Efficient ear alignment using a two‐stack hourglass network

Abstract Ear images have been shown to be a reliable modality for biometric recognition with desirable characteristics, such as high universality, distinctiveness, measurability and permanence. While a considerable amount of research has been directed towards ear recognition techniques, the problem...

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Main Authors: Anja Hrovatič, Peter Peer, Vitomir Štruc, Žiga Emeršič
Format: Article
Language:English
Published: Wiley 2023-03-01
Series:IET Biometrics
Subjects:
Online Access:https://doi.org/10.1049/bme2.12109
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author Anja Hrovatič
Peter Peer
Vitomir Štruc
Žiga Emeršič
author_facet Anja Hrovatič
Peter Peer
Vitomir Štruc
Žiga Emeršič
author_sort Anja Hrovatič
collection DOAJ
description Abstract Ear images have been shown to be a reliable modality for biometric recognition with desirable characteristics, such as high universality, distinctiveness, measurability and permanence. While a considerable amount of research has been directed towards ear recognition techniques, the problem of ear alignment is still under‐explored in the open literature. Nonetheless, accurate alignment of ear images, especially in unconstrained acquisition scenarios, where the ear appearance is expected to vary widely due to pose and view point variations, is critical for the performance of all downstream tasks, including ear recognition. Here, the authors address this problem and present a framework for ear alignment that relies on a two‐step procedure: (i) automatic landmark detection and (ii) fiducial point alignment. For the first (landmark detection) step, the authors implement and train a Two‐Stack Hourglass model (2‐SHGNet) capable of accurately predicting 55 landmarks on diverse ear images captured in uncontrolled conditions. For the second (alignment) step, the authors use the Random Sample Consensus (RANSAC) algorithm to align the estimated landmark/fiducial points with a pre‐defined ear shape (i.e. a collection of average ear landmark positions). The authors evaluate the proposed framework in comprehensive experiments on the AWEx and ITWE datasets and show that the 2‐SHGNet model leads to more accurate landmark predictions than competing state‐of‐the‐art models from the literature. Furthermore, the authors also demonstrate that the alignment step significantly improves recognition accuracy with ear images from unconstrained environments compared to unaligned imagery.
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spelling doaj-art-9e56a5eac85b44dfae3ae810585f097f2025-02-03T01:29:43ZengWileyIET Biometrics2047-49382047-49462023-03-01122779010.1049/bme2.12109Efficient ear alignment using a two‐stack hourglass networkAnja Hrovatič0Peter Peer1Vitomir Štruc2Žiga Emeršič3Computer Vision Lab Faculty of Computer and Information Science University of Ljubljana Ljubljana SloveniaComputer Vision Lab Faculty of Computer and Information Science University of Ljubljana Ljubljana SloveniaLaboratory for Machine Intelligence Faculty of Electrical Engineering University of Ljubljana Ljubljana SloveniaComputer Vision Lab Faculty of Computer and Information Science University of Ljubljana Ljubljana SloveniaAbstract Ear images have been shown to be a reliable modality for biometric recognition with desirable characteristics, such as high universality, distinctiveness, measurability and permanence. While a considerable amount of research has been directed towards ear recognition techniques, the problem of ear alignment is still under‐explored in the open literature. Nonetheless, accurate alignment of ear images, especially in unconstrained acquisition scenarios, where the ear appearance is expected to vary widely due to pose and view point variations, is critical for the performance of all downstream tasks, including ear recognition. Here, the authors address this problem and present a framework for ear alignment that relies on a two‐step procedure: (i) automatic landmark detection and (ii) fiducial point alignment. For the first (landmark detection) step, the authors implement and train a Two‐Stack Hourglass model (2‐SHGNet) capable of accurately predicting 55 landmarks on diverse ear images captured in uncontrolled conditions. For the second (alignment) step, the authors use the Random Sample Consensus (RANSAC) algorithm to align the estimated landmark/fiducial points with a pre‐defined ear shape (i.e. a collection of average ear landmark positions). The authors evaluate the proposed framework in comprehensive experiments on the AWEx and ITWE datasets and show that the 2‐SHGNet model leads to more accurate landmark predictions than competing state‐of‐the‐art models from the literature. Furthermore, the authors also demonstrate that the alignment step significantly improves recognition accuracy with ear images from unconstrained environments compared to unaligned imagery.https://doi.org/10.1049/bme2.12109convolutional neural netsear biometrics
spellingShingle Anja Hrovatič
Peter Peer
Vitomir Štruc
Žiga Emeršič
Efficient ear alignment using a two‐stack hourglass network
IET Biometrics
convolutional neural nets
ear biometrics
title Efficient ear alignment using a two‐stack hourglass network
title_full Efficient ear alignment using a two‐stack hourglass network
title_fullStr Efficient ear alignment using a two‐stack hourglass network
title_full_unstemmed Efficient ear alignment using a two‐stack hourglass network
title_short Efficient ear alignment using a two‐stack hourglass network
title_sort efficient ear alignment using a two stack hourglass network
topic convolutional neural nets
ear biometrics
url https://doi.org/10.1049/bme2.12109
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AT peterpeer efficientearalignmentusingatwostackhourglassnetwork
AT vitomirstruc efficientearalignmentusingatwostackhourglassnetwork
AT zigaemersic efficientearalignmentusingatwostackhourglassnetwork