Batch Processing of Images in GIMP

To perform batch processing of images in GIMP, you can get a plug-in called David's Batch Processor at the link - http://members.ozemail.com.au/~hodsond/dbp.html. Extract the dbp.exe file and put it at C:\Program Files\GIMP 2\lib\gimp\2.0\plug-ins. Then, open GIMP and click Filters menu -> Batch Process... command. A pop-up windows - David's Batch Processor will appear as shown in the following figure and you can do the batch processing that you want.

Selective Color Modification

I wanted to change the blue color of the road in the following picture to a green color. I wrote a MatLab program and run it in Octave. Although I can simply use rgb color model to swap blue and green, I feel like it is too specific. That is why, I used hsv color model to change a hue of a color in a more flexible manner.