NeoNet: Object centric training for image recognition

Transcription

1 Daniel Fontijne, Koen E. A. van de Sande, Eren Gölge, R. Blythe Towal, Anthony Sarah, Cees G. M. Snoek Qualcomm Technologies, Inc., December 17, 2015 NeoNet: Object centric training for image recognition Presented by: Daniel Fontijne Senior Staff Engineer 1

2 Summary Score Ranking Classification Localization Detection Places Key component: object centric training 2

3 Foundation Classification Localization Detection Places 2 Agenda 3

4 Ioffe & Szegedy ICML 2015 Foundation: Batch-normalized inception The base network for all our submissions is the inception network as introduced in the batch normalization paper by Ioffe & Szegedy. 4

5 Lin et al. ICLR 2014 Network in an inception module Note: the 5x5 path is not used. 5

6 Foundation Classification Localization Detection Places 2 Agenda 6

7 Classification overview Ensemble of 12 networks Train really long, 350 epochs. Randomized RELU. Test at 14 scales, 10 crops. Object preserving crops. Xu et al. ICML workshop

8 Quiz: What is this? 8

9 Answer: Flower 9

10 Quiz: In case you got that right, what is this? 10

11 Answer: Butterfly 11

12 Object preserving crops Random crop selection might miss the object of interest. Network tries to remember butterfly when presented with leaves. Solution: use provided boxes to assure crop contains the object. For images without box annotation, use best box predicted by localization system. X 12

13 Component breakdown Epochs Single view Multi-view First attempt at inception + batch norm % 6.58% Train ~325 epochs % 6.34% 32 images / mini-batch % 6.68% Object preserving, 32 images/mini-batch % 6.51% Object preserving with generated boxes % 6.46% Ensemble of % 13

14 Final classification results Top-5 classification error on test set MSRA ReCeption Trimps-Soushen NeoNet Ioffe & Szegedy, ICML '15 GoogLeNet ('14) Clarifai ('13) SuperVision ('12) NeoNet is competitive on object classification 14

15 Foundation Classification Localization Detection Places 2 Agenda 15

16 Localization overview Foundations. Generate box proposals using fast selective search. Train box-classification networks on crops. Uijlings et al. IJCV 2013 Girshik et al. PAMI 2016 Object centric training. Object pre-training network. Object localization network. Object alignment network. 16

17 Object centric pre-training Use the bounding box annotations for pre-training. Increase the number of classes from N to 2*N+1: N classes for the object, well-framed. N classes for partially framed objects. 1 class for background, i.e., object not visible. 1% 1.5% improvement compared to standard pre-training. 17

18 Object centric pre-training Dual-head network to account for missing bounding boxes. One with 1000 outputs. One with 2001 outputs. No error gradient when box annotation is missing. 18

19 Object localization network Fully connected layer on top of Inception 4e and 5b. Re-train Inception 5b and new head. Then fine-tune entire network. 19

20 Quiz: Is this an entire skyscraper? 20

21 Bordering the object A 40% border worked best. Such that in 7x7 resolution of Inception 5b there is a 1 pixel border. 21

22 Object alignment network Extra head for object box alignment. Classification head is also used, but with cross entropy cost. 22

23 Object alignment border Object box alignment moves corners up to 50% of the width and height. 100% border allows network to see full range of possible alignments. ~2% gain. 23

24 Component breakdown Top-5 localization error First attempt 24.0% 40% border, FC on top of inception 5b 22.5% FC on top of inception 5b+4e 21.8% Object centric pre-training 20.3% Ensemble of % Object alignment 15.5% Final result with ILSVRC blacklist applied 14.5% 24

25 Final localization results Top-5 localization error on test set MSRA 9.0 Trimps-Soushen NeoNet VGG ('14) 25.3 OverFeat ('13) 30.0 SuperVision ('12) 34.2 UvA ('11) NeoNet is competitive on object localization 25

26 Foundation Classification Localization Detection Places 2 Agenda 26

27 Improved selective search Fast Improved Color spaces 2 3 Segmentations 2 4 Similarity functions 2 4 Average boxes 1,600 5,000 MABO Time (s) map

28 Object detection network Five inception-style networks for feature extraction Two trained on 1,000 object classes, no input border, fine-tuning on detection boxes Three trained on 1,000 object windows with input border, no fine tuning 28

29 Component breakdown map on validation set Best object class network 44.6 Best object centric network 47.7 Ensemble of

30 Component breakdown map on validation set Best object class network 44.6 Best object centric network 47.7 Ensemble of context 53.2 Four classification networks fine tuned with 200 detection class labels 30

31 Component breakdown map on validation set Best object class network 44.6 Best object centric network 47.7 Ensemble of context object alignment

32 Final detection results Mean average precision on test set MSRA 62.1 NeoNet Deep-ID Net GoogLeNet ('14) 43.9 UvA/Euvision ('13) NeoNet is competitive on object detection 32

33 Foundation Classification Localization Detection Places 2 Agenda 33

34 Places 2 overview Our best submission: an ensemble of two inception nets. Reduce fully connected layer from 1,000 to 401 outputs. Use pre-trained weights from ImageNet 1,000 (~325 epochs). Train Inception 5b and fully connected layer for two epochs. Fine-tune entire network for eight epochs. Adding other networks reduced the accuracy 34

35 Component breakdown (top-5 error) Single view Multi view ~325 epochs pre-training 17.9% 16.8% First attempt. 112 epochs pre-training. 19.1% 17.9% 512 channel 5b, Alex-style FC head 20.0% 18.4% 32 images / batch 18.7% 17.6% Randomized RELU 18.2% 17.5% Ensemble of % Ensemble of % 35

36 Final places 2 results Top-5 classification error on test set WM SIAT_MMLAB NeoNet Trimps-Soushen ntu_rose MERL HiVision NeoNet is competitive on scene classification 36

37 On device recognition at 18 ms 37

38 Summary Score Ranking Classification Localization Detection Places Key component: object centric training 38

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