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Made a change to 1D decoding which looks for 100% instead of 150% of the start and end patterns when searching for quiet zones, but in exchange for that reduction, we reject rows whose quiet zones would run off either edge of the image.

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The result is complete elimination of all false positives in the new batch of 40 images I just checked in. Bettter than that, we come up with a net gain of 38 new barcodes decoded (counting rotation and try harder variations). We even get some of the reflective images that were impossible up to this point.

git-svn-id: https://zxing.googlecode.com/svn/trunk@620 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
dswitkin 2008-10-15 19:47:34 +00:00
parent 09ce5db11d
commit 8cb804ec9e
9 changed files with 29 additions and 23 deletions
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18
core/src/com/google/zxing/oned/AbstractUPCEANReader.java
View file

@ -35,7 +35,7 @@ import java.util.Hashtable;
*/
public abstract class AbstractUPCEANReader extends AbstractOneDReader implements UPCEANReader {
private static final int MAX_AVG_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.40625f);
private static final int MAX_AVG_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.42f);
private static final int MAX_INDIVIDUAL_VARIANCE = (int) (PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.7f);
/**
@ -92,9 +92,13 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
startRange = findGuardPattern(row, nextStart, false, START_END_PATTERN);
int start = startRange[0];
nextStart = startRange[1];
// As a check, we want to see some white in front of this "start pattern",
// maybe as wide as the 150% of the start pattern itself?
foundStart = row.isRange(Math.max(0, start - (3 * (nextStart - start)) / 2), start, false);
// Make sure there is a quiet zone at least as big as the start pattern before the barcode. If
// this check would run off the left edge of the image, do not accept this barcode, as it is
// very likely to be a false positive.
int quietStart = start - (nextStart - start);
if (quietStart >= 0) {
foundStart = row.isRange(quietStart, start, false);
}
}
return startRange;
}
@ -108,9 +112,11 @@ public abstract class AbstractUPCEANReader extends AbstractOneDReader implements
int endStart = decodeMiddle(row, startGuardRange, result);
int[] endRange = decodeEnd(row, endStart);
// Check for whitespace after the pattern -- 150% of size of end pattern
// Make sure there is a quiet zone at least as big as the end pattern after the barcode. The
// spec might want more whitespace, but in practice this is the maximum we can count on.
int end = endRange[1];
if (!row.isRange(end, Math.min(row.getSize(), end + (3 * (end - endRange[0])) / 2), false)) {
int quietEnd = end + (end - endRange[0]);
if (quietEnd >= row.getSize() || !row.isRange(end, quietEnd, false)) {
throw new ReaderException("Pattern not followed by whitespace");
}

6
core/test/src/com/google/zxing/negative/FalsePositivesBlackBoxTestCase.java
View file

@ -29,9 +29,9 @@ public final class FalsePositivesBlackBoxTestCase extends AbstractNegativeBlackB
public FalsePositivesBlackBoxTestCase() {
super(new File("test/data/blackbox/falsepositives"));
addTest(1, 0.0f);
addTest(1, 90.0f);
addTest(2, 180.0f);
addTest(2, 0.0f);
addTest(0, 90.0f);
addTest(0, 180.0f);
addTest(0, 270.0f);
}

8
core/test/src/com/google/zxing/negative/PartialBlackBoxTestCase.java
View file

@ -29,10 +29,10 @@ public final class PartialBlackBoxTestCase extends AbstractNegativeBlackBoxTestC
public PartialBlackBoxTestCase() {
super(new File("test/data/blackbox/partial"));
addTest(18, 0.0f);
addTest(19, 90.0f);
addTest(19, 180.0f);
addTest(18, 270.0f);
addTest(0, 0.0f);
addTest(1, 90.0f);
addTest(1, 180.0f);
addTest(0, 270.0f);
}
}

2
core/test/src/com/google/zxing/oned/EAN13BlackBox1TestCase.java
View file

@ -30,7 +30,7 @@ public final class EAN13BlackBox1TestCase extends AbstractBlackBoxTestCase {
public EAN13BlackBox1TestCase() {
super(new File("test/data/blackbox/ean13-1"), new MultiFormatReader(), BarcodeFormat.EAN_13);
addTest(28, 31, 0.0f);
addTest(25, 31, 180.0f);
addTest(27, 31, 180.0f);
}
}

4
core/test/src/com/google/zxing/oned/UPCABlackBox1TestCase.java
View file

@ -29,8 +29,8 @@ public final class UPCABlackBox1TestCase extends AbstractBlackBoxTestCase {
public UPCABlackBox1TestCase() {
super(new File("test/data/blackbox/upca-1"), new MultiFormatReader(), BarcodeFormat.UPC_A);
addTest(15, 17, 0.0f);
addTest(16, 19, 180.0f);
addTest(15, 16, 0.0f);
addTest(15, 19, 180.0f);
}
}

2
core/test/src/com/google/zxing/oned/UPCABlackBox2TestCase.java
View file

@ -29,7 +29,7 @@ public final class UPCABlackBox2TestCase extends AbstractBlackBoxTestCase {
public UPCABlackBox2TestCase() {
super(new File("test/data/blackbox/upca-2"), new MultiFormatReader(), BarcodeFormat.UPC_A);
addTest(26, 35, 0.0f);
addTest(25, 35, 0.0f);
addTest(25, 35, 180.0f);
}

4
core/test/src/com/google/zxing/oned/UPCABlackBox4TestCase.java
View file

@ -29,8 +29,8 @@ public final class UPCABlackBox4TestCase extends AbstractBlackBoxTestCase {
public UPCABlackBox4TestCase() {
super(new File("test/data/blackbox/upca-4"), new MultiFormatReader(), BarcodeFormat.UPC_A);
addTest(8, 10, 0.0f);
addTest(7, 12, 180.0f);
addTest(8, 13, 0.0f);
addTest(8, 12, 180.0f);
}
}

4
core/test/src/com/google/zxing/oned/UPCEBlackBox2TestCase.java
View file

@ -29,8 +29,8 @@ public final class UPCEBlackBox2TestCase extends AbstractBlackBoxTestCase {
public UPCEBlackBox2TestCase() {
super(new File("test/data/blackbox/upce-2"), new MultiFormatReader(), BarcodeFormat.UPC_E);
addTest(24, 34, 0.0f);
addTest(26, 34, 180.0f);
addTest(30, 35, 0.0f);
addTest(29, 35, 180.0f);
}
}

4
core/test/src/com/google/zxing/oned/UPCEBlackBox3ReflectiveTestCase.java
View file

@ -29,8 +29,8 @@ public final class UPCEBlackBox3ReflectiveTestCase extends AbstractBlackBoxTestC
public UPCEBlackBox3ReflectiveTestCase() {
super(new File("test/data/blackbox/upce-3"), new MultiFormatReader(), BarcodeFormat.UPC_E);
addTest(0, 0, 0.0f);
addTest(0, 0, 180.0f);
addTest(4, 8, 0.0f);
addTest(4, 8, 180.0f);
}
}