=Paper= {{Paper |id=Vol-1391/117-CR |storemode=property |title=X-ray Image Body Part Clustering using Deep Convolutional Neural Network: SNUMedinfo at ImageCLEF 2015 Medical Clustering Task |pdfUrl=https://ceur-ws.org/Vol-1391/117-CR.pdf |volume=Vol-1391 |dblpUrl=https://dblp.org/rec/conf/clef/Choi15 }} ==X-ray Image Body Part Clustering using Deep Convolutional Neural Network: SNUMedinfo at ImageCLEF 2015 Medical Clustering Task== https://ceur-ws.org/Vol-1391/117-CR.pdf
         X-ray image body part clustering using deep
        convolutional neural network: SNUMedinfo at
          ImageCLEF 2015 medical clustering task

                                        Sungbin Choi

    Department of Biomedical Engineering, Seoul National University, Republic of Korea

                                  wakeup06@empas.com



       Abstract. This paper describes our participation at the ImageCLEF 2015 Medical
       clustering task. The task is about clustering digital x-ray images into four groups
       with regard to the body parts. We experimented with deep convolutional neural
       network (GoogLeNet), finetuning pretrained models for ImageNet dataset. Ex-
       perimental results showed competitive performance with other top-performing
       runs.

       Keywords: Image clustering, Image classification, Deep convolutional neural
       network


1      Introduction

In this paper, we describe our participation at the ImageCLEF 2015 [1, 2] medical clus-
tering [3] task. Given digital x-ray images of various body parts, task purpose is clus-
tering images into four different body parts: head-neck, upper-limb, body and lower-
limb. For a detailed introduction of the task, please see the overview paper of this task
[4].


2      Methods

In this study, we experimented with deep convolutional neural network (CNN). In re-
cent years, CNN showed quite effective performance in image classification tasks [5].
We formulated this task as an image classification among four different body part la-
bels. We experimented with GoogLeNet which was used in recent ImageNet Challenge
[6]. GoogLeNet incorporates Inception module with the intention of increasing network
depth with computational efficiency.
We randomly divided training set into five-fold. Images from one fold is used as vali-
dation set, and images from other four fold is used as training set. We finetuned
GoogLeNet pretrained on ImageNet dataset (initial learning rate 0.001;
batch_size:40). 90 degree rotation (90’, 180’, 270’ and 360’) of images, mirroring
(random left-right flipping of image) and image cropping (random cropping 224 x
224 image window out of 300 x 300 resized image) is applied for input data augmen-
tation. Our trained CNN models scored 0.89~0.93 top-1 accuracy in our validation
set.
   We trained five separate CNNs. Five ranked list is combined into single ranking
using Borda-fuse method [7]. Only top-ranked body parts are marked as output in test
set. Borda-fuse method combines individual ranks without utilizing score. Combining
multiple CNN classification output is considered to be effective to cope with CNN’s
variance. We postponed experimenting with other metasearch techniques such as
CombSUM [8] to the future work.


3      Results

   In GoogLeNet, there are three output layers (loss1, loss2 and loss3), two of them
(loss1 and loss2) is located in the middle of layer hierarchy. We used these three layers
per each run. Our run SNUMedifo1 corresponds to the lowest output layer (loss1).
SNUMedinfo3 corresponds to the uppermost output layer (loss3).

                      Table 1. Evaluation results of our submitted runs

                        Exact match              Any match            Hamming similarity
     SNUMedinfo1            0.679                  0.820                   0.879
     SNUMedinfo2            0.699                  0.844                   0.890
     SNUMedinfo3            0.709                  0.856                   0.895

Evaluation results showed competitive performance. In our future study, we want to
experiment with more data augmentation options to improve CNN’s performance.


4      References

1.       Cappellato, L., Ferro, N., Jones, G., and San Juan, E., CLEF 2015 Labs and Workshops.
         2015, CEUR Workshop Proceedings (CEUR-WS.org).
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         Marvasti, N.B., Aldana, J.F., del Mar Roldan Garcia, M. General Overview of
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