OpenCV(Cpp) Segmentation and Labeling - minho0315/OpenCV GitHub Wiki

1. image Segmentation

์ด๋ฏธ์ง€ ์„ ๋ช…ํ™”๋ฅผ ์œ„ํ•ด filter2D ์‚ฌ์šฉ

์ด์ง„ ์ด๋ฏธ์ง€์˜ ํŒŒ์ƒ ํ‘œํ˜„์„ ์–ป๊ธฐ ์œ„ํ•ด distanceTransform ์‚ฌ์šฉ

watershed ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ด๋ฏธ์ง€์˜ ๊ฐœ์ฒด๋ฅผ ๋ฐฐ๊ฒฝ์—์„œ ๋ถ„๋ฆฌ

์‹ค์Šต ์ฝ”๋“œ

#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <iostream>
using namespace std;
using namespace cv;
int main(int argc, char* argv[])
{
    // Load the image
    Mat src = imread("coin.jpg");
    if (src.empty())
    {
        cout << "Could not open or find the image!\n" << endl;
        cout << "Usage: " << argv[0] << " <Input image>" << endl;
        return -1;
    }

    // Show source image
    imshow("Source Image", src);
   
    // ๋‚˜์ค‘์— ์ถ”์ถœํ•˜๋Š”๋ฐ ๋„์›€์ด๋˜๋ฏ€๋กœ ๋ฐฐ๊ฒฝ์„ ํฐ์ƒ‰์—ฃ ๊ฒ€์€ ์ƒ‰์œผ๋กœ ๋ณ€๊ฒฝ
    for (int i = 0; i < src.rows; i++) {
        for (int j = 0; j < src.cols; j++) {
            if (src.at<Vec3b>(i, j) == Vec3b(255, 255, 255))
            {
                src.at<Vec3b>(i, j)[0] = 0;
                src.at<Vec3b>(i, j)[1] = 0;
                src.at<Vec3b>(i, j)[2] = 0;
            }
        }
    }
    // Show output image
    imshow("Black Background Image", src);

    // ์ด๋ฏธ์ง€๋ฅผ ์„ ๋ช…ํ•˜๊ฒŒํ•˜๋Š” ๋ฐ ์‚ฌ์šฉํ•  ์ปค๋„์„ ๋งŒ๋“ ๋‹ค.
    Mat kernel = (Mat_<float>(3, 3) <<
        1, 1, 1,
        1, -8, 1,
        1, 1, 1); // an approximation of second derivative, a quite strong kernel

// do the laplacian filtering as it is
// well, we need to convert everything in something more deeper then CV_8U
// because the kernel has some negative values,
// and we can expect in general to have a Laplacian image with negative values
// BUT a 8bits unsigned int (the one we are working with) can contain values from 0 to 255
// so the possible negative number will be truncated
    Mat imgLaplacian;
    filter2D(src, imgLaplacian, CV_32F, kernel);
    Mat sharp;
    src.convertTo(sharp, CV_32F);
    Mat imgResult = sharp - imgLaplacian;
    // convert back to 8bits gray scale
    imgResult.convertTo(imgResult, CV_8UC3);
    imgLaplacian.convertTo(imgLaplacian, CV_8UC3);
    // imshow( "Laplace Filtered Image", imgLaplacian );
    imshow("New Sharped Image", imgResult);

    // Create binary image from source image
    Mat bw;
    cvtColor(imgResult, bw, COLOR_BGR2GRAY);
    threshold(bw, bw, 40, 255, THRESH_BINARY | THRESH_OTSU);
    imshow("Binary Image", bw);

    // Perform the distance transform algorithm
    Mat dist;
    distanceTransform(bw, dist, DIST_L2, 3);
    // Normalize the distance image for range = {0.0, 1.0}
    // so we can visualize and threshold it
    normalize(dist, dist, 0, 1.0, NORM_MINMAX);
    imshow("Distance Transform Image", dist);

    // Threshold to obtain the peaks
    // This will be the markers for the foreground objects
    threshold(dist, dist, 0.4, 1.0, THRESH_BINARY);
    // Dilate a bit the dist image
    Mat kernel1 = Mat::ones(3, 3, CV_8U);
    dilate(dist, dist, kernel1);
    imshow("Peaks", dist);

    // Create the CV_8U version of the distance image
    // It is needed for findContours()
    Mat dist_8u;
    dist.convertTo(dist_8u, CV_8U);
    // Find total markers
    vector<vector<Point> > contours;
    findContours(dist_8u, contours, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE);
    // Create the marker image for the watershed algorithm
    Mat markers = Mat::zeros(dist.size(), CV_32S);
    // Draw the foreground markers
    for (size_t i = 0; i < contours.size(); i++)
    {
        drawContours(markers, contours, static_cast<int>(i), Scalar(static_cast<int>(i) + 1), -1);
    }
    // Draw the background marker
    circle(markers, Point(5, 5), 3, Scalar(255), -1);
    imshow("Markers", markers * 10000);

    // Perform the watershed algorithm
    watershed(imgResult, markers);
    Mat mark;
    markers.convertTo(mark, CV_8U);
    bitwise_not(mark, mark);
    imshow("Markers_v2", mark); // uncomment this if you want to see how the mark
    // image looks like at that point
    // Generate random colors
    vector<Vec3b> colors;
    for (size_t i = 0; i < contours.size(); i++)
    {
        int b = theRNG().uniform(0, 256);
        int g = theRNG().uniform(0, 256);
        int r = theRNG().uniform(0, 256);
        colors.push_back(Vec3b((uchar)b, (uchar)g, (uchar)r));
    }
    // Create the result image
    Mat dst = Mat::zeros(markers.size(), CV_8UC3);
    // Fill labeled objects with random colors
    for (int i = 0; i < markers.rows; i++)
    {
        for (int j = 0; j < markers.cols; j++)
        {
            int index = markers.at<int>(i, j);
            if (index > 0 && index <= static_cast<int>(contours.size()))
            {
                dst.at<Vec3b>(i, j) = colors[index - 1];
            }
        }
    }
    // Visualize the final image
    imshow("Final Result", dst);
    waitKey();
    return 0;
}

๊ฒฐ๊ณผ

2

์ถœ์ฒ˜

์ฝ”๋“œ

https://docs.opencv.org/3.4.12/d2/dbd/tutorial_distance_transform.html

์ด๋ฏธ์ง€

http://www.ssacstat.com/base/cs/cs_05.php?com_board_basic=read_form&com_board_idx=543&topmenu=5&left=5&&com_board_search_code=&com_board_search_value1=&com_board_search_value2=&com_board_page=33&


2. Labeling

๋ ˆ์ด๋ธ”๋ง( labeling ) ์ด๋ž€?

์ธ์ ‘ํ•œ ๊ฐ™์€ ๊ฐ’์„ ๊ฐ–๋Š” ํ”ฝ์…€๋ผ๋ฆฌ ํ•˜๋‚˜์˜ ๊ทธ๋ฃน์œผ๋กœ ๋ฌถ์–ด์ฃผ๋Š” ์ž‘์—…์ด๋‹ค.

์‰ฝ๊ฒŒ ๋งํ•ด์„œ ์ด์ง„ํ™” ์ด๋ฏธ์ง€์—์„œ ๊ฒฝ๊ณ„๋ฅผ ์ด๋ฃฌ ์˜์—ญ์— ์ด๋ฆ„(์ˆซ์ž)์„ ๋ถ€์—ฌํ•˜๋Š” ์ž‘์—…์ด๋‹ค.

์‹ค์Šต ์ฝ”๋“œ

#include <opencv2/opencv.hpp>

#include <windows.h>

using namespace cv;
using namespace std;

int main(int ac, char** av)
{
	Mat img = imread("bacteria.tif");

	Mat img_resize;
	resize(img, img_resize, Size(img.cols * 3, img.rows * 3));

	Mat img_gray;
	cvtColor(img_resize, img_gray, COLOR_BGR2GRAY);

	Mat img_threshold;
	threshold(img_gray, img_threshold, 100, 255, THRESH_BINARY_INV);

	Mat img_labels, stats, centroids;
	int numOfLables = connectedComponentsWithStats(img_threshold, img_labels, stats, centroids, 8, CV_32S);

	// ๋ ˆ์ด๋ธ”๋ง ๊ฒฐ๊ณผ์— ์‚ฌ๊ฐํ˜• ๊ทธ๋ฆฌ๊ณ , ๋„˜๋ฒ„ ํ‘œ์‹œํ•˜๊ธฐ
	for (int j = 1; j < numOfLables; j++) {
		int area = stats.at<int>(j, CC_STAT_AREA);
		int left = stats.at<int>(j, CC_STAT_LEFT);
		int top = stats.at<int>(j, CC_STAT_TOP);
		int width = stats.at<int>(j, CC_STAT_WIDTH);
		int height = stats.at<int>(j, CC_STAT_HEIGHT);


		rectangle(img_resize, Point(left, top), Point(left + width, top + height),
			Scalar(0, 0, 255), 1);

		putText(img_resize, to_string(j), Point(left + 20, top + 20), FONT_HERSHEY_SIMPLEX, 1, Scalar(255, 0, 0), 1);
	}


	imshow("img_resize", img_resize);

	cout << "numOfLables : " << numOfLables - 1 << endl;	// ์ตœ์ข… ๋„˜๋ฒ„๋ง์—์„œ 1์„ ๋นผ์ค˜์•ผ ํ•จ
	waitKey(0);



	return 0;
}

๊ฒฐ๊ณผ

3

์ถœ์ฒ˜

https://diyver.tistory.com/139?category=911404

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