Support for JPEG2000 in VLIV

I have added minimal support for JPEG2000 in VLIV using Jasper. Current support is not very well tested, but I have been able to load sample images. They come from The Library of Congress American Memory Maps, and take quite a while to load (at least one minute, for 5000x2700 pixel image).

The implementation takes the form a a very simple C plugin, source is available on request. It can certainly be improved much, for example I use jas_image_readcmptsample 3 times for every pixel.

Please advise if you have ideas for performance or feature improvements.

UPDATE: it is now much faster using jas_image_readcmpt on whole image width...

New version of IJG JPEG library

A new version has appeared on IJG web site. It looks like new version called 7 (dated 27-Jun-2009) has few changes from previous one (6b dated 27-Mar-1998 !). Mostly it says that scaled DCT are implemented, I have found that this version is not binary compatible with previous one wrt scaling. I will have to experiment a little more before using this version in Vliv.

One of the other libs I use is zlib, latest version 1.2.3, dated July 18, 2005.

LibPng has not been updated for a while, only libtiff seems to be work in progress.

I am still looking for a JPEG2000 C library that is as good and simple as these ones.

Another impressive large image

Very large images do not have to be panoramas. This one is created by stitching hundreds of images coming from a Scanning Electron Microscope. You can find more information here.

Gigapixel images becoming mainstream on the web

Here is the latest gigapixel image available on the web. As it is related to Barack Obama's inaugural address, it has received all possible attention and reviews. Image credit goes to David Bergman.

While not new, such a large image is very interesting because of how it has been made, and how it is distributed.

The process for image creation involves a robotic arm called Gigapan Imager, that automatizes completely the process of taking an array of pictures. Having such almost perfectly aligned images allows their custom software to stitch the images with a very impressive quality. Device price is about $279 as Beta ($379 otherwise).

The image is then made available on the Web using a Google Maps like interface provided by Gigapan.org.

This makes creating and distributing giant images much easier than it was before.

Hacking the Webmail Notifier USB device

Some time ago I ordered the USB Webmail Notifier (only $17). When I received it, I was disapointed to find that the bundled software was very limited, only using the POP3 protocol. This protocol for example has no way of returning number unread mails, so the use cases are rather small.

So I decided to look at how I could code for this device. I found this very useful (albeit quite old) article on USB HID devices, a wery well though standard for this kind of devices (and keyboards, mouses, joysticks).

I also used a USB protocol analyzer to see what data was sent to the device. I managed to make it accept any color I want (whereas the bundled software only has green, red and blinking blue).

Each component is 5 bits, that makes some noticable transitions between adjacent colors. Also not all colors we use to get on LCD displays are available, because there is no black.

Here is a small image of an orange notifier.

I made 3 command line programs (building them requires the Windows DDK):

• a simple color setter, arguments are R G B
• a HUE wheel switcher
• a CPU usage related color, green beeing 0%, red 100%

There is certainly many other possible uses for this cheap device:

• An IMAP4 mail notifier, making use of all IMAP4 features
• An automatic build indicator, for example for CruiseControl
• an event remainder
• ...

As usual source code will be send on request.