I have a stack of RGB images in a 4d numpy array, so the shape is (n_images, height, width, n_channels) where n_channels is 3. How can I get a list of unique RGB values across all the images.
I found this question numpy: unique list of colors in the image for a single image but want to apply it to my stack of images without a for-loop.
You can use np.unique and set the axis, to look across the images. so basically it will look for unique pixel values.
i am reusing the answer from link you shared for your scenario.
np.unique(img.reshape(-1, img.shape[3]), axis=0)
The above code will result in an array of shape (unique_pixels_len,3)
The original answer had img.shape[2] i.e. the channels and in your case it is img.shape[3] which represents the channels.
