Hard Carbon Coating: A scratch resistant, weather resistant coating that is deposited on the front surface of germanium windows or lenses to improve the survivability of the element.
Heat: The transfer of energy from one object (or substance) to another. Heat has the same units as energy (Joules, in SI units).
Heat Capacity (also, Specific Heat): The amount of heat that must be supplied to a unit mass of material to increase its temperature by one degree. This can be thought of as the resistance of the material to temperature changes.
HFOV: Acronym for Horizontal Field of View, which is the lateral extent to which an imaging system can view a scene.
Hyperfocal Distance: The closest distance to which a lens can be focused that still allows objects at infinity to be within acceptable focus.
Hz: Acronym for Hertz, which is a unit of frequency, where 1 Hz is equal to one cycle per second.
