Shannon's Box

Claude Shannon, father of information theory, apparently once invented a box whose sole purpose was to, when switched on, turn itself off again. Recently I've got into scripting with CHDK (Canon Hackers Development Kit) - a firmware enhancement for Canon cameras. It allows you to turn your cheap point-and-shoot camera into something better, for free. Long exposures, very rapid shots, motion detection - you name it. I can tell I'm at the start of a beautiful friendship ... look at this!

You can write and upload scripts to automate processes. The language is uBASIC - really intuitive and easy. My first script is pretty basic - it has been to tell the camera to, when switched on, automatically take 3 photos and then turn itself off! I therefore called it Shannon's Box:

 rem Author Daniel Buscombe  
 @title Shannon's Box  
 @param a Shoot Count  
 @default a 3  
 shoot full  
 for n=2 to a  
 shoot full  
 if n=a then goto "shutdown"  
 next n  
 end  
 :shutdown  
 shut_down  

More, I'm sure, on CHDK in the following months.

Ubuntu Beautification

Tip #1:

It's amazing really - most fonts contain within them “hints” laid down by their designer about how they should look on-screen. Artistic meta-data! However, Ubuntu ignores them and uses a system called 'autohinting'.

It works well, but you might also want to try bytecode hinting. This uses the hinting built into the fonts. To activate bytecode hinting, open a terminal window and type:

$ sudo dpkg-reconfigure fontconfig-config

Using the cursor keys, select Native from the menu and then hit Enter.

On the next screen you’ll be asked if you want to activate subpixel rendering. This is good for TFT screens, so make the choice (or just select Automatic). Next you’ll be asked if you want to activate bitmap fonts, which are non-true type fonts good for use at low point levels. There’s no harm in using them, so select yes. The program will quit when it’s finished. Once that’s happened, type the following to write the changes to the system and update files:

$ sudo dpkg-reconfigure fontconfig
$ sudo dpkg-reconfigure defoma

System - Quit - Logout, and then log back in again. Letters will appear more rounded and the antialiasing will appear better.

Tip #2:

465 fonts of Brian Kent (http://www.aenigmafonts.com) are available to Ubuntu users. To install the fonts, you’ll need to add a new software repository:

System - Administration - Software Sources
- Third-Party Software tab - Add

type the following into the dialog box that appears:

deb http://ppa.launchpad.net/corenominal/ubuntu hardy main

Click 'Add Sources', then Close and, when prompted, agree to reload the package lists. Then use Synaptic to search for and install the 'ttf-aenigma' package. Once installed the fonts will be available for use straight away in all applications.

Enjoy your beautified Ubuntu!

How to get on youtube, twitter and myspace quicker

Well, the easiest way is save time when you boot your computer!

Whenever Ubuntu boots it runs several scripts that start necessary background services. By default these are set to run one-by-one but if you have a processor with more than one core, such as Intel’s CoreDuo series or AMD’s Athlon X2, you can configure Ubuntu to run the scripts
in parallel. This way all the cores are utilized and quite a bit of time can be saved at each boot. To make the change, type the following to open the necessary configuration file in Gedit:

$ gksu gedit /etc/init.d/rc

Look for the line that reads CONCURRENCY=none and change it so it reads CONCURRENCY=shell.

Then save the file and reboot your computer. This should save you several seconds of time every time you boot up, and you can go on being a handsome speedy devil

Every pixel tells a story

Recently the Daily Daniel ran a story (hark at me! I'm not The Times!) with a single photograph - a mosaic - each 'pixel' containing a separate photo. I've finally got round to explaining how it is done, if only to show that I didn't arrange the pictures manually - she is beautiful, admittedly, but I gotta work to eat!

Right, the Linux program is called 'metapixel' and is downloaded from here. If you've enough photographs, you can produce some incredible results

You need to issue 2 commands - one prepares the photos, then the other makes a mosaic out of them. Create a folder somewhere to store the prepared photos called, say, 'recast'

$ metapixel-preparee -r /directory/where/photos/are /directory/recast --width=40 --height=40

The larger the width and height, the longer it takes. Be sure to get the aspect ratio of the photos right - it doesnt check or automatically correct. Choose a single photo that you want to make a mosaic out of (e.g. /directory/in.png), then (be warned, this may/will take several hours for a big photo!):

$ metapixel /directory/in.png --library /directory/recast --scale=5 --distance=5

The scale tells it how big you want the output (i.e. here 5 x size of input image), and the distance tells it how far to look for matches - it matches by colour so its a really good idea to scale by the range of inputs. It will give you an error if the distance parameter is too large. The results can be mixed, but once you hone the inputs and parameters down, and you have a LOT of patience, you can get some really great mosaics!

Tweetdeck on ubuntu 64-bit

Right, the whole world's into twitter. The website is a little difficult to manage when you have a lot of people to follow. The software solution (isn't there always one!) is TweetDeck - unfortunately it runs under Adobe Air, which (surprise, surprise) is available for Linux but 64-bit architectures. So your computer requires a little bit of persuading ...

... you need a few libraries - issue the following commands at the terminal:

$ sudo apt-get lib32asound2 lib32gcc1 lib32ncurses5 lib32stdc++6 lib32z1 libc6 libc6-i386
$ sudo getlibs -l libnss3.so.1d
$ sudo getlibs -l libnssutil3.so.1d
$ sudo getlibs -l libsmime3.so.1d
$ sudo getlibs -l libssl3.so.1d
$ sudo getlibs -l libnspr4.so.0d
$ sudo getlibs -l libplc4.so.0d
$ sudo getlibs -l libplds4.so.0d
$ sudo getlibs -l libgnome-keyring.so
$ sudo getlibs -l libgnome-keyring.so.0
$ sudo getlibs -l libgnome-keyring.so.0.1.1
$ sudo ldconfig

Then install Adobe Air from here

download, then move to your home directory,

right click - properties - make executable

and type

$ chmod +x AdobeAIRInstaller.bin
$ sudo ./AdobeAIRInstaller.bin

Then grab the 'air' file from here, and install using Adobe Air

Happy tweeting!

Miscellaneous stuff of use

The documentation on the use of 'wget' is a little sketchy on one of its most powerful uses - automatically downloading loads of files from internet servers. Let's say you need the 1000 tiff files sitting at http://www.server.com/hypothetical_directory

Apparently wildcards are out, such as:

$ wget http://www.server.com/hypothetical_directory/*.tiff

because html does not support 'globbing'. So here's the solution:

$ wget -r -1l --no-parent -A.tiff http://www.server.com/hypothetical_directory

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Another thing I've needed to do recently is get ALL the metadata from an image file - you wouldn't believe how much information is recorded - channel statistics, histogram of shades, date/time, camera make, resolution - you name it, its recorded. It's a wonderful thing about using images for your research as well - you can keep track of all your metadata in the data files! Right, well I discovered that no amount of 'right-clicking' on the image - in any operating system - will tell you everything you need to know. The suitable command is:

$ identify -verbose myimage.jpg

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Finally, for now, a couple of sites that will help you if you need to make a purchase of hardware for your linux machine:

This one keeps a database of usb-devices which are known to be linux-friendly, and the following two help you out when choosing a compatible printer and scanner: here and here.

Keep on truckin'