如何获取图像中的边框像素或擦除区域答案

【问题标题】：How to get the border pixels or erased area in an image如何获取图像中的边框像素或擦除区域
【发布时间】：2020-11-07 19:36:29
【问题描述】：

想象一下，我有以下带有擦除区域的图像，现在我想知道该区域的边框像素，如何在 Python 中实现？ The image with one area being erased

【问题讨论】：

标签： python image image-processing computer-vision

【解决方案1】：

emmm我就直接把代码不跑了，以后你自己试试吧。

import numpy as np
import cv2 as cv
im = cv.imread('you_input_image.jpg')
imgray = cv.cvtColor(im, cv.COLOR_BGR2GRAY)
# assume the while area 255.255.255 are what you put manually and you want it removed. 
ret, thresh = cv.threshold(imgray, 254, 255, 0)
contours, hierarchy = cv.findContours(thresh, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
# There might be multiple are with 255. then you need to find the index of the largest contour
areas = [cv2.contourArea(c) for c in contours]
max_index = np.argmax(areas)
cnt=contours[max_index]
print cnt
# cnt contains all the point in this largest contour

【讨论】：

【解决方案2】：

您可以使用 opencv 来执行此操作。主要使用的函数是cv2.findContours

在下面用红色画出边框。

import cv2
import numpy as np
from skimage.color import rgb2gray
import matplotlib.pyplot as plt

im = plt.imread('uKTss.jpg')
gray = rgb2gray(im)

contours = cv2.findContours(gray.astype(np.uint8),cv2.RETR_TREE,cv2.CHAIN_APPROX_NONE)[-2]

for contour in contours:  
    cv2.drawContours(im, contour, -1, (255, 0, 0), 1)

plt.imshow(im)
plt.show()

【讨论】：