Question

我是opencv的新手并试图将RGB图像转换为LAB色彩空间。我正在使用下面的代码。

data_path = 'D:/Images/'
image_name= '1.png'
img = cv2.imread(os.path.join(data_path, image_name),cv2.IMREAD_COLOR) # Reads image from disk 
img = cv2.cvtColor(img, cv2.COLOR_BGR2LAB) # changes RGB to LAB color space

img = img [127.5, 1, 127.5]  # This i was trying to get a-channel only but gives error

现在我只想使用LAB Image的一个通道作为1通道输入提供给我的程序。如何仅使用LAB颜色空间图像的a通道？

Answer 1

我正在使用opencv2和python来解决这个问题

    import cv2
    input = cv2.imread('path_to_image.png')
    cv2.imshow('Hello World', input)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

    lab = cv2.cvtColor(input,cv2.COLOR_BGR2LAB)
    cv2.imshow("l*a*b",lab)

    L,A,B=cv2.split(lab)
    cv2.imshow("L_Channel",L) # For L Channel
    cv2.imshow("A_Channel",A) # For A Channel (Here's what You need)
    cv2.imshow("B_Channel",B) # For B Channel

    cv2.waitKey(0)
    cv2.destroyAllWindows()

希望这可以帮助您解决问题

Answer 2

我已用下面的代码行解决了我的问题

l_channel, a_channel, b_channel = cv2.split(img) #splits the image into 3 channles l, a and b

它将图像分成我想要的l，a和b通道。这很容易，但因为我是opencv的新手，所以我不知道。

Answer 3

这是在python中绘制实验室频道的方法。您可以在我用作参考的 this article 中找到更多详细信息。

    from keras.preprocessing.image import  img_to_array, load_img
    from skimage.color import rgb2lab, lab2rgb
    import matplotlib.pyplot as plt
    import numpy as np
    
    def extract_single_dim_from_LAB_convert_to_RGB(image,idim):
        '''
        image is a single lab image of shape (None,None,3)
        '''
        z = np.zeros(image.shape)
        if idim != 0 :
            z[:,:,0]=80 ## I need brightness to plot the image along 1st or 2nd axis
        z[:,:,idim] = image[:,:,idim]
        z = lab2rgb(z)
        return(z)
    
    def plot_lab_spectrums():
        # Get image
        img = img_to_array(load_img("<image_path>",target_size=(400,400)))
        lab = rgb2lab(img/255.0)
        lab_l = extract_single_dim_from_LAB_convert_to_RGB(lab,0)
        lab_a = extract_single_dim_from_LAB_convert_to_RGB(lab,1)
        lab_db = extract_single_dim_from_LAB_convert_to_RGB(lab,2)
    
        # Plot the results
        fig, axes = plt.subplots(ncols=3, figsize=(12, 4))
        data = [('L: lightness', lab_l), ('a: green-magenta channel', lab_a), ('b: blue-yellow channel', lab_db)]
    
        for ax, (title, img) in zip(axes, data):
            ax.set_title(title)
            ax.imshow(img)
            ax.axis('off')
    
        fig.tight_layout()
        plt.show()
    
    plot_lab_spectrums()

如何从python中的LAB（l * a * b）颜色空间获取a-channel

3 个答案: