How to implement the random lighting noise in datasets/transforms.lua?

[bryanyzhu]

Hi everybody, I was curious how to implement the random lighting noise(alexnet style) in datasets/transforms.lua. Specifically, how to get the pca eigenvalue and vectors for another dataset. like what is the dimension of the input matrix that lead to a 3X3 covariance matrix? Thanks. Any details would do.

[colesbury]

IIRC, you take a Tensor of size Nx3 and where N is all the pixels from a given channel (R/G/B) from lots of images.

Also, I found that this Alexnet style noise didn't seem to help.

[bryanyzhu]

@colesbury Thanks a lot, that's also the way I think, but I will still try to see if it helps.