Skip to content

optimize thinning implementation #3750

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: 4.x
Choose a base branch
from
Open

optimize thinning implementation #3750

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
fc18abe
use norm_l1 to replace absdiff
ansleliu May 31, 2024
e881f95
remove marker form thinningIteration and remove "if" from forEach
ansleliu May 31, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Next Next commit
use norm_l1 to replace absdiff
  • Loading branch information
@ansleliu
ansleliu authored May 31, 2024
commit fc18abefc46ccb839a5cf6c122469ac17b9339f8
36 changes: 3 additions & 33 deletions modules/ximgproc/src/thinning.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -110,9 +110,6 @@ static void thinningIteration(Mat img, int iter, int thinningType){

auto ptr = img.ptr(i, j); // p1

// p9 p2 p3
// p8 p1 p4
// p7 p6 p5
uchar p2 = ptr[-cols];
uchar p3 = ptr[-cols + 1];
uchar p4 = ptr[1];
Expand All @@ -128,16 +125,6 @@ static void thinningIteration(Mat img, int iter, int thinningType){
value = lut_zhang_iter0[neighbors];
else
value = lut_zhang_iter1[neighbors];

//int A = (p2 == 0 && p3 == 1) + (p3 == 0 && p4 == 1) +
// (p4 == 0 && p5 == 1) + (p5 == 0 && p6 == 1) +
// (p6 == 0 && p7 == 1) + (p7 == 0 && p8 == 1) +
// (p8 == 0 && p9 == 1) + (p9 == 0 && p2 == 1);
//int B = p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9;
//int m1 = iter == 0 ? (p2 * p4 * p6) : (p2 * p4 * p8);
//int m2 = iter == 0 ? (p4 * p6 * p8) : (p2 * p6 * p8);
//if (A == 1 && (B >= 2 && B <= 6) && m1 == 0 && m2 == 0) value = 0;
// else value = 1;
});
}
if(thinningType == THINNING_GUOHALL){
Expand All @@ -149,9 +136,6 @@ static void thinningIteration(Mat img, int iter, int thinningType){

auto ptr = img.ptr(i, j); // p1

// p9 p2 p3
// p8 p1 p4
// p7 p6 p5
uchar p2 = ptr[-cols];
uchar p3 = ptr[-cols + 1];
uchar p4 = ptr[1];
Expand All @@ -167,15 +151,6 @@ static void thinningIteration(Mat img, int iter, int thinningType){
value = lut_guo_iter0[neighbors];
else
value = lut_guo_iter1[neighbors];

//int C = ((!p2) & (p3 | p4)) + ((!p4) & (p5 | p6)) +
// ((!p6) & (p7 | p8)) + ((!p8) & (p9 | p2));
//int N1 = (p9 | p2) + (p3 | p4) + (p5 | p6) + (p7 | p8);
//int N2 = (p2 | p3) + (p4 | p5) + (p6 | p7) + (p8 | p9);
//int N = N1 < N2 ? N1 : N2;
//int m = iter == 0 ? ((p6 | p7 | (!p9)) & p8) : ((p2 | p3 | (!p5)) & p4);
//if ((C == 1) && ((N >= 2) && ((N <= 3)) & (m == 0))) value = 0;
// else value = 1;
});
}

Expand All @@ -188,21 +163,16 @@ void thinning(InputArray input, OutputArray output, int thinningType){
CV_CheckTypeEQ(processed.type(), CV_8UC1, "");
// Enforce the range of the input image to be in between 0 - 255
processed /= 255;

Mat prev = processed.clone();
Mat diff;

do {
thinningIteration(processed, 0, thinningType);
thinningIteration(processed, 1, thinningType);
absdiff(processed, prev, diff);
if (!hasNonZero(diff)) break;
const auto res = cv::norm(processed, prev, cv::NORM_L1);
if (res <= 0) { break; }
processed.copyTo(prev);
}
while (true);
} while (true);

processed *= 255;

output.assign(processed);
}

Expand Down