Two questions on image denoising

[tyshiwo]

Hi,

I have two questions and hope you can give me some suggestions.

You mentioned "we follow [16] to use 400 images of size 180180 for training" in your paper. I know the 400 images come from the train and test sets of BSD dataset. The original images in BSD have larger size than 180180. I'm wondering how do you crop the 180*180 region in the original image? If it is possible, can you send me a copy? (I have also sent you an email ==!)

Another question is we usually extract patches as the input for the network from the images. So, how do you add the additive gaussian noise? Add on the image and then extract patches from the noisy image, or firstly extract patches from the clean image and then add the noise?

Thanks in advance!