Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy

Eye tracking techniques based on deep learning are rapidly spreading in a wide variety of application fields. With this study, we want to exploit the potentiality of eye tracking techniques in ocular proton therapy (OPT) applications. We implemented a fully automatic approach based on two-stage conv...

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Main Authors: Luca Antonioli, Andrea Pella, Rosalinda Ricotti, Matteo Rossi, Maria Rosaria Fiore, Gabriele Belotti, Giuseppe Magro, Chiara Paganelli, Ester Orlandi, Mario Ciocca, Guido Baroni
Format: Article
Language:English
Published: MDPI AG 2021-06-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/21/13/4400
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author Luca Antonioli
Andrea Pella
Rosalinda Ricotti
Matteo Rossi
Maria Rosaria Fiore
Gabriele Belotti
Giuseppe Magro
Chiara Paganelli
Ester Orlandi
Mario Ciocca
Guido Baroni
author_facet Luca Antonioli
Andrea Pella
Rosalinda Ricotti
Matteo Rossi
Maria Rosaria Fiore
Gabriele Belotti
Giuseppe Magro
Chiara Paganelli
Ester Orlandi
Mario Ciocca
Guido Baroni
author_sort Luca Antonioli
collection DOAJ
description Eye tracking techniques based on deep learning are rapidly spreading in a wide variety of application fields. With this study, we want to exploit the potentiality of eye tracking techniques in ocular proton therapy (OPT) applications. We implemented a fully automatic approach based on two-stage convolutional neural networks (CNNs): the first stage roughly identifies the eye position and the second one performs a fine iris and pupil detection. We selected 707 video frames recorded during clinical operations during OPT treatments performed at our institute. 650 frames were used for training and 57 for a blind test. The estimations of iris and pupil were evaluated against the manual labelled contours delineated by a clinical operator. For iris and pupil predictions, Dice coefficient (median = 0.94 and 0.97), Szymkiewicz–Simpson coefficient (median = 0.97 and 0.98), Intersection over Union coefficient (median = 0.88 and 0.94) and Hausdorff distance (median = 11.6 and 5.0 (pixels)) were quantified. Iris and pupil regions were found to be comparable to the manually labelled ground truths. Our proposed framework could provide an automatic approach to quantitatively evaluating pupil and iris misalignments, and it could be used as an additional support tool for clinical activity, without impacting in any way with the consolidated routine.
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spelling doaj.art-d47ef6be08624c929ea2fb69a80cf16f2023-11-22T01:56:54ZengMDPI AGSensors1424-82202021-06-012113440010.3390/s21134400Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton TherapyLuca Antonioli0Andrea Pella1Rosalinda Ricotti2Matteo Rossi3Maria Rosaria Fiore4Gabriele Belotti5Giuseppe Magro6Chiara Paganelli7Ester Orlandi8Mario Ciocca9Guido Baroni10Bioengineering Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyBioengineering Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyBioengineering Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano University, 20133 Milan, ItalyRadiotherapy Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano University, 20133 Milan, ItalyMedical Physics Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano University, 20133 Milan, ItalyRadiotherapy Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyMedical Physics Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyBioengineering Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), 27100 Pavia, ItalyEye tracking techniques based on deep learning are rapidly spreading in a wide variety of application fields. With this study, we want to exploit the potentiality of eye tracking techniques in ocular proton therapy (OPT) applications. We implemented a fully automatic approach based on two-stage convolutional neural networks (CNNs): the first stage roughly identifies the eye position and the second one performs a fine iris and pupil detection. We selected 707 video frames recorded during clinical operations during OPT treatments performed at our institute. 650 frames were used for training and 57 for a blind test. The estimations of iris and pupil were evaluated against the manual labelled contours delineated by a clinical operator. For iris and pupil predictions, Dice coefficient (median = 0.94 and 0.97), Szymkiewicz–Simpson coefficient (median = 0.97 and 0.98), Intersection over Union coefficient (median = 0.88 and 0.94) and Hausdorff distance (median = 11.6 and 5.0 (pixels)) were quantified. Iris and pupil regions were found to be comparable to the manually labelled ground truths. Our proposed framework could provide an automatic approach to quantitatively evaluating pupil and iris misalignments, and it could be used as an additional support tool for clinical activity, without impacting in any way with the consolidated routine.https://www.mdpi.com/1424-8220/21/13/4400ocular proton therapyconvolutional neural networkseye trackingpupil segmentationiris segmentation
spellingShingle Luca Antonioli
Andrea Pella
Rosalinda Ricotti
Matteo Rossi
Maria Rosaria Fiore
Gabriele Belotti
Giuseppe Magro
Chiara Paganelli
Ester Orlandi
Mario Ciocca
Guido Baroni
Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy
Sensors
ocular proton therapy
convolutional neural networks
eye tracking
pupil segmentation
iris segmentation
title Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy
title_full Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy
title_fullStr Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy
title_full_unstemmed Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy
title_short Convolutional Neural Networks Cascade for Automatic Pupil and Iris Detection in Ocular Proton Therapy
title_sort convolutional neural networks cascade for automatic pupil and iris detection in ocular proton therapy
topic ocular proton therapy
convolutional neural networks
eye tracking
pupil segmentation
iris segmentation
url https://www.mdpi.com/1424-8220/21/13/4400
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