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#include "AlgorithmGrayCodeHorzVert.h"

#include <cmath>

#include <assert.h>

#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

AlgorithmGrayCodeHorzVert::AlgorithmGrayCodeHorzVert(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, NbitsHorz-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, NbitsVert-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 AlgorithmGrayCodeHorzVert::getEncodingPattern(unsigned int depth){

    return patterns[depth];

}

typedef struct intersection{

    unsigned int row;

    unsigned int col;

    unsigned long id;

    intersection() : row(0), col(0), id(0){}

    intersection(unsigned int _row, unsigned int _col, unsigned long long _id) :

        row(_row), col(_col), id(_id){}

} intersection;

static bool sortingLarger(intersection i,intersection j){ return (i.id<j.id);}

static bool sortingEqual(intersection i,intersection j){ return (i.id==j.id);}

static void getIntersectionLabels(const cv::Mat& codeHorz, const cv::Mat& codeVert, const int NbitsHorz, const int NbitsVert, std::vector<intersection>& intersections){

    int nRows = codeHorz.rows;

    int nCols = codeHorz.cols;

    int labelHorz;

    int labelVert;

    int labelHorzRight;

    int labelVertBelow;

    // collect intersections

    for(int row=0; row<nRows+1; row++){

        for(int col=0; col<nCols+1; col++){

            labelHorz = codeHorz.at<int>(row, col);

            labelHorzRight = codeHorz.at<int>(row, col+1);

            labelVert = codeVert.at<int>(row, col);

            labelVertBelow = codeVert.at<int>(row+1, col);

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

            if(labelHorz != -1 && labelHorzRight != -1 &&

               countBits(labelHorz^labelHorzRight) == 1 &&

               labelVert != -1 && labelVertBelow != -1 &&

               countBits(labelVert^labelVertBelow) == 1){

                // shift together labels to form unique intersection id

                unsigned long id = (labelHorz << NbitsHorz+2*NbitsVert) + (labelHorzRight << 2*NbitsVert) +

                                   (labelVert << NbitsVert) + labelVertBelow;

                // store intersection

                intersections.push_back(intersection(row, col, id));

            }

        }

    }

    // sort

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

    // remove duplicates

    std::vector<intersection>::iterator it;

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

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

}

static void getSubpixelCoordinates(const std::vector<intersection>& matches, const std::vector<cv::Mat>& frames, const int NbitsHorz, const int NbitsVert, std::vector<cv::Point2f> &q){

    int nMatches = matches.size();

    q.resize(nMatches);

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

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

        // shift the labels back out from id

        int labelHorz = (matches[i].id >> NbitsHorz+2*NbitsVert) & (1 << (NbitsHorz+1) - 1);

        int labelHorzRight = (matches[i].id >> 2*NbitsVert) & (1 << (NbitsHorz+1) - 1);

        int labelVert = (matches[i].id >> NbitsVert) & (1 << (NbitsVert+1) - 1);

        int labelVertBelow = matches[i].id  & (1 << (NbitsVert+1) - 1);

        // determine the levels at which the edges exists

        int levelHorz = NbitsHorz - leastSignificantBitSet(labelHorz^labelHorzRight);

        int levelVert = NbitsVert - leastSignificantBitSet(labelVert^labelVertBelow);

        // interpolate horizontal coordinate

        float row = matches[i].row;

        float col = matches[i].col;

        float colRight = col+1;

        float posHorz = frames0[2*levelHorz+2].at<char>(row, col);

        float negHorz = frames0[2*levelHorz+3].at<char>(row, col);

        float posHorzRight = frames0[2*levelHorz+2].at<char>(row, colRight);

        float negHorzRight = frames0[2*levelHorz+3].at<char>(row, colRight);

        float x = col + (posHorz - negHorz)/(negHorzRight - negHorz - posHorzRight + posHorz);

        // interpolate vertical coordinate

        float rowBelow = row+1;

        float posVert = frames[2*NbitsHorz+2*levelVert+2].at<char>(rowBelow, col);

        float negVert = frames[2*NbitsHorz+2*levelVert+3].at<char>(rowBelow, col);

        float posVertBelow = frames[2*NbitsHorz+2*levelVert+2].at<char>(rowBelow, col);

        float negVertBelow = frames[2*NbitsHorz+2*levelVert+3].at<char>(rowBelow, col);

        float y = row + (posVert - negVert)/(negVertBelow - negVert - posVertBelow + posVert);

        // write into return vector

        q[i] = cv::Vec2f(x, y);

    }

}

static 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 AlgorithmGrayCodeHorzVert::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[i], CV_RGB2GRAY);

        cv::cvtColor(frames1[i], frames1Gray[i], 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(NbitsHorz-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(NbitsHorz-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(NbitsVert-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(NbitsVert-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;

            }

        }

    }

    // matching

    std::vector<intersection> intersections0, intersections1;

    // intersection data structure containing [floor(row), floor(column), id]

    getIntersectionLabels(code0Horz, code0Vert, NbitsHorz, NbitsVert, intersections0);

    getIntersectionLabels(code1Horz, code1Vert, NbitsHorz, NbitsVert, intersections1);

    // match intersections

    std::vector<intersection> matches0, matches1;

    int i=0, j=0;

    while(i<intersections0.size() && j<intersections1.size()){

        if(intersections0[i].id == intersections1[j].id){

            matches0.push_back(intersections0[i]);

            matches1.push_back(intersections1[j]);

            i += 1;

            j += 1;

        } else if(intersections0[i].id < intersections1[j].id){

            i += 1;

        } else if(intersections0[i].id > intersections1[j].id){

            j += 1;

        }

    }

    int nMatches = matches0.size();

    if(nMatches < 1){

        Q.resize(0);

        color.resize(0);

        return;

    }

    std::vector<cv::Point2f> q0(nMatches), q1(nMatches);

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

//        q0[i] = cv::Vec2f(matches0[i].col, matches0[i].row);

//        q1[i] = cv::Vec2f(matches1[i].col, matches1[i].row);

//    }

    // subpixel refinement

    getSubpixelCoordinates(matches0, frames0, NbitsHorz, NbitsVert,q0);

    getSubpixelCoordinates(matches1, frames1, NbitsHorz, NbitsVert,q1);

    // retrieve color information (at subpixel coordinates)

    color.resize(nMatches);

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

//        cv::Vec3b c0 = color0.at<cv::Vec3b>(q0[i][1], q0[i][0]);

//        cv::Vec3b c1 = color1.at<cv::Vec3b>(q1[i][1], q1[i][0]);

        cv::Vec3b c0 = getColorSubpix(color0, q0[i]);

        cv::Vec3b c1 = getColorSubpix(color1, q1[i]);

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

    }

    // triangulate points

    cv::Mat P0(3, 4, CV_32F, cv::Scalar(0.0));

    cv::Mat(calibration.K0).copyTo(P0.colRange(0, 3));

    cv::Mat P1(3, 4, CV_32F), temp(3,4,CV_32F);

    cv::Mat(calibration.R1).copyTo(temp(cv::Range(0,3), cv::Range(0,3)));

    cv::Mat(calibration.T1).copyTo(temp(cv::Range(0,3), cv::Range(3,4)));

    P1 = cv::Mat(calibration.K1) * temp;

    //cv::correctMatches(calibration.F, q0, q1, q0, q1);

    cv::Mat QMatHomogenous, QMat;

    cv::triangulatePoints(P0, P1, q0, q1, QMatHomogenous);

    cvtools::convertMatFromHomogeneous(QMatHomogenous, QMat);

    cvtools::matToPoints3f(QMat, Q);

}