From b44ebbc96fa5e565f66a785858637054258c56e6 Mon Sep 17 00:00:00 2001
From: srowen <srowen@59b500cc-1b3d-0410-9834-0bbf25fbcc57>
Date: Wed, 11 Jun 2008 19:59:38 +0000
Subject: [PATCH] Fix bad logic black point estimator, improving threshold
 estimation performance (and adjust some == to .equals())

git-svn-id: http://zxing.googlecode.com/svn/trunk@417 59b500cc-1b3d-0410-9834-0bbf25fbcc57
---
 .../zxing/client/android/RGBMonochromeBitmapSource.java  | 2 +-
 .../src/com/google/zxing/common/BlackPointEstimator.java | 9 ++++++---
 .../com/google/zxing/oned/EAN13BlackBox1TestCase.java    | 4 ++--
 .../client/j2se/BufferedImageMonochromeBitmapSource.java | 2 +-
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java b/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java
index d84a9209..f6bf98b6 100755
--- a/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java
+++ b/android/src/com/google/zxing/client/android/RGBMonochromeBitmapSource.java
@@ -63,7 +63,7 @@ final class RGBMonochromeBitmapSource implements MonochromeBitmapSource {
     // If the current decoder calculated the blackPoint based on one row, assume we're trying to
     // decode a 1D barcode, and apply some sharpening.
     // TODO: We may want to add a fifth parameter to request the amount of shapening to be done.
-    if (lastMethod == BlackPointEstimationMethod.ROW_SAMPLING) {
+    if (lastMethod.equals(BlackPointEstimationMethod.ROW_SAMPLING)) {
       int left = computeRGBLuminance(pixelRow[0]);
       int center = computeRGBLuminance(pixelRow[1]);
       for (int i = 1; i < getWidth - 1; i++) {
diff --git a/core/src/com/google/zxing/common/BlackPointEstimator.java b/core/src/com/google/zxing/common/BlackPointEstimator.java
index a40a8530..ecaf96c4 100644
--- a/core/src/com/google/zxing/common/BlackPointEstimator.java
+++ b/core/src/com/google/zxing/common/BlackPointEstimator.java
@@ -47,7 +47,7 @@ public final class BlackPointEstimator {
   public static int estimate(int[] histogram) throws ReaderException{
 
     int numBuckets = histogram.length;
-
+    int maxBucketCount = 0;
     // Find tallest peak in histogram
     int firstPeak = 0;
     int firstPeakSize = 0;
@@ -56,6 +56,9 @@ public final class BlackPointEstimator {
         firstPeak = i;
         firstPeakSize = histogram[i];
       }
+      if (histogram[i] > maxBucketCount) {
+        maxBucketCount = histogram[i];
+      }
     }
 
     // Find second-tallest peak -- well, another peak that is tall and not
@@ -84,7 +87,7 @@ public final class BlackPointEstimator {
     // Decoding the image/line is either pointless, or may in some cases lead to a false positive
     // for 1D formats, which are relatively lenient.
     // We arbitrarily say "close" is "<= 1/16 of the total histogram buckets apart"
-    if (secondPeak - firstPeak <= histogram.length >> 4) {
+    if (secondPeak - firstPeak <= numBuckets >> 4) {
       throw new ReaderException("Too little dynamic range in luminance");
     }
 
@@ -95,7 +98,7 @@ public final class BlackPointEstimator {
       int fromFirst = i - firstPeak;
       // Favor a "valley" that is not too close to either peak -- especially not the black peak --
       // and that has a low value of course
-      int score = fromFirst * fromFirst * (secondPeak - i) * (256 - histogram[i]);
+      int score = fromFirst * fromFirst * (secondPeak - i) * (maxBucketCount - histogram[i]);
       if (score > bestValleyScore) {
         bestValley = i;
         bestValleyScore = score;
diff --git a/core/test/src/com/google/zxing/oned/EAN13BlackBox1TestCase.java b/core/test/src/com/google/zxing/oned/EAN13BlackBox1TestCase.java
index 7e28d886..772cf7ad 100644
--- a/core/test/src/com/google/zxing/oned/EAN13BlackBox1TestCase.java
+++ b/core/test/src/com/google/zxing/oned/EAN13BlackBox1TestCase.java
@@ -29,8 +29,8 @@ public final class EAN13BlackBox1TestCase extends AbstractBlackBoxTestCase {
 
   public EAN13BlackBox1TestCase() {
     super(new File("test/data/blackbox/ean13-1"), new MultiFormatReader(), BarcodeFormat.EAN_13);
-    addTest(25, 0.0f);
-    addTest(18, 180.0f);
+    addTest(26, 0.0f);
+    addTest(24, 180.0f);
   }
 
 }
\ No newline at end of file
diff --git a/javase/src/com/google/zxing/client/j2se/BufferedImageMonochromeBitmapSource.java b/javase/src/com/google/zxing/client/j2se/BufferedImageMonochromeBitmapSource.java
index 77c0d5c5..e8396b46 100644
--- a/javase/src/com/google/zxing/client/j2se/BufferedImageMonochromeBitmapSource.java
+++ b/javase/src/com/google/zxing/client/j2se/BufferedImageMonochromeBitmapSource.java
@@ -120,7 +120,7 @@ public final class BufferedImageMonochromeBitmapSource implements MonochromeBitm
     // If the current decoder calculated the blackPoint based on one row, assume we're trying to
     // decode a 1D barcode, and apply some sharpening.
     // TODO: We may want to add a fifth parameter to request the amount of shapening to be done.
-    if (lastMethod == BlackPointEstimationMethod.ROW_SAMPLING) {
+    if (lastMethod.equals(BlackPointEstimationMethod.ROW_SAMPLING)) {
       int left = computeRGBLuminance(pixelRow[0]);
       int center = computeRGBLuminance(pixelRow[1]);
       for (int i = 1; i < getWidth - 1; i++) {
-- 
2.20.1