opencv Python 图片颜色识别_colour-checker-detection-l-seg

https://data-flair.training/blogs/project-in-python-colour-detection/

想做颜色识别，于是找到了一个这样的教程。
发觉对于颜色的精确识别很困难，本文的方法是，找到鼠标敲击处的图片RGB值，在一定容差范围内与已知颜色表进行匹配，从而得到颜色名。

# -*- coding: utf-8 -*-
import argparse
import cv2
import numpy as np
import pandas as pd


"""directly give an image path from the command prompt"""
ap = argparse.ArgumentParser()
ap.add_argument('-i','--image',required=True,help='Image Path')
args = vars(ap.parse_args())
img_path = args['image']
"""reading image with opencv"""
img = cv2.imread(img_path)
"""declaring global variables (are used later on)"""
clicked = False
r = g = b = xpos = ypos = 0
"""reading csv file with pandas and giving names to each column"""
index = ['color','color_name','hex','R','G','B']
csv = pd.read_csv('colors.csv', names=index, header=None)


def draw_function(event, x, y, flags, parm):
    if event == cv2.EVENT_LBUTTONDBLCLK: #鼠标左击
        global b, g, r, xpos, ypos, clicked
        # global parameters, should be in the same file
        clicked = True
        xpos = x
        ypos = y
        b, g, r = img[y, x]
        b = int(b)
        g = int(g)
        r = int(r)


def getColorName(R, G, B):
    minimum = 10000
    for i in range(len(csv)):
        d = abs(R - int(csv.loc[i,"R"])) + abs(G - int(csv.loc[i,"G"])) \
            + abs(B - int(csv.loc[i,"B"]))
        if (d <= minimum):
            minimum = d
            cname = csv.loc[i, 'color_name']
    return cname


"""set a mouse callback event on a window"""
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_function) #鼠标事件响应

"""display image on the window"""
while(1):
    cv2.imshow('image', img)
    if (clicked):
        cv2.rectangle(img, (20, 20), (750, 60), (b,g,r), -1)
        """creating text string to display (color name and RGB valuse)"""
        text = getColorName(r, g, b) + "R=" + str(r) + "G=" + str(g) + "B=" + str(b)
        cv2.putText(img, text, (50,50), 2, 0.8, (255,255,255),2, cv2.LINE_AA)
        """For very light colours we will display text in black color"""
        if (r+g+b>=600):
            cv2.putText(img, text, (50,50), 2, 0.8, (0,0,0), cv2.LINE_AA)
        clicked = False
    if cv2.waitKey(20) & 0xFF == 27:
        break
cv2.destroyWindow()
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65

argparse.ArgumentParser() 用于添加参数
pandas 读取csv文件很方便

cv2一些函数：

cv2.rectangle(img, (bbox.left, bbox.top), (bbox.right, bbox.bottom), (0,0,255), 2)
1

靠确定对角线来画矩形。
各参数依次是：图片，左上角坐标，右下角坐标，填充颜色，线粗细（-1则为填充）

cv2.putText(img, str(i), (123,456)), font, 2, (0,255,0), 3)
1

各参数依次是：图片，添加的文字，左上角坐标，字体，字体大小，颜色，字体粗细