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opencv/modules/features2d/src/freak.cpp

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// freak.cpp
//
// Copyright (C) 2011-2012 Signal processing laboratory 2, EPFL,
// Kirell Benzi (kirell.benzi@epfl.ch),
// Raphael Ortiz (raphael.ortiz@a3.epfl.ch)
// Alexandre Alahi (alexandre.alahi@epfl.ch)
// and Pierre Vandergheynst (pierre.vandergheynst@epfl.ch)
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
#include "precomp.hpp"
#include <fstream>
#include <stdlib.h>
#include <algorithm>
#include <iostream>
#include <bitset>
#include <sstream>
#include <algorithm>
#include <iomanip>
#include <string.h>
namespace cv
{
static const double FREAK_SQRT2 = 1.4142135623731;
static const double FREAK_LOG2 = 0.693147180559945;
static const int FREAK_NB_ORIENTATION = 256;
static const int FREAK_NB_POINTS = 43;
static const int FREAK_SMALLEST_KP_SIZE = 7; // smallest size of keypoints
static const int FREAK_NB_SCALES = FREAK::NB_SCALES;
static const int FREAK_NB_PAIRS = FREAK::NB_PAIRS;
static const int FREAK_NB_ORIENPAIRS = FREAK::NB_ORIENPAIRS;
// default pairs
static const int FREAK_DEF_PAIRS[FREAK::NB_PAIRS] =
{
404,431,818,511,181,52,311,874,774,543,719,230,417,205,11,
560,149,265,39,306,165,857,250,8,61,15,55,717,44,412,
592,134,761,695,660,782,625,487,549,516,271,665,762,392,178,
796,773,31,672,845,548,794,677,654,241,831,225,238,849,83,
691,484,826,707,122,517,583,731,328,339,571,475,394,472,580,
381,137,93,380,327,619,729,808,218,213,459,141,806,341,95,
382,568,124,750,193,749,706,843,79,199,317,329,768,198,100,
466,613,78,562,783,689,136,838,94,142,164,679,219,419,366,
418,423,77,89,523,259,683,312,555,20,470,684,123,458,453,833,
72,113,253,108,313,25,153,648,411,607,618,128,305,232,301,84,
56,264,371,46,407,360,38,99,176,710,114,578,66,372,653,
129,359,424,159,821,10,323,393,5,340,891,9,790,47,0,175,346,
236,26,172,147,574,561,32,294,429,724,755,398,787,288,299,
769,565,767,722,757,224,465,723,498,467,235,127,802,446,233,
544,482,800,318,16,532,801,441,554,173,60,530,713,469,30,
212,630,899,170,266,799,88,49,512,399,23,500,107,524,90,
194,143,135,192,206,345,148,71,119,101,563,870,158,254,214,
276,464,332,725,188,385,24,476,40,231,620,171,258,67,109,
844,244,187,388,701,690,50,7,850,479,48,522,22,154,12,659,
736,655,577,737,830,811,174,21,237,335,353,234,53,270,62,
182,45,177,245,812,673,355,556,612,166,204,54,248,365,226,
242,452,700,685,573,14,842,481,468,781,564,416,179,405,35,
819,608,624,367,98,643,448,2,460,676,440,240,130,146,184,
185,430,65,807,377,82,121,708,239,310,138,596,730,575,477,
851,797,247,27,85,586,307,779,326,494,856,324,827,96,748,
13,397,125,688,702,92,293,716,277,140,112,4,80,855,839,1,
413,347,584,493,289,696,19,751,379,76,73,115,6,590,183,734,
197,483,217,344,330,400,186,243,587,220,780,200,793,246,824,
41,735,579,81,703,322,760,720,139,480,490,91,814,813,163,
152,488,763,263,425,410,576,120,319,668,150,160,302,491,515,
260,145,428,97,251,395,272,252,18,106,358,854,485,144,550,
131,133,378,68,102,104,58,361,275,209,697,582,338,742,589,
325,408,229,28,304,191,189,110,126,486,211,547,533,70,215,
670,249,36,581,389,605,331,518,442,822
};
// used to sort pairs during pairs selection
struct PairStat
{
double mean;
int idx;
};
struct sortMean
{
bool operator()( const PairStat& a, const PairStat& b ) const
{
return a.mean < b.mean;
}
};
void FREAK::buildPattern()
{
if( patternScale == patternScale0 && nOctaves == nOctaves0 && !patternLookup.empty() )
return;
nOctaves0 = nOctaves;
patternScale0 = patternScale;
patternLookup.resize(FREAK_NB_SCALES*FREAK_NB_ORIENTATION*FREAK_NB_POINTS);
double scaleStep = std::pow(2.0, (double)(nOctaves)/FREAK_NB_SCALES ); // 2 ^ ( (nOctaves-1) /nbScales)
double scalingFactor, alpha, beta, theta = 0;
// pattern definition, radius normalized to 1.0 (outer point position+sigma=1.0)
const int n[8] = {6,6,6,6,6,6,6,1}; // number of points on each concentric circle (from outer to inner)
const double bigR(2.0/3.0); // bigger radius
const double smallR(2.0/24.0); // smaller radius
const double unitSpace( (bigR-smallR)/21.0 ); // define spaces between concentric circles (from center to outer: 1,2,3,4,5,6)
// radii of the concentric cirles (from outer to inner)
const double radius[8] = {bigR, bigR-6*unitSpace, bigR-11*unitSpace, bigR-15*unitSpace, bigR-18*unitSpace, bigR-20*unitSpace, smallR, 0.0};
// sigma of pattern points (each group of 6 points on a concentric cirle has the same sigma)
const double sigma[8] = {radius[0]/2.0, radius[1]/2.0, radius[2]/2.0,
radius[3]/2.0, radius[4]/2.0, radius[5]/2.0,
radius[6]/2.0, radius[6]/2.0
};
// fill the lookup table
for( int scaleIdx=0; scaleIdx < FREAK_NB_SCALES; ++scaleIdx )
{
patternSizes[scaleIdx] = 0; // proper initialization
scalingFactor = std::pow(scaleStep,scaleIdx); //scale of the pattern, scaleStep ^ scaleIdx
for( int orientationIdx = 0; orientationIdx < FREAK_NB_ORIENTATION; ++orientationIdx )
{
theta = double(orientationIdx)* 2*CV_PI/double(FREAK_NB_ORIENTATION); // orientation of the pattern
int pointIdx = 0;
PatternPoint* patternLookupPtr = &patternLookup[0];
for( size_t i = 0; i < 8; ++i )
{
for( int k = 0 ; k < n[i]; ++k )
{
beta = CV_PI/n[i] * (i%2); // orientation offset so that groups of points on each circles are staggered
alpha = double(k)* 2*CV_PI/double(n[i])+beta+theta;
// add the point to the look-up table
PatternPoint& point = patternLookupPtr[ scaleIdx*FREAK_NB_ORIENTATION*FREAK_NB_POINTS+orientationIdx*FREAK_NB_POINTS+pointIdx ];
point.x = static_cast<float>(radius[i] * cos(alpha) * scalingFactor * patternScale);
point.y = static_cast<float>(radius[i] * sin(alpha) * scalingFactor * patternScale);
point.sigma = static_cast<float>(sigma[i] * scalingFactor * patternScale);
// adapt the sizeList if necessary
const int sizeMax = static_cast<int>(ceil((radius[i]+sigma[i])*scalingFactor*patternScale)) + 1;
if( patternSizes[scaleIdx] < sizeMax )
patternSizes[scaleIdx] = sizeMax;
++pointIdx;
}
}
}
}
// build the list of orientation pairs
orientationPairs[0].i=0; orientationPairs[0].j=3; orientationPairs[1].i=1; orientationPairs[1].j=4; orientationPairs[2].i=2; orientationPairs[2].j=5;
orientationPairs[3].i=0; orientationPairs[3].j=2; orientationPairs[4].i=1; orientationPairs[4].j=3; orientationPairs[5].i=2; orientationPairs[5].j=4;
orientationPairs[6].i=3; orientationPairs[6].j=5; orientationPairs[7].i=4; orientationPairs[7].j=0; orientationPairs[8].i=5; orientationPairs[8].j=1;
orientationPairs[9].i=6; orientationPairs[9].j=9; orientationPairs[10].i=7; orientationPairs[10].j=10; orientationPairs[11].i=8; orientationPairs[11].j=11;
orientationPairs[12].i=6; orientationPairs[12].j=8; orientationPairs[13].i=7; orientationPairs[13].j=9; orientationPairs[14].i=8; orientationPairs[14].j=10;
orientationPairs[15].i=9; orientationPairs[15].j=11; orientationPairs[16].i=10; orientationPairs[16].j=6; orientationPairs[17].i=11; orientationPairs[17].j=7;
orientationPairs[18].i=12; orientationPairs[18].j=15; orientationPairs[19].i=13; orientationPairs[19].j=16; orientationPairs[20].i=14; orientationPairs[20].j=17;
orientationPairs[21].i=12; orientationPairs[21].j=14; orientationPairs[22].i=13; orientationPairs[22].j=15; orientationPairs[23].i=14; orientationPairs[23].j=16;
orientationPairs[24].i=15; orientationPairs[24].j=17; orientationPairs[25].i=16; orientationPairs[25].j=12; orientationPairs[26].i=17; orientationPairs[26].j=13;
orientationPairs[27].i=18; orientationPairs[27].j=21; orientationPairs[28].i=19; orientationPairs[28].j=22; orientationPairs[29].i=20; orientationPairs[29].j=23;
orientationPairs[30].i=18; orientationPairs[30].j=20; orientationPairs[31].i=19; orientationPairs[31].j=21; orientationPairs[32].i=20; orientationPairs[32].j=22;
orientationPairs[33].i=21; orientationPairs[33].j=23; orientationPairs[34].i=22; orientationPairs[34].j=18; orientationPairs[35].i=23; orientationPairs[35].j=19;
orientationPairs[36].i=24; orientationPairs[36].j=27; orientationPairs[37].i=25; orientationPairs[37].j=28; orientationPairs[38].i=26; orientationPairs[38].j=29;
orientationPairs[39].i=30; orientationPairs[39].j=33; orientationPairs[40].i=31; orientationPairs[40].j=34; orientationPairs[41].i=32; orientationPairs[41].j=35;
orientationPairs[42].i=36; orientationPairs[42].j=39; orientationPairs[43].i=37; orientationPairs[43].j=40; orientationPairs[44].i=38; orientationPairs[44].j=41;
for( unsigned m = FREAK_NB_ORIENPAIRS; m--; )
{
const float dx = patternLookup[orientationPairs[m].i].x-patternLookup[orientationPairs[m].j].x;
const float dy = patternLookup[orientationPairs[m].i].y-patternLookup[orientationPairs[m].j].y;
const float norm_sq = (dx*dx+dy*dy);
orientationPairs[m].weight_dx = int((dx/(norm_sq))*4096.0+0.5);
orientationPairs[m].weight_dy = int((dy/(norm_sq))*4096.0+0.5);
}
// build the list of description pairs
std::vector<DescriptionPair> allPairs;
for( unsigned int i = 1; i < (unsigned int)FREAK_NB_POINTS; ++i )
{
// (generate all the pairs)
for( unsigned int j = 0; (unsigned int)j < i; ++j )
{
DescriptionPair pair = {(uchar)i,(uchar)j};
allPairs.push_back(pair);
}
}
// Input vector provided
if( !selectedPairs0.empty() )
{
if( (int)selectedPairs0.size() == FREAK_NB_PAIRS )
{
for( int i = 0; i < FREAK_NB_PAIRS; ++i )
descriptionPairs[i] = allPairs[selectedPairs0.at(i)];
}
else
{
CV_Error(Error::StsVecLengthErr, "Input vector does not match the required size");
}
}
else // default selected pairs
{
for( int i = 0; i < FREAK_NB_PAIRS; ++i )
descriptionPairs[i] = allPairs[FREAK_DEF_PAIRS[i]];
}
}
void FREAK::computeImpl( InputArray _image, std::vector<KeyPoint>& keypoints, OutputArray _descriptors ) const
{
Mat image = _image.getMat();
if( image.empty() )
return;
if( keypoints.empty() )
return;
((FREAK*)this)->buildPattern();
// Convert to gray if not already
Mat grayImage = image;
// if( image.channels() > 1 )
// cvtColor( image, grayImage, COLOR_BGR2GRAY );
// Use 32-bit integers if we won't overflow in the integral image
if ((image.depth() == CV_8U || image.depth() == CV_8S) &&
(image.rows * image.cols) < 8388608 ) // 8388608 = 2 ^ (32 - 8(bit depth) - 1(sign bit))
{
// Create the integral image appropriate for our type & usage
if (image.depth() == CV_8U)
computeDescriptors<uchar, int>(grayImage, keypoints, _descriptors);
else if (image.depth() == CV_8S)
computeDescriptors<char, int>(grayImage, keypoints, _descriptors);
else
CV_Error( Error::StsUnsupportedFormat, "" );
} else {
// Create the integral image appropriate for our type & usage
if ( image.depth() == CV_8U )
computeDescriptors<uchar, double>(grayImage, keypoints, _descriptors);
else if ( image.depth() == CV_8S )
computeDescriptors<char, double>(grayImage, keypoints, _descriptors);
else if ( image.depth() == CV_16U )
computeDescriptors<ushort, double>(grayImage, keypoints, _descriptors);
else if ( image.depth() == CV_16S )
computeDescriptors<short, double>(grayImage, keypoints, _descriptors);
else
CV_Error( Error::StsUnsupportedFormat, "" );
}
}
template <typename srcMatType>
void FREAK::extractDescriptor(srcMatType *pointsValue, void ** ptr) const
{
std::bitset<FREAK_NB_PAIRS>** ptrScalar = (std::bitset<FREAK_NB_PAIRS>**) ptr;
// extracting descriptor preserving the order of SSE version
int cnt = 0;
for( int n = 7; n < FREAK_NB_PAIRS; n += 128)
{
for( int m = 8; m--; )
{
int nm = n-m;
for(int kk = nm+15*8; kk >= nm; kk-=8, ++cnt)
{
(*ptrScalar)->set(kk, pointsValue[descriptionPairs[cnt].i] >= pointsValue[descriptionPairs[cnt].j]);
}
}
}
--(*ptrScalar);
}
#if CV_SSE2
template <>
void FREAK::extractDescriptor(uchar *pointsValue, void ** ptr) const
{
__m128i** ptrSSE = (__m128i**) ptr;
// note that comparisons order is modified in each block (but first 128 comparisons remain globally the same-->does not affect the 128,384 bits segmanted matching strategy)
int cnt = 0;
for( int n = FREAK_NB_PAIRS/128; n-- ; )
{
__m128i result128 = _mm_setzero_si128();
for( int m = 128/16; m--; cnt += 16 )
{
__m128i operand1 = _mm_set_epi8(pointsValue[descriptionPairs[cnt+0].i],
pointsValue[descriptionPairs[cnt+1].i],
pointsValue[descriptionPairs[cnt+2].i],
pointsValue[descriptionPairs[cnt+3].i],
pointsValue[descriptionPairs[cnt+4].i],
pointsValue[descriptionPairs[cnt+5].i],
pointsValue[descriptionPairs[cnt+6].i],
pointsValue[descriptionPairs[cnt+7].i],
pointsValue[descriptionPairs[cnt+8].i],
pointsValue[descriptionPairs[cnt+9].i],
pointsValue[descriptionPairs[cnt+10].i],
pointsValue[descriptionPairs[cnt+11].i],
pointsValue[descriptionPairs[cnt+12].i],
pointsValue[descriptionPairs[cnt+13].i],
pointsValue[descriptionPairs[cnt+14].i],
pointsValue[descriptionPairs[cnt+15].i]);
__m128i operand2 = _mm_set_epi8(pointsValue[descriptionPairs[cnt+0].j],
pointsValue[descriptionPairs[cnt+1].j],
pointsValue[descriptionPairs[cnt+2].j],
pointsValue[descriptionPairs[cnt+3].j],
pointsValue[descriptionPairs[cnt+4].j],
pointsValue[descriptionPairs[cnt+5].j],
pointsValue[descriptionPairs[cnt+6].j],
pointsValue[descriptionPairs[cnt+7].j],
pointsValue[descriptionPairs[cnt+8].j],
pointsValue[descriptionPairs[cnt+9].j],
pointsValue[descriptionPairs[cnt+10].j],
pointsValue[descriptionPairs[cnt+11].j],
pointsValue[descriptionPairs[cnt+12].j],
pointsValue[descriptionPairs[cnt+13].j],
pointsValue[descriptionPairs[cnt+14].j],
pointsValue[descriptionPairs[cnt+15].j]);
__m128i workReg = _mm_min_epu8(operand1, operand2); // emulated "not less than" for 8-bit UNSIGNED integers
workReg = _mm_cmpeq_epi8(workReg, operand2); // emulated "not less than" for 8-bit UNSIGNED integers
workReg = _mm_and_si128(_mm_set1_epi16(short(0x8080 >> m)), workReg); // merge the last 16 bits with the 128bits std::vector until full
result128 = _mm_or_si128(result128, workReg);
}
(**ptrSSE) = result128;
++(*ptrSSE);
}
(*ptrSSE) -= 8;
}
#endif
template <typename srcMatType, typename iiMatType>
void FREAK::computeDescriptors( InputArray _image, std::vector<KeyPoint>& keypoints, OutputArray _descriptors ) const {
Mat image = _image.getMat();
Mat imgIntegral;
integral(image, imgIntegral, DataType<iiMatType>::type);
std::vector<int> kpScaleIdx(keypoints.size()); // used to save pattern scale index corresponding to each keypoints
const std::vector<int>::iterator ScaleIdxBegin = kpScaleIdx.begin(); // used in std::vector erase function
const std::vector<cv::KeyPoint>::iterator kpBegin = keypoints.begin(); // used in std::vector erase function
const float sizeCst = static_cast<float>(FREAK_NB_SCALES/(FREAK_LOG2* nOctaves));
srcMatType pointsValue[FREAK_NB_POINTS];
int thetaIdx = 0;
int direction0;
int direction1;
// compute the scale index corresponding to the keypoint size and remove keypoints close to the border
if( scaleNormalized )
{
for( size_t k = keypoints.size(); k--; )
{
//Is k non-zero? If so, decrement it and continue"
kpScaleIdx[k] = std::max( (int)(std::log(keypoints[k].size/FREAK_SMALLEST_KP_SIZE)*sizeCst+0.5) ,0);
if( kpScaleIdx[k] >= FREAK_NB_SCALES )
kpScaleIdx[k] = FREAK_NB_SCALES-1;
if( keypoints[k].pt.x <= patternSizes[kpScaleIdx[k]] || //check if the description at this specific position and scale fits inside the image
keypoints[k].pt.y <= patternSizes[kpScaleIdx[k]] ||
keypoints[k].pt.x >= image.cols-patternSizes[kpScaleIdx[k]] ||
keypoints[k].pt.y >= image.rows-patternSizes[kpScaleIdx[k]]
)
{
keypoints.erase(kpBegin+k);
kpScaleIdx.erase(ScaleIdxBegin+k);
}
}
}
else
{
const int scIdx = std::max( (int)(1.0986122886681*sizeCst+0.5) ,0);
for( size_t k = keypoints.size(); k--; )
{
kpScaleIdx[k] = scIdx; // equivalent to the formule when the scale is normalized with a constant size of keypoints[k].size=3*SMALLEST_KP_SIZE
if( kpScaleIdx[k] >= FREAK_NB_SCALES )
{
kpScaleIdx[k] = FREAK_NB_SCALES-1;
}
if( keypoints[k].pt.x <= patternSizes[kpScaleIdx[k]] ||
keypoints[k].pt.y <= patternSizes[kpScaleIdx[k]] ||
keypoints[k].pt.x >= image.cols-patternSizes[kpScaleIdx[k]] ||
keypoints[k].pt.y >= image.rows-patternSizes[kpScaleIdx[k]]
)
{
keypoints.erase(kpBegin+k);
kpScaleIdx.erase(ScaleIdxBegin+k);
}
}
}
// allocate descriptor memory, estimate orientations, extract descriptors
if( !extAll )
{
// extract the best comparisons only
_descriptors.create((int)keypoints.size(), FREAK_NB_PAIRS/8, CV_8U);
_descriptors.setTo(Scalar::all(0));
Mat descriptors = _descriptors.getMat();
void *ptr = descriptors.data+(keypoints.size()-1)*descriptors.step[0];
for( size_t k = keypoints.size(); k--; ) {
// estimate orientation (gradient)
if( !orientationNormalized )
{
thetaIdx = 0; // assign 0° to all keypoints
keypoints[k].angle = 0.0;
}
else
{
// get the points intensity value in the un-rotated pattern
for( int i = FREAK_NB_POINTS; i--; ) {
pointsValue[i] = meanIntensity<srcMatType, iiMatType>(image, imgIntegral,
keypoints[k].pt.x, keypoints[k].pt.y,
kpScaleIdx[k], 0, i);
}
direction0 = 0;
direction1 = 0;
for( int m = 45; m--; )
{
//iterate through the orientation pairs
const int delta = (pointsValue[ orientationPairs[m].i ]-pointsValue[ orientationPairs[m].j ]);
direction0 += delta*(orientationPairs[m].weight_dx)/2048;
direction1 += delta*(orientationPairs[m].weight_dy)/2048;
}
keypoints[k].angle = static_cast<float>(atan2((float)direction1,(float)direction0)*(180.0/CV_PI));//estimate orientation
thetaIdx = int(FREAK_NB_ORIENTATION*keypoints[k].angle*(1/360.0)+0.5);
if( thetaIdx < 0 )
thetaIdx += FREAK_NB_ORIENTATION;
if( thetaIdx >= FREAK_NB_ORIENTATION )
thetaIdx -= FREAK_NB_ORIENTATION;
}
// extract descriptor at the computed orientation
for( int i = FREAK_NB_POINTS; i--; ) {
pointsValue[i] = meanIntensity<srcMatType, iiMatType>(image, imgIntegral,
keypoints[k].pt.x, keypoints[k].pt.y,
kpScaleIdx[k], thetaIdx, i);
}
// Extract descriptor
extractDescriptor<srcMatType>(pointsValue, &ptr);
}
}
else // extract all possible comparisons for selection
{
_descriptors.create((int)keypoints.size(), 128, CV_8U);
_descriptors.setTo(Scalar::all(0));
Mat descriptors = _descriptors.getMat();
std::bitset<1024>* ptr = (std::bitset<1024>*) (descriptors.data+(keypoints.size()-1)*descriptors.step[0]);
for( size_t k = keypoints.size(); k--; )
{
//estimate orientation (gradient)
if( !orientationNormalized )
{
thetaIdx = 0;//assign 0° to all keypoints
keypoints[k].angle = 0.0;
}
else
{
//get the points intensity value in the un-rotated pattern
for( int i = FREAK_NB_POINTS;i--; )
pointsValue[i] = meanIntensity<srcMatType, iiMatType>(image, imgIntegral,
keypoints[k].pt.x,keypoints[k].pt.y,
kpScaleIdx[k], 0, i);
direction0 = 0;
direction1 = 0;
for( int m = 45; m--; )
{
//iterate through the orientation pairs
const int delta = (pointsValue[ orientationPairs[m].i ]-pointsValue[ orientationPairs[m].j ]);
direction0 += delta*(orientationPairs[m].weight_dx)/2048;
direction1 += delta*(orientationPairs[m].weight_dy)/2048;
}
keypoints[k].angle = static_cast<float>(atan2((float)direction1,(float)direction0)*(180.0/CV_PI)); //estimate orientation
thetaIdx = int(FREAK_NB_ORIENTATION*keypoints[k].angle*(1/360.0)+0.5);
if( thetaIdx < 0 )
thetaIdx += FREAK_NB_ORIENTATION;
if( thetaIdx >= FREAK_NB_ORIENTATION )
thetaIdx -= FREAK_NB_ORIENTATION;
}
// get the points intensity value in the rotated pattern
for( int i = FREAK_NB_POINTS; i--; ) {
pointsValue[i] = meanIntensity<srcMatType, iiMatType>(image, imgIntegral,
keypoints[k].pt.x, keypoints[k].pt.y,
kpScaleIdx[k], thetaIdx, i);
}
int cnt(0);
for( int i = 1; i < FREAK_NB_POINTS; ++i )
{
//(generate all the pairs)
for( int j = 0; j < i; ++j )
{
ptr->set(cnt, pointsValue[i] >= pointsValue[j] );
++cnt;
}
}
--ptr;
}
}
}
// simply take average on a square patch, not even gaussian approx
template <typename imgType, typename iiType>
imgType FREAK::meanIntensity( InputArray _image, InputArray _integral,
const float kp_x,
const float kp_y,
const unsigned int scale,
const unsigned int rot,
const unsigned int point) const {
Mat image = _image.getMat(), integral = _integral.getMat();
// get point position in image
const PatternPoint& FreakPoint = patternLookup[scale*FREAK_NB_ORIENTATION*FREAK_NB_POINTS + rot*FREAK_NB_POINTS + point];
const float xf = FreakPoint.x+kp_x;
const float yf = FreakPoint.y+kp_y;
const int x = int(xf);
const int y = int(yf);
// get the sigma:
const float radius = FreakPoint.sigma;
// calculate output:
if( radius < 0.5 )
{
// interpolation multipliers:
const int r_x = static_cast<int>((xf-x)*1024);
const int r_y = static_cast<int>((yf-y)*1024);
const int r_x_1 = (1024-r_x);
const int r_y_1 = (1024-r_y);
unsigned int ret_val;
// linear interpolation:
ret_val = r_x_1*r_y_1*int(image.at<imgType>(y , x ))
+ r_x *r_y_1*int(image.at<imgType>(y , x+1))
+ r_x_1*r_y *int(image.at<imgType>(y+1, x ))
+ r_x *r_y *int(image.at<imgType>(y+1, x+1));
//return the rounded mean
ret_val += 2 * 1024 * 1024;
return static_cast<imgType>(ret_val / (4 * 1024 * 1024));
}
// expected case:
// calculate borders
const int x_left = int(xf-radius+0.5);
const int y_top = int(yf-radius+0.5);
const int x_right = int(xf+radius+1.5);//integral image is 1px wider
const int y_bottom = int(yf+radius+1.5);//integral image is 1px higher
iiType ret_val;
ret_val = integral.at<iiType>(y_bottom,x_right);//bottom right corner
ret_val -= integral.at<iiType>(y_bottom,x_left);
ret_val += integral.at<iiType>(y_top,x_left);
ret_val -= integral.at<iiType>(y_top,x_right);
ret_val = ret_val/( (x_right-x_left)* (y_bottom-y_top) );
//~ std::cout<<integral.step[1]<<std::endl;
return static_cast<imgType>(ret_val);
}
// pair selection algorithm from a set of training images and corresponding keypoints
std::vector<int> FREAK::selectPairs(const std::vector<Mat>& images
, std::vector<std::vector<KeyPoint> >& keypoints
, const double corrTresh
, bool verbose )
{
extAll = true;
// compute descriptors with all pairs
Mat descriptors;
if( verbose )
std::cout << "Number of images: " << images.size() << std::endl;
for( size_t i = 0;i < images.size(); ++i )
{
Mat descriptorsTmp;
computeImpl(images[i],keypoints[i],descriptorsTmp);
descriptors.push_back(descriptorsTmp);
}
if( verbose )
std::cout << "number of keypoints: " << descriptors.rows << std::endl;
//descriptor in floating point format (each bit is a float)
Mat descriptorsFloat = Mat::zeros(descriptors.rows, 903, CV_32F);
std::bitset<1024>* ptr = (std::bitset<1024>*) (descriptors.data+(descriptors.rows-1)*descriptors.step[0]);
for( int m = descriptors.rows; m--; )
{
for( int n = 903; n--; )
{
if( ptr->test(n) == true )
descriptorsFloat.at<float>(m,n)=1.0f;
}
--ptr;
}
std::vector<PairStat> pairStat;
for( int n = 903; n--; )
{
// the higher the variance, the better --> mean = 0.5
PairStat tmp = { fabs( mean(descriptorsFloat.col(n))[0]-0.5 ) ,n};
pairStat.push_back(tmp);
}
std::sort( pairStat.begin(),pairStat.end(), sortMean() );
std::vector<PairStat> bestPairs;
for( int m = 0; m < 903; ++m )
{
if( verbose )
std::cout << m << ":" << bestPairs.size() << " " << std::flush;
double corrMax(0);
for( size_t n = 0; n < bestPairs.size(); ++n )
{
int idxA = bestPairs[n].idx;
int idxB = pairStat[m].idx;
double corr(0);
// compute correlation between 2 pairs
corr = fabs(compareHist(descriptorsFloat.col(idxA), descriptorsFloat.col(idxB), HISTCMP_CORREL));
if( corr > corrMax )
{
corrMax = corr;
if( corrMax >= corrTresh )
break;
}
}
if( corrMax < corrTresh/*0.7*/ )
bestPairs.push_back(pairStat[m]);
if( bestPairs.size() >= 512 )
{
if( verbose )
std::cout << m << std::endl;
break;
}
}
std::vector<int> idxBestPairs;
if( (int)bestPairs.size() >= FREAK_NB_PAIRS )
{
for( int i = 0; i < FREAK_NB_PAIRS; ++i )
idxBestPairs.push_back(bestPairs[i].idx);
}
else
{
if( verbose )
std::cout << "correlation threshold too small (restrictive)" << std::endl;
CV_Error(Error::StsError, "correlation threshold too small (restrictive)");
}
extAll = false;
return idxBestPairs;
}
/*
// create an image showing the brisk pattern
void FREAKImpl::drawPattern()
{
Mat pattern = Mat::zeros(1000, 1000, CV_8UC3) + Scalar(255,255,255);
int sFac = 500 / patternScale;
for( int n = 0; n < kNB_POINTS; ++n )
{
PatternPoint& pt = patternLookup[n];
circle(pattern, Point( pt.x*sFac,pt.y*sFac)+Point(500,500), pt.sigma*sFac, Scalar(0,0,255),2);
// rectangle(pattern, Point( (pt.x-pt.sigma)*sFac,(pt.y-pt.sigma)*sFac)+Point(500,500), Point( (pt.x+pt.sigma)*sFac,(pt.y+pt.sigma)*sFac)+Point(500,500), Scalar(0,0,255),2);
circle(pattern, Point( pt.x*sFac,pt.y*sFac)+Point(500,500), 1, Scalar(0,0,0),3);
std::ostringstream oss;
oss << n;
putText( pattern, oss.str(), Point( pt.x*sFac,pt.y*sFac)+Point(500,500), FONT_HERSHEY_SIMPLEX,0.5, Scalar(0,0,0), 1);
}
imshow( "FreakDescriptorExtractor pattern", pattern );
waitKey(0);
}
*/
// -------------------------------------------------
/* FREAK interface implementation */
FREAK::FREAK( bool _orientationNormalized, bool _scaleNormalized
, float _patternScale, int _nOctaves, const std::vector<int>& _selectedPairs )
: orientationNormalized(_orientationNormalized), scaleNormalized(_scaleNormalized),
patternScale(_patternScale), nOctaves(_nOctaves), extAll(false), nOctaves0(0), selectedPairs0(_selectedPairs)
{
}
FREAK::~FREAK()
{
}
int FREAK::descriptorSize() const
{
return FREAK_NB_PAIRS / 8; // descriptor length in bytes
}
int FREAK::descriptorType() const
{
return CV_8U;
}
int FREAK::defaultNorm() const
{
return NORM_HAMMING;
}
} // END NAMESPACE CV