Feet Definition. A foot (pl. feet) is a common length unit used in Imperial system and the current US customary unit system. A foot is equal to 0.3048 meter. This unit of length has been used in Europe since the times of the Roman Empire and ancient Greece. A foot has 12 inches, and 3 foot make a yard.
Holography is the science and practice of making holograms. Typically, a hologram is a photographic recording of a light field, rather than of an image formed by a lens, and it is used to display a fully three-dimensional image of the holographed subject, which is seen without the aid of special glasses or other intermediate optics. The hologram itself is not an image and it is usually unintelligible when viewed under diffuse ambient light. It is an encoding of the light field as an interference
Some of the light is reflected off the object onto the recording medium. The second beam, known as the reference beam, is directed onto the recording medium. This way, it doesn't conflict with any imagery that comes from the object beam, and coordinates with it to create a more precise image in the hologram location.arious types of holograms have been made over the years, including transmission holograms, which allow light to be shined through them and the image to be viewed from the side; and rainbow holograms, which are used for security purposes â on credit cards and driver's licenses, for example. Recording a hologram.