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#include "AlgorithmLineShift.h"
#include <cmath>
#include "cvtools.h"
#include <opencv2/imgproc/imgproc.hpp>
#ifndef log2f
#define log2f(x) (log(x)/log(2.0))
#endif
static unsigned int nLineShifts = 8; // number of columns over which each line is shifted
/*
* 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 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
AlgorithmLineShift::AlgorithmLineShift(unsigned int _screenCols, unsigned int _screenRows) : Algorithm(_screenCols, _screenRows){
nGrayBits = ceilf(log2f((float)screenCols)) - floorf(log2f((float)nLineShifts));
N = 2 + 2*nGrayBits + nLineShifts;
// 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);
// Gray code patterns
for(unsigned int p=0; p<nGrayBits; 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, nGrayBits-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);
}
// line shifts
for(unsigned int p=0; p<nLineShifts; p++){
cv::Mat pattern(1, screenCols, CV_8UC3, cv::Scalar(0));
for(unsigned int j=p; j<screenCols; j+= nLineShifts)
pattern.at<cv::Vec3b>(0, j) = cv::Vec3b(255, 255, 255);
patterns.push_back(pattern);
}
}
cv::Mat AlgorithmLineShift::getEncodingPattern(unsigned int depth){
return patterns[depth];
}
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 getlineCenters(const cv::Mat& linesScanLine, const cv::Mat& codeScanLine, std::vector<cv::Vec2f>& lineCenters){
int nCols = linesScanLine.cols;
// fourth order derivative filtering
cv::Mat der(1, nCols, CV_8U);
for(int i=2; i<nCols-2; i++)
der.at<unsigned char>(0, i) = linesScanLine.at<unsigned char>(0, i-2)+linesScanLine.at<unsigned char>(0, i-1)-
linesScanLine.at<unsigned char>(0, i+1)-linesScanLine.at<unsigned char>(0, i+2);
for(int i=0; i<nCols; i++){
if(der.at<unsigned char>(0, i) > 0 && der.at<unsigned char>(0, i+1) < 0){
lineCenters.push_back(cv::Vec2f(i, codeScanLine.at<unsigned char>(0, i)));
// TODO: subpixel interpolation, non-max suppression
}
}
}
void AlgorithmLineShift::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;
// 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
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_BayerBG2GRAY);
cv::remap(temp, frames0Rect[i], map0X, map0Y, CV_INTER_LINEAR);
cv::cvtColor(frames1[i], temp, CV_BayerBG2GRAY);
cv::remap(temp, frames1Rect[i], map1X, map1Y, CV_INTER_LINEAR);
}
//cvtools::writeMat(frames0Rect[0], "frames0Rect_0.mat", "frames0Rect_0");
//cvtools::writeMat(frames0Rect[1], "frames0Rect_1.mat", "frames0Rect_1");
//cvtools::writeMat(frames0Rect[20], "frames0Rect_20.mat", "frames0Rect_20");
//cvtools::writeMat(frames0Rect[21], "frames0Rect_21.mat", "frames0Rect_21");
// color debayer and remap
cv::Mat color0Rect, color1Rect;
cv::cvtColor(frames0[0], color0Rect, CV_BayerBG2RGB);
cv::remap(color0Rect, color0Rect, map0X, map0Y, CV_INTER_LINEAR);
cv::cvtColor(frames1[0], color1Rect, CV_BayerBG2RGB);
cv::remap(color1Rect, color1Rect, map1X, map1Y, CV_INTER_LINEAR);
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 > 20) & (occlusion0Rect < 250);
cv::subtract(frames1Rect[0], frames1Rect[1], occlusion1Rect);
occlusion1Rect = (occlusion1Rect > 20) & (occlusion1Rect < 250);
//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(2,2));
cv::erode(occlusion0Rect, occlusion0Rect, strel);
cv::erode(occlusion1Rect, occlusion1Rect, strel);
// correct for texture modulation and ambient
cv::Mat A0 = frames0Rect[1];
cv::Mat M0 = frames0Rect[0]-frames0Rect[1];
cv::divide(256.0, M0, M0, CV_32F);
cv::Mat A1 = frames1Rect[1];
cv::Mat M1 = frames1Rect[0]-frames1Rect[1];
cv::divide(256.0, M1, M1, CV_32F);
for(int i=2; i<N; i++){
cv::multiply(frames0Rect[i]-A0, M0, frames0Rect[i], 1.0, CV_8UC1);
cv::multiply(frames1Rect[i]-A1, M1, frames1Rect[i], 1.0, CV_8UC1);
}
//cvtools::writeMat(frames0Rect[22], "frames0Rect_22.mat", "frames0Rect_22");
//cvtools::writeMat(frames0Rect[23], "frames0Rect_23.mat", "frames0Rect_23");
// divide into Gray coding frames and line shift frames
std::vector<cv::Mat> frames0GrayCode(frames0Rect.begin()+2, frames0Rect.begin()+2+nGrayBits);
std::vector<cv::Mat> frames0LineShift(frames0Rect.begin()+2+nGrayBits, frames0Rect.end());
std::vector<cv::Mat> frames1GrayCode(frames1Rect.begin()+2, frames1Rect.begin()+2+nGrayBits);
std::vector<cv::Mat> frames1LineShift(frames1Rect.begin()+2+nGrayBits, frames1Rect.end());
// decode patterns
cv::Mat code0Gray(frameRectRows, frameRectCols, CV_32S, cv::Scalar(0));
cv::Mat code1Gray(frameRectRows, frameRectCols, CV_32S, cv::Scalar(0));
// into gray code
for(int i=0; i<nGrayBits; i++){
cv::Mat temp, bit0, bit1;
cv::compare(frames0GrayCode[i*2], frames0GrayCode[i*2+1], temp, cv::CMP_GT);
temp.convertTo(bit0, CV_32S, 1.0/255.0);
cv::add(code0Gray, bit0*twopowi(nGrayBits-i-1), code0Gray, cv::noArray(), CV_32S);
cv::compare(frames1GrayCode[i*2], frames1GrayCode[i*2+1], temp, cv::CMP_GT);
temp.convertTo(bit1, CV_32S, 1.0/255.0);
cv::add(code1Gray, bit1*twopowi(nGrayBits-i-1), code1Gray, cv::noArray(), CV_32S);
}
// set occluded pixels to -1
for(int r=0; r<frameRectRows; r++){
for(int c=0; c<frameRectCols; c++){
if(occlusion0Rect.at<unsigned char>(r,c) == 0)
code0Gray.at<int>(r,c) = -1;
if(occlusion1Rect.at<unsigned char>(r,c) == 0)
code1Gray.at<int>(r,c) = -1;
}
}
// convert to standard binary
cv::Mat code0Binary(code0Gray.rows, code0Gray.cols, CV_32F);
cv::Mat code1Binary(code1Gray.rows, code1Gray.cols, CV_32F);
for(int r=0; r<frameRectRows; r++){
for(int c=0; c<frameRectCols; c++){
if(code0Gray.at<int>(r,c) != -1)
code0Binary.at<float>(r,c) = grayToBinary(code0Gray.at<int>(r,c));
if(code1Gray.at<int>(r,c) != -1)
code1Binary.at<float>(r,c) = grayToBinary(code1Gray.at<int>(r,c));
}
}
//cvtools::writeMat(code0Gray, "code0Gray.mat", "code0Gray");
//cvtools::writeMat(code1Gray, "code1Gray.mat", "code1Gray");
// TODO: iterate through all line frames
cv::Mat lines0 = frames0LineShift[0];
cv::Mat lines1 = frames1LineShift[0];
// matching
std::vector<cv::Vec2f> q0Rect, q1Rect;
for(int row=0; row<frameRectRows; row++){
// line center data structure containing [x-coordinate (sub-px), region-code]
std::vector<cv::Vec2f> lineCenters0, lineCenters1;
// sorted, unique line centers
getlineCenters(lines0.row(row), code0Binary.row(row), lineCenters0);
getlineCenters(lines1.row(row), code1Binary.row(row), lineCenters1);
// match and store
int i=0, j=0;
while(i<lineCenters0.size() && j<lineCenters1.size()){
if(lineCenters0[i][1] == lineCenters1[j][1]){
q0Rect.push_back(cv::Point2f(lineCenters0[0][0], row));
q1Rect.push_back(cv::Point2f(lineCenters1[0][0], row));
i += 1;
j += 1;
} else if(lineCenters0[i][1] < lineCenters1[j][1]){
i += 1;
} else if(lineCenters0[i][1] > lineCenters1[j][1]){
j += 1;
}
}
}
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::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);
}