Real Time Regional Differencing

I little while ago I produced a method for extracting interesting regions from images which I called regional differencing (see post). I have optimised the code, and it now runs in real time. It works very well as a simple edge detector with the ability to produce much thinner lines than the Sobel detector, notice in the image below the maximum line thickness is one pixel. The algorithm works by comparing more and less pixelated versions of an image to find local differences compared to a local mean.

To improve the algorithm I switched from the RGB colour space to NUV as this improved results (albeit reducing performance marginally). The detector doesn't quite have the quality of something like the Canny detector, but it requires a lot less processing which in flash is very important!

Anyway check out the demo by clicking on the link below, the slider changes the pixel size of the comparison bitmap, with some interesting results. The default settings use a size of 2 pixels producing lines of a maximum one pixel thick.

Visual Human Interfaces

Making human interfaces intuitive, simple and accurate is a huge challenge. Some of the biggest challenges lie in the field of motion and gesture detection. Analysing visual data in real time can be very processor intensive.

This is a fairly simple implementation of an interface which has the ability to track on screen button presses and swipes (it is part of an ongoing research project):

Click to launch a demo video:

Crossfade Using Pixelbender

I am currently doing some work for a client which involves background subtraction. I have been getting into using pixel bender to calculate filters in flash for a while now, but doing some research I found there is actually huge scope for using pixel bender to carry out other calculations (see this article).

The following example uses pixel bender as a part of the background subtraction process. Consecutive frames from the webcam are blended with all previous frames. The eventual result is to produce a good estimate of the background pixels. The example uses the blendShader property of a display object with blend mode set to BlendMode.SHADER, and a custom Pixelbender shader that mixes pixels. Check it out (click to launch):