일단

ch11/thershhold/main.cpp

@@ -0,0 +1,54 @@
+#include <iostream>
+#include "opencv2/opencv.hpp"
+
+using namespace cv;
+using namespace std;
+
+void on_trackbar(int pos, void* userdata);
+
+int main(int argc, char* argv[]) {
+	Mat src;
+
+	if (argc < 2)
+		src = imread("../../resources/images/neutrophils.png", IMREAD_GRAYSCALE);
+	else
+		src = imread(argv[1], IMREAD_GRAYSCALE);
+
+	if (src.empty()) {
+		cerr << "Image load failed!" << endl;
+		return -1;
+	}
+
+	namedWindow("dst");
+	createTrackbar("Threshold", "dst", 0, 255, on_trackbar, (void*)&src);
+	setTrackbarPos("Threshold", "dst", 128);
+
+	cv::waitKey();
+	cv::destroyAllWindows();
+}
+
+void on_trackbar(int pos, void* userdata) {
+	Mat src = *(Mat*)userdata;
+
+	Mat hist;
+	int channels[] = { 0 };
+	int dims = 1;
+	const int histSize[] = { 256 };
+	float graylevel[] = { 0, 256 };
+	const float* ranges[] = { graylevel };
+
+	calcHist(&src, 1, channels, noArray(), hist, dims, histSize, ranges);
+	double histMax;
+	minMaxLoc(hist, 0, &histMax);
+	Mat imgHist(100, 256, CV_8UC1, Scalar(255));
+	for (int i = 0; i < 256; i++) {
+		line(imgHist, Point(i, 100), Point(i, 100 - cvRound(hist.at<float>(i, 0) * 100 / histMax)), Scalar(0));
+	}
+	line(imgHist, Point(pos, 0), Point(pos, 100), 0, 1, LINE_AA);
+
+	Mat dst;
+	threshold(src, dst, pos, 255, THRESH_BINARY);
+
+	imshow("dst", dst);
+	imshow("hist", imgHist);
+}