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/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// Intel License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000, Intel Corporation, all rights reserved.
// Third party copyrights are property of their respective owners.
//
// 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 Intel Corporation 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.
//
//M*/
#include "precomp.hpp"
#include <limits>
#include <utility>
#include <algorithm>
#include <math.h>
namespace cv {
inline bool is_smaller(const std::pair<int, float>& p1, const std::pair<int, float>& p2)
{
return p1.second < p2.second;
}
static void orderContours(const std::vector<std::vector<Point> >& contours, Point2f point, std::vector<std::pair<int, float> >& order)
{
order.clear();
size_t i, j, n = contours.size();
for(i = 0; i < n; i++)
{
size_t ni = contours[i].size();
double min_dist = std::numeric_limits<double>::max();
for(j = 0; j < ni; j++)
{
double dist = norm(Point2f((float)contours[i][j].x, (float)contours[i][j].y) - point);
min_dist = MIN(min_dist, dist);
}
order.push_back(std::pair<int, float>((int)i, (float)min_dist));
}
std::sort(order.begin(), order.end(), is_smaller);
}
// fit second order curve to a set of 2D points
inline void fitCurve2Order(const std::vector<Point2f>& /*points*/, std::vector<float>& /*curve*/)
{
// TBD
}
inline void findCurvesCross(const std::vector<float>& /*curve1*/, const std::vector<float>& /*curve2*/, Point2f& /*cross_point*/)
{
}
static void findLinesCrossPoint(Point2f origin1, Point2f dir1, Point2f origin2, Point2f dir2, Point2f& cross_point)
{
float det = dir2.x*dir1.y - dir2.y*dir1.x;
Point2f offset = origin2 - origin1;
float alpha = (dir2.x*offset.y - dir2.y*offset.x)/det;
cross_point = origin1 + dir1*alpha;
}
static void findCorner(const std::vector<Point2f>& contour, Point2f point, Point2f& corner)
{
// find the nearest point
double min_dist = std::numeric_limits<double>::max();
int min_idx = -1;
// find corner idx
for(size_t i = 0; i < contour.size(); i++)
{
double dist = norm(contour[i] - point);
if(dist < min_dist)
{
min_dist = dist;
min_idx = (int)i;
}
}
CV_Assert(min_idx >= 0);
// temporary solution, have to make something more precise
corner = contour[min_idx];
return;
}
static int segment_hist_max(const Mat& hist, int& low_thresh, int& high_thresh)
{
Mat bw;
double total_sum = sum(hist).val[0];
double quantile_sum = 0.0;
//double min_quantile = 0.2;
double low_sum = 0;
double max_segment_length = 0;
int max_start_x = -1;
int max_end_x = -1;
int start_x = 0;
const double out_of_bells_fraction = 0.1;
for(int x = 0; x < hist.size[0]; x++)
{
quantile_sum += hist.at<float>(x);
if(quantile_sum < 0.2*total_sum) continue;
if(quantile_sum - low_sum > out_of_bells_fraction*total_sum)
{
if(max_segment_length < x - start_x)
{
max_segment_length = x - start_x;
max_start_x = start_x;
max_end_x = x;
}
low_sum = quantile_sum;
start_x = x;
}
}
if(start_x == -1)
{
return 0;
}
else
{
low_thresh = cvRound(max_start_x + 0.25*(max_end_x - max_start_x));
high_thresh = cvRound(max_start_x + 0.75*(max_end_x - max_start_x));
return 1;
}
}
}
bool cv::find4QuadCornerSubpix(InputArray _img, InputOutputArray _corners, Size region_size)
{
Mat img = _img.getMat(), cornersM = _corners.getMat();
int ncorners = cornersM.checkVector(2, CV_32F);
CV_Assert( ncorners >= 0 );
Point2f* corners = cornersM.ptr<Point2f>();
const int nbins = 256;
float ranges[] = {0, 256};
const float* _ranges = ranges;
Mat hist;
Mat black_comp, white_comp;
for(int i = 0; i < ncorners; i++)
{
int channels = 0;
Rect roi(cvRound(corners[i].x - region_size.width), cvRound(corners[i].y - region_size.height),
region_size.width*2 + 1, region_size.height*2 + 1);
Mat img_roi = img(roi);
calcHist(&img_roi, 1, &channels, Mat(), hist, 1, &nbins, &_ranges);
int black_thresh = 0, white_thresh = 0;
segment_hist_max(hist, black_thresh, white_thresh);
threshold(img, black_comp, black_thresh, 255.0, THRESH_BINARY_INV);
threshold(img, white_comp, white_thresh, 255.0, THRESH_BINARY);
const int erode_count = 1;
erode(black_comp, black_comp, Mat(), Point(-1, -1), erode_count);
erode(white_comp, white_comp, Mat(), Point(-1, -1), erode_count);
std::vector<std::vector<Point> > white_contours, black_contours;
std::vector<Vec4i> white_hierarchy, black_hierarchy;
findContours(black_comp, black_contours, black_hierarchy, RETR_LIST, CHAIN_APPROX_SIMPLE);
findContours(white_comp, white_contours, white_hierarchy, RETR_LIST, CHAIN_APPROX_SIMPLE);
if(black_contours.size() < 5 || white_contours.size() < 5) continue;
// find two white and black blobs that are close to the input point
std::vector<std::pair<int, float> > white_order, black_order;
orderContours(black_contours, corners[i], black_order);
orderContours(white_contours, corners[i], white_order);
const float max_dist = 10.0f;
if(black_order[0].second > max_dist || black_order[1].second > max_dist ||
white_order[0].second > max_dist || white_order[1].second > max_dist)
{
continue; // there will be no improvement in this corner position
}
const std::vector<Point>* quads[4] = {&black_contours[black_order[0].first], &black_contours[black_order[1].first],
&white_contours[white_order[0].first], &white_contours[white_order[1].first]};
std::vector<Point2f> quads_approx[4];
Point2f quad_corners[4];
for(int k = 0; k < 4; k++)
{
std::vector<Point2f> temp;
for(size_t j = 0; j < quads[k]->size(); j++) temp.push_back((*quads[k])[j]);
approxPolyDP(Mat(temp), quads_approx[k], 0.5, true);
findCorner(quads_approx[k], corners[i], quad_corners[k]);
quad_corners[k] += Point2f(0.5f, 0.5f);
}
// cross two lines
Point2f origin1 = quad_corners[0];
Point2f dir1 = quad_corners[1] - quad_corners[0];
Point2f origin2 = quad_corners[2];
Point2f dir2 = quad_corners[3] - quad_corners[2];
double angle = acos(dir1.dot(dir2)/(norm(dir1)*norm(dir2)));
if(cvIsNaN(angle) || cvIsInf(angle) || angle < 0.5 || angle > CV_PI - 0.5) continue;
findLinesCrossPoint(origin1, dir1, origin2, dir2, corners[i]);
}
return true;
}