Let's look at a basic machine vision camera. Here is a camera without a lens.
Above: typical machine vision camera
Let's look inside this camera to see the typical components: the front end printed circuit board with an imaging sensor and the back end PCBs with various purposes.
Above: Internal to the machine vision Camera will be the imaging sensor and back end circuitry boards
Logic in the back end circuitry will comprise numerous functionality -
Infrared sensors typically come in either cooled or uncooled versions. Below are some examples along with the wavelengths of light they are designed to detect.