shengwenliang / image-classification-caltech-256

Exploring CNNs and model quantization on Caltech-256 dataset

Image Classification Experiments on Caltech-256 dataset

Results

model	accuracy, %	top 5 accuracy, %	number of parameters
DenseNet-121	85	96	7,216,256
DenseNet-121 with trained ternary quantization	73	91	~7.2M 2-bit, ~79% zeros
DenseNet-121 with binary weights	41	67	~7.2M 1-bit
DenseNet-201	87	97	18,584,704
ResNet-18	81	94	11,307,840
ResNet-18 with trained ternary quantization	52	78	~11M 2-bit, ~86% zeros
ResNet-18 with stochastic depth	70	89	11,307,840
SqueezeNet v1.1	66	85	853,824
SqueezeNet v1.1 with entropy regularization	66	86	853,824
Delegating classifiers	77	93	-

Trained ternary quantization

Trained ternary quantization [2] is a method of reducing size of a neural network. It replaces all weights in a convolutional layer with +1, 0, -1 and two float scaling factors (one for +1 and one for -1).

Binary-Weights-Networks

Stochastic depth

Entropy regularization

Delegating classifiers

SmoothGrad

SmoothGrad is a method of computing nice sensitivity maps. Sensitivity maps show which image pixels influence class predictions. They require to compute gradients with respect to an input image. Here are a few examples:

Implementation details

Notes

• I often use cosine annealing [6] of the learning rate. I believe that this reduces training time a lot.

Requirements

• Python 3.5
• pytorch 0.2
• torchvision, Pillow
• numpy, pandas, sklearn, matplotlib, tqdm

References

[1] Regularizing Neural Networks by Penalizing Confident Output Distributions

[2] Trained Ternary Quantization

[3] Deep Networks with Stochastic Depth

[4] SmoothGrad: removing noise by adding noise

[5] XNOR-Net: ImageNet Classification Using Binary Convolutional Neural Networks

[6] Snapshot Ensembles: Train 1, get M for free