Getting the key (filename) of lmdb data from input layer

[tkra...@gmail.com]

I want to use the Amulet net (saliency prediction) with a lmdb database as input. Amulet outputs the saliency prediction as an image which I want to save under the same file name as the input image. Therefore, I want to know the key of the actually used input image from lmdb. What is the easiest way to get this key? Well, of course I can read in the lmdb separatly and iterate the keys during testing but I hope there is an easier way to do this.