分水岭算法是一种图像分割算法。它将图像分割为两个或多个连通区域。算法使用图像的梯度信息来确定图像中的“分水岭”。分水岭是指图像中的边界或轮廓。算法通过找到图像中的分水岭来将图像分割成不同的区域。
以下是分水岭算法Python 示例：
import cv2
import numpy as np
# Load the image
image = cv2.imread("image.jpg")
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
# Apply the thresholding to create a binary image
ret, thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV+cv2.THRESH_OTSU)
# Perform a distance transform
distance = cv2.distanceTransform(thresh, cv2.DIST_L2, 5)
ret, sure_fg = cv2.threshold(distance, 0.7*distance.max(), 255, 0)
# Perform the watershed algorithm
sure_fg = np.uint8(sure_fg)
unknown = cv2.subtract(thresh, sure_fg)
ret, markers = cv2.connectedComponents(sure_fg)
# Add one to all labels so that sure background is not 0, but 1
markers = markers+1
# Now, mark the region of unknown with zero
markers[unknown==255] = 0
markers = cv2.watershed(image, markers)
# Create the output image
image[markers == -1] = [255,0,0]
# Display the output image
cv2.imshow("Segmented Image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()
该代码首先加载图像，将其转换为灰度，应用阈值创建二值图像，执行距离变换，然后使用connectedComponents函数生成的标记应用分水岭算法。最后，它用蓝色的-1标记标记图像中的片段。
