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/* Copyright (c) 2012 Patrick Ruoff
* Copyright (c) 2015-2016 Stanislaw Halik <sthalik@misaki.pl>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*/
#include "point_extractor.h"
#include <QDebug>
#include "compat/util.hpp"
#include <opencv2/videoio.hpp>
#include <cmath>
#include <algorithm>
#include <cinttypes>
PointExtractor::PointExtractor()
{
blobs.reserve(max_blobs);
}
void PointExtractor::extract_points(cv::Mat& frame, std::vector<vec2>& points)
{
using std::sqrt;
using std::max;
using std::round;
using std::sort;
const int W = frame.cols;
const int H = frame.rows;
if (frame_gray.rows != frame.rows || frame_gray.cols != frame.cols)
{
frame_gray = cv::Mat(frame.rows, frame.cols, CV_8U);
frame_bin = cv::Mat(frame.rows, frame.cols, CV_8U);
frame_blobs = cv::Mat(frame.rows, frame.cols, CV_8U);
}
// convert to grayscale
cv::cvtColor(frame, frame_gray, cv::COLOR_RGB2GRAY);
const double region_size_min = s.min_point_size;
const double region_size_max = s.max_point_size;
if (!s.auto_threshold)
{
const int thres = s.threshold;
cv::threshold(frame_gray, frame_bin, thres, 255, cv::THRESH_BINARY);
}
else
{
cv::calcHist(std::vector<cv::Mat> { frame_gray },
std::vector<int> { 0 },
cv::Mat(),
hist,
std::vector<int> { 256 },
std::vector<float> { 0, 256 },
false);
static constexpr double min_radius = 2.5;
static constexpr double max_radius = 15;
const double radius = max(0., (max_radius-min_radius) * s.threshold / 255 + min_radius);
const float* ptr = reinterpret_cast<const float*>(hist.ptr(0));
const unsigned area = unsigned(round(3 * M_PI * radius*radius));
const unsigned sz = unsigned(hist.cols * hist.rows);
unsigned thres = 1;
for (unsigned i = sz-1, cnt = 0; i > 1; i--)
{
cnt += ptr[i];
if (cnt >= area)
{
thres = i;
break;
}
}
//val *= 240./256.;
//qDebug() << "thres" << thres;
cv::threshold(frame_gray, frame_bin, thres, 255, CV_THRESH_BINARY);
}
blobs.clear();
frame_bin.copyTo(frame_blobs);
unsigned idx = 0;
for (int y=0; y < frame_blobs.rows; y++)
{
const unsigned char* ptr_bin = frame_blobs.ptr(y);
for (int x=0; x < frame_blobs.cols; x++)
{
if (ptr_bin[x] != 255)
continue;
idx = blobs.size() + 1;
cv::Rect rect;
cv::floodFill(frame_blobs,
cv::Point(x,y),
cv::Scalar(idx),
&rect,
cv::Scalar(0),
cv::Scalar(0),
8);
// these are doubles since m10 and m01 could overflow theoretically
// log2(255^2 * 640^2 * pi) > 36
double m10 = 0;
double m01 = 0;
// norm can't overflow since there's no 640^2 component
int norm = 0;
int cnt = 0;
for (int i=rect.y; i < (rect.y+rect.height); i++)
{
unsigned char* ptr_blobs = frame_blobs.ptr(i);
const unsigned char* ptr_gray = frame_gray.ptr(i);
for (int j=rect.x; j < (rect.x+rect.width); j++)
{
if (ptr_blobs[j] != idx)
continue;
ptr_blobs[j] = 0;
// square as a weight gives better results
const int val(int(ptr_gray[j]) * int(ptr_gray[j]));
norm += val;
m01 += i * val;
m10 += j * val;
cnt++;
}
}
if (norm > 1e0)
{
const double radius = sqrt(cnt / M_PI);
if (radius > region_size_max || radius < region_size_min)
continue;
blob b(radius, cv::Vec2d(m10 / norm, m01 / norm), norm/sqrt(double(cnt)));
blobs.push_back(b);
{
char buf[64];
sprintf(buf, "%.2fpx", radius);
cv::putText(frame,
buf,
cv::Point((int)round(b.pos[0]+30), (int)round(b.pos[1]+20)),
cv::FONT_HERSHEY_DUPLEX,
1,
cv::Scalar(0, 0, 255),
1);
}
if (idx >= max_blobs) goto end;
}
}
}
end:
sort(blobs.begin(), blobs.end(), [](const blob& b1, const blob& b2) -> bool { return b2.brightness < b1.brightness; });
points.reserve(max_blobs);
points.clear();
for (auto& b : blobs)
{
vec2 p((b.pos[0] - W/2)/W, -(b.pos[1] - H/2)/W);
points.push_back(p);
}
}
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