simbaforrest's profile - activity

Thanks for the comment. I understand that. But I thought that cv2.imread(...,0) is loading it to color and then convert to gray. But the results are different. So This doesn't seem to be related to jpeg...

Did anyone notice that if you load a color image directly as gray scale, the resulting image is slightly different than loading it to a color image and then cvtColor to grayscale? Anyone know why?

img1=cv2.imread("imge.jpg", 0)
img2=cv2.imread("imge.jpg", 1)
img2=cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)
print np.max(img1!=img2)
# True
print np.max(img1.astype('float32')-img2.astype('float32'))
# 2.0

BTW, this happens under both Linux and Windows (either c++ or python).

I met with similar problem under ubuntu 12.04+opencv 2.4.3. After sucessfully compiling opencv, I tried "./video_homography 0" with my webcam and the video frame did not show after a few seconds and the program runs very slowly and after a while it will freeze. I have no idea why.