The TESS Input Catalog

The Transiting Exoplanet Survey Satellite (TESS), launched on April 18, has as its core mission goal to discover small transiting exoplanets orbiting nearby bright stars, and to do so it will conduct a nearly all-sky photometric ...

Image: Gullies of Matara Crater

Gullies on Martian sand dunes, like these in Matara Crater, have been very active, with many flows in the last 10 years. The flows typically occur when seasonal frost is present.

Image: The case of the Martian boulder piles

This image was originally meant to track the movement of sand dunes near the North Pole of Mars, but what's on the ground in between the dunes is just as interesting!

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Pixel

In digital imaging, a pixel, or pel, (picture element) is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled.

Each pixel has its own address. The address of a pixel corresponds to its coordinates. Pixels are normally arranged in a two-dimensional grid, and are often represented using dots or squares. Each pixel is a sample of an original image; more samples typically provide more accurate representations of the original. The intensity of each pixel is variable. In color image systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black.

In some contexts (such as descriptions of camera sensors), the term pixel is used to refer to a single scalar element of a multi-component representation (more precisely called a photosite in the camera sensor context, although the neologism sensel is sometimes used to describe the elements of a digital camera's sensor), while in others the term may refer to the entire set of such component intensities for a spatial position. In color systems that use chroma subsampling, the multi-component concept of a pixel can become difficult to apply, since the intensity measures for the different color components correspond to different spatial areas in a such a representation.

The word pixel is based on a contraction of pix ("pictures") and el (for "element"); similar formations with el  for "element" include the words voxel and texel.

This text uses material from Wikipedia, licensed under CC BY-SA