我需要阅读tiffs的pdf417条形码。图像上通常有多个条形码 -
这是我的代码：
InputStream in = null;
BufferedImage bfi = null;
File[] files = new File(DIR).listFiles();
for (int i = 0; i < files.length; i++) {
if (files[i].isFile()) {
try {
System.out.println(files[i].getName());
in = new FileInputStream(files[i]);
bfi = ImageIO.read(in);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
if (bfi != null) {
LuminanceSource ls = new BufferedImageLuminanceSource(bfi);
BinaryBitmap bmp = new BinaryBitmap(new HybridBinarizer(ls));
Reader reader = new MultiFormatReader();
Result result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = reader.decode(bmp, decodeHints);
} catch (NotFoundException e) {
e.printStackTrace();
} catch (ChecksumException e) {
e.printStackTrace();
} catch (FormatException e) {
e.printStackTrace();
}
System.out.println(result.getBarcodeFormat());
System.out.println("Text " + result.getText());
System.out
.println("-------------------------------------------------------");
} else {
System.out.println("No Buffered Image for "
+ files[i].getName());
}
}
}
这有时会起作用，但有时却不起作用，结果为空。
我查看了zxing的javadoc并找到了GenericMultipleBarcodeReader。 我尝试在我的代码中使用但是我做错了因为我得到了NullPointerException：
Reader reader = new MultiFormatReader();
GenericMultipleBarcodeReader greader = new GenericMultipleBarcodeReader(reader);
Result[] result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = greader.decodeMultiple(bmp, decodeHints);
} catch (NotFoundException e) {
e.printStackTrace();
}
for (int j = 0; j < result.length; j++) {
System.out.println(result[j].getBarcodeFormat());
System.out.println("Text " + result[j].getText());
}
Exception in thread "main" java.lang.NullPointerException
at com.google.zxing.multi.GenericMultipleBarcodeReader.translateResultPoints(GenericMultipleBarcodeReader.java:163)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:96)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:148)
at com.google.zxing.multi.GenericMultipleBarcodeReader.decodeMultiple(GenericMultipleBarcodeReader.java:65)
at barcode.ZXingTest.main(ZXingTest.java:77)
所以问题是：使用GenericMultipleBarcodeReader（或其他类）扫描图像上的多个条形码是否更好？如果是，我该如何实现呢？
更新：
for (int i = 0; i < files.length; i++) {
try (BufferedInputStream bfin = new BufferedInputStream(
new FileInputStream(files[i]))) {
dateiname = files[i].getName();
bfi = ImageIO.read(bfin);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (bfi != null) {
LuminanceSource ls = new BufferedImageLuminanceSource(bfi);
BinaryBitmap bmp = new BinaryBitmap(new HybridBinarizer(ls));
Reader reader = new MultiFormatReader();
GenericMultipleBarcodeReader greader = new GenericMultipleBarcodeReader(
new ByQuadrantReader(reader));
Result[] result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = greader.decodeMultiple(bmp, decodeHints);
} catch (NotFoundException e) {
e.printStackTrace();
System.out.println("No result");
System.out.println("+++++++++++++++++++++++++++++++");
}
if (result != null) {
for (int j = 0; j < result.length; j++) {
System.out.println(result[j].getText());
System.out.println("+++++++++++++++++++++++++++++++");
}
}
} else {
System.out.println("No Buffered Image for "
+ files[i].getName());
}
}
如果我在没有ByQuadrantReader的情况下尝试它，我会得到相同的NullPointerException。 我这样做的方式，result.length有时是1（返回一个String），有时我得到一个NotFoundException。
我希望我的代码中没有一个愚蠢的错误，我看不到......
第二次编辑：
Exception in thread "main" java.lang.NullPointerException
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:109)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:148)
at com.google.zxing.multi.GenericMultipleBarcodeReader.decodeMultiple(GenericMultipleBarcodeReader.java:65)
at barcode.ZXingTestMulti.main(ZXingTestMulti.java:86)
current version of code:
public static void main(final String[] args) {
BufferedImage bfi = null;
File[] files = new File(DIR).listFiles();
int counttiffs = 0;
String filename = null;
TreeMap<String, Exception> errormap = new TreeMap<String, Exception>();
int onebarcode = 0;
int twobarcodes = 0;
int threebarcodes = 0;
for (int i = 0; i < files.length; i++) {
if (files[i].isFile()) {
try (BufferedInputStream bfin = new BufferedInputStream(
new FileInputStream(files[i]))) {
filename = files[i].getName();
bfi = ImageIO.read(bfin);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (bfi != null) {
LuminanceSource ls = new BufferedImageLuminanceSource(bfi);
BinaryBitmap bmp = new BinaryBitmap(new HybridBinarizer(ls));
Reader reader = new MultiFormatReader();
GenericMultipleBarcodeReader greader = new GenericMultipleBarcodeReader(
reader);
Result[] result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = greader.decodeMultiple(bmp, decodeHints);
} catch (NotFoundException e) {
errormap.put(filename, e);
} catch (NullPointerException e) {
errormap.put(filename, e);
}
if (result != null) {
switch (result.length) {
case 1:
onebarcode++;
break;
case 3:
threebarcodes++;
break;
default:
twobarcodes++;
}
try (BufferedWriter bfwr = new BufferedWriter(
new FileWriter(FILE, true))) {
bfwr.write(filename + ": number of barcodes found = "
+ result.length);
bfwr.newLine();
for (int j = 0; j < result.length; j++) {
bfwr.write(result[j].getText());
}
bfwr.newLine();
bfwr.write("---------------------------------------------------------");
bfwr.newLine();
counttiffs++;
} catch (IOException e) {
e.printStackTrace();
}
}
}
else {
System.out.println("No Buffered Image for "
+ files[i].getName());
}
}
}
我正在使用核心和javase的快照3.1.1。
如你所见，我需要抓住NPE：
java.lang.NullPointerException
at com.google.zxing.multi.GenericMultipleBarcodeReader.translateResultPoints(GenericMultipleBarcodeReader.java:163)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:96)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:148)
at com.google.zxing.multi.GenericMultipleBarcodeReader.decodeMultiple(GenericMultipleBarcodeReader.java:65)
at zBarcodes_Test.ZXingTestMulti.main(ZXingTestMulti.java:72)
与第一个相同。在你第一次提交之后，我在不同的行上获得了一个NPE，但现在要么我使用了错误的依赖关系，要么再次发生了。
另一件事是：我扫描了大约2.500个tiff文件，每个文件上有两个pdf417条形码，有些倾斜，有些不完美（有些像素是白色而不是黑色）。我总共得到1644个错误，这些错误要么是由NotFoundException引起的，要么是由NullPointer异常引起的。在成功扫描的948个文件中，218个结果。长度为1（并且只找到一个条形码），68个，结果长度为3（但它扫描了2条条码）。
根据您的经验，如果条形码不是直线且边缘上的误差很小，而且像素没有完美打印，那么zxing是多么明智？
答案 0 :(得分：1)
这看起来像一个bug，我在https://github.com/zxing/zxing/commit/e715fec42a2f8643c8f53c331f7218a1e62b0dc2中修复了你可以尝试修复，也许是通过抓住3.1.1-SNAPSHOT？