Fssd.pytorch

A Pytorch0.4 re-implementation of Fssd detection network, with pretrained weights on VOC0712 and mAP=79.74.

Network	train data	test data	mAP	FPS	Download Link
FSSD	VOC 07+12	VOC 07 test	79.74	90	Baidu/Google

Official caffe implementation is here, and pytorch0.3 re-implementation is here.

For details, please read the paper: FSSD：Feature Fusion Single Shot Multibox Detector

Our re-implementation is slightly better than paper (79.74 vs 78.8). Inference time is tested on TITAN X Pasal and cudnn V5. More high performance models will be available soon.

About more details

• The implementation code abandons the bn layer after feature fusion.
• Because the limitation of amount of gpu, batch_size is set to 32. If use 64 or more, I believe it will produce better performance.
• If you want to re-produce more accurate model, I believe that adding BN to the body of FSSD and applying Mixup will be very effective.
• The code is mainly based on rfbNet. If you are interested in this project, please email me(yhao.chen0617@gmail.com)

Update

I add a prune file for FSSD, which bases on Network Slimming (ICCV 2017), for details, please refer to the paper: Network Slimming.

State	mAP	FPS	GPU	Model Size	Download Link
Original	79.74	90	TITAN X Pascal	136M	Baidu/Google
First Prune (50%)	79.64	150	TITAN X Pascal	52M	Bd(p6fe)/Gg
Second Prune

Steps for pruning the model:

• Training the FSSD with BN model, meanwhile applying L1 constraints to the parameters of BN
• Applying Network Slimming to the model trained in the previous step （Prune threshold is defaulted to 50%）
• Re-train the pruned model, approximate 200 epochs, drop 0.1% in accuracy.
• If still prune the model, I believe it can produce the result of mAP>79%, FPS~200. Of course, for the pruned model, BN can be merged to the convolution layer to be further accelerate.