matt.beghin

A production company contacted me to develop a Light Painting solution. The idea is to “draw” with lights captured with a Camera. As an ex-arKaos developer my first idea was to create an effect with shaders because it’s an environement I know well and shaders can be added easiely in arKaos GrandVJ / NuVJ or MediaMaster which makes the solution for many shows.

Also shaders code is executed by the graphic card in the arKaos engine resolution, which can be HD, and with the input stream from the camera that can be HD also in arKaos, so that makes a high quality setup.

The idea behind this is to set a treshold value that defines which part of the camera picture can be considered as desired lighting elements (neon, juggle balls etc). Pixels considered as part of a lighting element will be conserved along the time, eventually with a slow fade to black.

Result with the MacBook Pro internal webcam is:

I was really satisfied with this result but it didn’t seem so good when I was using a DV Cam. When moving my light source fastly, I could see dark spaces on the light way, like this:

So I tried to make the same effect in Quartz Composer. It was the first time I used it. I could get a result quite fastly and noticed the DV camera was responding better in QC. I suppose the deinterlacing in arKaos skips odd or even frames while QC has a more complex deinterlacing algorithm… So I finalized the QC and made an application with it. This tool is very efficient, intuitive and stable, which is not the case of most modular softwares… That’s a very good news that arKaos will now support Quartz Composer as sources and effects !

I’ll post another Light Painting movie when I found a good environement for that.

This entry was posted on Monday, November 30th, 2009 at 4:49 pm and is filed under News. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.