opencv/modules/imgproc/test/test_canny.cpp
Alexander Smorkalov fc9208cff5 Merge branch 4.x
2024-07-17 10:08:16 +03:00

229 lines
8.1 KiB
C++

/*M///////////////////////////////////////////////////////////////////////////////////////
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#include "test_precomp.hpp"
namespace opencv_test { namespace {
static void Canny_reference_follow( int x, int y, float lowThreshold, const Mat& mag, Mat& dst )
{
static const int ofs[][2] = {{1,0},{1,-1},{0,-1},{-1,-1},{-1,0},{-1,1},{0,1},{1,1}};
int i;
dst.at<uchar>(y, x) = (uchar)255;
for( i = 0; i < 8; i++ )
{
int x1 = x + ofs[i][0];
int y1 = y + ofs[i][1];
if( (unsigned)x1 < (unsigned)mag.cols &&
(unsigned)y1 < (unsigned)mag.rows &&
mag.at<float>(y1, x1) > lowThreshold &&
!dst.at<uchar>(y1, x1) )
Canny_reference_follow( x1, y1, lowThreshold, mag, dst );
}
}
static void Canny_reference( const Mat& src, Mat& dst,
double threshold1, double threshold2,
int aperture_size, bool use_true_gradient )
{
dst.create(src.size(), src.type());
int m = aperture_size;
Point anchor(m/2, m/2);
const double tan_pi_8 = tan(CV_PI/8.);
const double tan_3pi_8 = tan(CV_PI*3/8);
float lowThreshold = (float)MIN(threshold1, threshold2);
float highThreshold = (float)MAX(threshold1, threshold2);
int x, y, width = src.cols, height = src.rows;
Mat dxkernel = cvtest::calcSobelKernel2D( 1, 0, m, 0 );
Mat dykernel = cvtest::calcSobelKernel2D( 0, 1, m, 0 );
Mat dx, dy, mag(height, width, CV_32F);
cvtest::filter2D(src, dx, CV_32S, dxkernel, anchor, 0, BORDER_REPLICATE);
cvtest::filter2D(src, dy, CV_32S, dykernel, anchor, 0, BORDER_REPLICATE);
// calc gradient magnitude
for( y = 0; y < height; y++ )
{
for( x = 0; x < width; x++ )
{
int dxval = dx.at<int>(y, x), dyval = dy.at<int>(y, x);
mag.at<float>(y, x) = use_true_gradient ?
(float)sqrt((double)(dxval*dxval + dyval*dyval)) :
(float)(fabs((double)dxval) + fabs((double)dyval));
}
}
// calc gradient direction, do nonmaxima suppression
for( y = 0; y < height; y++ )
{
for( x = 0; x < width; x++ )
{
float a = mag.at<float>(y, x), b = 0, c = 0;
int y1 = 0, y2 = 0, x1 = 0, x2 = 0;
if( a <= lowThreshold )
continue;
int dxval = dx.at<int>(y, x);
int dyval = dy.at<int>(y, x);
double tg = dxval ? (double)dyval/dxval : DBL_MAX*CV_SIGN(dyval);
if( fabs(tg) < tan_pi_8 )
{
y1 = y2 = y; x1 = x + 1; x2 = x - 1;
}
else if( tan_pi_8 <= tg && tg <= tan_3pi_8 )
{
y1 = y + 1; y2 = y - 1; x1 = x + 1; x2 = x - 1;
}
else if( -tan_3pi_8 <= tg && tg <= -tan_pi_8 )
{
y1 = y - 1; y2 = y + 1; x1 = x + 1; x2 = x - 1;
}
else
{
CV_Assert( fabs(tg) > tan_3pi_8 );
x1 = x2 = x; y1 = y + 1; y2 = y - 1;
}
if( (unsigned)y1 < (unsigned)height && (unsigned)x1 < (unsigned)width )
b = (float)fabs(mag.at<float>(y1, x1));
if( (unsigned)y2 < (unsigned)height && (unsigned)x2 < (unsigned)width )
c = (float)fabs(mag.at<float>(y2, x2));
if( (a > b || (a == b && ((x1 == x+1 && y1 == y) || (x1 == x && y1 == y+1)))) && a > c )
;
else
mag.at<float>(y, x) = -a;
}
}
dst = Scalar::all(0);
// hysteresis threshold
for( y = 0; y < height; y++ )
{
for( x = 0; x < width; x++ )
if( mag.at<float>(y, x) > highThreshold && !dst.at<uchar>(y, x) )
Canny_reference_follow( x, y, lowThreshold, mag, dst );
}
}
//==============================================================================
// aperture, true gradient
typedef testing::TestWithParam<testing::tuple<int, bool>> Canny_Modes;
TEST_P(Canny_Modes, accuracy)
{
const int aperture = get<0>(GetParam());
const bool trueGradient = get<1>(GetParam());
const double range = aperture == 3 ? 300. : 1000.;
RNG & rng = TS::ptr()->get_rng();
for (int ITER = 0; ITER < 20; ++ITER)
{
SCOPED_TRACE(cv::format("iteration %d", ITER));
const std::string fname = cvtest::findDataFile("shared/fruits.png");
const Mat original = cv::imread(fname, IMREAD_GRAYSCALE);
const double thresh1 = rng.uniform(0., range);
const double thresh2 = rng.uniform(0., range * 0.3);
const Size sz(rng.uniform(127, 800), rng.uniform(127, 600));
const Size osz = original.size();
// preparation
Mat img;
if (sz.width >= osz.width || sz.height >= osz.height)
{
// larger image -> scale
resize(original, img, sz, 0, 0, INTER_LINEAR_EXACT);
}
else
{
// smaller image -> crop
Point origin(rng.uniform(0, osz.width - sz.width), rng.uniform(0, osz.height - sz.height));
Rect roi(origin, sz);
original(roi).copyTo(img);
}
GaussianBlur(img, img, Size(5, 5), 0);
// regular function
Mat result;
{
cv::Canny(img, result, thresh1, thresh2, aperture, trueGradient);
}
// custom derivatives
Mat customResult;
{
Mat dxkernel = cvtest::calcSobelKernel2D(1, 0, aperture, 0);
Mat dykernel = cvtest::calcSobelKernel2D(0, 1, aperture, 0);
Point anchor(aperture / 2, aperture / 2);
cv::Mat dx, dy;
cvtest::filter2D(img, dx, CV_16S, dxkernel, anchor, 0, BORDER_REPLICATE);
cvtest::filter2D(img, dy, CV_16S, dykernel, anchor, 0, BORDER_REPLICATE);
cv::Canny(dx, dy, customResult, thresh1, thresh2, trueGradient);
}
Mat reference;
Canny_reference(img, reference, thresh1, thresh2, aperture, trueGradient);
EXPECT_MAT_NEAR(result, reference, 0);
EXPECT_MAT_NEAR(customResult, reference, 0);
}
}
INSTANTIATE_TEST_CASE_P(/**/, Canny_Modes,
testing::Combine(
testing::Values(3, 5),
testing::Values(true, false)));
}} // namespace
/* End of file. */