Photonics Dictionary: C

The transmission of a color photograph by separating the colors into varying intensities of red, blue and green, and then sending separate transmissions of the three color signals to a receiving...

A television system that is capable of producing an image whose colors approximate the colors of the original, by the use of additive color mixing of the three primary colors.

A device containing two photocells behind deep red and blue filters to measure color temperatures. The amplifier gain is adjusted to give a set reading of one photocell; the reading of the other is a...

A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides objective and standardized color information, typically expressed in terms...

A photometer that uses a set of color filters to measure the intensity of light in various regions of the spectrum.

A lens aberration, resulting from different magnifications in the various lens zones, that occurs in that part of the image field that is some distance from the principal axis of the system....

A filter that passes a series of wavelength regions that are at equal distances from one another, such that its output resembles the teeth of a comb. In video transmission, a comb filter is used to...

Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging light, to maintain focus.

Complementary metal-oxide-semiconductor (CMOS) refers to a technology used in the fabrication of integrated circuits, particularly semiconductor devices like microprocessors, memory chips, and image...

A device for obtaining very low crosstalk in a crosspoint by arranging two simple switches along different arms of a passive crossover and connecting the switches with a curved connecting guide to...

The use of a computer to generate a series of interrelated images so that the images give the illusion of movement in space and time.

Computer vision enables computers to interpret and make decisions based on visual data, such as images and videos. It involves the development of algorithms, techniques, and systems that enable...

A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than traditional optical techniques. CGHs are generated entirely in digital form...

Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In the context of geometry or optics, a concave shape is one that curves or...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These mirrors are commonly used in optics for various applications, including...

1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from or converging upon a point are sometimes referred to as a cone of light. 2....

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

Hardware installed on fiber cable ends to provide cable attachment to a transmitter, receiver or other cable. Usually a device that can be connected and disconnected repeatedly.

That property of certain optical devices, e.g., a penta prism, that maintains the angular relationship between the entering and the emerging rays traversing the system regardless of the orientation...

Technique that uses high-pass filtering to reduce the local average to zero for all regions of the picture and then applies a gain factor equal to the reciprocal of the local standard deviation to...

The maximum number of users who are using a given communication channel. Typically, the number of users at any given time is below this maximum, with the contention rate representing a worst case...

Selection of specific brightness values or minimum threshold levels as contingencies for the display of digital data.

The apparent difference in brightness between light and dark areas of an image. For a light target against a dark background, contrast is computed as follows: where Lt is the luminance of the...

A filter designed to improve contrast in an imaging system. For visual and black and white photosystems, a yellow filter is used.

One area of image enhancement, accomplished by spatial filtering schemes, that usually involves attenuation of phase changes in the complex amplitude over a limited region of the Fourier spectrum of...

Convex is an adjective used to describe a surface or shape that curves outward, bulges, or has a rounded and outwardly extending appearance. In the context of geometry or optics, a convex shape is...

A powerful and flexible machine-learning approach that can be used in machine vision to help solve difficult problems. Inspired by biological processes, multiple layers of neurons process portions of...

The simplest lens in which all primary aberrations may be corrected. It consists of two positive crown elements on either side of, and spaced away from, a negative flint element.

The light-conducting portion of an optical fiber, defined by the region of high refractive index.

A corner cube, also known as a corner reflector or retroreflector prism, is a type of optical device used to reflect light or electromagnetic waves back towards their source with minimal deviation in...

A compound prism formed by cementing together two 30° prisms, one of right-handed and one of left-handed quartz. It has good ultraviolet-transmitting qualities and no double refraction.

Solar regions characterized by low density and open magnetic fields where high-speed solar wind streams originate. Originally believed to be "M'' regions, coronal holes are the precursors of the...

A formula indicating that, for an imaging lens system, the image brightness for off-axis points will fall off at a rate proportional to the cos4 of the off-axis field angle.

Law relating the illuminance (or irradiance) of a surface to the cosine of the angle, q, between the normal to the surface and the direction of the incident wave.

A coverslip, also known as a cover glass or cover slip, is a thin and flat piece of transparent material typically made of glass or plastic. It is used in microscopy to cover a specimen mounted on a...

Observed when alterations in the luminous sterance at the contour of an object create the illusion of the outer zones appearing darker than the inner regions, despite the consistent luminance of the...

Cresyl violet, also known as cresyl violet acetate or cresyl echt violet, is a synthetic organic compound belonging to the class of triarylmethane dyes. It is commonly used in histology and...

That wavelength at which the absorption of a given element or system begins to demonstrate an inconstant value.

The least angle of incidence at which total internal reflection takes place. The angle of incidence in a denser medium, at an interface between the denser and less dense medium, at which the light is...

In an optical system, the aperture size at which the lens gives its best overall performance.