opencv学习——计算掩模及目标远点

import cv2import numpy as npimg = cv2.imread('images/th.jpg')imgray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)ret,thresh = cv2.threshold(imgray,127,255,cv2.THRESH_BINARY_INV)#cv2.imwrite('thresh.jpg',thresh)_,contours,hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_NONE)#得到轮廓信息mask = np.zeros(imgray.shape, dtype=np.uint8)#第三个参数使用参数 -1, 绘制填充的轮廓,,cv2.drawContours(mask,contours,-1,255,-1)#0则绘制边界将轮廓所覆盖的地方全部画成白色pixelpoints = np.nonzero(mask)#存储的是非0的坐标pixelpoints1 = list(zip(pixelpoints[0],pixelpoints[1]))pixelpoints1 =np.array(pixelpoints1)cnt = np.reshape(pixelpoints1,(-1,1,2))#cnt = contoursmin_val, max_val, min_loc, max_loc = cv2.minMaxLoc(imgray,mask = mask)#计算像素最大最小值及其位置leftmost = np.array(cnt[cnt[:,:,0].argmin()][0])rightmost = np.array(cnt[cnt[:,:,0].argmax()][0])topmost =np.array(cnt[cnt[:,:,1].argmin()][0])bottommost = np.array(cnt[cnt[:,:,1].argmax()][0])point = np.array([leftmost,rightmost,topmost,bottommost])cv2.polylines(img,point.reshape(-1,1,2),True,(0,0,255),10 )cv2.imshow('lunkuo',mask)cv2.imshow('jizhidian',img)cv2.waitKey(0)cv2.destroyAllWindows()cv2.waitKey(0)cv2.waitKey(0)cv2.waitKey(0)cv2.waitKey(0)