python - 灰度图像到等温线轮廓

Question

我有灰度图像并想用等温线转换为强度轮廓，在我的代码中我只得到一个轮廓以及如何应用等温线？
目标:

import numpy as np
import cv2 as cv
img = cv2.imread(path)
imgray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
ret, thresh = cv.threshold(imgray, 127, 255, 0)
contours, hierarchy = cv.findContours(thresh, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)

cv.drawContours(img, contours, -1, (0,255,0), 3)

plt.imshow(img)

Answer 1

你在正确的轨道上，你所要做的就是接受 127你硬编码到代码中，并迭代几个不同的值。因此，拿起你所拥有的，添加一些东西(包括 viridis colormap 的插头):

import numpy as np
import cv2 

# I don't have your image, so I will just create a similar one.
H, W = 480, 640 
img = np.zeros([H, W, 3], dtype=np.uint8)
cv2.circle(img, (W//2, H//2), 200, (255,255,255), -1) 
img = cv2.GaussianBlur(img, (551, 551), 0)
imgray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

# The viridis colormap is better than the jet one you have used.
img_viridis = cv2.applyColorMap(imgray, cv2.COLORMAP_VIRIDIS)

# This for-loop allows you to draw isotherm lines at any value you want.
THRESHES = [30, 90, 170]
for val in THRESHES:
    ret, thresh = cv2.threshold(imgray, val, 255, 0)
    contours, hierarchy = cv2.findContours(thresh, cv2.RETR_TREE, 
                          cv2.CHAIN_APPROX_SIMPLE)
    cv2.drawContours(img_viridis, contours, -1, (0, 0, 255), 2)

cv2.imshow('img', img_viridis)
k = cv2.waitKey(0)

输出: