Large sharp barcode photos not correctly recognized

[GoogleCodeExporter]

What steps will reproduce the problem?
1. temporarily replace Error instances with a String in Exceptions since files 
seem to be missing.
2. compile j2se version.
3. test j2se version with test EAN_13 and UPC_A barcode images from 
code.google.com/p/zxing

What is the expected output? What do you see instead?
Very few of the barcodes are correctly recognized, even though most of the test 
images from 
zxing are larger, rather sharp photos (since zxing doesn't handle blur as jjil 
is designed to).  
Accuracy rate is low enough that I'm guessing there's a simple miscalculation 
somewhere and/or 
I'm not understanding how to correctly execute the code.

What version of the product are you using? On what operating system?
svn trunk as of 6/18/08

Please provide any additional information below.

Original issue reported on code.google.com by hanso...@gmail.com on 21 Jun 2008 at 6:27

[GoogleCodeExporter]

The previous code didn't really do barcode detection. I've added a new 
DetectBarcode
class to the barcode library and used it in ReadBarJ. I believe you will find
performance is much better. ReadBarJ will show the area of the image it 
detected the
barcode and also outline the approximate barcode edges with green lines. I 
updated
the source tree and also uploaded a new JAR file for ReadBarJ.

Original comment by jonaw...@gmail.com on 27 Jun 2008 at 8:15

[GoogleCodeExporter]

I created a larger monochrome version of barcodeEAN.png (see attached 
barcode_clean.png image).  All pixels 
are 0x000000 or 0xFFFFFF.  Each bar is exactly 3, 6, 9, or 12 pixels wide.  The 
total width of the barcode is 
285 pixels, centered within a 640 x 480 image with 0xFFFFFF background.

The output from the latest J2SE build is "The barcode could not be read".  The 
debug images look correct (see 
attachments); and the cYLeft, cYRight, wSlopeLeft, and wSlopeRight values 
passed to 
BarcodeReaderEan13.Decode() look good.  szCode is estimated as 8269992866737, 
4084483768866, 
5003443366630, and 1906153945336.  Estimated offsets seem good, so it appears 
there may be a bug in 
estimating the left and right codes?  Or maybe my image is just too perfect 
whereas the correlations expect 
more randomness?

Original comment by hanso...@gmail.com on 1 Jul 2008 at 9:42

Attachments:

• barcode_clean.png
• cropped.png
• edges.png
• test.jpg
• barcode.png

[GoogleCodeExporter]

Reattaching the image I created, which didn't upload correctly the first time.

Original comment by hanso...@gmail.com on 1 Jul 2008 at 9:45

Attachments:

• original.png

[GoogleCodeExporter]

-BarcodeReaderEan13.java line 800-803:

// estimate position of the middle of the barcode
// this will be the position of the second 0 in the
// string "0101010"
int dMidOffset =

It seems from the code that the string should be "1010101" where dMidOffset 
estimates the position of the second 1 (the first black bar in the "01010" 
center guard pattern)?  At 
least this is what the code estimates (x=187 in my attached cropped.png).  Or 
is the intention to estimate the left edge of the center guard pattern?

-BarcodeReaderEan13.java line 813-816:

// estimate position of the right of the barcode.
// this will be the position of the second 0 in the
// string "1010000"
int dRightOffset = 

It appears the code actually estimates the position of the first 0 (x=328 in my 
attached cropped.png).  Is this intentional, or should it be matching the 
second 0 as suggested in the 
comment?

Original comment by hanso...@gmail.com on 1 Jul 2008 at 11:04

[GoogleCodeExporter]

Narrowed the problem down to the following code from BarcodeReaderEan13.java 
(lines 1386-1393):

    private byte[] Stretch(byte[] bInput, int dLeft, int dRight, int dTargetWidth) {
        int dWidth = dRight - dLeft;
        byte[] bResult;
        if (dWidth % dTargetWidth == 0) {
            bResult = new byte[dTargetWidth];
            System.arraycopy(bInput, dLeft, bResult, 0, dTargetWidth);
            return bResult;
        }

in the case that (dWidth % dTargetWidth == 0), we should be creating a byte 
Array of width dWidth rather 
than dTarget width.  The current code truncates the array at the target width 
when the original data may have 
been a multiple of the target width.

Original comment by hanso...@gmail.com on 1 Jul 2008 at 11:47

[GoogleCodeExporter]

For the sake of completeness, the fix is (BarcodeReaderEan13.java lines 
1390-1391):

            bResult = new byte[dWidth];
            System.arraycopy(bInput, dLeft, bResult, 0, dWidth);

Original comment by hanso...@gmail.com on 1 Jul 2008 at 11:53

[GoogleCodeExporter]

Thanks, hansomli. I've made the change you suggested to the code and have given 
you
credit. The code now reads the 'original.png' image correctly. Please verify if 
you
have time.

Original comment by jonaw...@gmail.com on 18 Jul 2008 at 1:47

• Changed state: Fixed