WebSVN – seema-scanner – Diff – /src/algorithm/AlgorithmGrayCode.cpp


#include "AlgorithmGrayCode.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
AlgorithmGrayCode::AlgorithmGrayCode(unsigned int _screenCols, unsigned int _screenRows, CodingDir _dir) : Algorithm(_screenCols, _screenRows, _dir){
 
    // on/off patterns
    Nbits = ceilf(log2f((float)screenCols));
    N = 2 + Nbits*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<Nbits; 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);
    }
 
 
}
 
cv::Mat AlgorithmGrayCode::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 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));
}
 
void AlgorithmGrayCode::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);
 
//    for(int i=0; i<1920; i++){
//        std::cout << i << " " << binaryToGray(i) << " " << grayToBinary(binaryToGray(i)) << std::endl;
//    }
 
    int frameRows = frames0[0].rows;
    int frameCols = frames0[0].cols;
 
    // 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);
 
//    std::cout << "R0" << std::endl << R0 << std::endl;
//    std::cout << "P0" << std::endl << P0 << std::endl;
//    std::cout << "R1" << std::endl << R1 << std::endl;
//    std::cout << "P1" << std::endl << P1 << std::endl;
 
    // interpolation maps
    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);
 
    // gray-scale and remap
    std::vector<cv::Mat> frames0Rect(N);
    std::vector<cv::Mat> frames1Rect(N);
    for(int i=0; i<N; i++){
        cv::Mat temp;
        cv::cvtColor(frames0[i], temp, CV_RGB2GRAY);
        cv::remap(temp, frames0Rect[i], map0X, map0Y, CV_INTER_CUBIC);
        cv::cvtColor(frames1[i], temp, CV_RGB2GRAY);
        cv::remap(temp, frames1Rect[i], map1X, map1Y, CV_INTER_CUBIC);
    }
 
 
//    cv::imwrite("frames0[0].png", frames0[0]);
//    cv::imwrite("frames0Rect[0].png", frames0Rect[0]);
 
//    cv::imwrite("frames1[0].png", frames1[0]);
//    cv::imwrite("frames1Rect[0].png", frames1Rect[0]);
 
 
 
    // 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);
 
    int frameRectRows = frames0Rect[0].rows;
    int frameRectCols = frames0Rect[0].cols;
 
    // occlusion masks
    cv::Mat occlusion0Rect, occlusion1Rect;
    cv::subtract(frames0Rect[0], frames0Rect[1], occlusion0Rect);
    occlusion0Rect = occlusion0Rect > 50;
    cv::subtract(frames1Rect[0], frames1Rect[1], occlusion1Rect);
    occlusion1Rect = occlusion1Rect > 50;
 
    // 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);
 
//cvtools::writeMat(occlusion0Rect, "occlusion0Rect.mat", "occlusion0Rect");
//cvtools::writeMat(occlusion1Rect, "occlusion1Rect.mat", "occlusion1Rect");
 
    // decode patterns
    cv::Mat code0Rect(frameRectRows, frameRectCols, CV_32S, cv::Scalar(-1));
    cv::Mat code1Rect(frameRectRows, frameRectCols, CV_32S, cv::Scalar(-1));
    cv::add(code0Rect, 1, code0Rect, occlusion0Rect, CV_32S);
    cv::add(code1Rect, 1, code1Rect, occlusion1Rect, CV_32S);
 
    // into gray code
    for(int i=0; i<Nbits; i++){
        cv::Mat bit0;
        cv::subtract(frames0Rect[i*2+2], frames0Rect[i*2+3], bit0);
        bit0 = bit0 > 0;
        bit0.convertTo(bit0, CV_32S, 1.0/255.0);
//      cvtools::writeMat(bit0, "bit0.mat", "bit0");
        cv::add(code0Rect, bit0*twopowi(Nbits-i-1), code0Rect, occlusion0Rect, CV_32S);
        cv::Mat bit1;
        cv::subtract(frames1Rect[i*2+2], frames1Rect[i*2+3], bit1);
        bit1 = bit1 > 0;
        bit1.convertTo(bit1, CV_32S, 1.0/255.0);
        cv::add(code1Rect, bit1*twopowi(Nbits-i-1), code1Rect, occlusion1Rect, CV_32S);
    }
 
//cvtools::writeMat(code0Rect, "code0Rect.mat", "code0Rect");
//cvtools::writeMat(code1Rect, "code1Rect.mat", "code1Rect");
 
//    // convert to standard binary
//    for(int r=0; r<frameRectRows; r++){
//        for(int c=0; c<frameRectCols; c++){
//            if(code0Rect.at<int>(r,c) != -1)
//                code0Rect.at<int>(r,c) = grayToBinary(code0Rect.at<int>(r,c));
//            if(code1Rect.at<int>(r,c) != -1)
//                code1Rect.at<int>(r,c) = grayToBinary(code1Rect.at<int>(r,c));
//        }
//    }
 
//cvtools::writeMat(code0Rect, "code0Rect.mat", "code0Rect");
//cvtools::writeMat(code1Rect, "code1Rect.mat", "code1Rect");
 
    // matching
    std::vector<cv::Vec2f> q0Rect, q1Rect;
    for(int row=0; row<frameRectRows; row++){
 
        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
    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::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 rectification
    cv::Mat R0Inv;
    cv::Mat(R0.t()).convertTo(R0Inv, CV_32F);
    QMat = R0Inv*QMat;
 
    cvtools::matToPoints3f(QMat, Q);
 
}
 

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(root)/src/algorithm/AlgorithmGrayCode.cpp – Rev 68 → 69

Rev 68		Rev 69
1	`#include "AlgorithmGrayCode.h"`	1	`#include "AlgorithmGrayCode.h"`
2	`#include <cmath>`	2	`#include <cmath>`
3	`#include "cvtools.h"`	3	`#include "cvtools.h"`
4		4
5	`#ifndef log2f`	5	`#ifndef log2f`
6	`#define log2f(x) (log(x)/log(2.0))`	6	`#define log2f(x) (log(x)/log(2.0))`
7	`#endif`	7	`#endif`
8		8
9	`//using namespace std;`	9	`//using namespace std;`
10		10
11	`/*`	11	`/*`
12	`* The purpose of this function is to convert an unsigned`	12	`* The purpose of this function is to convert an unsigned`
13	`* binary number to reflected binary Gray code.`	13	`* binary number to reflected binary Gray code.`
14	`*`	14	`*`
15	`* The operator >> is shift right. The operator ^ is exclusive or.`	15	`* The operator >> is shift right. The operator ^ is exclusive or.`
16	`* Source: http://en.wikipedia.org/wiki/Gray_code`	16	`* Source: http://en.wikipedia.org/wiki/Gray_code`
17	`*/`	17	`*/`
18	`static unsigned int binaryToGray(unsigned int num) {`	18	`static unsigned int binaryToGray(unsigned int num) {`
19	`return (num >> 1) ^ num;`	19	`return (num >> 1) ^ num;`
20	`}`	20	`}`
21		21
22	`/*`	22	`/*`
23	`* From Wikipedia: http://en.wikipedia.org/wiki/Gray_code`	23	`* From Wikipedia: http://en.wikipedia.org/wiki/Gray_code`
24	`* The purpose of this function is to convert a reflected binary`	24	`* The purpose of this function is to convert a reflected binary`
25	`* Gray code number to a binary number.`	25	`* Gray code number to a binary number.`
26	`*/`	26	`*/`
27	`static unsigned int grayToBinary(unsigned int num){`	27	`static unsigned int grayToBinary(unsigned int num){`
28	`unsigned int mask;`	28	`unsigned int mask;`
29	`for(mask = num >> 1; mask != 0; mask = mask >> 1)`	29	`for(mask = num >> 1; mask != 0; mask = mask >> 1)`
30	`num = num ^ mask;`	30	`num = num ^ mask;`
31	`return num;`	31	`return num;`
32	`}`	32	`}`
33		33
34	`/*`	34	`/*`
35	`* Return the Nth bit of an unsigned integer number`	35	`* Return the Nth bit of an unsigned integer number`
36	`*/`	36	`*/`
37	`static bool getBit(int decimal, int N){`	37	`static bool getBit(int decimal, int N){`
38		38
39	`return decimal & 1 << (N-1);`	39	`return decimal & 1 << (N-1);`
40	`}`	40	`}`