diff --git a/modules/ximgproc/src/thinning.cpp b/modules/ximgproc/src/thinning.cpp
index 76e8ad154..abd71e76e 100644
--- a/modules/ximgproc/src/thinning.cpp
+++ b/modules/ximgproc/src/thinning.cpp
@@ -92,8 +92,7 @@ static uint8_t lut_guo_iter1[] = {
1, 1, 1, 1};
// Applies a thinning iteration to a binary image
-static void thinningIteration(Mat img, int iter, int thinningType){
- Mat marker = Mat::zeros(img.size(), CV_8UC1);
+static void thinningIteration(Mat &img, Mat &marker, const uint8_t* const lut) {
int rows = img.rows;
int cols = img.cols;
marker.col(0).setTo(1);
@@ -101,85 +100,27 @@ static void thinningIteration(Mat img, int iter, int thinningType){
marker.row(0).setTo(1);
marker.row(rows - 1).setTo(1);
- if(thinningType == THINNING_ZHANGSUEN){
- marker.forEach<uchar>([=](uchar& value, const int postion[]) {
- int i = postion[0];
- int j = postion[1];
- if (i == 0 || j == 0 || i == rows - 1 || j == cols - 1)
- return;
-
- 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];
- uchar p5 = ptr[cols + 1];
- uchar p6 = ptr[cols];
- uchar p7 = ptr[cols - 1];
- uchar p8 = ptr[-1];
- uchar p9 = ptr[-cols - 1];
-
- int neighbors = p9 | (p2 << 1) | (p3 << 2) | (p4 << 3) | (p5 << 4) | (p6 << 5) | (p7 << 6) | (p8 << 7);
-
- if (iter == 0)
- 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){
- marker.forEach<uchar>([=](uchar& value, const int postion[]) {
- int i = postion[0];
- int j = postion[1];
- if (i == 0 || j == 0 || i == rows - 1 || j == cols - 1)
- return;
-
- 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];
- uchar p5 = ptr[cols + 1];
- uchar p6 = ptr[cols];
- uchar p7 = ptr[cols - 1];
- uchar p8 = ptr[-1];
- uchar p9 = ptr[-cols - 1];
-
- int neighbors = p9 | (p2 << 1) | (p3 << 2) | (p4 << 3) | (p5 << 4) | (p6 << 5) | (p7 << 6) | (p8 << 7);
-
- if (iter == 0)
- 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;
- });
- }
+ marker.forEach<uchar>([=](uchar& value, const int postion[]) {
+ int i = postion[0];
+ int j = postion[1];
+ if (i == 0 || j == 0 || i == rows - 1 || j == cols - 1) { return; }
+
+ auto ptr = img.ptr(i, j); // p1
+ uchar p2 = ptr[-cols];
+ uchar p3 = ptr[-cols + 1];
+ uchar p4 = ptr[1];
+ uchar p5 = ptr[cols + 1];
+ uchar p6 = ptr[cols];
+ uchar p7 = ptr[cols - 1];
+ uchar p8 = ptr[-1];
+ uchar p9 = ptr[-cols - 1];
+
+ int neighbors = p9 | (p2 << 1) | (p3 << 2) | (p4 << 3) | (p5 << 4) | (p6 << 5) | (p7 << 6) | (p8 << 7);
+ value = lut[neighbors];
+ });
img &= marker;
+ marker.setTo(0);
}
// Apply the thinning procedure to a given image
@@ -188,21 +129,19 @@ 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;
-
+ Mat marker = Mat::zeros(processed.size(), CV_8UC1);
+ const auto lutIter0 = (thinningType == THINNING_GUOHALL) ? lut_guo_iter0 : lut_zhang_iter0;
+ const auto lutIter1 = (thinningType == THINNING_GUOHALL) ? lut_guo_iter1 : lut_zhang_iter1;
do {
- thinningIteration(processed, 0, thinningType);
- thinningIteration(processed, 1, thinningType);
- absdiff(processed, prev, diff);
- if (!hasNonZero(diff)) break;
+ thinningIteration(processed, marker, lutIter0);
+ thinningIteration(processed, marker, lutIter1);
+ 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);
}