使用 Python 检测图像上的区域及其颜色

Question

I have an image of a 7 segment display. I want to keep track of the color of each segment . As a starting point, I have created a program where I detect the edges of the segments with the Canny edge detection of OpenCV. I also have obtained the location of these edges.

My problem is that I don't know how to detect those areas that are inside the edges and obtain their color. Here, I post my program code:

import cv2
from PIL import Image
import numpy as np
from matplotlib import pyplot as plt

def size(name):
    """ Print width and height and return value """
    img = Image.open(name)
    width, height = img.size
    total=width*height
    print('Width=%s, Height=%s, Total=%s pixels'%(width, height,total))
    return width, height

def canny_edge_detection(name,minval,maxval):
    """ Edge detection function """
    image=cv2.imread(name)
    canny=cv2.Canny(image, minval, maxval)
    arrayimage=Image.fromarray(canny)
    cannylist=canny.tolist()
    return cannylist, image, canny

def edge_coordinates(pixel_list,color):
    """ Obtain the coordinates of each pixel of the edges to a list(i,j) """
    edgelocationlist=[]
    for i in range(0,height):
        rowpixels=edgepixels[i]
        for j in range(len(rowpixels)):
            if rowpixels[j]==255:
                edgelocationlist.append((i, j))
    return edgelocationlist

def plot_original_edge(original_image, edge_image):
    """ Create a subplot of the original image and the image of the edges. """
    plt.subplot(121),plt.imshow(original_image,cmap = 'gray')
    plt.title('Original Image'), plt.xticks([]), plt.yticks([])
    plt.subplot(122),plt.imshow(edge_image,cmap = 'gray')
    plt.title('Edge Image'), plt.xticks([]), plt.yticks([])
    plt.show()

This is a link to a subplot that I have created with both images, the original one and the edge one: 7segments: original image and edges picture .

Answer 1

For each segment, you have a single contour. You can create a mask for one segment by drawing the corresponding contour (white, filled) on a black image. Finally, use cv2.mean, which accepts a mask parameter to get the mean RGB values within that mask, ie for that segment. If the color is the same for the whole segment, so the mean will be.