In 3-D computer graphics, ray tracing is a technique for modeling light transport for use in a wide variety of rendering algorithms for generating digital images.
A retroreflector is a device or surface that reflects radiation back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence. Being directed, the retroflector's reflection is brighter than that of a diffuse reflector. Corner reflectors and cat's eye reflectors are the most used kinds.
In most mammals and birds, the iris is a thin, annular structure in the eye, responsible for controlling the diameter and size of the pupil, and thus the amount of light reaching the retina. Eye color is defined by the iris. In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm.
Op art, short for optical art, is a style of visual art that uses optical illusions.
In mineralogy, crystal habit is the characteristic external shape of an individual crystal or aggregate of crystals. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities due to limited space in the crystallizing medium.
The vitreous body is the clear gel that fills the space between the lens and the retina of the eyeball in humans and other vertebrates. It is often referred to as the vitreous humor or simply "the vitreous". Vitreous fluid or "liquid vitreous" is the liquid component of the vitreous gel, found after a vitreous detachment. It is not to be confused with the aqueous humor, the other fluid in the eye that is found between the cornea and lens.
Satellite images are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell images by licensing them to governments and businesses such as Apple Maps and Google Maps.
Four-dimensional space (4D) is the mathematical extension of the concept of three-dimensional space (3D). Three-dimensional space is the simplest possible abstraction of the observation that one needs only three numbers, called dimensions, to describe the sizes or locations of objects in the everyday world. For example, the volume of a rectangular box is found by measuring and multiplying its length, width, and height. This concept of ordinary space is called Euclidean space because it corresponds to Euclid's geometry, which was originally abstracted from the spatial experiences of everyday life.
A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon. This includes both crewed and robotic missions. The first human-made object to touch the Moon was the Soviet Union's Luna 2, on 13 September 1959.
The term composition means "putting together". It can be thought of as the organization of the elements of art according to the principles of art. Composition can apply to any work of art, from music through writing and into photography, that is arranged using conscious thought.
A periorbital hematoma, commonly called a black eye or a shiner, is bruising around the eye commonly due to an injury to the face rather than to the eye. The name refers to the dark-colored bruising which is the result of accumulated blood and fluid in the loose areolar tissue following a blow to the head. This blood tracks freely under the scalp producing a generalised swelling over the dome of the skull but cannot pass into either occipital or the temple regions because of the bony attachments of the occipitofrontalis muscle. But this fluid can, however, track forward into the eyelid because the occipitofrontalis muscle has no bony attachment anteriorly. This leads to formation of hematoma a few hours after the head injury or cranial operation. If injury is more extensive, potentially even a skull fracture, an apparent black eye can sometimes worsen and may require professional medical treatment before it will resolve. This is more likely if the area around both eyes has been injured or if there is a history of prior head injury or fracture around the eye. Though disfiguring, the vast majority of black eyes are not serious, require little or no treatment, and will resolve spontaneously within a week or two.
A scleral lens, also known as a scleral contact lens, is a large contact lens that rests on the sclera and creates a tear-filled vault over the cornea. Scleral lenses are designed to treat a variety of eye conditions, many of which do not respond to other forms of treatment.
The "Elements of Art" are the building blocks for works of physical art that cannot be simplified to more basic components. Elements of art become stylistic features that are included within an art piece to help the artist communicate. The seven most common elements include line, shape, texture, form, space, color and value, with the additions of mark making, and materiality. When analyzing these intentionally utilized elements, the viewer is guided towards a deeper understanding of the work.
In Gaussian optics, the cardinal points consist of three pairs of points located on the optical axis of a rotationally symmetric, focal, optical system. These are the focal points, the principal points, and the nodal points; there are two of each. For ideal systems, the basic imaging properties such as image size, location, and orientation are completely determined by the locations of the cardinal points; in fact, only four points are necessary: the two focal points and either the principal points or the nodal points. The only ideal system that has been achieved in practice is a plane mirror, however the cardinal points are widely used to approximate the behavior of real optical systems. Cardinal points provide a way to analytically simplify an optical system with many components, allowing the imaging characteristics of the system to be approximately determined with simple calculations.
The pigmented layer of retina or retinal pigment epithelium (RPE) is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells.
The anterior segment or anterior cavity is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens.
Tenon's capsule, also known as the Tenon capsule, fascial sheath of the eyeball or the fascia bulbi, is a thin membrane which envelops the eyeball from the optic nerve to the corneal limbus, separating it from the orbital fat and forming a socket in which it moves.
Cryobatrachus is an extinct genus of temnospondyl amphibian from the Early Triassic of Antarctica. The type species is Cryobatrachus kitchingi. It is known from a partial skull and an imprint of the skull roof, both found in the Fremouw Formation of the Transantarctic Mountains at about 85° south latitude and described in 1974. Many small bone fragments have also been identified, although they cannot be attributed with certainty to C. kitchingi. Cryobatrachus has been classified in the family Lydekkerinidae, as it is similar in appearance to the genus Lydekkerina from South Africa. Because only a small number of features distinguish it from other lydekkerinids, Cryobatrachus kitchingi has more recently been considered a nomen dubium, meaning that its distinction from other better-known species may be unwarranted.
Aurora Flight Sciences is an American aviation and aeronautics research subsidiary of Boeing which primarily specializes in the design and construction of special-purpose Unmanned aerial vehicles. Aurora has been established for 20+ years and their headquarters is at the Manassas Regional Airport in Manassas, Virginia.
Calvino is a crater on Mercury. Its name was adopted by the IAU in 2016, after the Italian writer Italo Calvino.
