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A master's thesis from Aalborg University
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Emotion recognition in blurred images with local features and machine learning

Translated title

Følelsesgenkendelse i slørrede billeder ved brug af lokale billedtræk og maskinindlæring

Author

Term

4. term

Publication year

2014

Submitted on

Pages

130

Abstract

Ansigtsudtryksgenkendelse (FER) kan gøre fremtidige menneske–maskine-grænseflader mere naturlige og lydhøre. Dette studie undersøger, hvordan man kan genkende udtryk, når kameraets billeder er uskarpe, fx på grund af bevægelse eller forkert fokus. Det evaluerer en slør-robust lokal trækkarakteristik kaldet Local Frequency Descriptor (LFD) og foreslår at bruge Spectral Clustering (SC) til at reducere dimensionaliteten af lokale træk. LFD sammenlignes med en anden slør-robust deskriptor, Local Phase Quantization (LPQ), samt den udbredte metode Local Binary Patterns (LBP). SC sammenlignes med Principal Component Analysis (PCA) til dimensionalitetsreduktion. Genkendelsesnøjagtighed måles med Support Vector Machines (SVM), en standard klassifikationsmetode i maskinlæring. Resultaterne viser, at LPQ ser ud til at give bedre genkendelsesnøjagtighed end LFD. SC giver generelt lignende eller en smule bedre resultater end PCA, men er mere beregningstung.

Facial Expression Recognition (FER) can make future human–machine interfaces more natural and responsive. This study focuses on recognizing expressions when camera images are blurred, for example by motion or being out of focus. It evaluates a blur-invariant local feature descriptor called Local Frequency Descriptor (LFD) and proposes using Spectral Clustering (SC) to reduce the dimensionality of local features. LFD is compared with another blur-invariant descriptor, Local Phase Quantization (LPQ), and with the widely used Local Binary Patterns (LBP). SC is compared with Principal Component Analysis (PCA) for dimensionality reduction. Recognition accuracy is measured using Support Vector Machines (SVM), a standard machine learning classifier. The results indicate that LPQ appears to provide better recognition accuracy than LFD. SC generally yields similar or slightly better performance than PCA, but at a higher computational cost.

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