mike's blog

Siggraph 2010, new preprints

Posted Mon, 26/07/2010 - 13:12 by mike

Hi folks,

just if you haven't heard, the annual SIGGRAPH is running and there is a website by Ke-Sen Huang which links to the available preprints.

As a local contrast addict, I'm most curious about Smoothed local Histogram Filters by Michael Kass and Justin Solomon. Since they also offer some pseudo code, I hope it won't take to long till it is available as open source. Let's see Wink

So, go ahead, read the news, Laughing out loud

greets mike

Adaptive saturation curve for LabCurves

Posted Fri, 09/07/2010 - 22:10 by mike

Hi folks,

finally here is the first update for LabCurves.

The main new feature is a saturation curve, which could be used in an absolute or adaptive way. You can change the saturation of certain colors or of certain luminosities. Furthermore it is now possible to have a linear curve which helps changing only the saturation of some colors. However, for the other curves this will not be very important. You can change these things in the context menues of the corresponding curve windows. Finally, there are several internal changes like the switch to lcms 2 and several improvements for multicore systems, on which it should be much faster now (depending on the number of cores).

LabCurves

However, because of lcms 2 I'm not able to share linux binaries at the moment, since lcms 2 is not yet included in most distributions. Statically linking would be a way to have binaries again, but I don't know how to do this, so please help me with it.

More about LabCurves here.

greets mike

Installation instructions

Posted Sun, 27/06/2010 - 12:17 by mike

 Hi folks, 

since I got several questions about installing LabCurves, here are some tips that might help you.

  • Make sure Gimp can use Python. You can test this with python scripts from the gimp plugin registry (files ending with "py"). Python on windows.
  • "7z" archives can be extracted with 7-zip.
  • On linux: You need the regular lcms, graphicsmagick and libqt4 packages, the dev packages are only needed if you want to recompile the program.
  • On linux: Copy the script and the folder containing the program to your gimp plugins (not scripts) directory.
  • On linux: Set the script and the program executable.
  • On windows: copy the script to your gimp plugins directory and the folder containing the program to "C:\Tools\". If you choose a different folder alter the script accordingly. Don't choose a subfolder of your gimp directories.
  • The filter is located in "Filters - MM Filters".

I hope this clarifies most of the questions.

greets mike

WIP: Saturation curve for GIMP

Posted Fri, 25/06/2010 - 21:31 by mike

Hi folks, 

just a few lines, to give you an impression of the next step for LabCurves (16 bit L*a*b* curves for GIMP).

Since a link to LabCurves is always followed by a link to L*a*b* color space basics, people seem to have troubles with this color model. Although it is very powerful for image enhancements it is rather unintuitive. Working with the luminance L* is still ok, but working with a* and b* seems more or less try and error.

So, here is an approach towards usability with L*a*b*: a saturation curve which will work relative to the luminance or relative to the hue. I hope this will be easier to handle than a* and b*. And since harsher saturation adjustments are prone to banding anyway, they will profit from the 16 bit in LabCurves.

It is still work in progress, so you still have to wait a few days... The image edited in the screenshots is a 8-bit jpeg, after some minor luminance adjustments you can see the effect of the saturation curve; one image plain, one image with adaptive saturation and one with absolute saturation applied. The x-axis corresponds to the hue (which is not yet reflected in the GUI), starting with red on the left side.

Enjoy your weekend, 

greets mike

EDIT: Added a newer screenshot.

Lab curves and edge avoiding wavelets for GIMP

Posted Fri, 18/06/2010 - 21:54 by mike

Hi folks,

so, out of the dlRaw development there are two small tools for you... I wanted to have a smaller version of dlRaw, which should be easy to adopt to new filters or new situations... To give it an additional purpose I added wrapper scripts for gimp and started with a long needed feature for GIMP: L*a*b* curves.

So you can finally play with curves in L*a*b* color space (using 16 bit calculation) and with preview. the best, it fits seemlessly into GIMP. Just call the script, the image is transferred to the program and when you're done, click save and you get back to you working space in gimp... 

Since the edge avoiding wavelets plugin (kindly offered by elsamuko) seems not to work on windows, I made an additional tool for edge avoiding wavelets on L* (which works on windows Wink).

Feedback is very welcome.

greets mike