Object recognition using deep convolutional neural networks with complete transfer and partial frozen layers

Object recognition using deep convolutional neural networks with complete transfer and partial frozen layers

Kruithof, M.C.
Bouma, H.
Fischer, N.M.
Schutte, K.

2016

Object recognition is important to understand the content of video and allow flexible querying in a large number of cameras, especially for security applications. Recent benchmarks show that deep convolutional neural networks are excellent approaches for object recognition. This paper describes an approach of domain transfer, where features learned from a large annotated dataset are transferred to a target domain where less annotated examples are available as is typical for the security and defense domain. Many of these networks trained on natural images appear to learn features similar to Gabor filters and color blobs in the first layer. These first-layer features appear to be generic for many datasets and tasks while the last layer is specific. In this paper, we study the effect of copying all layers and fine-tuning a variable number. We performed an experiment with a Caffe-based network on 1000 ImageNet classes that are randomly divided in two equal subgroups for the transfer from one to the other. We copy all layers and vary the number of layers that is fine-tuned and the size of the target dataset. We performed additional experiments with the Keras platform on CIFAR-10 dataset to validate general applicability. We show with both platforms and both datasets that the accuracy on the target dataset improves when more target data is used. When the target dataset is large, it is beneficial to freeze only a few layers. For a large target dataset, the network without transfer learning performs better than the transfer network, especially if many layers are frozen. When the target dataset is small, it is beneficial to transfer (and freeze) many layers. For a small target dataset, the transfer network boosts generalization and it performs much better than the network without transfer learning. Learning time can be reduced by freezing many layers in a network

Observation, Weapon & Protection Systems
II - Intelligent Imaging
TS - Technical Sciences
Defence Research
Defence, Safety and Security
Defense
Security
object recognition
Deep learning
Transfer learning
Big-data analysis

http://resolver.tudelft.nl/uuid:eae4c9a8-7548-4c18-bc7a-d2c287e4fc29

573204

SPIE, Edinburgh

Optics and Photonics for Counterterrorism, Crime Fighting, and Defence XII, Edinburgh, 27 september 2016, 9995

Proceedings of SPIE

conference paper