Question

我有一个图像，我要在其中提取一个圆的感兴趣区域然后裁剪。
我已经做了一些预处理，我正在共享结果和代码。
请让我知道我如何实现这一目标。

import imutils
import cv2
import numpy as np

#edge detection
image = cv2.imread('newimage.jpg')
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
image = cv2.GaussianBlur(image, (5, 5), 0)
canny = cv2.Canny(image, 30, 150)

#circle detection
img = cv2.medianBlur(image,5)
cimg = cv2.cvtColor(img,cv2.COLOR_GRAY2BGR)

circles = cv2.HoughCircles(canny,cv2.HOUGH_GRADIENT,1,20,
                            param1=50,param2=30,minRadius=0,maxRadius=0)

circles = np.uint16(np.around(circles))
for i in circles[0,:]:
    #outer circle
    cv2.circle(cimg,(i[0],i[1]),i[2],(0,255,0),2)
    #center of the circle
    cv2.circle(cimg,(i[0],i[1]),2,(0,0,255),3)

plt.title('Circle Detected')
plt.xticks([])
plt.yticks([])    
plt.imshow(cimg,cmap = 'gray')
plt.show()

Answer 1

在您的示例中，您应该获得最大半径为i[2]

的圆

max_circle = max(circles[0,:], key=lambda x:x[2])

print(max_circle)

i = max_circle
#outer circle
cv2.circle(cimg,(i[0],i[1]),i[2],(0,255,0),2)
#center of the circle
cv2.circle(cimg,(i[0],i[1]),2,(0,0,255),3)

Answer 2

检查一下，主要提示：

玩弄模糊的参数；
玩HoughCircles参数：minSize，maxSize和minDist （圆圈之间的最小距离）

img = cv2.imread('newimage.jpg', cv2.IMREAD_COLOR)

# Convert to grayscale and blur
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
gray_blurred = cv2.bilateralFilter(gray, 11, 30, 30)

# tune circles size
detected_circles = cv2.HoughCircles(gray_blurred,
                                    cv2.HOUGH_GRADIENT, 1,
                                    param1=50,
                                    param2=30,
                                    minDist=100,
                                    minRadius=50,
                                    maxRadius=70)

if detected_circles is not None:
    # Convert the circle parameters a, b and r to integers.
    detected_circles = np.uint16(np.around(detected_circles))

    for pt in detected_circles[0, :]:
        a, b, r = pt[0], pt[1], pt[2]

        # Draw the circumference of the circle.
        cv2.circle(img, (a, b), r, (0, 255, 0), 2)

        # Draw a small circle (of radius 1) to show the center.
        cv2.circle(img, (a, b), 1, (0, 0, 255), 3)

cv2.imshow("Detected circles", img)
cv2.waitKey(0)

小圆圈值：

minRadius=50
maxRadius=60

大圆圈值：

minRadius=100
maxRadius=200

从图像中检测圆并裁剪检测到的ROI python

2 个答案: