DataMatrixDemo

/** * libdmtx - Data Matrix Encoding/Decoding Library * Copyright 2008, 2009 Mike Laughton. All rights reserved. * * See LICENSE file in the main project directory for full * terms of use and distribution. * * Contact: Mike Laughton <mike@dragonflylogic.com> * * \file dmtxregion.c * \brief Detect barcode regions */ #include "dmtx.h" #include "dmtxstatic.h" #define DMTX_HOUGH_RES 180 /** * \brief Create copy of existing region struct * \param None * \return Initialized DmtxRegion struct */ extern DmtxRegion * dmtxRegionCreate(DmtxRegion *reg) { DmtxRegion *regCopy; regCopy = (DmtxRegion *)malloc(sizeof(DmtxRegion)); if(regCopy == NULL) return NULL; memcpy(regCopy, reg, sizeof(DmtxRegion)); return regCopy; } /** * \brief Destroy region struct * \param reg * \return void */ extern DmtxPassFail dmtxRegionDestroy(DmtxRegion **reg) { if(reg == NULL || *reg == NULL) return DmtxFail; free(*reg); *reg = NULL; return DmtxPass; } /** * \brief Find next barcode region * \param dec Pointer to DmtxDecode information struct * \param timeout Pointer to timeout time (NULL if none) * \return Detected region (if found) */ extern DmtxRegion * dmtxRegionFindNext(DmtxDecode *dec, DmtxTime *timeout) { int locStatus; DmtxPixelLoc loc; DmtxRegion *reg; /* Continue until we find a region or run out of chances */ for(;;) { locStatus = PopGridLocation(&(dec->grid), &loc); if(locStatus == DmtxRangeEnd) break; /* Scan location for presence of valid barcode region */ reg = dmtxRegionScanPixel(dec, loc.X, loc.Y); if(reg != NULL) return reg; /* Ran out of time? */ if(timeout != NULL && dmtxTimeExceeded(*timeout)) break; } return NULL; } /** * \brief Scan individual pixel for presence of barcode edge * \param dec Pointer to DmtxDecode information struct * \param loc Pixel location * \return Detected region (if any) */ extern DmtxRegion * dmtxRegionScanPixel(DmtxDecode *dec, int x, int y) { unsigned char *cache; DmtxRegion reg; DmtxPointFlow flowBegin; DmtxPixelLoc loc; loc.X = x; loc.Y = y; cache = dmtxDecodeGetCache(dec, loc.X, loc.Y); if(cache == NULL) return NULL; if((int)(*cache & 0x80) != 0x00) return NULL; /* Test for presence of any reasonable edge at this location */ flowBegin = MatrixRegionSeekEdge(dec, loc); if(flowBegin.mag < (int)(dec->edgeThresh * 7.65 + 0.5)) return NULL; memset(&reg, 0x00, sizeof(DmtxRegion)); /* Determine barcode orientation */ if(MatrixRegionOrientation(dec, &reg, flowBegin) == DmtxFail) return NULL; if(dmtxRegionUpdateXfrms(dec, &reg) == DmtxFail) return NULL; /* Define top edge */ if(MatrixRegionAlignCalibEdge(dec, &reg, DmtxEdgeTop) == DmtxFail) return NULL; if(dmtxRegionUpdateXfrms(dec, &reg) == DmtxFail) return NULL; /* Define right edge */ if(MatrixRegionAlignCalibEdge(dec, &reg, DmtxEdgeRight) == DmtxFail) return NULL; if(dmtxRegionUpdateXfrms(dec, &reg) == DmtxFail) return NULL; CALLBACK_MATRIX(&reg); /* Calculate the best fitting symbol size */ if(MatrixRegionFindSize(dec, &reg) == DmtxFail) return NULL; /* Found a valid matrix region */ return dmtxRegionCreate(&reg); } /** * * */ DmtxPointFlow MatrixRegionSeekEdge(DmtxDecode *dec, DmtxPixelLoc loc) { int i; int strongIdx; int channelCount; DmtxPointFlow flow, flowPlane[3]; DmtxPointFlow flowPos, flowPosBack; DmtxPointFlow flowNeg, flowNegBack; channelCount = dec->image->channelCount; /* Find whether red, green, or blue shows the strongest edge */ strongIdx = 0; for(i = 0; i < channelCount; i++) { flowPlane[i] = GetPointFlow(dec, i, loc, dmtxNeighborNone); if(i > 0 && flowPlane[i].mag > flowPlane[strongIdx].mag) strongIdx = i; } if(flowPlane[strongIdx].mag < 10) return dmtxBlankEdge; flow = flowPlane[strongIdx]; flowPos = FindStrongestNeighbor(dec, flow, +1); flowNeg = FindStrongestNeighbor(dec, flow, -1); if(flowPos.mag != 0 && flowNeg.mag != 0) { flowPosBack = FindStrongestNeighbor(dec, flowPos, -1); flowNegBack = FindStrongestNeighbor(dec, flowNeg, +1); if(flowPos.arrive == (flowPosBack.arrive+4)%8 && flowNeg.arrive == (flowNegBack.arrive+4)%8) { flow.arrive = dmtxNeighborNone; CALLBACK_POINT_PLOT(flow.loc, 1, 1, 1); return flow; } } return dmtxBlankEdge; } /** * * */ DmtxPassFail MatrixRegionOrientation(DmtxDecode *dec, DmtxRegion *reg, DmtxPointFlow begin) { int cross; int minArea; int scale; int symbolShape; int maxDiagonal; DmtxPassFail err; DmtxBestLine line1x, line2x; DmtxBestLine line2n, line2p; DmtxFollow fTmp; if(dec->sizeIdxExpected == DmtxSymbolSquareAuto || (dec->sizeIdxExpected >= DmtxSymbol10x10 && dec->sizeIdxExpected <= DmtxSymbol144x144)) symbolShape = DmtxSymbolSquareAuto; else if(dec->sizeIdxExpected == DmtxSymbolRectAuto || (dec->sizeIdxExpected >= DmtxSymbol8x18 && dec->sizeIdxExpected <= DmtxSymbol16x48)) symbolShape = DmtxSymbolRectAuto; else symbolShape = DmtxSymbolShapeAuto; if(dec->edgeMax != DmtxUndefined) { if(symbolShape == DmtxSymbolRectAuto) maxDiagonal = (int)(1.23 * dec->edgeMax + 0.5); /* sqrt(5/4) + 10% */ else maxDiagonal = (int)(1.56 * dec->edgeMax + 0.5); /* sqrt(2) + 10% */ } else { maxDiagonal = DmtxUndefined; } /* Follow to end in both directions */ err = TrailBlazeContinuous(dec, reg, begin, maxDiagonal); if(err == DmtxFail || reg->stepsTotal < 40) { TrailClear(dec, reg, 0x40); return DmtxFail; } /* Filter out region candidates that are smaller than expected */ if(dec->edgeMin != DmtxUndefined) { scale = dmtxDecodeGetProp(dec, DmtxPropScale); if(symbolShape == DmtxSymbolSquareAuto) minArea = (dec->edgeMin * dec->edgeMin)/(scale * scale); else minArea = (2 * dec->edgeMin * dec->edgeMin)/(scale * scale); if((reg->boundMax.X - reg->boundMin.X) * (reg->boundMax.Y - reg->boundMin.Y) < minArea) { TrailClear(dec, reg, 0x40); return DmtxFail; } } line1x = FindBestSolidLine(dec, reg, 0, 0, +1, DmtxUndefined); if(line1x.mag < 5) { TrailClear(dec, reg, 0x40); return DmtxFail; } err = FindTravelLimits(dec, reg, &line1x); if(line1x.distSq < 100 || line1x.devn * 10 >= sqrt((double)line1x.distSq)) { TrailClear(dec, reg, 0x40); return DmtxFail; } assert(line1x.stepPos >= line1x.stepNeg); fTmp = FollowSeek(dec, reg, line1x.stepPos + 5); line2p = FindBestSolidLine(dec, reg, fTmp.step, line1x.stepNeg, +1, line1x.angle); fTmp = FollowSeek(dec, reg, line1x.stepNeg - 5); line2n = FindBestSolidLine(dec, reg, fTmp.step, line1x.stepPos, -1, line1x.angle); if(max(line2p.mag, line2n.mag) < 5) return DmtxFail; if(line2p.mag > line2n.mag) { line2x = line2p; err = FindTravelLimits(dec, reg, &line2x); if(line2x.distSq < 100 || line2x.devn * 10 >= sqrt((double)line2x.distSq)) return DmtxFail; cross = ((line1x.locPos.X - line1x.locNeg.X) * (line2x.locPos.Y - line2x.locNeg.Y)) - ((line1x.locPos.Y - line1x.locNeg.Y) * (line2x.locPos.X - line2x.locNeg.X)); if(cross > 0) { /* Condition 2 */ reg->polarity = +1; reg->locR = line2x.locPos; reg->stepR = line2x.stepPos; reg->locT = line1x.locNeg; reg->stepT = line1x.stepNeg; reg->leftLoc = line1x.locBeg; reg->leftAngle = line1x.angle; reg->bottomLoc = line2x.locBeg; reg->bottomAngle = line2x.angle; reg->leftLine = line1x; reg->bottomLine = line2x; } else { /* Cond