How to convert multiple RGB images in one folder to grayscale in python

Question

Someone could help me please, I want to convert my RGB images in one folder to grayscale at one time. I've been looking for some Python codes but haven't found any. I tried to do as following but it didn't work.

Here is my code:

from skimage.color import rgb2gray
from skimage.io import imread, imsave
from skimage.filters import threshold_otsu
from skimage import img_as_uint

inp_image = imread("C:/RGB/*.JPG")
img_gray = rgb2gray(inp_image)

thresh = threshold_otsu(img_gray)
binary_thresh_img = img_gray & gt; thresh

imsave("C:/Grayscale", img_as_uint(binary_thresh_img))

And it gave me following error:

OSError: [Errno 22] Invalid argument: 'C:/RGB/*.JPG'

Answer 1

You can get the list with the filenames with glob() .

import glob
for filename in glob.glob("C:/RGB/*.JPG"):
    inp_image = imread(filename)
    [...]

Answer 2

To add to the list of solutions:

import os
from PIL import Image

ORIGIN_PATH = "./folder1/"
DESTIN_PATH = "./folder2/"

for filename in os.listdir(ORIGIN_PATH):                                                                                                                                                                
    img = Image.open(ORIGIN_PATH + filename).convert("LA")                                                                                                                                                
    img.save(DESTIN_PATH + filename)