PixelIn digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, pixels are the smallest element that can be manipulated through software. Each pixel is a sample of an original or synthetic image; more samples typically provide more accurate representations of the original. The intensity of each pixel is variable.
Google PixelGoogle Pixel is a brand of portable consumer electronic devices developed by Google that run either ChromeOS or the Android operating system. The main line of Pixel products consist of Android-powered smartphones, which have been produced since October 2016 as the replacement of the older Nexus, and of which the Pixel 7 is the current model. The Pixel brand also includes laptop and tablet computers, as well as several accessories, and was originally introduced in February 2013 with the Chromebook Pixel.
Pixel 6The Pixel 6 and Pixel 6 Pro are a pair of Android smartphones designed, developed, and marketed by Google as part of the Google Pixel product line. They collectively serve as the successor to the Pixel 5. The phones were first previewed in August 2021, confirming reports that they would be powered by a custom system-on-chip named Google Tensor. The cameras are housed in a horizontal bar on the back, while the front features a hole-punch display notch in the center.
X-ray tubeAn X-ray tube is a vacuum tube that converts electrical input power into X-rays. The availability of this controllable source of X-rays created the field of radiography, the imaging of partly opaque objects with penetrating radiation. In contrast to other sources of ionizing radiation, X-rays are only produced as long as the X-ray tube is energized. X-ray tubes are also used in CT scanners, airport luggage scanners, X-ray crystallography, material and structure analysis, and for industrial inspection.
Pixel 2The Pixel 2 and Pixel 2 XL are a pair of Android smartphones designed, developed, and marketed by Google as part of the Google Pixel product line. They collectively serve as the successors to the Pixel and Pixel XL. They were officially announced on October 4, 2017 at the Made by Google event and released in the United States on October 19. On October 9, 2018, they were succeeded by the Pixel 3 and Pixel 3 XL. In early March 2017, Google's Rick Osterloh confirmed that they would bring a "next-gen" Pixel smartphone later that year.
AttenuationIn physics, attenuation (in some contexts, extinction) is the gradual loss of flux intensity through a medium. For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at variable attenuation rates. Hearing protectors help reduce acoustic flux from flowing into the ears. This phenomenon is called acoustic attenuation and is measured in decibels (dBs). In electrical engineering and telecommunications, attenuation affects the propagation of waves and signals in electrical circuits, in optical fibers, and in air.
Pixel 4The Pixel 4 and Pixel 4 XL are a pair of Android smartphones designed, developed, and marketed by Google as part of the Google Pixel product line. They collectively serve as the successors to the Pixel 3 and Pixel 3 XL. They were officially announced on October 15, 2019 at the Made by Google event and released in the United States on October 24, 2019. On September 30, 2020, they were succeeded by the Pixel 5. Google confirmed the device's design in June 2019 after renders of it were leaked online.
X-rayX-ray radiation, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3e16Hz to 3e19Hz) and energies in the range 124 keV to 145 eV, respectively. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays.
X-ray spectroscopyX-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation. When an electron from the inner shell of an atom is excited by the energy of a photon, it moves to a higher energy level. When it returns to the low energy level, the energy which it previously gained by the excitation is emitted as a photon which has a wavelength that is characteristic for the element (there could be several characteristic wavelengths per element).
Inverse problemAn inverse problem in science is the process of calculating from a set of observations the causal factors that produced them: for example, calculating an image in X-ray computed tomography, source reconstruction in acoustics, or calculating the density of the Earth from measurements of its gravity field. It is called an inverse problem because it starts with the effects and then calculates the causes. It is the inverse of a forward problem, which starts with the causes and then calculates the effects.
