A program using pyramid scaling, Canny, contours and contour simplification to find squares in a list of images (pic1-6.png). Returns sequence of squares detected on the image.
#include <iostream>
static void help(const char* programName)
{
cout <<
"\nA program using pyramid scaling, Canny, contours and contour simplification\n"
"to find squares in a list of images (pic1-6.png)\n"
"Returns sequence of squares detected on the image.\n"
"Call:\n"
"./" << programName << " [file_name (optional)]\n"
"Using OpenCV version " <<
CV_VERSION <<
"\n" << endl;
}
int thresh = 50, N = 11;
const char* wndname = "Square Detection Demo";
{
double dx1 = pt1.
x - pt0.
x;
double dy1 = pt1.
y - pt0.
y;
double dx2 = pt2.
x - pt0.
x;
double dy2 = pt2.
y - pt0.
y;
return (dx1*dx2 + dy1*dy2)/
sqrt((dx1*dx1 + dy1*dy1)*(dx2*dx2 + dy2*dy2) + 1e-10);
}
static void findSquares(
const Mat& image, vector<vector<Point> >& squares )
{
squares.clear();
vector<vector<Point> > contours;
for( int c = 0; c < 3; c++ )
{
int ch[] = {c, 0};
for( int l = 0; l < N; l++ )
{
if( l == 0 )
{
Canny(gray0, gray, 0, thresh, 5);
}
else
{
gray = gray0 >= (l+1)*255/N;
}
vector<Point> approx;
for( size_t i = 0; i < contours.size(); i++ )
{
if( approx.size() == 4 &&
{
double maxCosine = 0;
for( int j = 2; j < 5; j++ )
{
double cosine = fabs(angle(approx[j%4], approx[j-2], approx[j-1]));
maxCosine =
MAX(maxCosine, cosine);
}
if( maxCosine < 0.3 )
squares.push_back(approx);
}
}
}
}
}
static void drawSquares(
Mat& image,
const vector<vector<Point> >& squares )
{
for( size_t i = 0; i < squares.size(); i++ )
{
const Point* p = &squares[i][0];
int n = (int)squares[i].size();
}
}
int main(int argc, char** argv)
{
static const char* names[] = { "data/pic1.png", "data/pic2.png", "data/pic3.png",
"data/pic4.png", "data/pic5.png", "data/pic6.png", 0 };
help(argv[0]);
if( argc > 1)
{
names[0] = argv[1];
names[1] = "0";
}
vector<vector<Point> > squares;
for( int i = 0; names[i] != 0; i++ )
{
{
cout << "Couldn't load " << filename << endl;
continue;
}
findSquares(image, squares);
drawSquares(image, squares);
if( c == 27 )
break;
}
return 0;
}