1.二值图像
- 灰度图像 0 - 255
- 二值图像 0（黑） / 255（白）
2.二值分割
五种阈值分割方法（阈值T）：
- 大于T为255，小于T为0
- 大于T为0，小于T为255
- 小于T为原值 else T
- 小于T为0 else 原值
- 大于T为0 else 原值
QString appPath = QCoreApplication::applicationDirPath(); QString imagePath = appPath + "/A.jpg"; Mat img = cv::imread(imagePath.toStdString()); if (img.empty()) { return; } namedWindow("input", WINDOW_AUTOSIZE); imshow("input", img); //To gray image Mat gray,binary; cvtColor(img, gray, COLOR_BGR2GRAY); imshow("gray", gray); //二值化 threshold(gray, binary, 127, 255, THRESH_BINARY); imshow("THRESH_BINARY", binary); threshold(gray, binary, 127, 255, THRESH_BINARY_INV); imshow("THRESH_BINARY_INV", binary); //阈值化 threshold(gray, binary, 127, 255, THRESH_TRUNC); imshow("THRESH_TRUNC", binary); threshold(gray, binary, 127, 255, THRESH_TOZERO); imshow("THRESH_TOZERO", binary); threshold(gray, binary, 127, 255, THRESH_TOZERO_INV); imshow("THRESH_TOZERO_INV", binary); waitKey(); destroyAllWindows();
3.阈值
（1）全局阈值
Scalar m = mean(gray); threshold(gray, binary, m[0], 255, THRESH_BINARY); imshow("THRESH_BINARY", binary); //OTSU double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU); imshow("THRESH_BINARY_OTSU", binary); //三角法:X光片等 double m_triangle = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_TRIANGLE); imshow("THRESH_BINARY_TRIANGLE", binary);
（2）自适应阈值
//均值c adaptiveThreshold(gray, binary, 255, ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, 25,10); imshow("ADAPTIVE_THRESH_MEAN_C", binary); //高斯c adaptiveThreshold(gray, binary, 255, ADAPTIVE_THRESH_GAUSSIAN_C, THRESH_BINARY, 25, 10); imshow("ADAPTIVE_THRESH_GAUSSIAN_C", binary);
