mirror of
https://github.com/starovoid/rxing.git
synced 2026-07-26 20:32:34 +00:00
moved java files for pre-convert
This commit is contained in:
Henry Schimke
405
src/qrcode/detector/Detector.java
Normal file
405
src/qrcode/detector/Detector.java
Normal file
@@ -0,0 +1,405 @@
|
||||
/*
|
||||
* Copyright 2007 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.qrcode.detector;
|
||||
|
||||
import com.google.zxing.DecodeHintType;
|
||||
import com.google.zxing.FormatException;
|
||||
import com.google.zxing.NotFoundException;
|
||||
import com.google.zxing.ResultPoint;
|
||||
import com.google.zxing.ResultPointCallback;
|
||||
import com.google.zxing.common.BitMatrix;
|
||||
import com.google.zxing.common.DetectorResult;
|
||||
import com.google.zxing.common.GridSampler;
|
||||
import com.google.zxing.common.PerspectiveTransform;
|
||||
import com.google.zxing.common.detector.MathUtils;
|
||||
import com.google.zxing.qrcode.decoder.Version;
|
||||
|
||||
import java.util.Map;
|
||||
|
||||
/**
|
||||
* <p>Encapsulates logic that can detect a QR Code in an image, even if the QR Code
|
||||
* is rotated or skewed, or partially obscured.</p>
|
||||
*
|
||||
* @author Sean Owen
|
||||
*/
|
||||
public class Detector {
|
||||
|
||||
private final BitMatrix image;
|
||||
private ResultPointCallback resultPointCallback;
|
||||
|
||||
public Detector(BitMatrix image) {
|
||||
this.image = image;
|
||||
}
|
||||
|
||||
protected final BitMatrix getImage() {
|
||||
return image;
|
||||
}
|
||||
|
||||
protected final ResultPointCallback getResultPointCallback() {
|
||||
return resultPointCallback;
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>Detects a QR Code in an image.</p>
|
||||
*
|
||||
* @return {@link DetectorResult} encapsulating results of detecting a QR Code
|
||||
* @throws NotFoundException if QR Code cannot be found
|
||||
* @throws FormatException if a QR Code cannot be decoded
|
||||
*/
|
||||
public DetectorResult detect() throws NotFoundException, FormatException {
|
||||
return detect(null);
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>Detects a QR Code in an image.</p>
|
||||
*
|
||||
* @param hints optional hints to detector
|
||||
* @return {@link DetectorResult} encapsulating results of detecting a QR Code
|
||||
* @throws NotFoundException if QR Code cannot be found
|
||||
* @throws FormatException if a QR Code cannot be decoded
|
||||
*/
|
||||
public final DetectorResult detect(Map<DecodeHintType,?> hints) throws NotFoundException, FormatException {
|
||||
|
||||
resultPointCallback = hints == null ? null :
|
||||
(ResultPointCallback) hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK);
|
||||
|
||||
FinderPatternFinder finder = new FinderPatternFinder(image, resultPointCallback);
|
||||
FinderPatternInfo info = finder.find(hints);
|
||||
|
||||
return processFinderPatternInfo(info);
|
||||
}
|
||||
|
||||
protected final DetectorResult processFinderPatternInfo(FinderPatternInfo info)
|
||||
throws NotFoundException, FormatException {
|
||||
|
||||
FinderPattern topLeft = info.getTopLeft();
|
||||
FinderPattern topRight = info.getTopRight();
|
||||
FinderPattern bottomLeft = info.getBottomLeft();
|
||||
|
||||
float moduleSize = calculateModuleSize(topLeft, topRight, bottomLeft);
|
||||
if (moduleSize < 1.0f) {
|
||||
throw NotFoundException.getNotFoundInstance();
|
||||
}
|
||||
int dimension = computeDimension(topLeft, topRight, bottomLeft, moduleSize);
|
||||
Version provisionalVersion = Version.getProvisionalVersionForDimension(dimension);
|
||||
int modulesBetweenFPCenters = provisionalVersion.getDimensionForVersion() - 7;
|
||||
|
||||
AlignmentPattern alignmentPattern = null;
|
||||
// Anything above version 1 has an alignment pattern
|
||||
if (provisionalVersion.getAlignmentPatternCenters().length > 0) {
|
||||
|
||||
// Guess where a "bottom right" finder pattern would have been
|
||||
float bottomRightX = topRight.getX() - topLeft.getX() + bottomLeft.getX();
|
||||
float bottomRightY = topRight.getY() - topLeft.getY() + bottomLeft.getY();
|
||||
|
||||
// Estimate that alignment pattern is closer by 3 modules
|
||||
// from "bottom right" to known top left location
|
||||
float correctionToTopLeft = 1.0f - 3.0f / modulesBetweenFPCenters;
|
||||
int estAlignmentX = (int) (topLeft.getX() + correctionToTopLeft * (bottomRightX - topLeft.getX()));
|
||||
int estAlignmentY = (int) (topLeft.getY() + correctionToTopLeft * (bottomRightY - topLeft.getY()));
|
||||
|
||||
// Kind of arbitrary -- expand search radius before giving up
|
||||
for (int i = 4; i <= 16; i <<= 1) {
|
||||
try {
|
||||
alignmentPattern = findAlignmentInRegion(moduleSize,
|
||||
estAlignmentX,
|
||||
estAlignmentY,
|
||||
i);
|
||||
break;
|
||||
} catch (NotFoundException re) {
|
||||
// try next round
|
||||
}
|
||||
}
|
||||
// If we didn't find alignment pattern... well try anyway without it
|
||||
}
|
||||
|
||||
PerspectiveTransform transform =
|
||||
createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension);
|
||||
|
||||
BitMatrix bits = sampleGrid(image, transform, dimension);
|
||||
|
||||
ResultPoint[] points;
|
||||
if (alignmentPattern == null) {
|
||||
points = new ResultPoint[]{bottomLeft, topLeft, topRight};
|
||||
} else {
|
||||
points = new ResultPoint[]{bottomLeft, topLeft, topRight, alignmentPattern};
|
||||
}
|
||||
return new DetectorResult(bits, points);
|
||||
}
|
||||
|
||||
private static PerspectiveTransform createTransform(ResultPoint topLeft,
|
||||
ResultPoint topRight,
|
||||
ResultPoint bottomLeft,
|
||||
ResultPoint alignmentPattern,
|
||||
int dimension) {
|
||||
float dimMinusThree = dimension - 3.5f;
|
||||
float bottomRightX;
|
||||
float bottomRightY;
|
||||
float sourceBottomRightX;
|
||||
float sourceBottomRightY;
|
||||
if (alignmentPattern != null) {
|
||||
bottomRightX = alignmentPattern.getX();
|
||||
bottomRightY = alignmentPattern.getY();
|
||||
sourceBottomRightX = dimMinusThree - 3.0f;
|
||||
sourceBottomRightY = sourceBottomRightX;
|
||||
} else {
|
||||
// Don't have an alignment pattern, just make up the bottom-right point
|
||||
bottomRightX = (topRight.getX() - topLeft.getX()) + bottomLeft.getX();
|
||||
bottomRightY = (topRight.getY() - topLeft.getY()) + bottomLeft.getY();
|
||||
sourceBottomRightX = dimMinusThree;
|
||||
sourceBottomRightY = dimMinusThree;
|
||||
}
|
||||
|
||||
return PerspectiveTransform.quadrilateralToQuadrilateral(
|
||||
3.5f,
|
||||
3.5f,
|
||||
dimMinusThree,
|
||||
3.5f,
|
||||
sourceBottomRightX,
|
||||
sourceBottomRightY,
|
||||
3.5f,
|
||||
dimMinusThree,
|
||||
topLeft.getX(),
|
||||
topLeft.getY(),
|
||||
topRight.getX(),
|
||||
topRight.getY(),
|
||||
bottomRightX,
|
||||
bottomRightY,
|
||||
bottomLeft.getX(),
|
||||
bottomLeft.getY());
|
||||
}
|
||||
|
||||
private static BitMatrix sampleGrid(BitMatrix image,
|
||||
PerspectiveTransform transform,
|
||||
int dimension) throws NotFoundException {
|
||||
|
||||
GridSampler sampler = GridSampler.getInstance();
|
||||
return sampler.sampleGrid(image, dimension, dimension, transform);
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>Computes the dimension (number of modules on a size) of the QR Code based on the position
|
||||
* of the finder patterns and estimated module size.</p>
|
||||
*/
|
||||
private static int computeDimension(ResultPoint topLeft,
|
||||
ResultPoint topRight,
|
||||
ResultPoint bottomLeft,
|
||||
float moduleSize) throws NotFoundException {
|
||||
int tltrCentersDimension = MathUtils.round(ResultPoint.distance(topLeft, topRight) / moduleSize);
|
||||
int tlblCentersDimension = MathUtils.round(ResultPoint.distance(topLeft, bottomLeft) / moduleSize);
|
||||
int dimension = ((tltrCentersDimension + tlblCentersDimension) / 2) + 7;
|
||||
switch (dimension & 0x03) { // mod 4
|
||||
case 0:
|
||||
dimension++;
|
||||
break;
|
||||
// 1? do nothing
|
||||
case 2:
|
||||
dimension--;
|
||||
break;
|
||||
case 3:
|
||||
throw NotFoundException.getNotFoundInstance();
|
||||
}
|
||||
return dimension;
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>Computes an average estimated module size based on estimated derived from the positions
|
||||
* of the three finder patterns.</p>
|
||||
*
|
||||
* @param topLeft detected top-left finder pattern center
|
||||
* @param topRight detected top-right finder pattern center
|
||||
* @param bottomLeft detected bottom-left finder pattern center
|
||||
* @return estimated module size
|
||||
*/
|
||||
protected final float calculateModuleSize(ResultPoint topLeft,
|
||||
ResultPoint topRight,
|
||||
ResultPoint bottomLeft) {
|
||||
// Take the average
|
||||
return (calculateModuleSizeOneWay(topLeft, topRight) +
|
||||
calculateModuleSizeOneWay(topLeft, bottomLeft)) / 2.0f;
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>Estimates module size based on two finder patterns -- it uses
|
||||
* {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the
|
||||
* width of each, measuring along the axis between their centers.</p>
|
||||
*/
|
||||
private float calculateModuleSizeOneWay(ResultPoint pattern, ResultPoint otherPattern) {
|
||||
float moduleSizeEst1 = sizeOfBlackWhiteBlackRunBothWays((int) pattern.getX(),
|
||||
(int) pattern.getY(),
|
||||
(int) otherPattern.getX(),
|
||||
(int) otherPattern.getY());
|
||||
float moduleSizeEst2 = sizeOfBlackWhiteBlackRunBothWays((int) otherPattern.getX(),
|
||||
(int) otherPattern.getY(),
|
||||
(int) pattern.getX(),
|
||||
(int) pattern.getY());
|
||||
if (Float.isNaN(moduleSizeEst1)) {
|
||||
return moduleSizeEst2 / 7.0f;
|
||||
}
|
||||
if (Float.isNaN(moduleSizeEst2)) {
|
||||
return moduleSizeEst1 / 7.0f;
|
||||
}
|
||||
// Average them, and divide by 7 since we've counted the width of 3 black modules,
|
||||
// and 1 white and 1 black module on either side. Ergo, divide sum by 14.
|
||||
return (moduleSizeEst1 + moduleSizeEst2) / 14.0f;
|
||||
}
|
||||
|
||||
/**
|
||||
* See {@link #sizeOfBlackWhiteBlackRun(int, int, int, int)}; computes the total width of
|
||||
* a finder pattern by looking for a black-white-black run from the center in the direction
|
||||
* of another point (another finder pattern center), and in the opposite direction too.
|
||||
*/
|
||||
private float sizeOfBlackWhiteBlackRunBothWays(int fromX, int fromY, int toX, int toY) {
|
||||
|
||||
float result = sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);
|
||||
|
||||
// Now count other way -- don't run off image though of course
|
||||
float scale = 1.0f;
|
||||
int otherToX = fromX - (toX - fromX);
|
||||
if (otherToX < 0) {
|
||||
scale = fromX / (float) (fromX - otherToX);
|
||||
otherToX = 0;
|
||||
} else if (otherToX >= image.getWidth()) {
|
||||
scale = (image.getWidth() - 1 - fromX) / (float) (otherToX - fromX);
|
||||
otherToX = image.getWidth() - 1;
|
||||
}
|
||||
int otherToY = (int) (fromY - (toY - fromY) * scale);
|
||||
|
||||
scale = 1.0f;
|
||||
if (otherToY < 0) {
|
||||
scale = fromY / (float) (fromY - otherToY);
|
||||
otherToY = 0;
|
||||
} else if (otherToY >= image.getHeight()) {
|
||||
scale = (image.getHeight() - 1 - fromY) / (float) (otherToY - fromY);
|
||||
otherToY = image.getHeight() - 1;
|
||||
}
|
||||
otherToX = (int) (fromX + (otherToX - fromX) * scale);
|
||||
|
||||
result += sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);
|
||||
|
||||
// Middle pixel is double-counted this way; subtract 1
|
||||
return result - 1.0f;
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>This method traces a line from a point in the image, in the direction towards another point.
|
||||
* It begins in a black region, and keeps going until it finds white, then black, then white again.
|
||||
* It reports the distance from the start to this point.</p>
|
||||
*
|
||||
* <p>This is used when figuring out how wide a finder pattern is, when the finder pattern
|
||||
* may be skewed or rotated.</p>
|
||||
*/
|
||||
private float sizeOfBlackWhiteBlackRun(int fromX, int fromY, int toX, int toY) {
|
||||
// Mild variant of Bresenham's algorithm;
|
||||
// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
|
||||
boolean steep = Math.abs(toY - fromY) > Math.abs(toX - fromX);
|
||||
if (steep) {
|
||||
int temp = fromX;
|
||||
fromX = fromY;
|
||||
fromY = temp;
|
||||
temp = toX;
|
||||
toX = toY;
|
||||
toY = temp;
|
||||
}
|
||||
|
||||
int dx = Math.abs(toX - fromX);
|
||||
int dy = Math.abs(toY - fromY);
|
||||
int error = -dx / 2;
|
||||
int xstep = fromX < toX ? 1 : -1;
|
||||
int ystep = fromY < toY ? 1 : -1;
|
||||
|
||||
// In black pixels, looking for white, first or second time.
|
||||
int state = 0;
|
||||
// Loop up until x == toX, but not beyond
|
||||
int xLimit = toX + xstep;
|
||||
for (int x = fromX, y = fromY; x != xLimit; x += xstep) {
|
||||
int realX = steep ? y : x;
|
||||
int realY = steep ? x : y;
|
||||
|
||||
// Does current pixel mean we have moved white to black or vice versa?
|
||||
// Scanning black in state 0,2 and white in state 1, so if we find the wrong
|
||||
// color, advance to next state or end if we are in state 2 already
|
||||
if ((state == 1) == image.get(realX, realY)) {
|
||||
if (state == 2) {
|
||||
return MathUtils.distance(x, y, fromX, fromY);
|
||||
}
|
||||
state++;
|
||||
}
|
||||
|
||||
error += dy;
|
||||
if (error > 0) {
|
||||
if (y == toY) {
|
||||
break;
|
||||
}
|
||||
y += ystep;
|
||||
error -= dx;
|
||||
}
|
||||
}
|
||||
// Found black-white-black; give the benefit of the doubt that the next pixel outside the image
|
||||
// is "white" so this last point at (toX+xStep,toY) is the right ending. This is really a
|
||||
// small approximation; (toX+xStep,toY+yStep) might be really correct. Ignore this.
|
||||
if (state == 2) {
|
||||
return MathUtils.distance(toX + xstep, toY, fromX, fromY);
|
||||
}
|
||||
// else we didn't find even black-white-black; no estimate is really possible
|
||||
return Float.NaN;
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>Attempts to locate an alignment pattern in a limited region of the image, which is
|
||||
* guessed to contain it. This method uses {@link AlignmentPattern}.</p>
|
||||
*
|
||||
* @param overallEstModuleSize estimated module size so far
|
||||
* @param estAlignmentX x coordinate of center of area probably containing alignment pattern
|
||||
* @param estAlignmentY y coordinate of above
|
||||
* @param allowanceFactor number of pixels in all directions to search from the center
|
||||
* @return {@link AlignmentPattern} if found, or null otherwise
|
||||
* @throws NotFoundException if an unexpected error occurs during detection
|
||||
*/
|
||||
protected final AlignmentPattern findAlignmentInRegion(float overallEstModuleSize,
|
||||
int estAlignmentX,
|
||||
int estAlignmentY,
|
||||
float allowanceFactor)
|
||||
throws NotFoundException {
|
||||
// Look for an alignment pattern (3 modules in size) around where it
|
||||
// should be
|
||||
int allowance = (int) (allowanceFactor * overallEstModuleSize);
|
||||
int alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance);
|
||||
int alignmentAreaRightX = Math.min(image.getWidth() - 1, estAlignmentX + allowance);
|
||||
if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3) {
|
||||
throw NotFoundException.getNotFoundInstance();
|
||||
}
|
||||
|
||||
int alignmentAreaTopY = Math.max(0, estAlignmentY - allowance);
|
||||
int alignmentAreaBottomY = Math.min(image.getHeight() - 1, estAlignmentY + allowance);
|
||||
if (alignmentAreaBottomY - alignmentAreaTopY < overallEstModuleSize * 3) {
|
||||
throw NotFoundException.getNotFoundInstance();
|
||||
}
|
||||
|
||||
AlignmentPatternFinder alignmentFinder =
|
||||
new AlignmentPatternFinder(
|
||||
image,
|
||||
alignmentAreaLeftX,
|
||||
alignmentAreaTopY,
|
||||
alignmentAreaRightX - alignmentAreaLeftX,
|
||||
alignmentAreaBottomY - alignmentAreaTopY,
|
||||
overallEstModuleSize,
|
||||
resultPointCallback);
|
||||
return alignmentFinder.find();
|
||||
}
|
||||
|
||||
}
|
||||
Reference in New Issue
Block a user