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Modified Uniformly Redundant Array
A modified uniformly redundant array (MURA) is a type of mask used in coded aperture imaging. They were first proposed by Gottesman and Fenimore in 1989. Mathematical Construction of MURAs MURAs can be generated in any length ''L'' that is prime and of the form : L = 4m +1, \ \ m = 1,2,3,..., the first five such values being L = 5,13,17,29,37. The binary sequence of a linear MURA is given by A = _^, where : A_i = \begin 0 & \mbox i = 0, \\ 1 & \mbox i \mbox L, i \neq 0,\\ 0 & \mbox \end These linear MURA arrays can also be arranged to form hexagonal MURA arrays. One may note that if L = 4m + 3 and A_0 = 1 , a uniformly redundant array(URA) is a generated. As with any mask in coded aperture imaging, an inverse sequence must also be constructed. In the MURA case, this inverse ''G'' can be constructed easily given the original coding pattern ''A'': : G_i = \begin +1 & \mbox i = 0, \\ +1 & \mbox A_i = 1, i \neq 0,\\ -1 & \mbox A_i = 0, i \neq 0, \end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coded Aperture
Coded apertures or coded-aperture masks are grids, gratings, or other patterns of materials opaque to various wavelengths of electromagnetic radiation. The wavelengths are usually high-energy radiation such as X-rays and gamma rays. By blocking radiation in a known pattern, a coded "shadow" is cast upon a plane. The properties of the original radiation sources can then be mathematically reconstructed from this shadow. Coded apertures are used in X- and gamma ray imaging systems, because these high-energy rays cannot be focused with lenses or mirrors that work for visible light. Rationale Imaging is usually done at optical wavelengths using lenses and mirrors. However, the energy of hard X-rays and γ-rays is too high to be reflected or refracted, and simply passes through the lenses and mirrors of optical telescopes. Image modulation by apertures is therefore often used instead. The pinhole camera is the most basic form of such a modulation imager, but its disadvantage is low th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MURA Mask, Size 101
Mura may refer to: Places * Mura (Drava), a tributary of the Drava in Austria, Hungary, Slovenia and Croatia * Mura (Angara), a tributary of the Angara in Russia * Mura, Lombardy, a ''comune'' in the Province of Brescia, Italy * Mura, Barcelona, a municipality in the Province of Barcelona, Catalonia, Spain * Mura Statistical Region, in Slovenia People * Mura (surname) * Saint Mura (c. 550–645), first abbot of the monastery at Fahan, County Donegal, Ireland * Mura, mother of Chandragupta Maurya, the founder of the Maurya Empire in ancient India * Munda people of Tripura, India * Mura people, an indigenous people in Brazil * Mura (actor), Filipino actor and comedian Slovenian football clubs * NK Mura, a defunct Slovenian football club * ND Mura 05, a defunct Slovenian football club * NŠ Mura, a Slovenian football club Other uses * MurA or UDP-N-acetylglucosamine enolpyruvyl transferase, an enzyme * Mura, administrative units of modern villages of Japan and Edo-period vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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