algorithm - 我如何计算特征图中轻小簇的数量

Question

假设我有这样的热图:

热图上像素的值范围为0-1。值越接近 0，像素越暗。上面有六个写簇，如图所示。有什么方法可以让我知道热图中有多少个光团？

Answer 1

来源 => 检测

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我的方法是:Gray => Threshold => FindContours(必要时按面积过滤)

#!/usr/bin/python3
# 2019/03/01
import cv2

img = cv2.imread("featmap.png")

# Gray => Threshold => FindContours (filter by area if necessary)
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
blured = cv2.medianBlur(gray, 3)
th, threshed = cv2.threshold(blured, 100, 255, cv2.THRESH_OTSU|cv2.THRESH_BINARY)
cnts = cv2.findContours(threshed, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)[-2]

print("nums: {}".format(len(cnts)))

# draw on the original
cv2.drawContours(img, cnts, -1, (0, 255, 0), 1, cv2.LINE_AA)
cv2.imwrite("dst.png", img)

使用 findContours 时要小心:How to use `cv2.findContours` in different OpenCV versions?