fanfuhan OpenCV 教學042 ~ opencv-042-二值化圖像OTSU演算法(THRESH_OTSU) – jashliao部落格

fanfuhan OpenCV 教學042 ~ opencv-042-二值化圖像OTSU演算法(THRESH_OTSU)

資料來源: https://fanfuhan.github.io/

https://fanfuhan.github.io/2019/04/13/opencv-042/

GITHUB:https://github.com/jash-git/fanfuhan_ML_OpenCV

C++

#include 
#include 

using namespace std;
using namespace cv;

/*
 * 图像二值寻找算法 – OTSU
 */
int main() {
    Mat src = imread("../images/test.png");
    if (src.empty()) {
        cout << "could not load image.." << endl;
    }
    imshow("input", src);

    // 自动阈值寻找与二值化
    Mat gray, binary;
    cvtColor(src, gray, COLOR_BGR2GRAY);
    double T = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
    cout << "threshold : " << T << endl;
    imshow("binary", binary);

    waitKey(0);
    return 0;
}

Python

import cv2 as cv
import numpy as np
#
# THRESH_BINARY = 0
# THRESH_BINARY_INV = 1
# THRESH_TRUNC = 2
# THRESH_TOZERO = 3
# THRESH_TOZERO_INV = 4
#
src = cv.imread("D:/images/lena.jpg")
cv.namedWindow("input", cv.WINDOW_AUTOSIZE)
cv.imshow("input", src)
h, w = src.shape[:2]

# 自动阈值分割 OTSU
gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
ret, binary = cv.threshold(gray, 0, 255, cv.THRESH_BINARY | cv.THRESH_OTSU)
print("ret :", ret)
cv.imshow("binary", binary)

result = np.zeros([h, w*2, 3], dtype=src.dtype)
result[0:h,0:w,:] = src
result[0:h,w:2*w,:] = cv.cvtColor(binary, cv.COLOR_GRAY2BGR)
cv.putText(result, "input", (10, 30), cv.FONT_ITALIC, 1.0, (0, 0, 255), 2)
cv.putText(result, "binary, threshold = " + str(ret), (w+10, 30), cv.FONT_ITALIC, 1.0, (0, 0, 255), 2)
cv.imshow("result", result)
cv.imwrite("D:/binary_result.png", result)

cv.waitKey(0)
cv.destroyAllWindows()