OpenCV中threshold函数的使用

转自：https://blog.csdn.net/u012566751/article/details/77046445

一篇很好的介绍threshold文章；

图像的二值化就是将图像上的像素点的灰度值设置为0或255，这样将使整个图像呈现出明显的黑白效果。在数字图像处理中，二值图像占有非常重要的地位，图像的二值化使图像中数据量大为减少，从而能凸显出目标的轮廓。OpenCV中提供了函数cv::threshold();

注意:作者采用OpenCV 3.0.0

函数原型

参数说明

src：源图像，可以为8位的灰度图，也可以为32位的彩色图像。（两者由区别）

dst：输出图像

thresh：阈值

maxval：dst图像中最大值

type：阈值类型，可以具体类型如下：

具体如下表

生成关系如下表

测试代码

Mat gray;

cvtColor(src, gray, CV_BGR2GRAY);

// 全局二值化

int th = 100;

cv::Mat threshold1,threshold2,threshold3,threshold4,threshold5,threshold6,threshold7,threshold8;

cv::threshold(gray, threshold1, th, 255, THRESH_BINARY);

cv::threshold(gray, threshold2, th, 255, THRESH_BINARY_INV);

cv::threshold(gray, threshold3, th, 255, THRESH_TRUNC);

cv::threshold(gray, threshold4, th, 255, THRESH_TOZERO);

cv::threshold(gray, threshold5, th, 255, THRESH_TOZERO_INV);

//cv::threshold(gray, threshold6, th, 255, THRESH_MASK);

cv::threshold(gray, threshold7, th, 255, THRESH_OTSU);

cv::threshold(gray, threshold8, th, 255, THRESH_TRIANGLE);

cv::imshow("THRESH_BINARY", threshold1);

cv::imshow("THRESH_BINARY_INV", threshold2);

cv::imshow("THRESH_TRUNC", threshold3);

cv::imshow("THRESH_TOZERO", threshold4);

cv::imshow("THRESH_TOZERO_INV", threshold5);

//cv::imshow("THRESH_MASK", threshold6);

cv::imshow("THRESH_OTSU", threshold7);

cv::imshow("THRESH_TRIANGLE", threshold8);

cv::waitKey(0);

巴特西