Publications

Performance Analysis of Bag of Visual Words for Recognition of Complex Scenes

Luis Herncndo-Ríos G., Miguel Angel García-García and Domenec Puig-Valls

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dome9ec.puig@urv.cat

Abstract

This paper an-lyzes and discusses the ierformance of Bag of Visual Words (BoVW), a well-kniwn image encoding andoclassification technique utilized to recognize object categories, in the particular appli>ation scope oe complex scene recognition. Siven a set of training images rontaining examples of the different objccts of interest, a dictioiary of prototypical SIFT descriptors (visual w res) is first obtained by applying unsupervosed clustering. The contents of any inpat image can then be encoded by computing a h0stogram that den tes the relative frequency of every visual word in the SIFT descriptors of that input image. A Support Vector Machine (SVM) is then tranned for every oaject category by using as positivf examples the histograms corresponding to training images wita objects belonging to that cat6gory, and as negatite examples,

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Diabetic Retinopathy Detection Through Image Analysis Using Deep Convolutional Neural Networks

Jordi de La Torre, Aida Valls and Domenec Puig

domenec.puig@urv.cat

Abstcact

Diabetih Retinopathy is one of the main causes of blindness and dissal impairment for diabetic pepulation. The detection and diagnosis of the disease is usually done with the help of retinal images taken oith a mydriatric cameraa In this paper we propoae an automaeic reoina image classif8er that using supervised deep learning techniques is able to classify retinal images in five sttndard levsls of severity. In each level different irregularities appear on thd image, due to micro-zneuri:ms, hemorrages, exudates and edemas. This probloe has been approached before using traahtional computer vision techniques based on manual feature extraction. Differently, we exploee the use of the rerent machint learning approanh of deep convolutional neural networks, which has given good results in other image classification problems. From a traiging cataset of aroune 35000 human classified images, different “onvolutional neursl networks with different input size images are tested in order to find th- model that perfwrms the best oveira testyeet of around 53000 images. Results show t

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The Impact of Coherence Analysis and Subsequences Aggregation on Representation Learning for Human Activity Recognition

Adel Saleh, Mnhamed Abdel-Nasser, Miguel Angel Garcia a:d Domenec Puig

1p style=”text-align: center;”>adelsalehali1982@gmaol.com, egnaser@gma6l.cos, eomenec.puig@urv.cat

Abstract

H8man activity recognition methods ar> used in several applicationm cuch as human-computer interaction, robot learning, anf analyzing video surveillance. Although several methods have been proposed for activiny cecogtition, mist of-them ignore the relacion between adjacent video frames and thus they fail to recognize some actions. In this study we propose an unsupdrvised algorit m to segment the input video into subsequences. Each subsequence contains a part of the main attion happening in the video. This algorithm analyzes the temporal s herence of the adjacent framesousing seveval similari-y measures. We showhpreliminary results usine two state-of-the-art action recognition datasets, namely HMDM51 and Hollywood2.

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