints.put(DecodeHintType.POSSIBLE_FORMATS, Arrays.asList(BarcodeFormat.DATA_MATRIX));
decode(image, hints);
}
public static void decode(BufferedImage tmpBfrImage, Hashtable<DecodeHintType, Object> hintsMap) {
if (tmpBfrImage == null)
throw new IllegalArgumentException("Could not decode image.");
LuminanceSource tmpSource = new BufferedImageLuminanceSource(tmpBfrImage);
BinaryBitmap tmpBitmap = new BinaryBitmap(new HybridBinarizer(tmpSource));
MultiFormatReader tmpBarcodeReader = new MultiFormatReader();
Result tmpResult;
String tmpFinalResult;
try {
if (hintsMap != null && !hintsMap.isEmpty())
tmpResult = tmpBarcodeReader.decode(tmpBitmap, hintsMap);
else
tmpResult = tmpBarcodeReader.decode(tmpBitmap);
// setting results.
tmpFinalResult = String.valueOf(tmpResult.getText());
System.out.println("tmpFinalResult=" + tmpFinalResult);
} catch (Exception tmpExcpt) {
tmpExcpt.printStackTrace();
}
}
}
and those images found on the net :
sfr-facture-1048469311-1.jpg
sfr-facture-1048469311-1.png
But I get this exception regardless of the image format: com.google.zxing.NotFoundException
May you advise me an lib which parses the page and detect the datamatrix coordinates for a pre-processing cropping?
Or a better a example of code which read the datamatrix?

Answer 1

I have a solution to my problem. I use opencv to locate any barcode then, after extraction according to the returned coordinates, I read them with zxing.
I based my solution the work of http://karthikj1.github.io/BarcodeLocalizer/
this the code i use :
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.Reader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
import barcodelocalizer.Barcode;
import barcodelocalizer.CandidateResult;
import barcodelocalizer.ImageDisplay;
import barcodelocalizer.MatrixBarcode;
import barcodelocalizer.TryHarderFlags;
public class OpencvUtils {
private static boolean SHOW_INTERMEDIATE_STEPS = false;
private static boolean showImages = false;
public static String process_bufferedImage(BufferedImage bufferedImage) {
Barcode barcode;
String barcodeText = null;
// instantiate a class of type MatrixBarcode with the image filename
try {
barcode = new MatrixBarcode(bufferedImage, SHOW_INTERMEDIATE_STEPS, TryHarderFlags.VERY_SMALL_MATRIX);
// locateBarcode() returns a List<CandidateResult> with all possible candidate
// barcode regions from
// within the image. These images then get passed to a decoder(we use ZXing here
// but could be any decoder)
List<CandidateResult> results = barcode.locateBarcode();
System.out.println("Decoding buffered image " + results.size() + " candidate codes found");
String barcodeName = barcode.getName();
barcodeText = decodeBarcode(results, barcodeName, "Localizer");
} catch (IOException ioe) {
System.out.println("IO Exception when finding barcode " + ioe.getMessage());
}
return barcodeText;
}
public static String process_image(String imgFile) {
Barcode barcode;
String barcodeText = null;
// instantiate a class of type MatrixBarcode with the image filename
try {
barcode = new MatrixBarcode(imgFile, SHOW_INTERMEDIATE_STEPS, TryHarderFlags.VERY_SMALL_MATRIX);
// locateBarcode() returns a List<CandidateResult> with all possible candidate
// barcode regions from
// within the image. These images then get passed to a decoder(we use ZXing here
// but could be any decoder)
List<CandidateResult> results = barcode.locateBarcode();
System.out.println("Decoding " + imgFile + " " + results.size() + " candidate codes found");
String barcodeName = barcode.getName();
barcodeText = decodeBarcode(results, barcodeName, "Localizer");
} catch (IOException ioe) {
System.out.println("IO Exception when finding barcode " + ioe.getMessage());
}
return barcodeText;
}
private static String decodeBarcode(List<CandidateResult> candidateCodes, String filename, String caption) {
// decodes barcode using ZXing and either print the barcode text or says no
// barcode found
BufferedImage decodedBarcode = null;
String title = null;
Result result = null;
String barcodeText = null;
for (CandidateResult cr : candidateCodes) {
BufferedImage candidate = cr.candidate;
decodedBarcode = null;
LuminanceSource source = new BufferedImageLuminanceSource(candidate);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Reader reader = new MultiFormatReader();
Map<DecodeHintType, Object> hints = new EnumMap<>(DecodeHintType.class);
hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = reader.decode(bitmap, hints);
decodedBarcode = candidate;
title = filename + " " + caption + " - barcode text " + result.getText() + " " + cr.getROI_coords();
} catch (ReaderException re) {
}
if (decodedBarcode == null) {
title = filename + " - no barcode found - " + cr.getROI_coords();
if (showImages)
ImageDisplay.showImageFrame(candidate, title);
} else {
if (showImages)
ImageDisplay.showImageFrame(decodedBarcode, title);
System.out.println("Barcode text for " + filename + " is " + result.getText());
barcodeText = result.getText();
}
}
return barcodeText;
}
}
i added the method process_bufferedImage which process a java.awt.image.BufferedImage of a String filename.
And this sub-method to get the matrix of the BufferedImage bi.
protected Mat loadBufferedImage(BufferedImage bi) throws IOException {
// reads the BufferedImage passed in parameter
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(bi, "png", byteArrayOutputStream);
byteArrayOutputStream.flush();
Mat mat = Imgcodecs.imdecode(new MatOfByte(byteArrayOutputStream.toByteArray()), Imgcodecs.IMREAD_UNCHANGED);
return mat;
}