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Separated rectangle detection from decoder for reuse

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git-svn-id: https://zxing.googlecode.com/svn/trunk@824 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2009-01-14 10:44:46 +00:00
parent 37fbeaa36a
commit 5efb6ef335
3 changed files with 222 additions and 157 deletions
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212
core/src/com/google/zxing/common/detector/MonochromeRectangleDetector.java Normal file
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@ -0,0 +1,212 @@
/*
* Copyright 2009 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.common.detector;
import com.google.zxing.MonochromeBitmapSource;
import com.google.zxing.ReaderException;
import com.google.zxing.ResultPoint;
import com.google.zxing.BlackPointEstimationMethod;
import com.google.zxing.common.BitArray;
import com.google.zxing.common.GenericResultPoint;
/**
* <p>A somewhat generic detector that looks for a barcode-like rectangular region within an image.
* It looks within a mostly white region of an image for a region of black and white, but mostly black.
* It returns the four corners of the region, as best it can determine.</p>
*
* @author Sean Owen
*/
public final class MonochromeRectangleDetector {
private static final int MAX_MODULES = 32;
private final MonochromeBitmapSource image;
public MonochromeRectangleDetector(MonochromeBitmapSource image) {
this.image = image;
}
/**
* <p>Detects a rectangular region of black and white -- mostly black -- with a region of mostly
* white, in an image.</p>
*
* @return {@link ResultPoint[]} describing the corners of the rectangular region. The first and last points
* are opposed on the diagonal, as are the second and third. The first point will be the topmost point and
* the last, the bottommost. The second point will be leftmost and the third, the rightmost
* @throws ReaderException if no Data Matrix Code can be found
*/
public ResultPoint[] detect() throws ReaderException {
if (!BlackPointEstimationMethod.TWO_D_SAMPLING.equals(image.getLastEstimationMethod())) {
image.estimateBlackPoint(BlackPointEstimationMethod.TWO_D_SAMPLING, 0);
}
int height = image.getHeight();
int width = image.getWidth();
int halfHeight = height >> 1;
int halfWidth = width >> 1;
int iSkip = Math.max(1, height / (MAX_MODULES << 3));
int jSkip = Math.max(1, width / (MAX_MODULES << 3));
int minI = 0;
int maxI = height;
int minJ = 0;
int maxJ = width;
ResultPoint pointA = findCornerFromCenter(halfHeight, -iSkip, minI, maxI, halfWidth, 0, minJ, maxJ, halfWidth >> 1);
minI = (int) pointA.getY() - 1;
ResultPoint pointB = findCornerFromCenter(halfHeight, 0, minI, maxI, halfWidth, -jSkip, minJ, maxJ, halfHeight >> 1);
minJ = (int) pointB.getX() - 1;
ResultPoint pointC = findCornerFromCenter(halfHeight, 0, minI, maxI, halfWidth, jSkip, minJ, maxJ, halfHeight >> 1);
maxJ = (int) pointC.getX() + 1;
ResultPoint pointD = findCornerFromCenter(halfHeight, iSkip, minI, maxI, halfWidth, 0, minJ, maxJ, halfWidth >> 1);
maxI = (int) pointD.getY() + 1;
// Go try to find point A again with better information -- might have been off at first.
pointA = findCornerFromCenter(halfHeight, -iSkip, minI, maxI, halfWidth, 0, minJ, maxJ, halfWidth >> 2);
return new ResultPoint[] { pointA, pointB, pointC, pointD };
}
/**
* Attempts to locate a corner of the barcode by scanning up, down, left or right from a center
* point which should be within the barcode.
*
* @param centerI center's i componennt (vertical)
* @param di change in i per step. If scanning up this is negative; down, positive; left or right, 0
* @param minI minimum value of i to search through (meaningless when di == 0)
* @param maxI maximum value of i
* @param centerJ center's j component (horizontal)
* @param dj same as di but change in j per step instead
* @param minJ see minI
* @param maxJ see minJ
* @param maxWhiteRun maximum run of white pixels that can still be considered to be within
* the barcode
* @return a {@link com.google.zxing.ResultPoint} encapsulating the corner that was found
* @throws com.google.zxing.ReaderException if such a point cannot be found
*/
private ResultPoint findCornerFromCenter(int centerI, int di, int minI, int maxI,
int centerJ, int dj, int minJ, int maxJ,
int maxWhiteRun) throws ReaderException {
int[] lastRange = null;
for (int i = centerI, j = centerJ;
i < maxI && i >= minI && j < maxJ && j >= minJ;
i += di, j += dj) {
int[] range;
if (dj == 0) {
// horizontal slices, up and down
range = blackWhiteRange(i, maxWhiteRun, minJ, maxJ, true);
} else {
// vertical slices, left and right
range = blackWhiteRange(j, maxWhiteRun, minI, maxI, false);
}
if (range == null) {
if (lastRange == null) {
throw ReaderException.getInstance();
}
// lastRange was found
if (dj == 0) {
int lastI = i - di;
if (lastRange[0] < centerJ) {
if (lastRange[1] > centerJ) {
// straddle, choose one or the other based on direction
return new GenericResultPoint(di > 0 ? lastRange[0] : lastRange[1], lastI);
}
return new GenericResultPoint(lastRange[0], lastI);
} else {
return new GenericResultPoint(lastRange[1], lastI);
}
} else {
int lastJ = j - dj;
if (lastRange[0] < centerI) {
if (lastRange[1] > centerI) {
return new GenericResultPoint(lastJ, dj < 0 ? lastRange[0] : lastRange[1]);
}
return new GenericResultPoint(lastJ, lastRange[0]);
} else {
return new GenericResultPoint(lastJ, lastRange[1]);
}
}
}
lastRange = range;
}
throw ReaderException.getInstance();
}
/**
* Computes the start and end of a region of pixels, either horizontally or vertically, that could be
* part of a Data Matrix barcode.
*
* @param fixedDimension if scanning horizontally, this is the row (the fixed vertical location) where
* we are scanning. If scanning vertically it's the colummn, the fixed horizontal location
* @param maxWhiteRun largest run of white pixels that can still be considered part of the barcode region
* @param minDim minimum pixel location, horizontally or vertically, to consider
* @param maxDim maximum pixel location, horizontally or vertically, to consider
* @param horizontal if true, we're scanning left-right, instead of up-down
* @return int[] with start and end of found range, or null if no such range is found (e.g. only white was found)
*/
private int[] blackWhiteRange(int fixedDimension, int maxWhiteRun, int minDim, int maxDim, boolean horizontal) {
int center = (minDim + maxDim) / 2;
BitArray rowOrColumn = horizontal ? image.getBlackRow(fixedDimension, null, 0, image.getWidth())
: image.getBlackColumn(fixedDimension, null, 0, image.getHeight());
// Scan left/up first
int start = center;
while (start >= minDim) {
if (rowOrColumn.get(start)) {
start--;
} else {
int whiteRunStart = start;
do {
start--;
} while (start >= minDim && !rowOrColumn.get(start));
int whiteRunSize = whiteRunStart - start;
if (start < minDim || whiteRunSize > maxWhiteRun) {
start = whiteRunStart + 1; // back up
break;
}
}
}
start++;
// Then try right/down
int end = center;
while (end < maxDim) {
if (rowOrColumn.get(end)) {
end++;
} else {
int whiteRunStart = end;
do {
end++;
} while (end < maxDim && !rowOrColumn.get(end));
int whiteRunSize = end - whiteRunStart;
if (end >= maxDim || whiteRunSize > maxWhiteRun) {
end = whiteRunStart - 1;
break;
}
}
}
end--;
if (end > start) {
return new int[] { start, end };
} else {
return null;
}
}
}

164
core/src/com/google/zxing/datamatrix/detector/Detector.java
View file

@ -19,14 +19,13 @@ package com.google.zxing.datamatrix.detector;
import com.google.zxing.MonochromeBitmapSource;
import com.google.zxing.ReaderException;
import com.google.zxing.ResultPoint;
import com.google.zxing.BlackPointEstimationMethod;
import com.google.zxing.common.BitArray;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.Collections;
import com.google.zxing.common.Comparator;
import com.google.zxing.common.DetectorResult;
import com.google.zxing.common.GenericResultPoint;
import com.google.zxing.common.GridSampler;
import com.google.zxing.common.detector.MonochromeRectangleDetector;
import java.util.Enumeration;
import java.util.Hashtable;
@ -48,9 +47,11 @@ public final class Detector {
{ new Integer(0), new Integer(1), new Integer(2), new Integer(3), new Integer(4) };
private final MonochromeBitmapSource image;
private final MonochromeRectangleDetector rectangleDetector;
public Detector(MonochromeBitmapSource image) {
this.image = image;
rectangleDetector = new MonochromeRectangleDetector(image);
}
/**
@ -61,31 +62,11 @@ public final class Detector {
*/
public DetectorResult detect() throws ReaderException {
if (!BlackPointEstimationMethod.TWO_D_SAMPLING.equals(image.getLastEstimationMethod())) {
image.estimateBlackPoint(BlackPointEstimationMethod.TWO_D_SAMPLING, 0);
}
int height = image.getHeight();
int width = image.getWidth();
int halfHeight = height >> 1;
int halfWidth = width >> 1;
int iSkip = Math.max(1, height / (MAX_MODULES << 3));
int jSkip = Math.max(1, width / (MAX_MODULES << 3));
int minI = 0;
int maxI = height;
int minJ = 0;
int maxJ = width;
ResultPoint pointA = findCornerFromCenter(halfHeight, -iSkip, minI, maxI, halfWidth, 0, minJ, maxJ, halfWidth >> 1);
minI = (int) pointA.getY() - 1;
ResultPoint pointB = findCornerFromCenter(halfHeight, 0, minI, maxI, halfWidth, -jSkip, minJ, maxJ, halfHeight >> 1);
minJ = (int) pointB.getX() - 1;
ResultPoint pointC = findCornerFromCenter(halfHeight, 0, minI, maxI, halfWidth, jSkip, minJ, maxJ, halfHeight >> 1);
maxJ = (int) pointC.getX() + 1;
ResultPoint pointD = findCornerFromCenter(halfHeight, iSkip, minI, maxI, halfWidth, 0, minJ, maxJ, halfWidth >> 1);
maxI = (int) pointD.getY() + 1;
// Go try to find point A again with better information -- might have been off at first.
pointA = findCornerFromCenter(halfHeight, -iSkip, minI, maxI, halfWidth, 0, minJ, maxJ, halfWidth >> 2);
ResultPoint[] cornerPoints = rectangleDetector.detect();
ResultPoint pointA = cornerPoints[0];
ResultPoint pointB = cornerPoints[1];
ResultPoint pointC = cornerPoints[2];
ResultPoint pointD = cornerPoints[3];
// Point A and D are across the diagonal from one another,
// as are B and C. Figure out which are the solid black lines
@ -178,71 +159,6 @@ public final class Detector {
return new DetectorResult(bits, new ResultPoint[] {pointA, pointB, pointC, pointD});
}
/**
* Attempts to locate a corner of the barcode by scanning up, down, left or right from a center
* point which should be within the barcode.
*
* @param centerI center's i componennt (vertical)
* @param di change in i per step. If scanning up this is negative; down, positive; left or right, 0
* @param minI minimum value of i to search through (meaningless when di == 0)
* @param maxI maximum value of i
* @param centerJ center's j component (horizontal)
* @param dj same as di but change in j per step instead
* @param minJ see minI
* @param maxJ see minJ
* @param maxWhiteRun maximum run of white pixels that can still be considered to be within
* the barcode
* @return a {@link ResultPoint} encapsulating the corner that was found
* @throws ReaderException if such a point cannot be found
*/
private ResultPoint findCornerFromCenter(int centerI, int di, int minI, int maxI,
int centerJ, int dj, int minJ, int maxJ,
int maxWhiteRun) throws ReaderException {
int[] lastRange = null;
for (int i = centerI, j = centerJ;
i < maxI && i >= minI && j < maxJ && j >= minJ;
i += di, j += dj) {
int[] range;
if (dj == 0) {
// horizontal slices, up and down
range = blackWhiteRange(i, maxWhiteRun, minJ, maxJ, true);
} else {
// vertical slices, left and right
range = blackWhiteRange(j, maxWhiteRun, minI, maxI, false);
}
if (range == null) {
if (lastRange == null) {
throw ReaderException.getInstance();
}
// lastRange was found
if (dj == 0) {
int lastI = i - di;
if (lastRange[0] < centerJ) {
if (lastRange[1] > centerJ) {
// straddle, choose one or the other based on direction
return new GenericResultPoint(di > 0 ? lastRange[0] : lastRange[1], lastI);
}
return new GenericResultPoint(lastRange[0], lastI);
} else {
return new GenericResultPoint(lastRange[1], lastI);
}
} else {
int lastJ = j - dj;
if (lastRange[0] < centerI) {
if (lastRange[1] > centerI) {
return new GenericResultPoint(lastJ, dj < 0 ? lastRange[0] : lastRange[1]);
}
return new GenericResultPoint(lastJ, lastRange[0]);
} else {
return new GenericResultPoint(lastJ, lastRange[1]);
}
}
}
lastRange = range;
}
throw ReaderException.getInstance();
}
/**
* Increments the Integer associated with a key by one.
*/
@ -251,70 +167,6 @@ public final class Detector {
table.put(key, value == null ? INTEGERS[1] : INTEGERS[value.intValue() + 1]);
}
/**
* Computes the start and end of a region of pixels, either horizontally or vertically, that could be
* part of a Data Matrix barcode.
*
* @param fixedDimension if scanning horizontally, this is the row (the fixed vertical location) where
* we are scanning. If scanning vertically it's the colummn, the fixed horizontal location
* @param maxWhiteRun largest run of white pixels that can still be considered part of the barcode region
* @param minDim minimum pixel location, horizontally or vertically, to consider
* @param maxDim maximum pixel location, horizontally or vertically, to consider
* @param horizontal if true, we're scanning left-right, instead of up-down
* @return int[] with start and end of found range, or null if no such range is found (e.g. only white was found)
*/
private int[] blackWhiteRange(int fixedDimension, int maxWhiteRun, int minDim, int maxDim, boolean horizontal) {
int center = (minDim + maxDim) / 2;
BitArray rowOrColumn = horizontal ? image.getBlackRow(fixedDimension, null, 0, image.getWidth())
: image.getBlackColumn(fixedDimension, null, 0, image.getHeight());
// Scan left/up first
int start = center;
while (start >= minDim) {
if (rowOrColumn.get(start)) {
start--;
} else {
int whiteRunStart = start;
do {
start--;
} while (start >= minDim && !rowOrColumn.get(start));
int whiteRunSize = whiteRunStart - start;
if (start < minDim || whiteRunSize > maxWhiteRun) {
start = whiteRunStart + 1; // back up
break;
}
}
}
start++;
// Then try right/down
int end = center;
while (end < maxDim) {
if (rowOrColumn.get(end)) {
end++;
} else {
int whiteRunStart = end;
do {
end++;
} while (end < maxDim && !rowOrColumn.get(end));
int whiteRunSize = end - whiteRunStart;
if (end >= maxDim || whiteRunSize > maxWhiteRun) {
end = whiteRunStart - 1;
break;
}
}
}
end--;
if (end > start) {
return new int[] { start, end };
} else {
return null;
}
}
private static BitMatrix sampleGrid(MonochromeBitmapSource image,
ResultPoint topLeft,
ResultPoint bottomLeft,

3
javase/src/com/google/zxing/client/j2se/CommandLineRunner.java
View file

@ -33,6 +33,7 @@ import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.charset.Charset;
import java.util.Hashtable;
@ -72,7 +73,7 @@ public final class CommandLineRunner {
}
private static void decodeOneArgument(String argument, Hashtable<DecodeHintType, Object> hints,
boolean dumpResults) throws Exception {
boolean dumpResults) throws IOException, URISyntaxException {
File inputFile = new File(argument);
if (inputFile.exists()) {