How can I find Imagenet data labels?

Question

I have two questions about how to load Imagenet datas. I downloaded ILSVRC2012 validation sets(Cause training sets are too large) but I have two problems.

1. I can't understand how can I find out the labels. There are only jpeg files with file names like "ILSVRC2012_val_00000001.JPEG" but there's no labels. How can I find them?

2. As far as I know, Imagenet uses 224 * 224 pixel image and the problem is just "classification" not "detection", but ILSVRC2012 sets have much more and different pixel sizes. So, how can I get proper boxes for 224 * 224 pixels?

Answer 1

1. You will download three tar archives: one for training data, one for validation data, and one for test data.

   Training data is contained in 1000 folders, one folder per class (each folder should contain 1,300 JPEG images). Validation data is a single folder with 50k JPEG images, look for the corresponding ILSVRC2012_validation_ground_truth.txt file in (as darren1231 mentioned, it needs to be downloaded separately as part of DevKit).

Test data is similar to validation data, but it does not have labels (labels are not provided to you because you need to submit your predicted labels to them, as part of the competition).

2. ImageNet images have variable resolution, 482x415 on average, and it's up to you how you want to process them to train your model. Most people process it as following: First downsize each image so that its shorter side is 256 pixels. Then crop a random 224x224 patch. Use those patches for training (you will get different crops each epoch). During test, do the same, but extract a center 224x224 patch, and use that for evaluating classification accuracy. Some people also use multiple patches for testing. Again, it's up to you, and you can use higher resolution if you like.