Available online at www.ijournalse.org
Emerging Science Journal
(ISSN: 2610-9182)
Vol. 7, No. 1, February, 2023
Page | 116
Continuous Capsule Network Method for Improving
Electroencephalogram-Based Emotion Recognition
I Made Agus Wirawan
1, 2
, Retantyo Wardoyo
1*
, Danang Lelono
1
,
Sri Kusrohmaniah
3
1
Department of Computer Science and Electronics, Faculty of Mathematics and Natural Science, Universitas Gadjah Mada,
Yogyakarta 55281, Indonesia.
2
Education of Informatics Engineering Department, Faculty of Engineering and Vocational, Universitas Pendidikan Ganesha,
Singaraja 81116, Indonesia.
3
Department of Psychology, Faculty of Psychology, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia.
Abstract
The convolution process in the Capsule Network method can result in a loss of spatial data from the
Electroencephalogram signal, despite its ability to characterize spatial information from
Electroencephalogram signals. Therefore, this study applied the Continuous Capsule Network
method to overcome problems associated with emotion recognition based on Electroencephalogram
signals using the optimal architecture of the (1) 1
st
, 2
nd
, 3
rd
, and 4
th
Continuous Convolution layers
with values of 64, 128, 256, and 64, respectively, and (2) kernel sizes of 2×2×4, 2×2×64, and
2×2×128 for the 1
st
, 2
nd
, and 3
rd
Continuous Convolution layers, and 1×1×256 for the 4
th
. Several
methods were also used to support the Continuous Capsule Network process, such as the Differential
Entropy and 3D Cube methods for the feature extraction and representation processes. These
methods were chosen based on their ability to characterize spatial and low-frequency information
from Electroencephalogram signals. By testing the DEAP dataset, these proposed methods achieved
accuracies of 91.35, 93.67, and 92.82% for the four categories of emotions, two categories of
arousal, and valence, respectively. Furthermore, on the DREAMER dataset, these proposed methods
achieved accuracies of 94.23, 96.66, and 96.05% for the four categories of emotions, the two
categories of arousal, and valence, respectively. Finally, on the AMIGOS dataset, these proposed
methods achieved accuracies of 96.20, 97.96, and 97.32% for the four categories of emotions, the
two categories of arousal, and valence, respectively.
Keywords:
Electroencephalogram;
Emotion Recognition;
Differential Entropy;
Baseline Reduction;
3D Cube; Capsule Network;
Continuous Convolution.
Article History:
Received: 09 June 2022
Revised: 17 August 2022
Accepted: 14 September 2022
Available online: 07 November 2022
1- Introduction
Emotions are psychological reactions to daily social interactions [1], which emerge due to certain conditions or
problems encountered in achieving the desired target [2]. It is categorized into arousal and valence, with positive and
negative values, respectively. Valence is an individual's reaction toward an event, while arousal is the excitement to
behave accordingly or express the feeling [3]. A combination of arousal and valence labels is categorized into four
quadrants: the 1
st
represents high arousal and positive valence (HAPV), 2
nd
depicts high arousal and negative valence
(HANV), 3
rd
implies low arousal and negative valence (LANV), while the 4
th
describes low arousal and positive valence
(LAPV) [4, 5]. The emotional reactions in each quadrant represent mental health and human performance [6]. It is
essential to recognize the emotions in each quadrant to understand these individuals' mental state and performance.
*
CONTACT: rw@ugm.ac.id
DOI: http://dx.doi.org/10.28991/ESJ-2023-07-01-09
© 2023 by the authors. Licensee ESJ, Italy. This is an open access article under the terms and conditions of the Creative
Commons Attribution (CC-BY) license (https://creativecommons.org/licenses/by/4.0/).