www.pudn.com > Real-Time-Structured-Light.zip > CodecGrayCode.cpp, change:2016-09-19,size:6630b

```#include "CodecGrayCode.h"
#include <cmath>
#include <iomanip>

#include "cvtools.h"

static unsigned int Nhorz = 10;
static unsigned int Nvert = 6;

#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 grayToBinary(unsigned num, unsigned numBits)
{
for (unsigned shift = 1; shift < numBits; shift <<= 1){
num ^= num >> shift;
}
return num;
}

/*
* Function takes the decimal number
* Function takes the Nth bit (1 to 31)
* Return the value of Nth bit from decimal
* Source: http://icfun.blogspot.com/2009/04/get-n-th-bit-value-of-any-integer.html
*/
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;
}

// If the bit is not set, return 0
return 0;
}

static inline int powi(int num, unsigned int exponent){
// NOT EQUIVALENT TO pow()
if(exponent == 0)
return 1;

float res = num;
for(unsigned int i=0; i<exponent-1; i++)
res *= num;

return res;
}

// Encoder
EncoderGrayCode::EncoderGrayCode(unsigned int _screenCols, unsigned int _screenRows, CodecDir _dir) : Encoder(_screenCols, _screenRows, _dir){

N = 2;

// Set total pattern number
if(dir & CodecDirHorizontal)
this->N += Nhorz;

if(dir & CodecDirVertical)
this->N += Nvert;

// Encode every pixel column
int NbitsHorz = ceilf(log2f((float)screenCols));

// Number of vertical encoding patterns
int NbitsVert = ceilf(log2f((float)screenRows));

cv::Mat patternOn(1, 1, CV_8UC3, cv::Scalar(0));
patternOn.at<cv::Vec3b>(0,0) = cv::Vec3b(255, 255, 255);
patterns.push_back(patternOn);

cv::Mat patternOff(1, 1, CV_8UC3, cv::Scalar(0));
patterns.push_back(patternOff);

if(dir & CodecDirHorizontal){
// Precompute horizontally encoding patterns
for(unsigned int p=0; p<Nhorz; p++){
cv::Mat patternP(1, screenCols, CV_8UC3);
// Loop through columns in first row
for(unsigned int j=0; j<screenCols; j++){
unsigned int jGray = binaryToGray(j);
// Amplitude of channels
float amp = get_bit(jGray, NbitsHorz-p);
patternP.at<cv::Vec3b>(0,j) = cv::Vec3b(255.0*amp,255.0*amp,255.0*amp);
}
patterns.push_back(patternP);
}
}
if(dir & CodecDirVertical){
// Precompute vertical encoding patterns
for(unsigned int p=0; p<Nvert; p++){
cv::Mat patternP(screenRows, 1, CV_8UC3);

// Loop through rows in first column
for(unsigned int i=0; i<screenRows; i++){

unsigned int iGray = binaryToGray(i);

// Amplitude of channels
float amp = get_bit(iGray, NbitsVert-p);
patternP.at<cv::Vec3b>(i,0) = cv::Vec3b(255.0*amp,255.0*amp,255.0*amp);
}
patterns.push_back(patternP);
}
}

#if 0
for(unsigned int i=0; i<patterns.size(); i++){
std::stringstream fileNameStream;
fileNameStream << "pattern_" << std::setw(2) << std::setfill('0') << i << ".bmp";
cv::imwrite(fileNameStream.str(), patterns[i]);
}

#endif
}

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

// Decoder
DecoderGrayCode::DecoderGrayCode(unsigned int _screenCols, unsigned int _screenRows, CodecDir _dir) : Decoder(_screenCols, _screenRows, _dir){

N = 2;

if(dir & CodecDirHorizontal)
this->N += Nhorz;

if(dir & CodecDirVertical)
this->N += Nvert;

frames.resize(N);

}

void DecoderGrayCode::setFrame(unsigned int depth, const cv::Mat frame){
frames[depth] = frame;
}

// min image
cv::Mat minImage = frames[1];

// Binarize frames. TODO: subpixel interpolation.
vector<cv::Mat> framesBinary(frames.size());
for(unsigned int i=0; i<frames.size(); i++){
// Foreground pixels 1, background 0
//cv::threshold(frames[i], framesBinary[i], 80, 1, cv::THRESH_BINARY);
framesBinary[i].create(frames[0].size(), CV_8U);
cv::threshold(framesBinary[i], framesBinary[i], 1, 1, cv::THRESH_BINARY);
}

// Encode every pixel column
int NbitsHorz = ceilf(log2f((float)screenCols));

// Number of vertical encoding patterns
int NbitsVert = ceilf(log2f((float)screenRows));

if(dir & CodecDirHorizontal){
vector<cv::Mat> framesHorz(framesBinary.begin()+2, framesBinary.begin()+Nhorz+2);

// Construct up image.
for(int i = 0; i < up.rows; i++){
for(int j = 0; j < up.cols; j++){
unsigned int enc = 0;
for(unsigned int f=0; f<framesHorz.size(); f++){
// Gray decimal
enc += powi(2, NbitsHorz-f-1)*framesHorz[f].at<unsigned char>(i,j);
}
// Standard decimal
enc = grayToBinary(enc, Nhorz);
up.at<float>(i,j) = enc;

}
}
}

//    cvtools::writeMat(up, "up.mat", "up");

if(dir & CodecDirVertical){
vector<cv::Mat> framesVert(framesBinary.end()-Nvert, framesBinary.end());

// Construct vp image.
for(int i = 0; i < vp.rows; i++){
for(int j = 0; j < vp.cols; j++){
unsigned int enc = 0;
for(unsigned int f=0; f<framesVert.size(); f++){
// Gray decimal
enc += powi(2, NbitsVert-f-1)*framesVert[f].at<unsigned char>(i,j);
}
// Standard decimal
enc = grayToBinary(enc, Nvert);
vp.at<float>(i,j) = enc;
}
}
}
}
```