1. RGB值

RGB即使用红色（R）、绿色（G）、蓝色（B）作为三元色，以三者不同比例的混合产生不同颜色。

dic = {0:'牡丹粉', 1:'苋菜红', 2:'鼠背灰', 3:'卵石紫', 4:'钢青', 5:'竹绿', 6:'油菜花黄'}
img_all = [[[0 for i in range(3)]for j in range(7)]for k in range(1)]
for i in range(1, 7):
    path = str(i) + '.png'
    img = cv2.imread(path)
    b= img[0][0][0]
    g= img[0][0][1]
    r= img[0][0][2]
    print(f'{dic[i-1]}:\t[r,g,b]:[{r},{g},{b}]') 

结果：

牡丹粉:	[r,g,b]:[164,27,41]	
苋菜红:	[r,g,b]:[113,85,90]	
鼠背灰:	[r,g,b]:[47,22,28]	
卵石紫:	[r,g,b]:[20,34,51]	
钢青:	[r,g,b]:[27,166,131]	
竹绿:	[r,g,b]:[247,215,64]	

代码中之所以并非以RGB的顺序读取，是因为cv2的文档中指出虽然cv2读取的格式是“RGB”但是是以BGR的顺序读取

输出图像验证：

dic = {0:'牡丹粉', 1:'苋菜红', 2:'鼠背灰', 3:'卵石紫', 4:'钢青', 5:'竹绿', 6:'油菜花黄'}
img_all = [[[0 for i in range(3)]for j in range(7)]for k in range(1)]
for i in range(1, 7):
    path = str(i) + '.png'
    img = cv2.imread(path)
    b= img[0][0][0]
    g= img[0][0][1]
    r= img[0][0][2]
    img_all[0][i-1][0] = r
    img_all[0][i-1][1] = g
    img_all[0][i-1][2] = b
    print(f'{dic[i-1]}:\t[r,g,b]:[{r},{g},{b}]') 
plt.imshow(img_all)

原始图像：

        

        

        

 

 输出图像：

 

 2. RGB --> HSI

用色调（H）、色饱和度（S）、亮度描述色彩（I）。HSI色彩空间可以用一个圆锥空间模型来描述。通常把色调和饱和度通称为色度，用来表示颜色的类别与深浅程度。

转换公式：

转换代码：

def Rgb2Hsi(r, g, b):
    r /= 255
    g /= 255
    b /= 255
    eps = 1e-8
    h, s, i = 0, 0, 0
    sum_rgb = r + g + b
    min_rgb = min(r, g, b)
    s = 1 - 3  * min_rgb / (sum_rgb + eps)
    h = np.arccos((0.5 * (r + r - g - b)) / (((r - g) ** 2 + (r - b) * (g - b) + eps)) ** 0.5)
    if b > g:
        h = 2 * np.pi - h
    h = h / (2 * np.pi)
    if s == 0:
        h = 0
    i = sum_rgb / 3
    return round(h, 2), round(s, 2), round(i, 2)


dic = {0:'牡丹粉', 1:'苋菜红', 2:'鼠背灰', 3:'卵石紫', 4:'钢青', 5:'竹绿', 6:'油菜花黄'}
for i in range(7):
    path = str(i) + '.png'
    img = cv2.imread(path)
    b= img[0][0][0]
    g= img[0][0][1]
    r= img[0][0][2]
    H, S, I = Rgb2Hsi(r, g, b)
    print(f'{dic[i]}:\t[r,g,b]:[{r},{g},{b}]\t[h,s,i]:[{H},{S},{I}]') 

 结果：

牡丹粉:	[r,g,b]:[234,159,161]	[h,s,i]:[1.0,0.14,0.72]
苋菜红:	[r,g,b]:[164,27,41]	    [h,s,i]:[0.99,0.65,0.3]
鼠背灰:	[r,g,b]:[113,85,90]	    [h,s,i]:[0.97,0.11,0.38]
卵石紫:	[r,g,b]:[47,22,28]	    [h,s,i]:[0.96,0.32,0.13]
钢青:	[r,g,b]:[20,34,51]	    [h,s,i]:[0.59,0.43,0.14]
竹绿:	[r,g,b]:[27,166,131]	[h,s,i]:[0.46,0.75,0.42]
油菜花黄:[r,g,b]:[247,215,64]	[h,s,i]:[0.14,0.63,0.69]