Read image grayscale opencv 3.0.0-dev

Question

I am trying to read images directly as black and white.

I recently updated my OpenCv version to 3.0.0-dev, and the code that I used before does not work anymore.

   img = cv2.imread(f, cv2.CV_LOAD_IMAGE_GRAYSCALE)

works fine for 2.4 but does not work for the new version, as there is no field CV_LOAD_IMAGE_GRAYSCALE.

Any suggestions?

Note: I know that cv2.imread(f,0) will work, but I do not like having unnamed constants in my code. Thanks!

Answer 1

The flag has been renamed to cv2.IMREAD_GRAYSCALE. Generally speaking, flags now have names prefixed in a manner that relates to the function to which they refer. (e.g. imread flags start with IMREAD_, cvtColor flags start with COLOR_, etc.)

Answer 2

Try this it works for me

import cv2
im_gray = cv2.imread('gray_image.png', cv2.IMREAD_GRAYSCALE)
thresh = 127
im_bw = cv2.threshold(im_gray, thresh, 255, cv2.THRESH_BINARY)[1]
cv2.imwrite('blackwhite.png', im_bw)

Answer 3

Try this, it works for me everytime

import cv2
gray_img = cv2.imread('img.png', 0)
cv2.imshow(gray_img)