22,011 research outputs found
LEARNet Dynamic Imaging Network for Micro Expression Recognition
Unlike prevalent facial expressions, micro expressions have subtle,
involuntary muscle movements which are short-lived in nature. These minute
muscle movements reflect true emotions of a person. Due to the short duration
and low intensity, these micro-expressions are very difficult to perceive and
interpret correctly. In this paper, we propose the dynamic representation of
micro-expressions to preserve facial movement information of a video in a
single frame. We also propose a Lateral Accretive Hybrid Network (LEARNet) to
capture micro-level features of an expression in the facial region. The LEARNet
refines the salient expression features in accretive manner by incorporating
accretion layers (AL) in the network. The response of the AL holds the hybrid
feature maps generated by prior laterally connected convolution layers.
Moreover, LEARNet architecture incorporates the cross decoupled relationship
between convolution layers which helps in preserving the tiny but influential
facial muscle change information. The visual responses of the proposed LEARNet
depict the effectiveness of the system by preserving both high- and micro-level
edge features of facial expression. The effectiveness of the proposed LEARNet
is evaluated on four benchmark datasets: CASME-I, CASME-II, CAS(ME)^2 and SMIC.
The experimental results after investigation show a significant improvement of
4.03%, 1.90%, 1.79% and 2.82% as compared with ResNet on CASME-I, CASME-II,
CAS(ME)^2 and SMIC datasets respectively.Comment: Dynamic imaging, accretion, lateral, micro expression recognitio
MicroExpNet: An Extremely Small and Fast Model For Expression Recognition From Face Images
This paper is aimed at creating extremely small and fast convolutional neural
networks (CNN) for the problem of facial expression recognition (FER) from
frontal face images. To this end, we employed the popular knowledge
distillation (KD) method and identified two major shortcomings with its use: 1)
a fine-grained grid search is needed for tuning the temperature hyperparameter
and 2) to find the optimal size-accuracy balance, one needs to search for the
final network size (or the compression rate). On the other hand, KD is proved
to be useful for model compression for the FER problem, and we discovered that
its effects gets more and more significant with the decreasing model size. In
addition, we hypothesized that translation invariance achieved using
max-pooling layers would not be useful for the FER problem as the expressions
are sensitive to small, pixel-wise changes around the eye and the mouth.
However, we have found an intriguing improvement on generalization when
max-pooling is used. We conducted experiments on two widely-used FER datasets,
CK+ and Oulu-CASIA. Our smallest model (MicroExpNet), obtained using knowledge
distillation, is less than 1MB in size and works at 1851 frames per second on
an Intel i7 CPU. Despite being less accurate than the state-of-the-art,
MicroExpNet still provides significant insights for designing a
microarchitecture for the FER problem.Comment: International Conference on Image Processing Theory, Tools and
Applications (IPTA) 2019 camera ready version. Codes are available at:
https://github.com/cuguilke/microexpne
Facial expression of pain: an evolutionary account.
This paper proposes that human expression of pain in the presence or absence of caregivers, and the detection of pain by observers, arises from evolved propensities. The function of pain is to demand attention and prioritise escape, recovery, and healing; where others can help achieve these goals, effective communication of pain is required. Evidence is reviewed of a distinct and specific facial expression of pain from infancy to old age, consistent across stimuli, and recognizable as pain by observers. Voluntary control over amplitude is incomplete, and observers can better detect pain that the individual attempts to suppress rather than amplify or simulate. In many clinical and experimental settings, the facial expression of pain is incorporated with verbal and nonverbal vocal activity, posture, and movement in an overall category of pain behaviour. This is assumed by clinicians to be under operant control of social contingencies such as sympathy, caregiving, and practical help; thus, strong facial expression is presumed to constitute and attempt to manipulate these contingencies by amplification of the normal expression. Operant formulations support skepticism about the presence or extent of pain, judgments of malingering, and sometimes the withholding of caregiving and help. To the extent that pain expression is influenced by environmental contingencies, however, "amplification" could equally plausibly constitute the release of suppression according to evolved contingent propensities that guide behaviour. Pain has been largely neglected in the evolutionary literature and the literature on expression of emotion, but an evolutionary account can generate improved assessment of pain and reactions to it
Interpretable Explainability in Facial Emotion Recognition and Gamification for Data Collection
Training facial emotion recognition models requires large sets of data and
costly annotation processes. To alleviate this problem, we developed a gamified
method of acquiring annotated facial emotion data without an explicit labeling
effort by humans. The game, which we named Facegame, challenges the players to
imitate a displayed image of a face that portrays a particular basic emotion.
Every round played by the player creates new data that consists of a set of
facial features and landmarks, already annotated with the emotion label of the
target facial expression. Such an approach effectively creates a robust,
sustainable, and continuous machine learning training process. We evaluated
Facegame with an experiment that revealed several contributions to the field of
affective computing. First, the gamified data collection approach allowed us to
access a rich variation of facial expressions of each basic emotion due to the
natural variations in the players' facial expressions and their expressive
abilities. We report improved accuracy when the collected data were used to
enrich well-known in-the-wild facial emotion datasets and consecutively used
for training facial emotion recognition models. Second, the natural language
prescription method used by the Facegame constitutes a novel approach for
interpretable explainability that can be applied to any facial emotion
recognition model. Finally, we observed significant improvements in the facial
emotion perception and expression skills of the players through repeated game
play.Comment: 8 pages, 8 figures, 2022 10th International Conference on Affective
Computing and Intelligent Interaction (ACII
Explainable automated recognition of emotional states from canine facial expressions: the case of positive anticipation and frustration.
In animal research, automation of affective states recognition has so far mainly addressed pain in a few species. Emotional states remain uncharted territories, especially in dogs, due to the complexity of their facial morphology and expressions. This study contributes to fill this gap in two aspects. First, it is the first to address dog emotional states using a dataset obtained in a controlled experimental setting, including videos from (n = 29) Labrador Retrievers assumed to be in two experimentally induced emotional states: negative (frustration) and positive (anticipation). The dogs' facial expressions were measured using the Dogs Facial Action Coding System (DogFACS). Two different approaches are compared in relation to our aim: (1) a DogFACS-based approach with a two-step pipeline consisting of (i) a DogFACS variable detector and (ii) a positive/negative state Decision Tree classifier; (2) An approach using deep learning techniques with no intermediate representation. The approaches reach accuracy of above 71% and 89%, respectively, with the deep learning approach performing better. Secondly, this study is also the first to study explainability of AI models in the context of emotion in animals. The DogFACS-based approach provides decision trees, that is a mathematical representation which reflects previous findings by human experts in relation to certain facial expressions (DogFACS variables) being correlates of specific emotional states. The deep learning approach offers a different, visual form of explainability in the form of heatmaps reflecting regions of focus of the network's attention, which in some cases show focus clearly related to the nature of particular DogFACS variables. These heatmaps may hold the key to novel insights on the sensitivity of the network to nuanced pixel patterns reflecting information invisible to the human eye
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