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| @@ -1,26 +1,26 @@ | ||
| # Fix-CA | ||
| # GIMP3-Fix-CA | ||
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| ## Overview | ||
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| Fix-CA is a [GIMP](http://www.gimp.org/) plug-in to correct Chromatic Aberration | ||
| (CA). For a general explanation about Chromatic Aberration, you can find | ||
| information from | ||
| [Wikipedia](http://en.wikipedia.org/wiki/Chromatic_aberration). | ||
| Fix-CA is able to fix Lateral CA colored fringing caused by light travelling | ||
| through lenses, and Directional CA caused by light travelling through dense | ||
| material such as glass and water. | ||
| GIMP3-Fix-CA is a [GIMP](http://www.gimp.org/) plug-in to correct Chromatic Aberration | ||
| (CA). For a general explanation about Chromatic Aberration, you can find information | ||
| from [Wikipedia](http://en.wikipedia.org/wiki/Chromatic_aberration). | ||
| GIMP3-Fix-CA can fix Lateral CA colored fringing caused by light travelling through | ||
| lenses, and Directional CA caused by light travelling through dense material such as | ||
| glass or water. | ||
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| This plug-in was written by Kriang Lerdsuwanakij [email protected] | ||
| and is distributed under [GNU General Public License Version 3](COPYING) (GPLv3). | ||
| Several patches and improvements were later added in 2023,2024 by Jose Da Silva. | ||
| GIMP2-Fix-CA was written by Kriang Lerdsuwanakij [email protected], and | ||
| several patches and improvements were later added in 2023,2024 by Jose Da Silva. | ||
| GIMP3-Fix-CA uses a lot of the same code with modifications to run for GIMP3. | ||
| Fix-CA is distributed under [GNU General Public License Version 3](COPYING) (GPLv3). | ||
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| ## Using Fix-CA | ||
| ## Using GIMP3-Fix-CA | ||
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| Fix-CA plug-in can be accessed via the menu 'Filters->Colors->Chromatic Aberration' | ||
| There are two different types of Chromatic Aberration that can be corrected by Fix-CA: | ||
| Lateral and Directional. | ||
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| There are two types of Chromatic Aberration that can be corrected by GIMP3-Fix-CA: | ||
| Lateral and Directional. | ||
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| ### Lateral CA | ||
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@@ -45,12 +45,13 @@ Below is the image used to demonstrate Fix-CA plug-in capability | |
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| This is 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 purposes. | ||
| The actual processing is done on the full sized image (with green rectangles | ||
| left "as-is" on a different layer, unaffected by the plug-in). | ||
| rectangles. Note that the reduced size here is only for display purposes here. | ||
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| Below are 200% zoom of the four areas. The chromatic aberration (CA) is | ||
| visible on the images as red and blue lines around bright area. | ||
| The actual processing is done on the full sized image (with green pixels left in | ||
| same positions "as-is", and the blue or red pixels are moved outwards or inwards. | ||
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| Below are 200% zoom of the four areas before processing. The Chromatic Aberration | ||
| (CA) is visible on these images as red and blue lines around bright areas. | ||
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|  | ||
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@@ -59,27 +60,42 @@ but can be quite visible when the image is cropped to a smaller area and then | |
| expanded. | ||
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| Invoking Fix-CA plug-in using the menu 'Filters->Colors->Chromatic Aberration' | ||
| With the settings shown below image (for version 2.1.0), much of the CA can be | ||
| eliminated (for version 3.0.0 blue and red settings are moved into group 'Lateral'). | ||
| with the 'Lateral' settings shown below can help improve or this image. | ||
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|  | ||
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| When you are going to correct for Lateral CA, you should look around the edges. | ||
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| The corners tend to have the worst Lateral CA, and you begin correcting there. | ||
| If you correct one corner, the rest of the picture should look okay too, therefore | ||
| check the other corners and edges using preview ON/OFF as you look around. | ||
| If the image center is not the lens center, or some alignment is off, then you | ||
| will want to move the lens center around a little bit a little bit off center, | ||
| and then check the corners and edges again until it looks okay to you. | ||
| The poor man's zoom of the branches (shown below) is an example you can try where | ||
| the lens center is off-center, and the lens alignment may be a little skewed too. | ||
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| In the dialog box, setting red to -1.5 will shift the red channel inward to | ||
| the maximum of 1.5 pixels. Here the positive number means moving outward, | ||
| while the negative number means inward. Since the orientation of this photo | ||
| is portrait, the red channel of top and bottom border will moved by 1.5 pixels. | ||
| is portrait, the red channel of top and bottom border will move 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 a landscape image, the | ||
| left and right border will be moved by 1.5 pixels instead). | ||
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| The LensX=1296/LensY=1944 is the image center, which is also the assumed optical | ||
| lens center. The lens center point can be moved around if you find one side needs | ||
| more correcting than the other side. Setting LensX=-1/LensY=-1 is also the same | ||
| as choosing the image center. | ||
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| The interpolation parameter controls how the plug-in deals with fractional | ||
| pixels, 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 | ||
| the surrounding pixels while 'None' will pick the nearest pixel (for this | ||
| example by moving 1 full pixel). | ||
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| The 'Preview saturation' setting changes the saturation for the preview image. | ||
| This may help you spot CA problems. The setting does not have any effect on the | ||
| This helps you spot CA problems. This setting does not have any effect on the | ||
| final image produced by this filter. | ||
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| Below is the 200% zoom for the resulting change using the above corrections. | ||
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@@ -88,29 +104,45 @@ Below is the 200% zoom for the resulting change using the above corrections. | |
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| In this example above we need to trade off between bottom right area (which | ||
| suffers from less CA) and the left area (the most CA). | ||
| If the image used is cropped, you can concentrate on fixing in the part of the | ||
| image that is actually used and ignore the rest. Just remember, a better result | ||
| can be expected if you correct CA before cropping. | ||
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| Now that we know one side has more CA than the other, we can improve this image | ||
| further by moving the lens center towards the direction of less CA... | ||
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| If we move the lens center right to approx LensX=1406, and increase Red=-2.0 | ||
| due to the added distance on the left, this seems to resolve both left and right | ||
| sides. If you look at the bottom left corner, you will see some blue beginning | ||
| to appear, so if you change Blue=+0.6 this seems to fix that too....but we also | ||
| seem to have negative changes happening towards the wall near the roof.... | ||
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| ...let's try again.... reset LensX=1296/LensY=1944 (or use LensX=-1/LensY=-1). | ||
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| Before we start moving LensX/LensY, let us change saturation=100%, and let us | ||
| also try changing Red=-1.5 to Red=+1.5 instead, this is actually looking better. | ||
| ...and seeing some blue let us also change Blue=-1.2, and we see better results | ||
| everywhere... and we also did not have to change LensX/LensY from image center. | ||
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| For the majority of your pictures and images, you can assume the lens center is | ||
| also at the image center (unless you're working with a cropped image). If you want | ||
| to fix the [full sized original here](img-fix-ca/full-Wat_Pathum_Wanaram.jpg) | ||
| image further, then Fix-CA (version 4.0) now adds the ability to also move the | ||
| lens centerpoint (default is center of image). | ||
| Below you will see added variables LensX, LensY, allowing you to move the lens centerpoint to another location on the image. | ||
| also at the image center (unless you notice more left/right or up/down CA), or | ||
| if you are working with a cropped picture which may have the center elsewhere. | ||
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| Today's digital self-contained cameras are unlikely to have lateral problems | ||
| since they likely have built in software to correct for lateral problems, but you | ||
| can probably expect some amount of lateral CA for older analog type cameras. | ||
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| Below is an example image using a poor man's zoom attached to a smartphone. | ||
| Even though a smartphone can correct an image for it's own lens, the poor man's | ||
| zoom attachment adds Lateral CA as well as having the lens center off to one side. | ||
| You may notice the pixel corrections seem like large values like 6.0, but this | ||
| applies to the (black) corners, and reduces down to about 3.0 around the edges of | ||
| where the lens image begins, eventually 0 pixel shift at lens center (658,1280). | ||
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|  | ||
|  | ||
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| To correct this, you may notice the pixel corrections seem like large values | ||
| like 6.0, but this applies to the (black) corners, and reduces down to about | ||
| 3.0 around the edges of where the lens image begins, eventually a zero pixel | ||
| shift what seems to be a lens center of LensX=658/LensY=1280. | ||
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|  | ||
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| Below is a Preview (off) of the leaves (showing blue). This can be corrected | ||
| using the Lateral CA settings shown above (can be seen with Preview on). | ||
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@@ -124,9 +156,7 @@ The [full sized original is here](img-fix-ca/full-branches.jpg). | |
| In Directional Chromatic Aberration, the amount of CA is assumed to be the | ||
| same throughout the image. This happen, for example, when photographing | ||
| fish in an aquarium. Light travels through dense water and glass and bends | ||
| differently depending on the color and angle from the glass. This CA correction | ||
| mode was 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. | ||
| differently depending on the color and angle from the glass. | ||
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| This example is a complete photo of a sleeping sea turtle. | ||
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@@ -150,35 +180,37 @@ The picture below shows (50% zoom) corrected image of the interested region. | |
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|  | ||
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| ## Download and building Fix-CA | ||
| ## Download and building GIMP3-Fix-CA | ||
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| Fortunately, everything is in just one file. 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 | ||
| ```sh | ||
| gimptool-2.0 --install fix-ca.c | ||
| gimptool-3.0 --install fix-ca.c | ||
| ``` | ||
| will automatically compile and install into the local plug-in directory | ||
| of your account. For Windows users, if you wish to make the plug-in | ||
| of your home account. For Windows users, if you wish to make the plug-in | ||
| available to all users of the machine, use | ||
| ```sh | ||
| gimptool-2.0 --install-admin fix-ca.c | ||
| gimptool-3.0 --install-admin fix-ca.c | ||
| ``` | ||
| instead. (use the Installation method below for other OSes). Type | ||
| ```sh | ||
| gimptool-2.0 --help | ||
| gimptool-3.0 --help | ||
| ``` | ||
| for further help. | ||
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| 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 the GIMP menu. | ||
| plug-in to be detected. The following displays GIMP3-Fix-CA information from | ||
| the GIMP menu. | ||
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|  | ||
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| ## Installation method | ||
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| Developers and Distro installers will be more interested in this install method. | ||
| This method also includes local language support (for included languages). | ||
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| Installing from Git master requires 2 preparatory steps: | ||
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@@ -222,6 +254,11 @@ make install | |
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| ## Version History | ||
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| GIMP3-Fix-CA | ||
| - 0.0 (May 15, 2024) First version. | ||
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| GIMP2-Fix-CA | ||
| - 4.0 (February 29, 2024) Upgraded code to use GIMP-2.10 API. Now Gimp-Fix-CA works with RGB/RGBA with precisions of 8bit, 16bit, 32bit, or double for each color of R,G,B,A. Also added Lens X/Y center and a lens centerline in the preview window. Local Language support now included for the installable Gimp-Fix-CA. This version is bumped to 4.0 since it requires GIMP-2.10.xx, and also because non-interactive scripting also requires Lateral Lens X/Y positions (default=-1,-1) | ||
| - 3.0.4 (December 2, 2023) mostly edits around make system. Minimal mods to fix-ca.c code (which needs updating). | ||
| - 3.0.3 (October 8, 2022) autoconf/automake/configure/make added for building fix.ca | ||
| - 3.0.2 (December 22, 2007) Add the missing tile cache that speed up preview. | ||
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@@ -232,4 +269,6 @@ make install | |
| - 1.0.0 (November 30, 2006) First version. | ||
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| Note: The Original Web page content and pictures are copyrighted (c) 2006, 2007 by Kriang Lerdsuwanakij. | ||
| Note: The Original Web page content and pictures are copyrighted (c) 2006, 2007 | ||
| by Kriang Lerdsuwanakij. New Added images and web page content added 2022..2024 | ||
| by Jose Da Silva are under the same license as this GPL3+ project. | ||
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