[转]opencv+python对图像中对象的中点进行检测

# -*- coding: utf-8 -*-
"""
Created on Thu Nov 30 12:11:24 2017

@author: zzz
"""
#import necessary packages

import imutils
import cv2

#load the image,convert it to grayscale,blur it slightly
# and threshold it
image = cv2.imread('shapes_and_colors.png')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)#grayscale conversion
blurred = cv2.GaussianBlur(gray, (5, 5), 0)#Gaussian smoothing using a 5 x 5 kernel
thresh = cv2.threshold(blurred, 60, 255, cv2.THRESH_BINARY)[1]#thresholding

#find contours in the thresholded image
cnts = cv2.findContours(thresh.copy(),cv2.RETR_EXTERNAL,
                        cv2.CHAIN_APPROX_SIMPLE)
#return the set of outlines
cnts = cnts[0] if imutils.is_cv2() else cnts[1]
#grap appropriate tuple value
#loop over the contours 
for c in cnts:
    #compute the center of the contour
    M = cv2.moments(c)
    cX=int(M["m10"]/M["m00"])
    cY=int(M["m01"]/M["m00"])
    
    #draw the contour and center of the shape on the image
    cv2.drawContours(image,[c],-1,(0,255,0),2)
    cv2.circle(image,(cX,cY),7,(255,255,255),-1)
    cv2.putText(image,"center",(cX - 20 ,cY - 20),
                cv2.FONT_HERSHEY_SIMPLEX,0.5,(255,255,255),2)
    
    #show the image
    cv2.imshow("Image",image)
    k=cv2.waitKey(0)
    if k == 27:
        cv2.destroyAllWindows()
    elif k ==ord('s'):
        cv2.imwrite('ahh.png',image)
        cv2.destroyAllWindows()

原文链接：https://www.pyimagesearch.com/2016/02/01/opencv-center-of-contour/

给定一张图片，要检测轮廓的中心。

 

首先，要对其进行预处理。包括

grayscale conversion
Gaussian smoothing
thresholding等等。

然后调用函数cv2.findcontours，找到这些图形的轮廓并返回一个轮廓集cnts。

M = cv2.moments(c)
    cX=int(M["m10"]/M["m00"])
    cY=int(M["m01"]/M["m00"])

遍历这些轮廓并计算出他们的中心位置。

然后在原图上面画出轮廓，得到的图是这样的，