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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);
}