Batch GIMP script for auto-sharpen, white-balance and colour enhance

Like you, my point-and-shoot camera in auto-ISO mode often, if not always, gives me pictures which need a little adjustment to realise their full potential.

In GIMP, I usually use the 'auto white balance' option which usually gives great results. Often, I also use the 'auto color enhance' option and, occasionally, I use a simple filter to sharpen the features in the image.

Here's a GIMP script which will automate the process for a folder of pictures There are four input parameters. The first is the 'pattern' to find the files, e.g. "*.tiff" gives you all the tiff files in the directory. The next three inputs refer only to the sharpening filter. I use the (confusingly named) 'unsharp' filter which works by comparing using the difference of the image and a gaussian-blurred version of the image.

'radius' (pixels) of the blur (>1, suggested 5)
'amount' refers to the strength of the effect (suggested 0.5)
'threshold' refers to the pixel value beyond which the effects are applied (0 - 255, suggested 0)

These require a little bit of trial and error, depending on the type of picture. In the command line, the script is called like this:

 gimp -i -b '(batch-auto-fix "*.JPG" 5.0 0.5 0)' -b '(gimp-quit 0)'  

An obligatory example. Before:




and after:






Enjoy!

Convert movies to be compatible with ZEN X-Fi media player

Creative - another company which doesn't provide support for non-Windows users. Get with the times, losers!

The ZEN player needs a specific format of movie (bit-rate and aspect ratio). Here's how to do it with mencoder (available for free on all platforms)

 mencoder 'MyMovie.avi' -oac mp3lame -lameopts cbr:mode=2:br=96 -af resample=44100 -srate 44100 -ofps 20 -ovc lavc -lavcopts vcodec=mpeg4:mbd=2:cbp:trell:vbitrate=300 -vf scale=320:240 -ffourcc XVID -o MyMovie4zen.avi  

Granular Therapy

Here's a relaxing movie I just made of spinning modelled sand grains:



I'm not going to divulge the details of the model of how to create the sand grains (a current research project of mine). I can tell you I used these rather excellent functions for MATLAB:

Volume interpolation Crust algorithm, described more here

A toolbox for Multi-Parametric Optimisation

I used 'recordmydesktop' to capture the grains in my MATLAB figure window. It created an OGV format video (which I renamed to 'beautiful_grains.ogv'). I then used the following code to decode the video into jpegs

 mkdir out_pics  
 mplayer -ao null -ss 00:00:03 -endpos 50 beautiful_grains.ogv -vo jpeg:outdir=out_pics  

I needed to crop the pictures to just the grains, then turn the cropped pictures back into a video. I used this:

 cd out_pics  
 for image in *.jpg  
 do  
 # crop the image  
 convert $image -crop 600x600+350+135 grains%05d.tiff  
 done  
 # make movie from the cropped tiffs  
 ffmpeg -r 25 -i grains%05d.tiff -y -an spinning_grains_small.avi  

et voila! Now sit back with a cuppa and relax to those spinning grains.

Updated Power Spectrum from an Image

A while back I posted on using ImageMagick to do a full frequency-decomposition on an image, and create a power spectrum. It had several inaccuracies. Here's an update with how to do it better

First, you need to install a version of IM which is HDRI enabled (see here)

# test for valid version of Image Magick

 im_version=`convert -list configure | \  
  sed '/^LIB_VERSION_NUMBER /!d; s//,/; s/,/,0/g; s/,0*\([0-9][0-9]\)/\1/g'`  
 [ "$im_version" -lt "06050407" ] && errMsg "--- REQUIRES IM VERSION 6.5.4-7 OR HIGHER ---"  

# test for hdri enabled

 hdri_on=`convert -list configure | grep "enable-hdri"`  
 [ "$hdri_on" = "" ] && errMsg "--- REQUIRES HDRI ENABLED IN IM COMPILE ---"  

#read $file, load and converting to greyscale

 convert $file -colorspace gray in_grey.tiff  

# crop image to smallest dimension

 min=`convert in_grey.tiff -format "%[fx: min(w,h)]" info:`  

# crop image, and convert to png (why?)

 convert in_grey.tiff -background white -gravity center -extent ${min}x${min} in_grey_crop.png  

# get data, find mean as proportion, convert mean to percent, and de-mean image

 data=`convert in_grey_crop.png -verbose info:`  
 mean=`echo "$data" | sed -n '/^.*[Mm]ean:.*[(]\([0-9.]*\).*$/{ s//\1/; p; q; }'`  
 m=`echo "scale=1; $mean *100 / 1" | bc`  
 convert in_grey_crop.png -evaluate subtract ${m}% in_grey_crop_dm.png  

# pad to power of 2

 p2=`convert in_grey_crop_dm.png -format "%[fx:2^(ceil(log(max(w,h))/log(2)))]" info:`  
 convert in_grey_crop_dm.png -background white -gravity center -extent ${p2}x${p2} in_grey_crop_dm_pad.png  

# fft

 convert in_grey_crop_dm_pad.png -fft in_ft.png  

# get spectrum

 convert in_ft-0.png -contrast-stretch 0 -evaluate log 10000 in_spec.png  

... but it's still not quite right. Any tips?

Turn your OGV movie section into a cropped animated GIF

An example from a recent project

 # make directory for output jpg  
 mkdir out_pics   
 # section to the ogv video file into jpegs  
 mplayer -ao null -ss 00:00:03 -endpos 50 beautiful_movie.ogv -vo jpeg:outdir=out_pics  
 cd out_pics  
 # loop over each image and crop into desired rectangle  
 for image in *.jpg  
 do  
 convert $image -crop 600x600+350+135 "$image crop.tiff"  
 done  
 # turn into an animated gif  
 convert -page 600x600+0+0 -coalesce -loop 0 *.tiff beautiful_animation.gif  

Miscellaneous useful bash

For my benefit more than anything - things I use over and over again, but do not have the mental capacity to remember

# number of files in current directory

 ls -1R | grep .*.<file extension> | wc -l  

# check if you have a program installed

 aptitude show <name of program> | grep State  

# only list the (sub-)directories in your current directory

 ls -l | grep ^d  

# remove backup files

 find ./ -name '*~' | xargs rm  

# use zenity get the directory where the file you want is

 zenity --info --title="My Program" --text="Select  
 which directory contains the file(s) you want"  
 export target_dir=`zenity --file-selection --directory`  

# list all txt files in this directory

 x=$( ls $target_dir | grep .*.txt |sort|zenity --list --title="Select" --column="coordinate file" )  

# get this directory

 export raw_dir=`zenity --file-selection --directory`  

# removes .txt (for example, for later use as start of filename)

 str="$x"  
 Var1=`echo $str | awk -F\. '{print $1}'`  

# gets the rest of the file name

 str="$Var1"  
 Var2=`echo $str | awk -F\- '{print $2}'`   

# turn string into (indexable) array

 e=$(echo $mystring | sed 's/\(.\)/\1 /g')  
 b=($e)  

# get max and min dimensions of an image

 min=`convert image1.tiff -format "%[fx: min(w,h)]" info:`  
 max=`convert image1.tiff -format "%[fx: max(w,h)]" info:`  

# take away 1 from both

 min=$((min-1))   
 max=$((max-1))  

Unlock the power of ImageMagick to HDRI

My primary motivation to do this has been to use ImageMagick for Fast Fourier Transforms, which have a myriad of applicability in image processing and filtering

First, you have to install perlmagick. Using apt,

 sudo apt-get install perlmagick  

Then the perl libraries

 sudo apt-get install libperl-dev  

Install the rather magnificent fftw libraries

 sudo apt-get install libfftw3-dev fftw-dev  

wget the source code, untar, move it, cd home

 wget ftp://ftp.imagemagick.org/pub/ImageMagick/ImageMagick.tar.gz   
 tar xvfz ImageMagick.tar.gz   
 mv ImageMagick-6.6.0-8 $HOME  
 cd $HOME/ImageMagick-6.6.0-8   

Install (see here for instructions)

 make distclean   
 ./configure --enable-hdri LDFLAGS='-L/usr/local/lib -R/usr/local/lib'  

see also here for a bug fix, and also see here for instructions

make & sudo make install
make check


To see whether the fft commands are working properly, you could issue the following:

 if [ -s lena.png] #check to see if the file exists  
 then  
 # do fft and ifft roundtrip  
 convert lena.png -fft -ift lena_mp_roundtrip.png  
 else  
 #first download  
 wget http://optipng.sourceforge.net/pngtech/img/lena.png  
 #then convert  
 convert lena.png -fft -ift lena_mp_roundtrip.png  
 fi  

see here for further information on fft transforms with, and watch your world spin faster

Installing NCVIEW for Ubuntu

Recently I ran into problems installing NCVIEW, which is a tool for efficiently viewing the contents of a NetCDF data file. The problem was something to do with the X terminal. So here's how to install it from source:

 wget ftp://cirrus.ucsd.edu/pub/ncview/ncview-1.93g.tar.gz  
 sudo apt-get install libxaw7-dev  
 tar -xvvf ncview-1.93g.tar.gz  
 cd ncview-1.93g/  
 ./configure --x-libraries=/usr/X11R6/lib  
 make  
 make install