File:Zonenplatte_Cosinus.png
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Summary
DescriptionZonenplatte Cosinus.png |
Deutsch: Frenelsche Zonenplatte mit Sinusförmiger Transparenzfunktion. Programmcode zur Berechnung siehe unten.
English: Frenel's zone plate with sinusoidal transparency. For calculation code see below. |
Date | |
Source | Home brewed picture |
Author | Georg Wiora (Dr. Schorsch) |
Permission (Reusing this file) |
CC-BY-SA 2.5, 2.0, 1.0 and GFDL by the Author |
Licensing
This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic, 2.0 Generic and 1.0 Generic license.
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I, the copyright holder of this work, hereby publish it under the following licenses:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. | ||
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How To
The 8-bit intensity values of this image were computed by the following formula:
where is the distance to the image center in pixels.
The image has been computed with IDL (Interactive Data Language from www.rsinc.com ). The source code is provided here. Copy it into a file named "Zoneplatecosinus.pro" and execute it with IDL.
PRO ZONEPLATECOSINUS ; Pixel size of the image siz=1000 ; Coordinate array xc = LINDGEN(siz,siz) yc = xc / siz xc = TEMPORARY(xc) MOD siz ; Distances to center of array d = SQRT((FLOAT(xc)-siz/2.)^2+(FLOAT(yc)-siz/2.)^2) ; The image of the zone-plate zone = COS(d^2/5120) WINDOW,XSIZE=siz,YSIZE=siz ; Display it TVSCL,zone ; Save as PNG write_png,'zonenplatte2.png',BYTSCL(zone) END
Items portrayed in this file
depicts
19 August 2005
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 05:29, 17 May 2008 | 1,000 × 1,000 (260 KB) | Falcorian | pngout compression. | |
14:11, 19 August 2005 | 1,000 × 1,000 (296 KB) | Xorx | {{Information| |Description = Frenel's zone plate with sinusoidal transparency. |Source = Home brewed picture |Date = created 19. Aug. 2005 |Author = Georg Wiora ~~~ |Permission = Put under the GFDL by the Author. |other_versions = - }} {{GFDL-self}} |
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