用霍夫变换原理检测圆 python

霍夫变换是一种常见的图像处理方法，可以用于检测圆。在 Python 中，可以使用 OpenCV 库来实现霍夫变换检测圆。

以下是实现步骤：

1. 导入 OpenCV 库和 numpy 库

import cv2
import numpy as np

2. 读取图像并转换为灰度图像

img = cv2.imread('image.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

3. 进行边缘检测

edges = cv2.Canny(gray, 50, 150, apertureSize=3)

4. 进行霍夫变换检测圆

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

5. 绘制检测到的圆

if circles is not None:
    circles = np.uint16(np.around(circles))
    for i in circles[0, :]:
        # 绘制圆心
        cv2.circle(img, (i[0], i[1]), 2, (0, 0, 255), 3)
        # 绘制圆
        cv2.circle(img, (i[0], i[1]), i[2], (0, 255, 0), 2)

完整代码如下：

import cv2
import numpy as np

img = cv2.imread('image.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
edges = cv2.Canny(gray, 50, 150, apertureSize=3)
circles = cv2.HoughCircles(edges, cv2.HOUGH_GRADIENT, dp=1, minDist=20, param1=50, param2=30, minRadius=0, maxRadius=0)

if circles is not None:
    circles = np.uint16(np.around(circles))
    for i in circles[0, :]:
        # 绘制圆心
        cv2.circle(img, (i[0], i[1]), 2, (0, 0, 255), 3)
        # 绘制圆
        cv2.circle(img, (i[0], i[1]), i[2], (0, 255, 0), 2)

cv2.imshow('image', img)
cv2.waitKey(0)
cv2.destroyAllWindows()