Infrared Ray Camera can obtain an image of a subject even on a dark night using an infrared light source that cannot be seen by a human. 

IR Pass Filter passes through an infrared light source entering an image sensor to identify a subject even at night. 

IR Cut Filter blocks an infrared light source entering an image sensor to show only visible light. 

Illuminance is intensity of light received by a certain aspect, and the speed of incident light per unit area. The unit uses Lux.