Converting RGB to HSL differently
Sometimes when working with bitmaps you might find the need to work in a HSL (Hue, Saturation, Luminance) mode, for example when trying to detect skintones in an image. So what you do is probably to use the classic formula from Wikipedia that uses min/max and a whole lot of ifs: http://en.wikipedia.org/wiki/HSL_and_HSV Well, here is a little alternative method: whilst working with the YUV colorspace I figured that since Y contains all the luminance information, the U + V channels must thus contain the hue and saturation. And it turns out that indeed when looking at u and v as

Pibeca - Pixel Bender for Canvas
Let me say this first - I am not a fan of Canvas and tinkering around with this project I realized why I prefer programming in AS3 so much more to Javascript: my goodness - this language is a dirty mess, how can anyone get anything done with it? But for fairness sake - I guess there must be some pro development tools out there which I don't know about and my using of notepad might not be the true JS developer experience. So even though I think that compared to the capabilities of the Flash Player Canvas still lacks

Galactose - Emergent Behavior of Particles
I have added a new experiment called Galactose to my Incubator. The motion of a particle field is controlled by the shape of the random clusters they form among each other. The orientation of the clusters control each particle's further motion which leads to all kind of interesting feedback effects and emergent patterns. The core algorithm which calculates the overall alignment and orientation of the clusters is written in Pixel Bender.

Bloom


Flash Median Filter
As you might have read in Eugene's blog, he, Nicoptere and me were having a little competition who could come up with the fastest implementation of a median filter. Median filters have the unpleasant property that they can not be as easily optimized as for example blur filters. The median filter is also one of those types of filters that are not very well suited for an implementation in Pixel Bender due to the way Pixel Bender processes images (except maybe for a trivial 3x3 median). What a median filter does is to take all the pixels within a certain

Flash Player Memory Management
Whilst working with some huge bitmaps for Aviary I had to face the undeniable fact that huge bitmaps are memory hogs and that the memory that is made available to the Flash Player by the browser is not unlimited. Actually it is quite limited - on my Vista machine that has 4GB of RAM I max out the memory at ca 1.5GB in FireFox 3.5.2. - that theoretically allows to keep 25 of the 64MB 4095*4095 bitmaps in memory which are the maximum sized bitmaps that Flash Player 10 allows for. In practice it turns out though that this value

Automated Threshold & Edge Detection
It's a tiny bit late maybe, but here are two image processing techniques that deal with automated thresholding and edge detection that I showed in my "2d or not 2d" talk in 2007 and in "The Pixel Whisperer" in 2008. I've had a look at my presentation demos and repackaged their code into a single class called ThresholdBitmap. This is a BitmapData class with a few extras that help you if you plan to extract blobs or edges from a camera stream or some other bitmap. The general problem when you do camera based experiments is that you have unnown

A fix for createGradientBox()
Whilst playing around with some geometry that involved gradient fills I had to realize that the native implementation of Flash's createGradientBox() is unfortunately entirely useless as soon as you try to introduce rotation and scaling to a gradient. The reason seems to be that internally the order of matrix operations is unsuited for that task. Maybe I've searched not thoroughly enough, but I didn't find any solution for this out there. So I've written a tiny class that fixes it. Here's a comparison of the difference between matrix.createGradientBox() and my new GradientMatrix.getGradientBox() var fo = new FlashObject("http://www.quasimondo.com/examples/gradientMatrix/GradientBoxDemo.swf", "gradientBox", "500", "400",

Face Tracking Fun
I've started to have a bit of fun with the optimized Marilena face-tracking class and build a webcam based magic mirror. The specialty here is that it tries to displace your face only and leave the rest of the scenery untouched and additionaly adjusts the displacement scale based on how close you are to the camera: Check out Manic Mirror at the Incubator

Optimizing Flash Based Face Detection
Yesterday Seb-Lee Delisle pointed us via Twitter to this great example of a Flash based real-time face detection. It turns out that already more than half a year ago Ohtsuka Masakazu had been porting the face detection part of OpenCV to AS3 and added the source code to the Spark project - which is like a Actionscript candy box full of surprises. So I had a look at the source code and found one feature which I wanted to change: face detection is based on so-called Haar Cascades, simplified one could say that this is a very long list of

#tweetcoding Round 1 - a few more
Here are a few more of my entries for #tweetcoding: "Moskitos": g.clear();ls(1);o[i++]=[mouseX,mouseY,2*r(),2*r()]; for each(p in o){mt(p[0],p[1]); lt(p[0]+=2*s(p[1]*p[2]),p[1]+=2*s(p[0]*p[3])); };i%=2000 "Love in 3D": if(i "Hyperdrive": if (!o.b)addChild(o.c=new Bitmap(o.b=new BitmapData(500,500))),o.b.noise(2); z=s(i-=0.01)*15;o.c.z=-z;o.b.draw(this,o.o,o.o,"hardlight"); "Fibonacci Sequence": if(!i)i=1,o.b=0,o.c=addChild(new TextField),o.c.autoSize="left",o.c.wordWrap=o.c.multiline=1; o.c.appendText(" "+i),o.a=o.b,o.b=i,i+=o.a "All Invaders": if(!i) g.beginFill(0),a=b=i=64,d=511; g.drawRect(a&=d,b&=d,i,i); g.drawRect(d-a+1-i,b,i,i); a+=r() "The Golden Days": g.clear();g.beginFill(0); x=y=20;for(i=81;i--;g.drawCircle(40*a,40*b,d*2)) a=(i%9),b=int(i/9), d=m.sqrt((d=mouseX/40-a)*d+(d=mouseY/40-b)*d) "Superstar": g.beginFill(r()

#tweetcoding Round 1 - 1967 / Boids
Another two entries for #tweetcoding. "1967": i+=0.06;g.clear();g.beginFill(0);for(x=80;x--;){g.drawCircle(25+70*(x%9),25+70*(y=int(x/9)),70+(s(x%9*0.7+i+s(y*0.7+i)))*35)} var fo = new FlashObject("http://www.quasimondo.com/scrapyard/drawing1.swf", "tweetcode2", "500", "360", "10", "#e0e0e0"); fo.write("tweetcode2");

#tweetcoding Round 1 - Alien Vacation
Grant Skinner has started a litte competition on Twitter called tweetcoding where the goal is to create something nice in 140 chars of Actionscript 3. And the fine folks at Adobe actually will give a free copy of Flash CS4 to the winner, who will be picked on March 1st. As a starting point there is a small wrapper which predefines a few common functions and objects with short variable names. Above you see my first entry - which requires Flash Player 10 btw: which looks like this as a tweet

Getting the First Non-transparent Pixel in an Image
I just came across Sakri Rosenstrom's posts (1 2) about his methods of finding the first non-transparent pixel in a bitmap. Looks like he got inspired by my talk at MAX Europe - unfortunately he seems to have misunderstood my explanation back then. My bad - I should have posted my method a long time ago - so here we go. [Notice: it turns out that Sakri's method is faster than mine - please check the update at the bottom of this post] Here's a little demo. First you might ask what the hell this method is needed for at

New Stuff at the Incubator
In an attack of serious procrastination during the last days I've added a few new pieces to my Incubator: "Twittoscope" is a little Twitter mashup that analyzes the lengths of a Twitter user's tweets and generates a histogram from that - which can serve as a guide as to what kind of messages you can expect from that user in the long run. "Feedback" is a webcam experiment which started with a little Pixelbender feedback filter but grew into a kind of hypnotic visual toy that wants to be explored. In "Passing By" I have revisited my Anavision engine and