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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 nSteps = 20; // number of shifts/steps in primary

static float pPrimary = 200; // primary period

// 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){

    // Set N

    N = 2+nSteps+3;

    // Determine the secondary (wider) period

    float pSecondary = (screenCols*pPrimary)/(screenCols-pPrimary);

    // 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);

    // Precompute encoded patterns

    const float pi = M_PI;

    // Primary encoding patterns

    for(unsigned int i=0; i<nSteps; i++){

        float phase = 2.0*pi/nSteps * i;

        float pitch = pPrimary;

        cv::Mat patternI(1,1,CV_8U);

        patternI = computePhaseVector(screenCols, phase, pitch);

        patterns.push_back(patternI.t());

    }

    // Secondary encoding patterns

    for(unsigned int i=0; i<3; i++){

        float phase = 2.0*pi/3 * i;

        float pitch = pSecondary;

        cv::Mat patternI(1,1,CV_8U);

        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, float 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 everything

    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> frames0Primary(frames0Gray.begin()+2, frames0Gray.begin()+2+nSteps);

    std::vector<cv::Mat> frames0Secondary(frames0Gray.begin()+2+nSteps, frames0Gray.begin()+2+nSteps+3);

    std::vector<cv::Mat> F0Enc = getDFTComponents(frames0Primary);

    cv::Mat up0Primary;

    cv::phase(F0Enc[2], -F0Enc[3], up0Primary);

    cv::Mat up0Secondary = getPhase(frames0Secondary[0], frames0Secondary[1], frames0Secondary[2]);

    cv::Mat up0Equivalent = up0Primary - up0Secondary;

    up0Equivalent = cvtools::modulo(up0Equivalent, 2*pi);

    cv::Mat up0 = unwrapWithCue(up0Primary, up0Equivalent, (float)screenCols/pPrimary);

    up0 *= screenCols/(2*pi);

    // Decode camera1

    std::vector<cv::Mat> frames1Primary(frames1Gray.begin()+2, frames1Gray.begin()+2+nSteps);

    std::vector<cv::Mat> frames1Secondary(frames1Gray.begin()+2+nSteps, frames1Gray.begin()+2+nSteps+3);

    std::vector<cv::Mat> F1Enc = getDFTComponents(frames1Primary);

    cv::Mat up1Primary;

    cv::phase(F1Enc[2], -F1Enc[3], up1Primary);

    cv::Mat up1Secondary = getPhase(frames1Secondary[0], frames1Secondary[1], frames1Secondary[2]);

    cv::Mat up1Equivalent = up1Primary - up1Secondary;

    up1Equivalent = cvtools::modulo(up1Equivalent, 2*pi);

    cv::Mat up1 = unwrapWithCue(up1Primary, up1Equivalent, (float)screenCols/pPrimary);

    up1 *= screenCols/(2*pi);

    // 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(5,5));

    cv::erode(occlusion0Rect, occlusion0Rect, strel);

    cv::erode(occlusion1Rect, occlusion1Rect, strel);

    // Threshold on gradient of phase

    cv::Mat edges0;

    cv::Sobel(up0Rect, edges0, -1, 1, 0, 5);

    occlusion0Rect = occlusion0Rect & (abs(edges0) < 150);

    cv::Mat edges1;

    cv::Sobel(up1Rect, edges1, -1, 1, 0, 5);

    occlusion1Rect = occlusion1Rect & (abs(edges1) < 150);

//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) && (up0i-up1Left < 1) && (up1Right-up0i < 1)){

                    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

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

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

            if(!occlusion1Rect.at<char>(row,col))

                continue;

            float up1i = up1Rect.at<float>(row,col);

            for(int col0=0; col0<up0Rect.cols-1; col0++){

                if(!occlusion0Rect.at<char>(row,col0) || !occlusion0Rect.at<char>(row,col0+1))

                    continue;

                float up0Left = up0Rect.at<float>(row,col0);

                float up0Right = up0Rect.at<float>(row,col0+1);

                if((up0Left <= up1i) && (up1i <= up0Right) && (up1i-up0Left < 1) && (up0Right-up1i < 1)){

                    float col0i = col0 + (up1i-up0Left)/(up0Right-up0Left);

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

                    q0Rect.push_back(cv::Point2f(col0i, row));

                    break;

                }

            }

        }

    }

    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);

}