fix-ca
fix-ca
overview
fix-ca is a gimp plug-in to correct
chromatic aberration (ca).
for general explanation about chromatic aberration, you can find
information from
wikipedia
and
writings
by paul van walree.
fix-ca is able to fix lateral ca caused by lens and colored fringing caused
by light travel through dense material such as glass and water (which is
called directional ca in the program).
current version of fix-ca is 3.0.1. the plug-in is written
by kriang lerdsuwanakij
<lerdsuwa@users.sourceforge.net>
and is distributed
under gnu general public license version 2 (gplv2).
it comes with absolutely no warranty. contact the author for any support
or bug report.
download and building fix-ca
fix-ca can be downloaded from
here.
just get the c source file.
to compile and install the plug-in, you need the development library
for gimp. usually it's in gimp-devel package in your distribution.
use the command
gimptool --install fix-ca.c
will automatically compile and install into the plug-in directory
of your account. if you wish to make the plug-in available to all
users of the machine, use
gimptool --install-admin fix-ca.c
instead. type gimptool --help for further help.
if gimp is already running in your system, exit and restart gimp
for the new plug-in to be detected. the following displays
fix-ca version 2.1.0 information from gimp xtns->plug-in browser menu.
using fix-ca
fix-ca plug-in can be accessed via the menu filters->colors->chromatic aberration....
there are two different modes of chromatic aberration that can be corrected by fix-ca:
lateral and directional.
lateral ca
lateral chromatic aberration appears due to lens imperfection.
for this type of ca, the center of the image has no ca and the ca
gradually increase toward the border. so the original image, rather than a cropped version,
should be used to eliminate the ca.
below left is the image used to demonstrate fix-ca plug-in capability
(full sized original here,
available under
gnu free documentation license
version 1.2 (gfdl) license). it's a photo of wat pathum wanaram,
a buddhist temple next to siam paragon, a major shopping mall in bangkok.
the areas of interest are marked with green rectangles.
note that the reduced size here is only for display purpose.
the actual processing is done on full sized image (with
green rectangles on a different layer, unaffected by the plug-in).
below right is 2x zoom of the areas.
the chromatic aberration (ca) is visible on the right images as red and
blue lines around bright area.
normally it is not noticable in the final image. but can be quite
visible when the image is cropped to smaller area and then used
(poor man's zoom).
invoking fix-ca plug-in via the menu filters->colors->chromatic
aberration....
with the settings shown in below left image (for version 2.1.0),
much of ca can be eliminated.
for version 3.0.0 blue and red settings depicted are moved
under the group lateral.
below right is the 2x zoom for the resulting change.
in the dialog box, setting red to -1.5 will shift the red channel inward to
the maximum of 1.5 pixels.
here positive number means moving outward, while negative number means inward.
since the orientation of this photo is portrait, the red channel of top and
bottom border will be moved by 1.5 pixels.
pixels at the inner part the red channel will be moved less
while the pixels at the center of image will not be moved at all.
(for landscape image, the left and right border will be moved by 1.5 pixels instead).
the interpolation parameter will control how the plug-in deals with fractional
pixel, for example, if the plug-in decides to move an image pixel by 0.8 pixel,
linear and cubic settings will try to get a value by averaging surrounding
pixels while none will pick the nearest pixel (for this example by moving 1 full pixel).
the setting preview saturation changes the saturation for the preview image.
this may help spotting ca problem. the setting does not have any effect on the
final image produced by this filter.
in this example we need to trade off between bottom right area (which suffers from
less ca) and the left area (the most ca).
when image is used cropped, you can concentrate on fixing in the part of image
that is actually used and ignore the rest. a better result can be expected.
just remember to correct ca before cropping.
directional ca
in directional chromatic aberration, the amount of ca is assumed to be the same
throughout the image. this can happen, for example, when photographing fishes
in an aquarium. light travels through dense water and glass and bends differently
depending on the color. this ca correction mode is introduced in fix-ca version 3.0.0.
you can specify the amount of shift for blue and red along both x and y axis.
(example to be added.)
version history
3.0.1 (july 5, 2007) fix a bug involving image row cache that cause bad ca
correction when the number of pixel moved is large.
3.0.0 (july 3, 2007) add ca fix in x and y axis.
2.1.0 (january 24, 2007) add saturation in preview. (suggested by reiner.)
2.0.0 (december 5, 2006) improve speed. add linear and cubic interpolation.
1.0.0 (november 30, 2006) first version.
future plan
a long target is for the plug-in to work automatically without
requiring user to carefully choose the amount of shift.
comments are also welcome.
web page content is copyrighted (c) 2006, 2007 by kriang lerdsuwanakij.
Acceuil
suivante
fix-ca Matrix Infinity Fix sur PsTwo - PsTwo la nouvelle PS2 de Sony ... Stop The ACLU » Blog Archive » Fred Thompson Proposes Social ... SPECIAL BATIMAT - De l'inédit chez Sader : Top Fix®, la Pâte à ... How to fix your iTunes artwork - Download Squad Offre d’emploi FIX Connectivity Specialist Investment Banking ... Thèses de l'ULP - Auteur: FIX, Thomas La Gallerie du Kap Course :: Beach volley by fix!!! Pattex - Ni Clou Ni Vis Fix & Défix : Toutcoller.com Siège coque - Créatis Fix BB Red - Fnac éveil et jeux - achat en ligne Operator @FIX - RSA, The Security Division of EMC FixMyVista.com - Your One Stop Windows Vista Fix It Site Groupe 0-0+, Cabrio Fix de Maxi Cosi : Aubert Pants'Fix trousers solution men homme - Vidéos Actualités Mode ... Fix Iraq - Free US Casualty In Iraq counter, join the discussion ... MacSlash iMac Freeze Fix Promised Fix You de Coldplay : paroles et extrait - Fluctuat.net Theory Fix (Isabelle2005: October 2005) Télécharger Object Fix Zip - 01net. Telecharger.com ... How to fix the Firefox memory leak (Firefox hack) « // Internet ... BYO - In Memoriam: Dr. George J. Fix III Jackie Craven: The Fix Tax Fix Avi Fix Repair Joiner : télécharger Avi Fix Repair Joiner Forums de wow-europe.com -> [INADMETTABLE] Fix teh banner ffs ... Développeur C++ /Protocoles FIX/ Bourse - Freelance-info Restaurant Fix Saint Geneys Haute-loire Restaurants Fix Saint Geneys Neowin.net - Apple Releases Fix for iMac Freeze Issue, fix not enough Fix-It : Home IBM - 6.0.2.7: WebSphere Application Server V6.0.2 Fix Pack 7 for ... Reborn Mr Fix-it, Ahmed Chalabi, pulls Iraq out of darkness ... KIT FIX ALFA/FIAT Howto fix Firefox Flash Video Sound on Ubuntu Linux Dapper ideal ... Bebe Confort Creatis Fix - Comparer les prix pour Bebe Confort ... Chevilles SPIT FIX II - BTP MAT If it ain't broke, don't fix it! (uit Engels in Frans translation ... Dvorak Uncensored » Blog Comment Spam Fix Numlock Fix for Linux Fix-Saint-Geneys - vue photo satellite Welkom op de Homepage van C-Fix Pants'Fix trousers solution women femme - Vidéos Actualités Mode ... Fix de rando sur piste ? - Skitour BANQUETTE PIANO CONCERT 172 FIX CUIR NOIR CAPITONNE (PORT OFFERT ... FPL annonce que le langage FIX Algorithmic Trading Definition ... Mobistar Fix Professionnal Nouveaux tarifs Mobistar Fix Professional Data Theft: How to Fix the Mess - New York Times Code Reviews: Find and Fix Vulnerabilities Before Your Application ... Philippe Fix - auteur-illustrateur jeunesse Fix design Recharge 750ml PHP Maximus CMS - Fix sécurité du module Sections Galerie Photo Plongée sous-marine de Plongeur.com - fix Galerie ... Air - Fix - Tecni.art Fix L'Oréal Professionnel sur Beauté-test.com Base Fixante à Paupières Fix It Essence sur Beauté-test.com sonnerie fix you (Sonnerie monophonique fix you) (suonerie.vnunet.it) Inside the Fix -nearly DTC. INSIDE THE FIX PRESENTE LE DOSSIER DU MOIS: La bibliothèque d'images du Wiki Autrans :: Autrans2004 par Fix Video: Your daily Tesla fix! - AutoblogGreen 156 Useful Run Commands