Bicycles can be categorized in many different ways: by function, by number of riders, by general construction, by gearing or by means of propulsion. The more common types include utility bicycles, mountain bicycles, racing bicycles, touring bicycles, hybrid bicycles, cruiser bicycles, and BMX bikes. Less common are tandems, low riders, tall bikes, fixed gear, folding models, amphibious bicycles, cargo bikes, recumbents and electric bicycles. Unicycles, tricycles and quadracycles are not strictly bicycles, as they have respectively one, three and four wheels, but are often referred to informally as bikes or cycles.
Light Reflectance Value (LRV) is the total quantity of visible and useable light reflected by a surface in all directions and at all wavelengths when illuminated by a light source. (ref.
An underwater remotely operated vehicle (ROV) is a mobile robot designed for aquatic work environments. Remote control is usually carried out through copper or fiber optic cables. A human operator sits in a shore-based station, boat or submarine bubble while watching a display that shows what the robot sees..