What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance
Single-level principal component analysis (PCA) and multi-level PCA (mPCA) methods are applied here to a set of (2D frontal) facial images from a group of 80 Finnish subjects (34 male; 46 female) with two different facial expressions (smiling and neutral) per subject. Inspection of eigenvalues gives...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-12-01
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| Series: | Journal of Imaging |
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| Online Access: | http://www.mdpi.com/2313-433X/5/1/2 |
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| author | Damian J.J. Farnell Jennifer Galloway Alexei I. Zhurov Stephen Richmond David Marshall Paul L. Rosin Khtam Al-Meyah Pertti Pirttiniemi Raija Lähdesmäki |
| author_facet | Damian J.J. Farnell Jennifer Galloway Alexei I. Zhurov Stephen Richmond David Marshall Paul L. Rosin Khtam Al-Meyah Pertti Pirttiniemi Raija Lähdesmäki |
| author_sort | Damian J.J. Farnell |
| collection | DOAJ |
| description | Single-level principal component analysis (PCA) and multi-level PCA (mPCA) methods are applied here to a set of (2D frontal) facial images from a group of 80 Finnish subjects (34 male; 46 female) with two different facial expressions (smiling and neutral) per subject. Inspection of eigenvalues gives insight into the importance of different factors affecting shapes, including: biological sex, facial expression (neutral versus smiling), and all other variations. Biological sex and facial expression are shown to be reflected in those components at appropriate levels of the mPCA model. Dynamic 3D shape data for all phases of a smile made up a second dataset sampled from 60 adult British subjects (31 male; 29 female). Modes of variation reflected the act of smiling at the correct level of the mPCA model. Seven phases of the dynamic smiles are identified: rest pre-smile, onset 1 (acceleration), onset 2 (deceleration), apex, offset 1 (acceleration), offset 2 (deceleration), and rest post-smile. A clear cycle is observed in standardized scores at an appropriate level for mPCA and in single-level PCA. mPCA can be used to study static shapes and images, as well as dynamic changes in shape. It gave us much insight into the question “what’s in a smile?”. |
| first_indexed | 2024-12-10T04:18:00Z |
| format | Article |
| id | doaj.art-3e90e7781ffb421ebc1aaa00f4dd1f2c |
| institution | Directory Open Access Journal |
| issn | 2313-433X |
| language | English |
| last_indexed | 2024-12-10T04:18:00Z |
| publishDate | 2018-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Imaging |
| spelling | doaj.art-3e90e7781ffb421ebc1aaa00f4dd1f2c2022-12-22T02:02:32ZengMDPI AGJournal of Imaging2313-433X2018-12-0151210.3390/jimaging5010002jimaging5010002What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and AppearanceDamian J.J. Farnell0Jennifer Galloway1Alexei I. Zhurov2Stephen Richmond3David Marshall4Paul L. Rosin5Khtam Al-Meyah6Pertti Pirttiniemi7Raija Lähdesmäki8School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UKSchool of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UKSchool of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UKSchool of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UKSchool of Computer Science and Informatics, Cardiff University, CF24 3AA Cardiff, UKSchool of Computer Science and Informatics, Cardiff University, CF24 3AA Cardiff, UKSchool of Computer Science and Informatics, Cardiff University, CF24 3AA Cardiff, UKResearch Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, FI-90014, Oulu, FinlandResearch Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, FI-90014, Oulu, FinlandSingle-level principal component analysis (PCA) and multi-level PCA (mPCA) methods are applied here to a set of (2D frontal) facial images from a group of 80 Finnish subjects (34 male; 46 female) with two different facial expressions (smiling and neutral) per subject. Inspection of eigenvalues gives insight into the importance of different factors affecting shapes, including: biological sex, facial expression (neutral versus smiling), and all other variations. Biological sex and facial expression are shown to be reflected in those components at appropriate levels of the mPCA model. Dynamic 3D shape data for all phases of a smile made up a second dataset sampled from 60 adult British subjects (31 male; 29 female). Modes of variation reflected the act of smiling at the correct level of the mPCA model. Seven phases of the dynamic smiles are identified: rest pre-smile, onset 1 (acceleration), onset 2 (deceleration), apex, offset 1 (acceleration), offset 2 (deceleration), and rest post-smile. A clear cycle is observed in standardized scores at an appropriate level for mPCA and in single-level PCA. mPCA can be used to study static shapes and images, as well as dynamic changes in shape. It gave us much insight into the question “what’s in a smile?”.http://www.mdpi.com/2313-433X/5/1/2multilevel principal components analysisshape and image texturefacial expression |
| spellingShingle | Damian J.J. Farnell Jennifer Galloway Alexei I. Zhurov Stephen Richmond David Marshall Paul L. Rosin Khtam Al-Meyah Pertti Pirttiniemi Raija Lähdesmäki What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance Journal of Imaging multilevel principal components analysis shape and image texture facial expression |
| title | What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance |
| title_full | What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance |
| title_fullStr | What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance |
| title_full_unstemmed | What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance |
| title_short | What’s in a Smile? Initial Analyses of Dynamic Changes in Facial Shape and Appearance |
| title_sort | what s in a smile initial analyses of dynamic changes in facial shape and appearance |
| topic | multilevel principal components analysis shape and image texture facial expression |
| url | http://www.mdpi.com/2313-433X/5/1/2 |
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