One of the first Blogs worldwide to link to this project was “ang pilipino GIMP” from the Philipines. And now I am linking back. 
He describes a new packet called gimp-plugin-registry in the repositories of Ubuntu 8.10 (Intrepid Ibex), that contains 14 useful plugins. Among them stuff for making exposure blends, monochrome images with film look and feel, David’s Batch Processor, Liquid Rescale and GREYCstoration. Look at his posting for more details.
Will this title scare more people away than catch by curiosity? Who knows…..
The barrel distortion that gave me such problems last week is removed by using a built in filter for correcting (or simulating) lens distortions. You can find it in the image menu at Filters/Distorts/Lens Distortion.
As I have a lot of images with this error, I go out and write a special Python plugin to do this task. It’s not as complicated as it seems – I have a good template and the Web and Gimp give a lot of useful information. You can find the scripts used in this episode here on the Download Page
EDIT: If you are using Windows and GIMP 2.4.x, have a look here for informations about setting up Python for GIMP.
EDIT2: This is supposed to be even easier.
This is the finished Python program:
#!/usr/bin/env python
import math
from gimpfu import *def remove_barrel_distortion(img, drw):
img.disable_undo()
layer_corr = drw.copy(True)
layer_corr.mode = NORMAL_MODE
layer_corr.name = “Barrel corrected”
img.add_layer(layer_corr, -1)pdb.plug_in_lens_distortion(img, layer_corr, 0.0, 0.0, -12.0, 0.0, 0.0, 0.0)
img.enable_undo()
gimp.displays_flushregister(
“remove_barrel_distortion”,
“Removes the barrel distortion of a Sanyo CA65″,
“”,
“Rolf Steinort <info @meetgimp.org>”,
“public domain”,
“2008″,
“<image>/Filters/Distorts/B_arrel distortion removal CA65″,
“RGB*, GRAY*”,
[],
[],
remove_barrel_distortion)main()
You find a similar program in this posting. There I have torn it apart and described all the parts. The Python for GIMP documentation and this website can be helpful.
Don’t forget the challenge! Make a monochrome image and post it in our meetthegimp.org photogroup at 23 and be sure to use the tag “mtg-monochrome”. The challenge ends March 31 1600GMT and I’ll draw a winner by random choice.
You can leave your comments on this blog or write me a mail.
00:23 Update from the last episode
01:50 Lens Distortion
06:02 Comments on the blog
08:47 Programming in Python
09:40 – Discussion on the blog
10:56 – Explaining the Python program
20:33 – Procedure browser
25:31 – Parameters
27:35 – Error messages
29:30 – Adding a new layer
32:33 – Summary
34:01 “23″ image hosting
36:09 The End
TOC made by paynekj
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
You can get a new version of the liquid rescale plugin of episode 14. Buralex mailed me that info – thanks! And he said that the plugin is indeed improved. I copy that part of his mail here:
I found it much easier to work with – you might want to retry the “cows” to see if you agree 
Changes are:
* Faster engine
* Different use of preserve/discard layers
* Works on floating selections
* Rigidity introduced to control the seams Interface
* New interface with notebook
* Output to new layer option
* Visualization of seams in a separate layer
* Refresh button
* Create new layer button
* More sensible strength scale
* Added tooltips
New version changes the preferred way to use the plug-in.
Now you
1. Open the dialog and click “New” in “Feature preservation mask” group.
2. Temporarily move the dialog somewhere and use the brush to mark features to preserve in the new layer that LqR has just created for you. Note that color of brush has automagically changed to green.
3. Go back to the dialog and click “Refresh”. Preview will be updated, so small preview of the layer above will.
4. If you need to remove some features, do the same with “Feature discard mask”. Note that color of the brush will automatically change to red.
5. Define new size, strength for each mask, gradient function etc. Click OK.
New Rigidity option is useful when you have a number of “structured” objects (e.g. architecture, windows etc.) that have straight lines that should not be distorted.
Thanks for the mail, Alec! I’ll try that after I have worked out my email trouble.
Liquid Rescaling or Seam Carving – two names for a new way to change the proportions of pictures while keeping the content in shape. The Gimp now has such a plugin and I’ll show you how to use it. COWS? Well, they are important…..
Edit: There is a new version of the plugin out.
I promised some links:
Don’t forget to make a triptych and post it in the photogroup. I’ll draw a winner for the one year 23Plus membership sponsored by 23 in show 16. So you have still time to Oct. 18 to submit an entry. The pictures there are already worth to be looked at.
00:23 Welcome
00:32 Liquid rescaling
02:34 Getting the plug-in
03:24 The start image
03:50 Shrinking the standard way
05:07 Shrink using liquid rescale
06:40 Comparing the two results
08:40 Protecting some areas
10:25 Removing some parts
10:55 Running the plug-in
12:58 Making a panorama
15:50 Not quite so wide
16:55 Stretching the panorama again
20:10 23hq photo sharing
24:13 The end
TOC made by paynekj
You can leave your comments on this blog or write me a mail.
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
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