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Merge pull request #19951 from stal12:3.4

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* Fix #4363 - wrong hierarchy (CV_RETR_TREE) in findContours

* Add regression test for findContours

* use C++11 => C++98 on 3.4 branch
This commit is contained in:
Stefano Allegretti 2021-04-22 20:20:12 +02:00 committed by GitHub
parent 2e143b8799
commit 1b64851fa8
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2 changed files with 78 additions and 3 deletions
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30
modules/imgproc/src/contours.cpp
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@ -625,7 +625,8 @@ icvFetchContour( schar *ptr,
/*
trace contour until certain point is met.
returns 1 if met, 0 else.
returns 1 if met and this is the last contour
encountered by a raster scan reaching the point, 0 else.
*/
static int
icvTraceContour( schar *ptr, int step, schar *stop_ptr, int is_hole )
@ -668,16 +669,41 @@ icvTraceContour( schar *ptr, int step, schar *stop_ptr, int is_hole )
break;
}
if( i3 == stop_ptr || (i4 == i0 && i3 == i1) )
if (i3 == stop_ptr) {
if (!(*i3 & 0x80)) {
/* it's the only contour */
return 1;
}
/* check if this is the last contour */
/* encountered during a raster scan */
schar *i5;
int t = s;
while (true)
{
t = (t - 1) & 7;
i5 = i3 + deltas[t];
if (*i5 != 0)
break;
if (t == 0)
return 1;
}
}
if( (i4 == i0 && i3 == i1) )
break;
i3 = i4;
s = (s + 4) & 7;
} /* end of border following loop */
}
else {
return i3 == stop_ptr;
}
return 0;
}
static void
icvFetchContourEx( schar* ptr,

49
modules/imgproc/test/test_contours.cpp
View File

@ -485,6 +485,55 @@ TEST(Imgproc_FindContours, border)
ASSERT_EQ(0, cvtest::norm(img, img_draw_contours, NORM_INF));
}
TEST(Imgproc_FindContours, regression_4363_shared_nbd)
{
// Create specific test image
Mat1b img(12, 69, (const uchar&)0);
img(1, 1) = 1;
// Vertical rectangle with hole sharing the same NBD
for (int r = 1; r <= 10; ++r) {
for (int c = 3; c <= 5; ++c) {
img(r, c) = 1;
}
}
img(9, 4) = 0;
// 124 small CCs
for (int r = 1; r <= 7; r += 2) {
for (int c = 7; c <= 67; c += 2) {
img(r, c) = 1;
}
}
// Last CC
img(9, 7) = 1;
vector< vector<Point> > contours;
vector<Vec4i> hierarchy;
findContours(img, contours, hierarchy, RETR_TREE, CHAIN_APPROX_NONE);
bool found = false;
size_t index = 0;
for (vector< vector<Point> >::const_iterator i = contours.begin(); i != contours.end(); ++i)
{
const vector<Point>& c = *i;
if (!c.empty() && c[0] == Point(7, 9))
{
found = true;
index = (size_t)(i - contours.begin());
break;
}
}
EXPECT_TRUE(found) << "Desired result: point (7,9) is a contour - Actual result: point (7,9) is not a contour";
if (found)
{
EXPECT_LT(hierarchy[index][3], 0) << "Desired result: (7,9) has no parent - Actual result: parent of (7,9) is another contour. index = " << index;
}
}
TEST(Imgproc_PointPolygonTest, regression_10222)
{
vector<Point> contour;