opencv轮廓检测（Python）

import cv2 import numpy as np #实现图像堆叠 def stackImages(scale,imgArray): rows = len(imgArray) cols = len(imgArray[0]) rowsAvailable = isinstance(imgArray[0], list) width = imgArray[0][0].shape[1] height = imgArray[0][0].shape[0] if rowsAvailable: for x in range ( 0, rows): for y in range(0, cols): if imgArray[x][y].shape[:2] == imgArray[0][0].shape [:2]: imgArray[x][y] = cv2.resize(imgArray[x][y], (0, 0), None, scale, scale) else: imgArray[x][y] = cv2.resize(imgArray[x][y], (imgArray[0][0].shape[1], imgArray[0][0].shape[0]), None, scale, scale) if len(imgArray[x][y].shape) == 2: imgArray[x][y]= cv2.cvtColor( imgArray[x][y], cv2.COLOR_GRAY2BGR) imageBlank = np.zeros((height, width, 3), np.uint8) hor = [imageBlank]*rows hor_con = [imageBlank]*rows for x in range(0, rows): hor[x] = np.hstack(imgArray[x]) ver = np.vstack(hor) else: for x in range(0, rows): if imgArray[x].shape[:2] == imgArray[0].shape[:2]: imgArray[x] = cv2.resize(imgArray[x], (0, 0), None, scale, scale) else: imgArray[x] = cv2.resize(imgArray[x], (imgArray[0].shape[1], imgArray[0].shape[0]), None,scale, scale) if len(imgArray[x].shape) == 2: imgArray[x] = cv2.cvtColor(imgArray[x], cv2.COLOR_GRAY2BGR) hor= np.hstack(imgArray) ver = hor return ver #轮廓检测 def getContours(img): # “CV_RETR_EXTERNAL”，method取值“CV_CHAIN_APPROX_NONE”，即只检测最外层轮廓，并且保存轮廓上所有点 contours,hierarchy = cv2.findContours(img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_NONE) for cnt in contours: #计算面积 area = cv2.contourArea(cnt) print(area) if area>500: #画轮廓 cv2.drawContours(imgContour, cnt, -1, (255, 0, 0), 3) # 计算轮廓的周长 peri = cv2.arcLength(cnt,True) #print(peri) #把一个连续光滑曲线折线化 approx = cv2.approxPolyDP(cnt,0.02*peri,True) print(len(approx)) objCor = len(approx) #画外接矩形，x，y是矩阵左上点的坐标，w，h是矩阵的宽和高 x, y, w, h = cv2.boundingRect(approx) if objCor ==3: objectType ="Tri" elif objCor == 4: aspRatio = w/float(h) if aspRatio >0.98 and aspRatio <1.03: objectType= "Square" else:objectType="Rectangle" elif objCor>4: objectType= "Circles" else:objectType="None" cv2.rectangle(imgContour,(x,y),(x+w,y+h),(0,255,0),2) cv2.putText(imgContour,objectType, (x+(w//2)-10,y+(h//2)-10),cv2.FONT_HERSHEY_COMPLEX,0.7, (0,0,0),2) path = 'Resources/shapes.png' img = cv2.imread(path) imgContour = img.copy() imgGray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY) imgBlur = cv2.GaussianBlur(imgGray,(7,7),1) imgCanny = cv2.Canny(imgBlur,50,50) getContours(imgCanny) imgBlank = np.zeros_like(img) imgStack = stackImages(0.8,([img,imgGray,imgContour])) cv2.imshow("Stack", imgStack) cv2.waitKey(0)

效果图： 一步步注释下来，感觉还是挺好懂的。