# Facial Emotion Recognition System Based on PCA and Gradient Features

> Research article (National Academy Science Letters, 2018) · cited 27× · AI/ML

**Wikidata**: [openalex:W2891096297](https://www.wikidata.org/wiki/openalex:W2891096297)  
**Source**: https://4ort.xyz/entity/facial-emotion-recognition-system-based-on-pca-and-gradient-features