Oulu-CASIA stands for Oulu-CASIA NIR&VIS facial expression database, which is a facial expression dataset. The dataset contains 80 people, ranging in age from 23 to 58 years old, and 73.81% of the subjects are male.

The dataset contains 6 basic facial expressions (anger, disgust, fear, happiness, sadness, surprise) and is taken under three lighting conditions (darkness, strong light, weak light). There are 18-30 images in each condition, for a total of 2,400 images. The dataset is divided into infrared and visible light. The image resolution is 320 × 240 pixels.