[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
[APML] New Digital Threatment Challenge
Hi guys, we have been talking a lot about vigneting, flat fields... so i guess that this could be of your interest
Here is a new digital threatment challenge. This time is about vigneting. All you have to do is generate a mask, o apply any algorithm to erradicate the unieven field illumination of this image. At the same time you have to pay attention to a portion of the Milky Way and a shadow from the dome (in oppositing sites of the image). Another problem is that it has a lot of sky pollution and the nearly radial profile isn't centered.
This image has been done in Cerro Pochoco Observatory, Santiago of Chile, and it is part of a series of exposures made to test the optical quality of a lens I have. It is a Canon nFD 50mm f/1.4 at f/2, 5 minutes with E200+2. Scanned using a Polaroid SprintScan 35 @ 2700dpi, and downsampled to the 50%. Only the dust and scratches has been deleted, no further proccessing.
You can use any way you want, and any program. You only have to: describe the whole proccess as much detailed as you can and send that text with the followind images: Mask (if you generated any) and the final image. This final image must have a levels adjustement (black and white points, with a clipping nearly the 0.01% of each channels pixels) and the gamma value changed to obtain a background with the RGB values (40,40,40).
Both images must be downsampled to the 50%. Also it a good idea to send the final image's histogram before the downsampling... All the images must be in "JPG" format..
You can do the levels adjustments anytime you want.
The main purpose of this challenge is to compare between different methods, programs, mask applications, etc., so please try as much methods as you can.
Regards,
Carlos Milovic F.
-------------------------
Astro & Photo - CMF
http://www.astrophoto.vze.com
-------------------------
Visita "AstroFoto", el foro de astrofotografía en español
http://espanol.groups.yahoo.com/group/astrofoto
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo
