| | Name of classifier | Addressed emotions |
| | DCNN + RLPS [42] | Anger, disgust, fear, happiness, sadness, surprise, and neutral | | 3DCLS [43] | Angry, sad, happy, and neutral | | AdaBoost, relevance feedback [44] | Fear, sadness, and joy | | HMM [45] | Sadness, happiness, anger, fear, disgust, and surprise | | LDA [46] | Joy, acceptance, fear, surprise, sadness, disgust, anger, and anticipation | | Inception V3 [47] | Boredom, confusion, engagement, and frustration | | Modified CNN [48] | Ekman’s basic emotions | | LSTM [49] | Boredom, confusion, engagement, and frustration | | Facial action coding system [50] | Ekman’s basic emotions | | Decision trees, Kinect V2 [51] | Engagement and frustration | | WEKA and OpenFace [52] | Boredom, confusion, engagement, and frustration | | Linear SVMs [53] | Engagement, liking, and familiarity | | PSO, kNN [54] | Happiness, sadness, anger, and fear | | Information aggregation, decision fusion [55] | A neutral, slight smile, large smile, small laugh, giant laugh, and thrilled | | Hybrid CNNs [56] | Engaged, bored, and neutral | | ResNet-18 model and transformers [57] | Fear, angry, sad, happy, contempt, disgust, and surprise | | Multitask CNN [58] | Happiness, fear, disgust, and surprise |
|
|
