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#include "AlgorithmGrayCodeHQ.h"

#include <cmath>

#include "cvtools.h"

#ifndef log2f

#define log2f(x) (log(x)/log(2.0))

#endif

//using namespace std;

/*

 * The purpose of this function is to convert an unsigned

 * binary number to reflected binary Gray code.

 *

 * The operator >> is shift right. The operator ^ is exclusive or.

 * Source: http://en.wikipedia.org/wiki/Gray_code

 */

static unsigned int binaryToGray(unsigned int num) {

    return (num >> 1) ^ num;

}

/*

 * From Wikipedia: http://en.wikipedia.org/wiki/Gray_code

 * The purpose of this function is to convert a reflected binary

 * Gray code number to a binary number.

 */

static unsigned int grayToBinary(unsigned int num){

    unsigned int mask;

    for(mask = num >> 1; mask != 0; mask = mask >> 1)

        num = num ^ mask;

    return num;

}

/*

 * Return the Nth bit of an unsigned integer number

 */

static bool getBit(int decimal, int N){

    return decimal & 1 << (N-1);

}

/*

 * Return the number of bits set in an integer

 */

static int countBits(int n) {

  unsigned int c; // c accumulates the total bits set in v

  for (c = 0; n>0; c++)

    n &= n - 1; // clear the least significant bit set

  return c;

}

/*

 * Return the position of the least significant bit that is set

 */

static int leastSignificantBitSet(int x){

  if(x == 0)

      return 0;

  int val = 1;

  while(x>>=1)

      val++;

  return val;

}

//static int get_bit(int decimal, int N){

//    // Shifting the 1 for N-1 bits

//    int constant = 1 << (N-1);

//    // If the bit is set, return 1

//    if( decimal & constant )

//        return 1;

//    else

//        return 0;

//}

static inline unsigned int powi(int num, unsigned int exponent){

    if(exponent == 0)

        return 1;

    float res = num;

    for(unsigned int i=0; i<exponent-1; i++)

        res *= num;

    return res;

}

static inline unsigned int twopowi(unsigned int exponent){

    return 1 << exponent;

}

// Algorithm

AlgorithmGrayCodeHQ::AlgorithmGrayCodeHQ(unsigned int _screenCols, unsigned int _screenRows) : Algorithm(_screenCols, _screenRows){

    NbitsHorz = ceilf(log2f((float)screenCols));

    NbitsVert =  ceilf(log2f((float)screenRows));

    N = 2 + (NbitsHorz+NbitsVert)*2;

    // all on pattern

    cv::Mat allOn(1, screenCols, CV_8UC3, cv::Scalar::all(255));

    patterns.push_back(allOn);

    // all off pattern

    cv::Mat allOff(1, screenCols, CV_8UC3, cv::Scalar::all(0));

    patterns.push_back(allOff);

    // horizontally encoding patterns

    for(unsigned int p=0; p<NbitsHorz; p++){

        cv::Mat pattern(1, screenCols, CV_8UC3);

        cv::Mat patternInv(1, screenCols, CV_8UC3);

        for(unsigned int j=0; j<screenCols; j++){

            unsigned int jGray = binaryToGray(j);

            // Amplitude of channels

            int bit = (int)getBit(jGray, Nbits-p);

            pattern.at<cv::Vec3b>(0,j) = cv::Vec3b(255.0*bit,255.0*bit,255.0*bit);

            int invBit = bit^1;

            patternInv.at<cv::Vec3b>(0,j) = cv::Vec3b(255.0*invBit,255.0*invBit,255.0*invBit);

        }

        patterns.push_back(pattern);

        patterns.push_back(patternInv);

    }

    // vertical encoding patterns

    for(unsigned int p=0; p<NbitsVert; p++){

        cv::Mat pattern(screenRows, 1, CV_8UC3);

        cv::Mat patternInv(screenRows, 1, CV_8UC3);

        for(unsigned int j=0; j<screenRows; j++){

            unsigned int jGray = binaryToGray(j);

            // Amplitude of channels

            int bit = (int)getBit(jGray, Nbits-p);

            pattern.at<cv::Vec3b>(j,0) = cv::Vec3b(255.0*bit,255.0*bit,255.0*bit);

            int invBit = bit^1;

            patternInv.at<cv::Vec3b>(j,0) = cv::Vec3b(255.0*invBit,255.0*invBit,255.0*invBit);

        }

        patterns.push_back(pattern);

        patterns.push_back(patternInv);

    }

}

cv::Mat AlgorithmGrayCodeHQ::getEncodingPattern(unsigned int depth){

    return patterns[depth];

}

bool sortingLarger(cv::Vec4i i,cv::Vec4i j){ return (i[3]<j[3]);}

bool sortingEqual(cv::Vec4i i,cv::Vec4i j){ return (i[3]==j[3]);}

void getEdgeLabels(const cv::Mat& scanLine, int Nbits, std::vector<cv::Vec4i>& edges){

    int nCols = scanLine.cols;

    const int *data = scanLine.ptr<const int>(0);

    int labelLeft;

    int labelRight = data[0];

    // collect edges

    for(int col=1; col<nCols; col++){

        labelLeft = labelRight;

        labelRight = data[col];

        // labels need to be non-background, and differ in exactly one bit

        if(labelLeft != -1 && labelRight != -1 && countBits(labelLeft^labelRight) == 1){

            int orderingRelation = (labelLeft << Nbits) + labelRight;

            // store left label column

            edges.push_back(cv::Vec4i(col-1, labelLeft, labelRight, orderingRelation));

        }

    }

    // sort

    std::sort(edges.begin(), edges.end(), sortingLarger);

    // remove duplicates

    std::vector<cv::Vec4i>::iterator it;

    it = std::unique(edges.begin(), edges.end(), sortingEqual);

    edges.resize(std::distance(edges.begin(),it));

}

cv::Vec3b getColorSubpix(const cv::Mat& img, cv::Point2f pt){

    assert(!img.empty());

    assert(img.channels() == 3);

    int x = (int)pt.x;

    int y = (int)pt.y;

    int x0 = cv::borderInterpolate(x,   img.cols, cv::BORDER_REFLECT_101);

    int x1 = cv::borderInterpolate(x+1, img.cols, cv::BORDER_REFLECT_101);

    int y0 = cv::borderInterpolate(y,   img.rows, cv::BORDER_REFLECT_101);

    int y1 = cv::borderInterpolate(y+1, img.rows, cv::BORDER_REFLECT_101);

    float a = pt.x - (float)x;

    float c = pt.y - (float)y;

    uchar b = (uchar)cvRound((img.at<cv::Vec3b>(y0, x0)[0] * (1.f - a) + img.at<cv::Vec3b>(y0, x1)[0] * a) * (1.f - c)

                           + (img.at<cv::Vec3b>(y1, x0)[0] * (1.f - a) + img.at<cv::Vec3b>(y1, x1)[0] * a) * c);

    uchar g = (uchar)cvRound((img.at<cv::Vec3b>(y0, x0)[1] * (1.f - a) + img.at<cv::Vec3b>(y0, x1)[1] * a) * (1.f - c)

                           + (img.at<cv::Vec3b>(y1, x0)[1] * (1.f - a) + img.at<cv::Vec3b>(y1, x1)[1] * a) * c);

    uchar r = (uchar)cvRound((img.at<cv::Vec3b>(y0, x0)[2] * (1.f - a) + img.at<cv::Vec3b>(y0, x1)[2] * a) * (1.f - c)

                           + (img.at<cv::Vec3b>(y1, x0)[2] * (1.f - a) + img.at<cv::Vec3b>(y1, x1)[2] * a) * c);

    return cv::Vec3b(b, g, r);

}

void AlgorithmGrayCodeHQ::get3DPoints(SMCalibrationParameters calibration, const std::vector<cv::Mat>& frames0, const std::vector<cv::Mat>& frames1, std::vector<cv::Point3f>& Q, std::vector<cv::Vec3b>& color){

    assert(frames0.size() == N);

    assert(frames1.size() == N);

    int frameRows = frames0[0].rows;

    int frameCols = frames0[0].cols;

    // gray-scale

    std::vector<cv::Mat> frames0Gray(N);

    std::vector<cv::Mat> frames1Gray(N);

    for(int i=0; i<N; i++){

        cv::cvtColor(frames0[i], frames0Gray, CV_RGB2GRAY);

        cv::cvtColor(frames1[i], frames1Gray, CV_RGB2GRAY);

    }

    // colors

    cv::Mat color0 = frames0[0];

    cv::Mat color1 = frames1[0];

    // occlusion masks

    cv::Mat occlusion0, occlusion1;

    cv::subtract(frames0Gray[0], frames0Gray[1], occlusion0);

    occlusion0 = occlusion0 > 25;

    cv::subtract(frames1Gray[0], frames1Gray[1], occlusion1);

    occlusion1 = occlusion1 > 25;

    // erode occlusion masks

    cv::Mat strel = cv::getStructuringElement(cv::MORPH_ELLIPSE, cv::Size(3,3));

    cv::erode(occlusion0, occlusion0, strel);

    cv::erode(occlusion1, occlusion1, strel);

//cvtools::writeMat(occlusion0, "occlusion0.mat", "occlusion0");

//cvtools::writeMat(occlusion1, "occlusion1.mat", "occlusion1");

    // decode patterns

    cv::Mat code0Horz(frameRows, frameCols, CV_32S, cv::Scalar(0));

    cv::Mat code1Horz(frameRows, frameCols, CV_32S, cv::Scalar(0));

    cv::Mat code0Vert(frameRows, frameCols, CV_32S, cv::Scalar(0));

    cv::Mat code1Vert(frameRows, frameCols, CV_32S, cv::Scalar(0));

    // horizontal codes into gray code

    for(int i=0; i<NbitsHorz; i++){

        cv::Mat bit0;

        cv::subtract(frames0Gray[i*2+2], frames0Gray[i*2+3], bit0);

        bit0 = bit0 > 0;

        bit0.convertTo(bit0, CV_32S, 1.0/255.0);

        cv::add(code0Horz, bit0*twopowi(Nbits-i-1), code0Horz, cv::Mat(), CV_32S);

        cv::Mat bit1;

        cv::subtract(frames1Gray[i*2+2], frames1Gray[i*2+3], bit1);

        bit1 = bit1 > 0;

        bit1.convertTo(bit1, CV_32S, 1.0/255.0);

        cv::add(code1Horz, bit1*twopowi(Nbits-i-1), code1Horz, cv::Mat(), CV_32S);

    }

    // vertical codes into gray code

    for(int i=0; i<NbitsVert; i++){

        cv::Mat bit0;

        cv::subtract(frames0Gray[i*2+NbitsHorz+2], frames0Gray[i*2+NbitsHorz+3], bit0);

        bit0 = bit0 > 0;

        bit0.convertTo(bit0, CV_32S, 1.0/255.0);

        cv::add(code0Vert, bit0*twopowi(Nbits-i-1), code0Vert, cv::Mat(), CV_32S);

        cv::Mat bit1;

        cv::subtract(frames1Gray[i*2+NbitsHorz+2], frames1Gray[i*2+NbitsHorz+3], bit1);

        bit1 = bit1 > 0;

        bit1.convertTo(bit1, CV_32S, 1.0/255.0);

        cv::add(code1Vert, bit1*twopowi(Nbits-i-1), code1Vert, cv::Mat(), CV_32S);

    }

//cvtools::writeMat(code0Horz, "code0Horz.mat", "code0Horz");

//cvtools::writeMat(code1Horz, "code1Horz.mat", "code1Horz");

//cvtools::writeMat(code0Vert, "code0Vert.mat", "code0Vert");

//cvtools::writeMat(code1Vert, "code1Vert.mat", "code1Vert");

    // set occluded pixels to -1

    for(int r=0; r<frameRows; r++){

        for(int c=0; c<frameCols; c++){

            if(occlusion0.at<char>(r,c) == 0){

                code0Horz.at<float>(r,c) = -1;

                code0Vert.at<float>(r,c) = -1;

            }

            if(occlusion1.at<char>(r,c) == 0){

                code1Horz.at<float>(r,c) = -1;

                code1Vert.at<float>(r,c) = -1;

            }

        }

    }

    // TODO: REWRITE TO PERFORM HORIZONTAL + VERTICAL MATCHING

//    // matching

//    std::vector<cv::Vec2f> q0Rect, q1Rect;

//    for(int row=0; row<frameRectRows; row++){

//        // edge data structure containing [floor(column), labelLeft, labelRight, orderingRelation]

//        std::vector<cv::Vec4i> edges0, edges1;

//        // sorted, unique edges

//        getEdgeLabels(code0Rect.row(row), Nbits, edges0);

//        getEdgeLabels(code1Rect.row(row), Nbits, edges1);

//        // match edges

//        std::vector<cv::Vec4i> matchedEdges0, matchedEdges1;

//        int i=0, j=0;

//        while(i<edges0.size() && j<edges1.size()){

//            if(edges0[i][3] == edges1[j][3]){

//                matchedEdges0.push_back(edges0[i]);

//                matchedEdges1.push_back(edges1[j]);

//                i += 1;

//                j += 1;

//            } else if(edges0[i][3] < edges1[j][3]){

//                i += 1;

//            } else if(edges0[i][3] > edges1[j][3]){

//                j += 1;

//            }

//        }

//        // crude subpixel refinement

//        // finds the intersection of linear interpolants in the positive/negative pattern

//        for(int i=0; i<matchedEdges0.size(); i++){

//            int level = Nbits - leastSignificantBitSet(matchedEdges0[i][1]^matchedEdges0[i][2]);

//            // refine for camera 0

//            float c0 = matchedEdges0[i][0];

//            float c1 = c0+1;

//            float pos0 = frames0Rect[2*level+2].at<char>(row, c0);

//            float pos1 = frames0Rect[2*level+2].at<char>(row, c1);

//            float neg0 = frames0Rect[2*level+3].at<char>(row, c0);

//            float neg1 = frames0Rect[2*level+3].at<char>(row, c1);

//            float col = c0 + (pos0 - neg0)/(neg1 - neg0 - pos1 + pos0);

//            q0Rect.push_back(cv::Point2f(col, row));

//            // refine for camera 1

//            c0 = matchedEdges1[i][0];

//            c1 = c0+1;

//            pos0 = frames1Rect[2*level+2].at<char>(row, c0);

//            pos1 = frames1Rect[2*level+2].at<char>(row, c1);

//            neg0 = frames1Rect[2*level+3].at<char>(row, c0);

//            neg1 = frames1Rect[2*level+3].at<char>(row, c1);

//            col = c0 + (pos0 - neg0)/(neg1 - neg0 - pos1 + pos0);

//            q1Rect.push_back(cv::Point2f(col, row));

//        }

//    }

//    int nMatches = q0Rect.size();

//    if(nMatches < 1){

//        Q.resize(0);

//        color.resize(0);

//        return;

//    }

//    // retrieve color information (at integer coordinates)

//    color.resize(nMatches);

//    for(int i=0; i<nMatches; i++){

//        cv::Vec3b c0 = color0Rect.at<cv::Vec3b>(q0Rect[i][1], q0Rect[i][0]);

//        cv::Vec3b c1 = color1Rect.at<cv::Vec3b>(q1Rect[i][1], q1Rect[i][0]);

////        cv::Vec3b c0 = getColorSubpix(color0Rect, q0Rect[i]);

////        cv::Vec3b c1 = getColorSubpix(color1Rect, q0Rect[i]);

//        color[i] = 0.5*c0 + 0.5*c1;

//    }

//    // triangulate points

//    cv::Mat QMatHomogenous, QMat;

////    cv::Mat C0 = P0.clone();

////    cv::Mat C1 = P1.clone();

////    C0.colRange(0, 3) = C0.colRange(0, 3)*R0;

////    C1.colRange(0, 3) = C1.colRange(0, 3)*R1.t();

//    cv::triangulatePoints(P0, P1, q0Rect, q1Rect, QMatHomogenous);

//    cvtools::convertMatFromHomogeneous(QMatHomogenous, QMat);

//    // undo rectifying rotation

//    cv::Mat R0Inv;

//    cv::Mat(R0.t()).convertTo(R0Inv, CV_32F);

//    QMat = R0Inv*QMat;

//    cvtools::matToPoints3f(QMat, Q);

}