Playing around with CHDK and HDR imaging

I had stumbled upon the CHDK firmware for Canon cameras through a Wired article some time back, and finally got around to trying it out on my PowerShot A630 today. I also discovered that it is possible to create HDR images by shooting images at different exposures and subsequent manipulation through appropriate software (tutorials: Photoshop / CS2, GIMP / GIMP using a script, Paint.NET or Photomatix).

So, the first thing I did was to download the CHDK build for my camera (I used the AllBest oneusage instructions). Then, I followed the instructions and copied the files to a spare SD card I had, and put it into the camera. I started the camera in play mode and used the menu to activate the CHDK firmware (this is only temporary, and needs to be activated every time the camera is switched on). Once activated, I could switch between the two versions using the Print button. There are a ton of options in the CHDK menu including support for scripts (written in uBasic), enabling additional shutter speeds and indicators among many others.

With the firmware nicely set, I went ahead and started shooting for making HDR images. Initially I tried an HDR bracketing script available to shoot some of the photos. The script seemed to have some problems focusing at times, but I managed to get some shots. I also discovered the ability to do exposure bracketing in the continuous shooting mode, which I also used to shoot a few photos.

I then used the trial version of Photomatix to create the HDR images as I was feeling too lazy to go through all the steps to create HDR images in GIMP (there is a contrast blending script which takes of this though) or Paint.NET. The only drawback of using the trial version is that it inserts a watermark into the end result. This is ok since I was experimenting with HDR imaging, and I’ll switch to GIMP or Paint.NET for serious photos. One of the things I noticed in the resulting HDR images is that they can tend to look a bit cartoonish or unnatural.  Anyway, here are a couple of results.

I have created a collection on flickr for the HDR images (both sources and results are included). I’ll be adding to the collection as and when I get the opportunity. There are quite a few HDR groups on flickr too, and they do have some good looking photos. For something more interesting, have a look at this (not by me).

Update: Just discovered an open source HDR imaging software – Qtpfsgui. The output (sample on this post) appears to be a bit more cartoony due to a different algorithm being used. (via)

A pseudo IDE for Google App Engine – Komodo Edit

I signed up last week for the Google App Engine, and tried out the tutorial for creating a guest book. It is a pretty simple tutorial, but one of the things I noticed about the App Engine is that there is no add-on for any IDE/editor at the moment, unlike the Android SDK which has its own eclipse plug-in or even the Web Toolkit which has a utility to generate an eclipse project.

Initially, I tried using Notepad++ which I have installed as my basic text editor, but I didn’t get much support beyond basic syntax highlighting. It does have a built in run command, but is not very configurable. This is when I decided to give Komodo Edit a try (it is open source). It is a lightweight version of the Komodo IDE, but has support for a variety of languages along with a useful set of tools. Incidentally, it is based off the Mozilla code base, and has support for add-ons just like Firefox, Thunderbird and Flock.

You can organise files into projects, which comes in handy for the Google App Engine applications, which is typically composed of a set of files based in a folder. The editor also has some basic syntax checking in addition to syntax highlighting. However, the code intelligence/auto-complete is limited to the base Python installation, and so will not be able to help with the Google App Engine.


In addition to this, the editor also has a customisable run command, which can be used to launch the development server. Shown below is my customised run command which can be used on the main .py file of the application (E.g. form the tutorial), and launches the development server in a new console (set using the “Run in” option). The “Start in” parameter is also important as the server needs to be launched from the parent folder of the folder in which the application is stored, i.e., if the application files are stored in “D:\Dev Stuff\gAppEng\helloworld”, the server needs to be launched from “D:\Dev Stuff\gAppEng”. Here, I have used the “ask” option with a default value for the “start in” location, so that I am prompted for the path at the time of server launch.

Komodo IDE Run config

There are quite a few other tools available in the editor, like file compare, spell checker, templates etc, which I haven’t tried out yet. Now, if I could only think of my own project for the App Engine. Suggestions anyone?

Update: Just noticed that another person has posted instructions for using Komodo Edit as an IDE for Google App Engine (on Linux it seems), including steps for setting up the uploader among others. (via)