Concentration of light, especially sunlight, can burn. The word caustic, in fact, comes from the Greek καυστός, burnt, via the Latin causticus, burning. A common situation where caustics are visible is when light optical Textures 1 PDF on a drinking glass.
Författare: Vincenzo Sguera.
The glass casts a shadow, but also produces a curved region of bright light. Another familiar caustic is the rainbow. Scattering of light by raindrops causes different wavelengths of light to be refracted into arcs of differing radius, producing the bow. In computer graphics, most modern rendering systems support caustics. Some of them even support volumetric caustics.
This is accomplished by raytracing the possible paths of a light beam, accounting for the refraction and reflection. Photon mapping is one implementation of this. The focus of most computer graphics systems is aesthetics rather than physical accuracy. This is especially true when it comes to real-time graphics in computer games where generic pre-calculated textures are mostly used instead of physically correct calculations.
Researchers have found that they can make use of caustics to create a desired image by shaping transparent material in a particular way. GPU Gems: Programming Techniques, Tips and Tricks for Real-Time Graphics. Caustics water texturing using Unity 3D”. Natural Focusing and Fine Structure of Light: Caustics and Wave Dislocations. Real-time volume caustics with adaptive beam tracing”.
Symposium on Interactive 3D Graphics and Games. Cephalopod molluscs such as this cuttlefish can change color rapidly for signalling or to match their backgrounds. Active camouflage or adaptive camouflage is camouflage that adapts, often rapidly, to the surroundings of an object such as an animal or military vehicle. In theory, active camouflage could provide perfect concealment from visual detection. Active camouflage is used in several groups of animals, including reptiles on land, and cephalopod molluscs and flatfish in the sea. Military counter-illumination camouflage was first investigated during World War II for marine use.
More recent research has aimed to achieve crypsis by using cameras to sense the visible background, and by controlling Peltier panels or coatings that can vary their appearance. Active camouflage provides concealment by making an object not merely generally similar to its surroundings, but effectively invisible with “illusory transparency” through accurate mimicry, and by changing the appearance of the object as changes occur in its background. Yehudi Lights prototype raised the average brightness of a Grumman Avenger from a dark shape to the same as the sky. Military interest in active camouflage has its origins in Second World War studies of counter-illumination.
Using visual data from a camera, an object could perhaps be camouflaged well enough to avoid detection by the human eye and optical sensors when stationary. An invisibility cloak using active camouflage by Susumu Tachi. Left: The cloth seen without a special device. Active camouflage technology exists only in theory and proof-of-concept prototypes. In 2003 researchers at the University of Tokyo under Susumu Tachi created a prototype active camouflage system using material impregnated with retroreflective glass beads. In 2010, the Israeli company Eltics created an early prototype of a system of tiles for infrared camouflage of vehicles. In 2011, BAE Systems announced their Adaptiv infrared camouflage technology.