Abstract
Joint modeling of the intensity of facial action units (AUs) from face images is challenging due to the large number of AUs (30+) and their intensity levels (6). This is in part due to the lack of suitable models that can efficiently handle such a large number of outputs/classes simultaneously, but also due to the lack of labelled target data. For this reason, majority of the methods proposed so far resort to independent classifiers for the AU intensity. This is suboptimal for at least two reasons: the facial appearance of some AUs changes depending on the intensity of other AUs, and some AUs co-occur more often than others. Encoding this is expected to improve the estimation of target AU intensities, especially in the case of noisy image features, head-pose variations and imbalanced training data. To this end, we introduce a novel modeling framework, Copula Ordinal Regression (COR), that leverages the power of copula functions and CRFs, to detangle the probabilistic modeling of AU dependencies from the marginal modeling of the AU intensity. Consequently, the COR model achieves the joint learning and inference of intensities of multiple AUs, while being computationally tractable. We show on two challenging datasets of naturalistic facial expressions that the proposed approach consistently outperforms (i) independent modeling of AU intensities, and (ii) the state-ofthe-art approach for the target task.
Original language | Undefined |
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Pages | 4902-4910 |
Number of pages | 9 |
DOIs | |
Publication status | Published - 26 Jun 2016 |
Event | 29th IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2016 - Las Vegas, NV, USA, Las Vegas, United States Duration: 26 Jun 2016 → 1 Jul 2016 Conference number: 29 |
Conference
Conference | 29th IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2016 |
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Abbreviated title | CVPR 2016 |
Country/Territory | United States |
City | Las Vegas |
Period | 26/06/16 → 1/07/16 |
Other | 29 June - 1 July 2016 |
Keywords
- IR-104071
- HMI-HF: Human Factors
- EWI-27131
- facial action units
- Copula Ordinal Regression (COR)
- Human facial expressions