Hi,
As part of my research on binary descriptor, I'm implementing a rotation invariant version of BRIEF. Basically, I rotate the sampling points by the angle of the patch (given from the detector).
First question: Is this something that I can contribute to OpenCV? will the moderators be interested?
Now, I'm having linking problems with the function:
AlgorithmInfo* info() const;
I'm getting "unresolved external symbol" with the function's name.
Here is my code: in fetures2d.hpp":
class CV_EXPORTS InvariantBriefDescriptorExtractor : public DescriptorExtractor
{
public:
static const int PATCH_SIZE = 48;
static const int KERNEL_SIZE = 9;
// bytes is a length of descriptor in bytes. It can be equal 16, 32 or 64 bytes.
InvariantBriefDescriptorExtractor(int bytes = 32);
virtual void read(const FileNode&);
virtual void write(FileStorage&) const;
virtual int descriptorSize() const;
virtual int descriptorType() const;
AlgorithmInfo* info() const;
protected:
virtual void computeImpl(const Mat& image, vector<KeyPoint>& keypoints, Mat& descriptors) const;
typedef void(*PixelTestFn)(const Mat&, const vector<KeyPoint>&, const int *, Mat&);
int bytes_;
PixelTestFn test_fn_;
static int bit_pattern_64_[512 * 4];
};
And the file BriefRI.cpp (which contains the implementation):
#include "precomp.hpp"
#include <algorithm>
#include <vector>
#include <iostream>
#include <iomanip>
using namespace cv;
static void calculateSums(const Mat &sum, const int &count, const int *pattern, float &cos_theta, float &sin_theta, KeyPoint pt);
inline int smoothedSum(const Mat& sum, const KeyPoint& pt, int y, int x)
{
static const int HALF_KERNEL = BriefDescriptorExtractor::KERNEL_SIZE / 2;
int img_y = (int)(pt.pt.y + 0.5) + y;
int img_x = (int)(pt.pt.x + 0.5) + x;
return sum.at<int>(img_y + HALF_KERNEL + 1, img_x + HALF_KERNEL + 1)
- sum.at<int>(img_y + HALF_KERNEL + 1, img_x - HALF_KERNEL)
- sum.at<int>(img_y - HALF_KERNEL, img_x + HALF_KERNEL + 1)
+ sum.at<int>(img_y - HALF_KERNEL, img_x - HALF_KERNEL);
}
static void pixelTests16(const Mat& sum, const std::vector<KeyPoint>& keypoints, const int *pattern, Mat& descriptors)
{
for (int i = 0; i < (int)keypoints.size(); ++i)
{
uchar* desc = descriptors.ptr(i);
const KeyPoint& pt = keypoints[i];
float angle = pt.angle;
angle *= (float)(CV_PI / 180.f);
float cos_theta = cos(angle);
float sin_theta = sin(angle);
int count = 0;
for (int ix = 0; ix < 16; ix++){
for (int jx = 7; jx >= 0; jx--){
int suma, sumb;
calculateSums(sum, count, pattern,cos_theta, sin_theta, pt);
desc[ix] += (uchar)((suma< sumb) << jx);
count += 4;
}
}
}
}
static void pixelTests32(const Mat& sum, const std::vector<KeyPoint>& keypoints, const int *pattern, Mat& descriptors)
{
for (int i = 0; i < (int)keypoints.size(); ++i)
{
uchar* desc = descriptors.ptr(i);
const KeyPoint& pt = keypoints[i];
float angle = pt.angle;
angle *= (float)(CV_PI / 180.f);
float cos_theta = cos(angle);
float sin_theta = sin(angle);
int count = 0;
for (int ix = 0; ix < 32; ix++){
for (int jx = 7; jx >= 0; jx--){
int suma, sumb;
calculateSums(sum, count, pattern,cos_theta, sin_theta, pt);
desc[ix] += (uchar)((suma< sumb) << jx);
count += 4;
}
}
}
}
static void pixelTests64(const Mat& sum, const std::vector<KeyPoint>& keypoints, const int *pattern, Mat& descriptors)
{
for (int i = 0; i < (int)keypoints.size(); ++i)
{
uchar* desc = descriptors.ptr(i);
const KeyPoint& pt = keypoints[i];
float angle = pt.angle;
angle *= (float)(CV_PI / 180.f);
float cos_theta = cos(angle);
float sin_theta = sin(angle);
int count = 0;
for (int ix = 0; ix < 64; ix++){
for (int jx = 7; jx >= 0; jx--){
int suma, sumb;
calculateSums(sum, count,pattern, cos_theta, sin_theta, pt);
desc[ix] += (uchar)((suma< sumb) << jx);
count += 4;
}
}
}
}
static void calculateSums(const Mat &sum, const int &count, const int *pattern, float &cos_theta, float &sin_theta, KeyPoint pt){
int ax = pattern[count];
int ay = pattern[count + 1];
int bx = pattern[count + 2];
int by = pattern[count + 3];
int ax2 = ((float)ax)*cos_theta - ((float)ay)*sin_theta;
int ay2 = ((float)ax)*sin_theta + ((float)ay)*cos_theta;
int bx2 = ((float)bx)*cos_theta - ((float)by)*sin_theta;
int by2 = ((float)bx)*sin_theta + ((float)by)*cos_theta;
int suma = smoothedSum(sum, pt, ay, ax);
int sumb = smoothedSum(sum, pt, by, bx);
}
namespace cv
{
InvariantBriefDescriptorExtractor::InvariantBriefDescriptorExtractor(int bytes) :
bytes_(bytes), test_fn_(NULL)
{
switch (bytes)
{
case 16:
test_fn_ = pixelTests16;
break;
case 32:
test_fn_ = pixelTests32;
break;
case 64:
test_fn_ = pixelTests64;
break;
default:
CV_Error(CV_StsBadArg, "bytes must be 16, 32, or 64");
}
}
int InvariantBriefDescriptorExtractor::descriptorSize() const
{
return bytes_;
}
int InvariantBriefDescriptorExtractor::descriptorType() const
{
return CV_8UC1;
}
void InvariantBriefDescriptorExtractor::read(const FileNode& fn)
{
int dSize = fn["descriptorSize"];
switch (dSize)
{
case 16:
test_fn_ = pixelTests16;
break;
case 32:
test_fn_ = pixelTests32;
break;
case 64:
test_fn_ = pixelTests64;
break;
default:
CV_Error(CV_StsBadArg, "descriptorSize must be 16, 32, or 64");
}
bytes_ = dSize;
}
void InvariantBriefDescriptorExtractor::write(FileStorage& fs) const
{
fs << "descriptorSize" << bytes_;
}
void InvariantBriefDescriptorExtractor::computeImpl(const Mat& image, std::vector<KeyPoint>& keypoints, Mat& descriptors) const
{
// Construct integral image for fast smoothing (box filter)
Mat sum;
Mat grayImage = image;
if (image.type() != CV_8U) cvtColor(image, grayImage, CV_BGR2GRAY);
///TODO allow the user to pass in a precomputed integral image
//if(image.type() == CV_32S)
// sum = image;
//else
integral(grayImage, sum, CV_32S);
//Remove keypoints very close to the border
KeyPointsFilter::runByImageBorder(keypoints, image.size(), PATCH_SIZE / 2 + KERNEL_SIZE / 2);
descriptors = Mat::zeros((int)keypoints.size(), bytes_, CV_8U);
test_fn_(sum, keypoints, bit_pattern_64_,descriptors);
}
int InvariantBriefDescriptorExtractor:: bit_pattern_64_[512 * 4] =
{ -1, -2, -1, 7
, -1, -14, 3, -3
, -2, 1, 2, 11
, 6, 1, -7, -10
, 2, 13, 0, -1
, 5, -14, -3, 5
, 8, -2, 4, 2
, 8, -11, 5, -15
(LONG LIST)
Thanks in advance!
Gil