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#include "AlgorithmPhaseShift.h"
#include <math.h>

#include "cvtools.h"

#ifndef M_PI
    #define M_PI 3.14159265358979323846
#endif

static unsigned int nPhases = 40;
static unsigned int nSteps = 20;

// Algorithm
static cv::Mat computePhaseVector(unsigned int length, float phase, float pitch){

    cv::Mat phaseVector(length, 1, CV_8UC3);
    //phaseVector.setTo(0);

    const float pi = M_PI;

    // Loop through vector
    for(int i=0; i<phaseVector.rows; i++){
        // Amplitude of channels
        float amp = 0.5*(1+cos(2*pi*i/pitch - phase));
        phaseVector.at<cv::Vec3b>(i, 0) = cv::Vec3b(255.0*amp,255.0*amp,255.0*amp);
    }

    return phaseVector;
}

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

    // 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);

    // Set N
    N = 2+nSteps+3;

    // Precompute encoded patterns
    const float pi = M_PI;

    // Horizontally encoding patterns
    for(unsigned int i=0; i<nSteps; i++){
        float phase = 2.0*pi/nSteps * i;
        float pitch = (float)screenCols/(float)nPhases;
        cv::Mat patternI(1,1,CV_8U);
        patternI = computePhaseVector(screenCols, phase, pitch);
        patterns.push_back(patternI.t());
    }

    // Phase cue patterns
    for(unsigned int i=0; i<3; i++){
        float phase = 2.0*pi/3.0 * i;
        float pitch = screenCols;
        cv::Mat patternI;
        patternI = computePhaseVector(screenCols, phase, pitch);
        patterns.push_back(patternI.t());
    }

}

cv::Mat AlgorithmPhaseShift::getEncodingPattern(unsigned int depth){
    return patterns[depth];
}


// Absolute phase from 3 frames
cv::Mat getPhase(const cv::Mat I1, const cv::Mat I2, const cv::Mat I3){

    cv::Mat_<float> I1_(I1);
    cv::Mat_<float> I2_(I2);
    cv::Mat_<float> I3_(I3);

    cv::Mat phase;

    // One call approach
    cv::phase(2.0*I1_-I3_-I2_, sqrt(3.0)*(I2_-I3_), phase);
    return phase;

}

// Phase unwrapping by means of a phase cue
cv::Mat unwrapWithCue(const cv::Mat up, const cv::Mat upCue, unsigned int nPhases){

    const float pi = M_PI;

    // Determine number of jumps
    cv::Mat P = (upCue*nPhases-up)/(2*pi);

    // Round to integers
    P.convertTo(P, CV_8U);
    P.convertTo(P, CV_32F);

    // Add to phase
    cv::Mat upUnwrapped = up + P*2*pi;

    // Scale to range [0; 2pi]
    upUnwrapped *= 1.0/nPhases;

    return upUnwrapped;
}

// Absolute phase and magnitude from N frames
std::vector<cv::Mat> getDFTComponents(const std::vector<cv::Mat> frames){

    unsigned int N = frames.size();

//    std::vector<cv::Mat> framesReverse = frames;
//    std::reverse(framesReverse.begin(), framesReverse.end());

    // DFT approach
    cv::Mat I;
    cv::merge(frames, I);
    unsigned int w = I.cols;
    unsigned int h = I.rows;
    I = I.reshape(1, h*w);
    I.convertTo(I, CV_32F);
    cv::Mat fI;
    cv::dft(I, fI, cv::DFT_ROWS + cv::DFT_COMPLEX_OUTPUT);
    fI = fI.reshape(N*2, h);

    std::vector<cv::Mat> fIcomp;
    cv::split(fI, fIcomp);

    return fIcomp;

}

void AlgorithmPhaseShift::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){

    const float pi = M_PI;

    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);
    }

    // Decode camera0
    std::vector<cv::Mat> frames0Enc(frames0Gray.begin()+2, frames0Gray.begin()+2+nSteps);
    std::vector<cv::Mat> frames0Cue(frames0Gray.begin()+2+nSteps, frames0Gray.begin()+2+nSteps+3);
    std::vector<cv::Mat> f0Icomp = getDFTComponents(frames0Enc);
    cv::Mat up0;
    cv::phase(f0Icomp[2], -f0Icomp[3], up0);
cvtools::writeMat(up0, "up0.mat", "up0");
    cv::Mat up0Cue = getPhase(frames0Cue[0], frames0Cue[1], frames0Cue[2]);
    up0 = unwrapWithCue(up0, up0Cue, nPhases);
    up0 *= screenCols/(2*pi);

    // Decode camera1
    std::vector<cv::Mat> frames1Enc(frames1Gray.begin()+2, frames1Gray.begin()+2+nSteps);
    std::vector<cv::Mat> frames1Cue(frames1Gray.begin()+2+nSteps, frames1Gray.begin()+2+nSteps+3);
    std::vector<cv::Mat> f1Icomp = getDFTComponents(frames1Enc);
    cv::Mat up1;
    cv::phase(f1Icomp[2], -f1Icomp[3], up1);
cvtools::writeMat(up1, "up1.mat", "up1");
    cv::Mat up1Cue = getPhase(frames1Cue[0], frames1Cue[1], frames1Cue[2]);
    up1 = unwrapWithCue(up1, up1Cue, nPhases);
    up1 *= screenCols/(2*pi);

cvtools::writeMat(up0Cue, "up0Cue.mat", "up0Cue");
cvtools::writeMat(up1Cue, "up1Cue.mat", "up1Cue");

    // Rectifying homographies (rotation+projections)
    cv::Size frameSize(frameCols, frameRows);
    cv::Mat R, T;
    // stereoRectify segfaults unless R is double precision
    cv::Mat(calibration.R1).convertTo(R, CV_64F);
    cv::Mat(calibration.T1).convertTo(T, CV_64F);
    cv::Mat R0, R1, P0, P1, QRect;
    cv::stereoRectify(calibration.K0, calibration.k0, calibration.K1, calibration.k1, frameSize, R, T, R0, R1, P0, P1, QRect, 0);

    // Interpolation maps (lens distortion and rectification)
    cv::Mat map0X, map0Y, map1X, map1Y;
    cv::initUndistortRectifyMap(calibration.K0, calibration.k0, R0, P0, frameSize, CV_32F, map0X, map0Y);
    cv::initUndistortRectifyMap(calibration.K1, calibration.k1, R1, P1, frameSize, CV_32F, map1X, map1Y);

    // Phase remaps
    cv::Mat up0Rect, up1Rect;
    cv::remap(up0, up0Rect, map0X, map0Y, CV_INTER_CUBIC);
    cv::remap(up1, up1Rect, map1X, map1Y, CV_INTER_CUBIC);

cvtools::writeMat(up0Rect, "up0Rect.mat", "up0Rect");
cvtools::writeMat(up1Rect, "up1Rect.mat", "up1Rect");

    // Color remaps
    cv::Mat color0Rect, color1Rect;
    cv::remap(frames0[0], color0Rect, map0X, map0Y, CV_INTER_CUBIC);
    cv::remap(frames1[0], color1Rect, map1X, map1Y, CV_INTER_CUBIC);

cvtools::writeMat(color0Rect, "color0Rect.mat", "color0Rect");
cvtools::writeMat(color1Rect, "color1Rect.mat", "color1Rect");

    // On/off remaps
    cv::Mat frames0OnRect, frames0OffRect;
    cv::remap(frames0Gray[0], frames0OnRect, map0X, map0Y, CV_INTER_CUBIC);
    cv::remap(frames0Gray[1], frames0OffRect, map0X, map0Y, CV_INTER_CUBIC);

    cv::Mat frames1OnRect, frames1OffRect;
    cv::remap(frames1Gray[0], frames1OnRect, map1X, map1Y, CV_INTER_CUBIC);
    cv::remap(frames1Gray[1], frames1OffRect, map1X, map1Y, CV_INTER_CUBIC);

    // Occlusion masks
    cv::Mat occlusion0Rect, occlusion1Rect;
    cv::subtract(frames0OnRect, frames0OffRect, occlusion0Rect);
    occlusion0Rect = occlusion0Rect > 50;
    cv::subtract(frames1OnRect, frames1OffRect, occlusion1Rect);
    occlusion1Rect = occlusion1Rect > 50;

cvtools::writeMat(occlusion0Rect, "occlusion0Rect.mat", "occlusion0Rect");
cvtools::writeMat(occlusion1Rect, "occlusion1Rect.mat", "occlusion1Rect");

    // Erode occlusion masks
    cv::Mat strel = cv::getStructuringElement(cv::MORPH_ELLIPSE, cv::Size(3,3));
    cv::erode(occlusion0Rect, occlusion0Rect, strel);
    cv::erode(occlusion1Rect, occlusion1Rect, strel);

    // Threshold on gradient of phase
    cv::Mat edges0;
    cv::Sobel(up0Rect, edges0, -1, 1, 1, 5);
    occlusion0Rect = occlusion0Rect & (abs(edges0) < 5);

    cv::Mat edges1;
    cv::Sobel(up1Rect, edges1, -1, 1, 1, 5);
    occlusion1Rect = occlusion1Rect & (abs(edges1) < 5);

cvtools::writeMat(edges0, "edges0.mat", "edges0");
cvtools::writeMat(edges1, "edges1.mat", "edges1");

    // Match phase maps
    int frameRectRows = map0X.rows;
    int frameRectCols = map0X.cols;

    // camera0 against camera1
    std::vector<cv::Vec2f> q0Rect, q1Rect;
    for(int row=0; row<frameRectRows; row++){

        for(int col=0; col<frameRectCols; col++){

            if(!occlusion0Rect.at<char>(row,col))
                continue;

            float up0i = up0Rect.at<float>(row,col);
            for(int col1=0; col1<up1Rect.cols-1; col1++){

                if(!occlusion1Rect.at<char>(row,col1) || !occlusion1Rect.at<char>(row,col1+1))
                    continue;

                float up1Left = up1Rect.at<float>(row,col1);
                float up1Right = up1Rect.at<float>(row,col1+1);

                if((up1Left <= up0i) && (up0i <= up1Right)){

                    float col1i = col1 + (up0i-up1Left)/(up1Right-up1Left);

                    q0Rect.push_back(cv::Point2f(col, row));
                    q1Rect.push_back(cv::Point2f(col1i, row));

                    break;
                }

            }

        }

    }

    // camera1 against camera0
    //[...]

    int nMatches = q0Rect.size();

    if(nMatches < 1){
        Q.resize(0);
        color.resize(0);

        return;
    }

    // Retrieve color information
    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]);

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

    // Triangulate points
    cv::Mat QMatHomogenous, QMat;
    cv::triangulatePoints(P0, P1, q0Rect, q1Rect, QMatHomogenous);
    cvtools::convertMatFromHomogeneous(QMatHomogenous, QMat);

    // Undo rectification
    cv::Mat R0Inv;
    cv::Mat(R0.t()).convertTo(R0Inv, CV_32F);
    QMat = R0Inv*QMat;

    cvtools::matToPoints3f(QMat, Q);

}