/// <returns> the 3 best {@link FinderPattern}s from our list of candidates. The "best" are /// those that have been detected at least {@link #CENTER_QUORUM} times, and whose module /// size differs from the average among those patterns the least /// </returns> /// <throws> ReaderException if 3 such finder patterns do not exist </throws> private FinderPattern[][] selectBestPatterns() { var possibleCenters = PossibleCenters; int size = possibleCenters.Count; if (size < 3) { // Couldn't find enough finder patterns throw ReaderException.Instance; } /* * Begin HE modifications to safely detect multiple codes of equal size */ if (size == 3) { return new FinderPattern[][]{new FinderPattern[]{(FinderPattern) possibleCenters[0], (FinderPattern) possibleCenters[1], (FinderPattern) possibleCenters[2]}}; } // Sort by estimated module size to speed up the upcoming checks Collections.insertionSort(possibleCenters, new ModuleSizeComparator()); /* * Now lets start: build a list of tuples of three finder locations that * - feature similar module sizes * - are placed in a distance so the estimated module count is within the QR specification * - have similar distance between upper left/right and left top/bottom finder patterns * - form a triangle with 90° angle (checked by comparing top right/bottom left distance * with pythagoras) * * Note: we allow each point to be used for more than one code region: this might seem * counterintuitive at first, but the performance penalty is not that big. At this point, * we cannot make a good quality decision whether the three finders actually represent * a QR code, or are just by chance layouted so it looks like there might be a QR code there. * So, if the layout seems right, lets have the decoder try to decode. */ List<FinderPattern[]> results = new List<FinderPattern[]>(10); // holder for the results for (int i1 = 0; i1 < (size - 2); i1++) { FinderPattern p1 = (FinderPattern) possibleCenters[i1]; if (p1 == null) { continue; } for (int i2 = i1 + 1; i2 < (size - 1); i2++) { FinderPattern p2 = (FinderPattern) possibleCenters[i2]; if (p2 == null) { continue; } // Compare the expected module sizes; if they are really off, skip float vModSize12 = (p1.EstimatedModuleSize - p2.EstimatedModuleSize) / (System.Math.Min(p1.EstimatedModuleSize, p2.EstimatedModuleSize)); float vModSize12A = System.Math.Abs(p1.EstimatedModuleSize - p2.EstimatedModuleSize); if (vModSize12A > DIFF_MODSIZE_CUTOFF && vModSize12 >= DIFF_MODSIZE_CUTOFF_PERCENT) { // break, since elements are ordered by the module size deviation there cannot be // any more interesting elements for the given p1. break; } for (int i3 = i2 + 1; i3 < size; i3++) { FinderPattern p3 = (FinderPattern) possibleCenters[i3]; if (p3 == null) { continue; } // Compare the expected module sizes; if they are really off, skip float vModSize23 = (p2.EstimatedModuleSize - p3.EstimatedModuleSize) / (System.Math.Min(p2.EstimatedModuleSize, p3.EstimatedModuleSize)); float vModSize23A = System.Math.Abs(p2.EstimatedModuleSize - p3.EstimatedModuleSize); if (vModSize23A > DIFF_MODSIZE_CUTOFF && vModSize23 >= DIFF_MODSIZE_CUTOFF_PERCENT) { // break, since elements are ordered by the module size deviation there cannot be // any more interesting elements for the given p1. break; } FinderPattern[] test = new FinderPattern[]{p1, p2, p3}; ResultPoint.orderBestPatterns(test); // Calculate the distances: a = topleft-bottomleft, b=topleft-topright, c = diagonal FinderPatternInfo info = new FinderPatternInfo(test); float dA = ResultPoint.distance(info.TopLeft, info.BottomLeft); float dC = ResultPoint.distance(info.TopRight, info.BottomLeft); float dB = ResultPoint.distance(info.TopLeft, info.TopRight); // Check the sizes float estimatedModuleCount = ((dA + dB) / p1.EstimatedModuleSize) / 2; if (estimatedModuleCount > MAX_MODULE_COUNT_PER_EDGE || estimatedModuleCount < MIN_MODULE_COUNT_PER_EDGE) { continue; } // Calculate the difference of the edge lengths in percent float vABBC = System.Math.Abs(((dA - dB) / System.Math.Min(dA, dB))); if (vABBC >= 0.1f) { continue; } // Calculate the diagonal length by assuming a 90° angle at topleft //UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'" float dCpy = (float) System.Math.Sqrt(dA * dA + dB * dB); // Compare to the real distance in % float vPyC = System.Math.Abs(((dC - dCpy) / System.Math.Min(dC, dCpy))); if (vPyC >= 0.1f) { continue; } // All tests passed! results.Add(test); } // end iterate p3 } // end iterate p2 } // end iterate p1 if (!(results.Count == 0)) { FinderPattern[][] resultArray = new FinderPattern[results.Count][]; for (int i = 0; i < results.Count; i++) { resultArray[i] = (FinderPattern[]) results[i]; } return resultArray; } // Nothing found! throw ReaderException.Instance; }
public FinderPatternInfo[] findMulti(System.Collections.Generic.Dictionary<Object, Object> hints) { bool tryHarder = hints != null && hints.ContainsKey(DecodeHintType.TRY_HARDER); BitMatrix image = Image; int maxI = image.Height; int maxJ = image.Width; // We are looking for black/white/black/white/black modules in // 1:1:3:1:1 ratio; this tracks the number of such modules seen so far // Let's assume that the maximum version QR Code we support takes up 1/4 the height of the // image, and then account for the center being 3 modules in size. This gives the smallest // number of pixels the center could be, so skip this often. When trying harder, look for all // QR versions regardless of how dense they are. //UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'" int iSkip = (int) (maxI / (MAX_MODULES * 4.0f) * 3); if (iSkip < MIN_SKIP || tryHarder) { iSkip = MIN_SKIP; } int[] stateCount = new int[5]; for (int i = iSkip - 1; i < maxI; i += iSkip) { // Get a row of black/white values stateCount[0] = 0; stateCount[1] = 0; stateCount[2] = 0; stateCount[3] = 0; stateCount[4] = 0; int currentState = 0; for (int j = 0; j < maxJ; j++) { if (image.get_Renamed(j, i)) { // Black pixel if ((currentState & 1) == 1) { // Counting white pixels currentState++; } stateCount[currentState]++; } else { // White pixel if ((currentState & 1) == 0) { // Counting black pixels if (currentState == 4) { // A winner? if (foundPatternCross(stateCount)) { // Yes bool confirmed = handlePossibleCenter(stateCount, i, j); if (!confirmed) { do { // Advance to next black pixel j++; } while (j < maxJ && !image.get_Renamed(j, i)); j--; // back up to that last white pixel } // Clear state to start looking again currentState = 0; stateCount[0] = 0; stateCount[1] = 0; stateCount[2] = 0; stateCount[3] = 0; stateCount[4] = 0; } else { // No, shift counts back by two stateCount[0] = stateCount[2]; stateCount[1] = stateCount[3]; stateCount[2] = stateCount[4]; stateCount[3] = 1; stateCount[4] = 0; currentState = 3; } } else { stateCount[++currentState]++; } } else { // Counting white pixels stateCount[currentState]++; } } } // for j=... if (foundPatternCross(stateCount)) { handlePossibleCenter(stateCount, i, maxJ); } // end if foundPatternCross } // for i=iSkip-1 ... FinderPattern[][] patternInfo = selectBestPatterns(); List<FinderPatternInfo> result = new List<FinderPatternInfo>(10); for (int i = 0; i < patternInfo.Length; i++) { FinderPattern[] pattern = patternInfo[i]; ResultPoint.orderBestPatterns(pattern); result.Add(new FinderPatternInfo(pattern)); } if ((result.Count == 0)) { return EMPTY_RESULT_ARRAY; } else { FinderPatternInfo[] resultArray = new FinderPatternInfo[result.Count]; for (int i = 0; i < result.Count; i++) { resultArray[i] = (FinderPatternInfo) result[i]; } return resultArray; } }
protected internal virtual DetectorResult processFinderPatternInfo(FinderPatternInfo info) { FinderPattern topLeft = info.TopLeft; FinderPattern topRight = info.TopRight; FinderPattern bottomLeft = info.BottomLeft; float moduleSize = calculateModuleSize(topLeft, topRight, bottomLeft); if (moduleSize < 1.0f) { throw ReaderException.Instance; } int dimension = computeDimension(topLeft, topRight, bottomLeft, moduleSize); Version provisionalVersion = Version.getProvisionalVersionForDimension(dimension); int modulesBetweenFPCenters = provisionalVersion.DimensionForVersion - 7; AlignmentPattern alignmentPattern = null; // Anything above version 1 has an alignment pattern if (provisionalVersion.AlignmentPatternCenters.Length > 0) { // Guess where a "bottom right" finder pattern would have been float bottomRightX = topRight.X - topLeft.X + bottomLeft.X; float bottomRightY = topRight.Y - topLeft.Y + bottomLeft.Y; // Estimate that alignment pattern is closer by 3 modules // from "bottom right" to known top left location //UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'" float correctionToTopLeft = 1.0f - 3.0f / (float) modulesBetweenFPCenters; //UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'" int estAlignmentX = (int) (topLeft.X + correctionToTopLeft * (bottomRightX - topLeft.X)); //UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'" int estAlignmentY = (int) (topLeft.Y + correctionToTopLeft * (bottomRightY - topLeft.Y)); // Kind of arbitrary -- expand search radius before giving up for (int i = 4; i <= 16; i <<= 1) { try { //UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'" alignmentPattern = findAlignmentInRegion(moduleSize, estAlignmentX, estAlignmentY, (float) i); break; } catch (ReaderException 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); }