CODEWITHSUNDEEP
pythonrgbgrayscale
Andrea Russett
Andrea Russett

Reputation: 91

Python Fastest way to check if image is greyscale or color?

I want to check if an image is greyscale or color using Python. I know we can read in the image and check easily, however, I am wondering if there is a way to check without reading the full image?

I have around 200 million images (200x200), so reading in each image is not feasible in terms of runtime.

Thanks

Upvotes: 2

Views: 4486

Answers (1)

AzyCrw4282
AzyCrw4282

Reputation: 7744

Though I can't say for sure this would be the most efficient, I am certain that it would perform better than most operations.

So consider using ImageStat module.

from PIL import Image, ImageStat

def is_grayscale(path="image.jpg")
    im = Image.open(path).convert("RGB")
    stat = ImageStat.Stat(im)
    if sum(stat.sum)/3 == stat.sum[0]: #check the avg with any element value
        return True #if grayscale
    else:
        return False #else its colour

stat.sum gives us a sum of all pixels in list view = [R, G, B] for example [568283302.0, 565746890.0, 559724236.0]. For grayscale image all elements of list are equal.

Upvotes: 4

Related Questions