93 lines
3.2 KiB
C++
93 lines
3.2 KiB
C++
#include "precomp.hpp"
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using namespace std;
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namespace cv {
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namespace ximgproc {
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// Applies a thinning iteration to a binary image
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static void thinningIteration(Mat img, int iter, int thinningType){
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Mat marker = Mat::zeros(img.size(), CV_8UC1);
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if(thinningType == THINNING_ZHANGSUEN){
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for (int i = 1; i < img.rows-1; i++)
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{
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for (int j = 1; j < img.cols-1; j++)
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{
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uchar p2 = img.at<uchar>(i-1, j);
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uchar p3 = img.at<uchar>(i-1, j+1);
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uchar p4 = img.at<uchar>(i, j+1);
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uchar p5 = img.at<uchar>(i+1, j+1);
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uchar p6 = img.at<uchar>(i+1, j);
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uchar p7 = img.at<uchar>(i+1, j-1);
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uchar p8 = img.at<uchar>(i, j-1);
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uchar p9 = img.at<uchar>(i-1, j-1);
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int A = (p2 == 0 && p3 == 1) + (p3 == 0 && p4 == 1) +
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(p4 == 0 && p5 == 1) + (p5 == 0 && p6 == 1) +
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(p6 == 0 && p7 == 1) + (p7 == 0 && p8 == 1) +
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(p8 == 0 && p9 == 1) + (p9 == 0 && p2 == 1);
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int B = p2 + p3 + p4 + p5 + p6 + p7 + p8 + p9;
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int m1 = iter == 0 ? (p2 * p4 * p6) : (p2 * p4 * p8);
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int m2 = iter == 0 ? (p4 * p6 * p8) : (p2 * p6 * p8);
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if (A == 1 && (B >= 2 && B <= 6) && m1 == 0 && m2 == 0)
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marker.at<uchar>(i,j) = 1;
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}
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}
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}
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if(thinningType == THINNING_GUOHALL){
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for (int i = 1; i < img.rows-1; i++)
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{
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for (int j = 1; j < img.cols-1; j++)
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{
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uchar p2 = img.at<uchar>(i-1, j);
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uchar p3 = img.at<uchar>(i-1, j+1);
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uchar p4 = img.at<uchar>(i, j+1);
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uchar p5 = img.at<uchar>(i+1, j+1);
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uchar p6 = img.at<uchar>(i+1, j);
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uchar p7 = img.at<uchar>(i+1, j-1);
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uchar p8 = img.at<uchar>(i, j-1);
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uchar p9 = img.at<uchar>(i-1, j-1);
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int C = ((!p2) & (p3 | p4)) + ((!p4) & (p5 | p6)) +
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((!p6) & (p7 | p8)) + ((!p8) & (p9 | p2));
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int N1 = (p9 | p2) + (p3 | p4) + (p5 | p6) + (p7 | p8);
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int N2 = (p2 | p3) + (p4 | p5) + (p6 | p7) + (p8 | p9);
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int N = N1 < N2 ? N1 : N2;
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int m = iter == 0 ? ((p6 | p7 | (!p9)) & p8) : ((p2 | p3 | (!p5)) & p4);
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if ((C == 1) && ((N >= 2) && ((N <= 3)) & (m == 0)))
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marker.at<uchar>(i,j) = 1;
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}
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}
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}
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img &= ~marker;
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}
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// Apply the thinning procedure to a given image
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void thinning(InputArray input, OutputArray output, int thinningType){
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Mat processed = input.getMat().clone();
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// Enforce the range of the input image to be in between 0 - 255
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processed /= 255;
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Mat prev = Mat::zeros(processed.size(), CV_8UC1);
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Mat diff;
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do {
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thinningIteration(processed, 0, thinningType);
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thinningIteration(processed, 1, thinningType);
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absdiff(processed, prev, diff);
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processed.copyTo(prev);
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}
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while (countNonZero(diff) > 0);
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processed *= 255;
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output.assign(processed);
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}
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} //namespace ximgproc
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} //namespace cv
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