/knowledge-distillation-keras

A machine learning experiment

Primary LanguageJupyter Notebook

Knowledge distillation with Keras

Keras implementation of Hinton's knowledge distillation (KD), a way of transferring knowledge from a large model into a smaller model.

Summary

  • I use Caltech-256 dataset for a demonstration of the technique.
  • I transfer knowledge from Xception to MobileNet-0.25 and SqueezeNet v1.1.
  • Results:
model accuracy, % top 5 accuracy, % logloss
Xception 82.3 94.7 0.705
MobileNet-0.25 64.6 85.9 1.455
MobileNet-0.25 with KD 66.2 86.7 1.464
SqueezeNet v1.1 67.2 86.5 1.555
SqueezeNet v1.1 with KD 68.9 87.4 1.297

Implementation details

  • I use pretrained on ImageNet models.
  • For validation I use 20 images from each category.
  • For training I use 100 images from each category.
  • I use random crops and color augmentation to balance the dataset.
  • I resize all images to 299x299.
  • In all models I train the last two layers.

Notes on flow_from_directory

I use three slightly different versions of Keras' ImageDataGenerator.flow_from_directory:

  • original version for initial training of Xception and MobileNet.
  • ver1 for getting logits from Xception. Now DirectoryIterator.next also outputs image names.
  • ver2 for knowledge transfer. Here DirectoryIterator.next packs logits with hard true targets. All three versions only differ in DirectoryIterator.next function.

Requirements

  • Python 3.5
  • Keras 2.0.6
  • torchvision, Pillow
  • numpy, pandas, tqdm

References

[1] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, Distilling the Knowledge in a Neural Network