Radar imaging is a technique that uses radar pulses to extrapolate an image, picture, or video of an object, rather than just its position or direction of movement. This is typically accomplished through radar image processing, which is a computationally intense activity that uses algorithms to form images from radar pulse backscatter. The information received in the form of backscatter is processed in order to determine the precise electromagnetic scattering coefficient of various objects, in order to form a visual image. In order to deal with the high computational requirements of radar image processing, specialized central processing units (CPUs) and networked computer clusters are often employed.
Traditional radar systems are designed to send out electromagnetic pulses, which are reflected back when they hit certain types of objects. By examining various factors, such as how long it takes a reflected pulse to return, it is possible to determine the presence of an object and what direction it is moving in. This technology has existed since the 1940s, though the initial concepts date back to the late 1800s. It is also possible to use electromagnetic radar pulses to recreate a visual image of an object, though that is a much more complex operation that typically requires intensive signal processing.
The process of radar imaging is similar to traditional radar, in that it involves sending out electromagnetic pulses. Backscatter from the pulses is examined more thoroughly though, and subjected to a process referred to as radar image processing. There are a few different ways to examine radar backscatter in order to extrapolate an image, though they typically involve calculating the scattering coefficient of the areas that are under observation. Radar image processing breaks these areas up into pixels, or picture elements, and the precise behavior of the backscatter is used to extrapolate an image.
Complex algorithms are typically used in order to create accurate images through radar image processing. In order to facilitate these computationally intense activities, specialized CPUs with signal processing architecture are sometimes used. Clusters of workstations working in parallel are sometimes also necessary to carry out radar image processing, in order to perform the necessary level of computations in a reasonable time frame.
Radar imaging can be carried out by ground based installations, airplanes, and even satellites. The technology has created images of the surface of the Earth, in addition to various celestial objects such as the moon, other planets, and some asteroids. Radar imaging also has military applications in addition to scientific uses, since it can be used to create accurate images of potential targets.