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https://github.com/zxing/zxing.git
synced 2025-02-02 05:41:08 -08:00
Cleaned up a number of comments and code to fit in 100 columns and added some TODO items.
git-svn-id: https://zxing.googlecode.com/svn/trunk@1013 59b500cc-1b3d-0410-9834-0bbf25fbcc57
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dswitkin
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e44f00ba75
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af2ce46c37
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@ -26,10 +26,8 @@ import com.google.zxing.common.GridSampler;
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import java.util.Hashtable;
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/**
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* <p>
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* Encapsulates logic that can detect a PDF417 Code in an image, even if the
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* PDF417 Code is rotated or skewed, or partially obscured.
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* </p>
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* <p>Encapsulates logic that can detect a PDF417 Code in an image, even if the
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* PDF417 Code is rotated or skewed, or partially obscured.</p>
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*
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* @author SITA Lab (kevin.osullivan@sita.aero)
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*/
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@ -59,12 +57,9 @@ public final class Detector {
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}
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/**
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* <p>
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* Detects a PDF417 Code in an image, simply.
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* </p>
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* <p>Detects a PDF417 Code in an image, simply.</p>
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*
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* @return {@link DetectorResult} encapsulating results of detecting a PDF417
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* Code
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* @return {@link DetectorResult} encapsulating results of detecting a PDF417 Code
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* @throws ReaderException if no QR Code can be found
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*/
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public DetectorResult detect() throws ReaderException {
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@ -72,32 +67,23 @@ public final class Detector {
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}
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/**
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* <p>
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* Detects a PDF417 Code in an image, simply.
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* </p>
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* <p>Detects a PDF417 Code in an image. Only checks 0 and 180 degree rotations.</p>
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*
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* @param hints optional hints to detector
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* @return {@link DetectorResult} encapsulating results of detecting a PDF417
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* Code
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* @return {@link DetectorResult} encapsulating results of detecting a PDF417 Code
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* @throws ReaderException if no PDF417 Code can be found
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*/
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public DetectorResult detect(Hashtable hints) throws ReaderException {
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// Fetch the 1 bit matrix once up front.
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BitMatrix matrix = image.getBlackMatrix();
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// Try to find the vertices assuming the image is upright.
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ResultPoint[] vertices = findVertices(matrix);
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if (vertices == null) { // Couldn't find the vertices
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if (vertices == null) {
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// Maybe the image is rotated 180 degrees?
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vertices = findVertices180(matrix);
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/*
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* // Don't need this because the PDF417 code won't fit into // the
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* camera view finder when it is rotated. if (vertices == null) { //
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* Couldn't find the vertices // Maybe the image is rotated 90 degrees?
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* vertices = findVertices90(image); if (vertices == null) { //
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* Couldn't find the vertices // Maybe the image is rotated 270
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* degrees? vertices = findVertices270(image); } }
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*/
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}
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if (vertices != null) {
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float moduleWidth = computeModuleWidth(vertices);
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if (moduleWidth < 1.0f) {
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@ -107,10 +93,9 @@ public final class Detector {
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int dimension = computeDimension(vertices[4], vertices[6],
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vertices[5], vertices[7], moduleWidth);
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// Deskew and sample image
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// Deskew and sample image.
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BitMatrix bits = sampleGrid(matrix, vertices[4], vertices[5],
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vertices[6], vertices[7], dimension);
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//bits.setModuleWidth(moduleWidth);
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return new DetectorResult(bits, new ResultPoint[]{vertices[4],
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vertices[5], vertices[6], vertices[7]});
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} else {
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@ -126,12 +111,15 @@ public final class Detector {
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* TODO: Scanning every row is very expensive. We should only do this for TRY_HARDER.
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*
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* @param matrix the scanned barcode image.
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* @return the an array containing the vertices. vertices[0] x, y top left
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* barcode vertices[1] x, y bottom left barcode vertices[2] x, y top
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* right barcode vertices[3] x, y bottom right barcode vertices[4] x,
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* y top left codeword area vertices[5] x, y bottom left codeword
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* area vertices[6] x, y top right codeword area vertices[7] x, y
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* bottom right codeword area
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* @return an array containing the vertices:
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* vertices[0] x, y top left barcode
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* vertices[1] x, y bottom left barcode
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* vertices[2] x, y top right barcode
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* vertices[3] x, y bottom right barcode
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* vertices[4] x, y top left codeword area
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* vertices[5] x, y bottom left codeword area
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* vertices[6] x, y top right codeword area
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* vertices[7] x, y bottom right codeword area
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*/
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private static ResultPoint[] findVertices(BitMatrix matrix) throws ReaderException {
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int height = matrix.getHeight();
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@ -203,12 +191,15 @@ public final class Detector {
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* TODO: Scanning every row is very expensive. We should only do this for TRY_HARDER.
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*
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* @param matrix the scanned barcode image.
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* @return the an array containing the vertices. vertices[0] x, y top left
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* barcode vertices[1] x, y bottom left barcode vertices[2] x, y top
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* right barcode vertices[3] x, y bottom right barcode vertices[4] x,
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* y top left codeword area vertices[5] x, y bottom left codeword
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* area vertices[6] x, y top right codeword area vertices[7] x, y
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* bottom right codeword area
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* @return an array containing the vertices:
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* vertices[0] x, y top left barcode
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* vertices[1] x, y bottom left barcode
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* vertices[2] x, y top right barcode
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* vertices[3] x, y bottom right barcode
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* vertices[4] x, y top left codeword area
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* vertices[5] x, y bottom left codeword area
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* vertices[6] x, y top right codeword area
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* vertices[7] x, y bottom right codeword area
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*/
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private static ResultPoint[] findVertices180(BitMatrix matrix) throws ReaderException {
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int height = matrix.getHeight();
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@ -272,15 +263,18 @@ public final class Detector {
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}
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/**
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* <p>
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* Estimates module size (pixels in a module) based on the Start and End
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* <p>Estimates module size (pixels in a module) based on the Start and End
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* finder patterns.</p>
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*
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* @param vertices [] vertices[0] x, y top left barcode vertices[1] x, y bottom
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* left barcode vertices[2] x, y top right barcode vertices[3] x, y
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* bottom right barcode vertices[4] x, y top left Codeword area
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* vertices[5] x, y bottom left Codeword area vertices[6] x, y top
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* right Codeword area vertices[7] x, y bottom right Codeword area
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* @param vertices an array of vertices:
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* vertices[0] x, y top left barcode
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* vertices[1] x, y bottom left barcode
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* vertices[2] x, y top right barcode
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* vertices[3] x, y bottom right barcode
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* vertices[4] x, y top left codeword area
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* vertices[5] x, y bottom left codeword area
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* vertices[6] x, y top right codeword area
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* vertices[7] x, y bottom right codeword area
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* @return the module size.
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*/
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private static float computeModuleWidth(ResultPoint[] vertices) {
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@ -306,12 +300,8 @@ public final class Detector {
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*/
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private static int computeDimension(ResultPoint topLeft, ResultPoint topRight,
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ResultPoint bottomLeft, ResultPoint bottomRight, float moduleWidth) {
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int topRowDimension = round(ResultPoint
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.distance(topLeft, topRight)
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/ moduleWidth);
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int bottomRowDimension = round(ResultPoint.distance(bottomLeft,
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bottomRight)
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/ moduleWidth);
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int topRowDimension = round(ResultPoint.distance(topLeft, topRight) / moduleWidth);
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int bottomRowDimension = round(ResultPoint.distance(bottomLeft, bottomRight) / moduleWidth);
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return ((((topRowDimension + bottomRowDimension) >> 1) + 8) / 17) * 17;
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/*
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* int topRowDimension = round(ResultPoint.distance(topLeft,
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@ -328,8 +318,7 @@ public final class Detector {
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ResultPoint bottomLeft, ResultPoint topRight, ResultPoint bottomRight, int dimension)
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throws ReaderException {
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// Note that unlike in the QR Code sampler, we didn't find the center of
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// modules, but the
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// Note that unlike the QR Code sampler, we didn't find the center of modules, but the
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// very corners. So there is no 0.5f here; 0.0f is right.
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GridSampler sampler = GridSampler.getInstance();
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@ -349,7 +338,6 @@ public final class Detector {
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bottomRight.getY(), // p3FromY
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bottomLeft.getX(), // p4FromX
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bottomLeft.getY()); // p4FromY
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}
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/**
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@ -365,12 +353,14 @@ public final class Detector {
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* @param column x position to start search
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* @param row y position to start search
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* @param width the number of pixels to search on this row
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* @param pattern pattern of counts of number of black and white pixels that are
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* being searched for as a pattern
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* @param pattern pattern of counts of number of black and white pixels that are
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* being searched for as a pattern
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* @return start/end horizontal offset of guard pattern, as an array of two ints.
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*/
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static int[] findGuardPattern(BitMatrix matrix, int column, int row, int width, int[] pattern) {
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int patternLength = pattern.length;
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// TODO: Find a way to cache this array, as this method is called hundreds of times
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// per image, and we want to allocate as seldom as possible.
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int[] counters = new int[patternLength];
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boolean isWhite = false;
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@ -408,8 +398,8 @@ public final class Detector {
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* the total variance from the expected pattern proportions across all
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* pattern elements, to the length of the pattern.
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*
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* @param counters observed counters
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* @param pattern expected pattern
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* @param counters observed counters
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* @param pattern expected pattern
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* @param maxIndividualVariance The most any counter can differ before we give up
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* @return ratio of total variance between counters and pattern compared to
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* total pattern size, where the ratio has been multiplied by 256.
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@ -417,8 +407,7 @@ public final class Detector {
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* variance between counters and patterns equals the pattern length,
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* higher values mean even more variance
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*/
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public static int patternMatchVariance(int[] counters, int[] pattern,
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int maxIndividualVariance) {
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public static int patternMatchVariance(int[] counters, int[] pattern, int maxIndividualVariance) {
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int numCounters = counters.length;
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int total = 0;
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int patternLength = 0;
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@ -428,15 +417,12 @@ public final class Detector {
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}
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if (total < patternLength) {
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// If we don't even have one pixel per unit of bar width, assume this
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// is too small
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// to reliably match, so fail:
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// is too small to reliably match, so fail:
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return Integer.MAX_VALUE;
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}
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// We're going to fake floating-point math in integers. We just need to
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// use more bits.
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// Scale up patternLength so that intermediate values below like
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// scaledCounter will have
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// more "significant digits"
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// We're going to fake floating-point math in integers. We just need to use more bits.
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// Scale up patternLength so that intermediate values below like scaledCounter will have
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// more "significant digits".
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int unitBarWidth = (total << 8) / patternLength;
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maxIndividualVariance = (maxIndividualVariance * unitBarWidth) >> 8;
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@ -444,8 +430,7 @@ public final class Detector {
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for (int x = 0; x < numCounters; x++) {
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int counter = counters[x] << 8;
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int scaledPattern = pattern[x] * unitBarWidth;
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int variance = counter > scaledPattern ? counter - scaledPattern
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: scaledPattern - counter;
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int variance = counter > scaledPattern ? counter - scaledPattern : scaledPattern - counter;
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if (variance > maxIndividualVariance) {
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return Integer.MAX_VALUE;
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}
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