标签：color block trunc val 部分 container target set truncate
cv2.threshold介绍，如下图所示，每个数字代表起本身的灰度值大小
cv2.threshod接收５种类参数形式，分别是cv2.THRESH_BINARY，cv2.THRESH_BINARY_INV，cv2.THRESH_TRUNC ，cv2.THRESH_TOZERO,cv2.THRESH_TOZERO_INV
(1)THRESH_BINARY(Binary Thresholding)
# Binary Threshold,原图像素＞阈值，该像素点的值保持不变，否则为０．即大于阈值的部分变成像素最大值，小于阈值的部分变为０ if src(x,y) > thresh dst(x,y) = maxValue else dst(x,y) = 0
(2)THRESH_BINARY_INV(Inverse Binary Thresholding)
# Inverse Binary Threshold，原图像素＜阈值，该像素点的值为０，否则保持不变．与（１）相反，大于阈值的部分变为０，小于阈值的部分变成像素最大值 if src(x,y) > thresh dst(x,y) = 0 else dst(x,y) = maxValue
(3)THRESH_TRUNC(Truncate Thresholding)
# Truncate Threshold，原图像素＞阈值，该像素点的值等于阈值，否则保持不变．即，将所有像素变成阈值以下水平 if src(x,y) > thresh dst(x,y) = thresh else dst(x,y) = src(x,y)
(4)THRESH_TOZERO(Threshold to Zero)
# Threshold to Zero if src(x,y) > thresh dst(x,y) = src(x,y) else dst(x,y) = 0
(5)THRESH_TOZERO_INV(Inverted Threshold to Zero)
# Inverted Threshold to Zero if src(x,y) > thresh dst(x,y) = 0 else dst(x,y) = src(x,y)
以上图为例，python代码为：
‘‘‘ OpenCV Threshold Example Copyright 2015 by Satya Mallick <spmallick@gmail.com> ‘‘‘ # import opencv import cv2 # Read image src = cv2.imread("threshold.png", cv2.IMREAD_GRAYSCALE); # Basic threhold example th, dst = cv2.threshold(src, 0, 255, cv2.THRESH_BINARY); cv2.imwrite("opencv-threshold-example.jpg", dst); # Thresholding with maxValue set to 128 th, dst = cv2.threshold(src, 0, 128, cv2.THRESH_BINARY); cv2.imwrite("opencv-thresh-binary-maxval.jpg", dst); # Thresholding with threshold value set 127 th, dst = cv2.threshold(src,127,255, cv2.THRESH_BINARY); cv2.imwrite("opencv-thresh-binary.jpg", dst); # Thresholding using THRESH_BINARY_INV th, dst = cv2.threshold(src,127,255, cv2.THRESH_BINARY_INV); cv2.imwrite("opencv-thresh-binary-inv.jpg", dst); # Thresholding using THRESH_TRUNC th, dst = cv2.threshold(src,127,255, cv2.THRESH_TRUNC); cv2.imwrite("opencv-thresh-trunc.jpg", dst); # Thresholding using THRESH_TOZERO th, dst = cv2.threshold(src,127,255, cv2.THRESH_TOZERO); cv2.imwrite("opencv-thresh-tozero.jpg", dst); # Thresholding using THRESH_TOZERO_INV th, dst = cv2.threshold(src,127,255, cv2.THRESH_TOZERO_INV); cv2.imwrite("opencv-thresh-to-zero-inv.jpg", dst);
结果图：
(1) (2) (3)
(4) (5)
参考连接：
http://www.learnopencv.com/opencv-threshold-python-cpp/
http://docs.opencv.org/trunk/d7/d4d/tutorial_py_thresholding.html
标签：color block trunc val 部分 container target set truncate
原文地址：http://www.cnblogs.com/qinxinboheliang/p/6821143.html
