如何使用Python OpenCV提取物体轮廓详解

import cv2
 
img = cv2.imread("mouse.png")
cv2.imshow("origin",img)
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
ret,binary = cv2.threshold(gray,128,255,cv2.THRESH_BINARY)
cv2.imshow("binary",binary)
 
contours, hierarchy = cv2.findContours(binary,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
cv2.drawContours(img,contours,-1,(0,0,255),3)
cv2.imshow("result", img)
cv2.waitKey(0)

blured = cv2.blur(img,(5,5))
cv2.imshow("blur",blured)

mask = np.zeros((h+2, w+2), np.uint8)       #掩码长和宽都比输入图像多两个像素点，泛洪填充不会超出掩码的非零边缘  
#进行泛洪填充
cv2.floodFill(blured, mask, (10,10), (255,255,255), (2,2,2),(3,3,3),8)
cv2.imshow("floodfill", blured)

 gray = cv2.cvtColor(blured,cv2.COLOR_BGR2GRAY)  
 cv2.imshow("gray", gray)  

 #定义结构元素  
 kernel = cv2.getStructuringElement(cv2.MORPH_RECT,(50, 50))
 #开闭运算，先开运算去除背景噪声，再继续闭运算填充目标内的孔洞
 opened = cv2.morphologyEx(gray, cv2.MORPH_OPEN, kernel)  
 closed = cv2.morphologyEx(opened, cv2.MORPH_CLOSE, kernel)  
 cv2.imshow("closed", closed) 

 #找到轮廓
 _,contours, hierarchy = cv2.findContours(binary,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)  
 #绘制轮廓
 cv2.drawContours(img,contours,-1,(0,0,255),3)  
 #绘制结果
 cv2.imshow("result", img)

#coding=utf-8
import cv2
import numpy as np
 
img = cv2.imread("temp.jpg")                #载入图像
h, w = img.shape[:2]                        #获取图像的高和宽
cv2.imshow("Origin", img)                   #显示原始图像
 
blured = cv2.blur(img,(5,5))                #进行滤波去掉噪声
cv2.imshow("Blur", blured)                  #显示低通滤波后的图像
 
mask = np.zeros((h+2, w+2), np.uint8)       #掩码长和宽都比输入图像多两个像素点，满水填充不会超出掩码的非零边缘
#进行泛洪填充
cv2.floodFill(blured, mask, (w-1,h-1), (255,255,255), (2,2,2),(3,3,3),8)
cv2.imshow("floodfill", blured)
 
#得到灰度图
gray = cv2.cvtColor(blured,cv2.COLOR_BGR2GRAY)
cv2.imshow("gray", gray)
 
 
#定义结构元素
kernel = cv2.getStructuringElement(cv2.MORPH_RECT,(50, 50))
#开闭运算，先开运算去除背景噪声，再继续闭运算填充目标内的孔洞
opened = cv2.morphologyEx(gray, cv2.MORPH_OPEN, kernel)
closed = cv2.morphologyEx(opened, cv2.MORPH_CLOSE, kernel)
cv2.imshow("closed", closed)
 
#求二值图
ret, binary = cv2.threshold(closed,250,255,cv2.THRESH_BINARY)
cv2.imshow("binary", binary)
 
#找到轮廓
_,contours, hierarchy = cv2.findContours(binary,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
#绘制轮廓
 
cv2.drawContours(img,contours,-1,(0,0,255),3)
#绘制结果
cv2.imshow("result", img)
 
cv2.waitKey(0)
cv2.destroyAllWindows()