In the example below you’ll see two balls that change colour and position when hit. Code is in the zip-file.

See my post about Frame differencing for other Flash and Processing examples.

Example (Flash Player 10 or higher)

You need a webcam and give Flashplayer access to the camera to see the example below :

Used resources

• Using BitmapData.hitTest for Collision Detection by Mike Chambers
• code snippet from Zevan

Download : Framedifferencing collision detection – source code

If you have suggestions for more improvements, please give your feedback in the comments.

Modifications

• Implemented Adaptive Threshold by Quasimondo (Mario Klingemann) in the GetQRimage Class.
• Added the substract blur method that Mario Klingemann explains in his lecture about the process of reading QR codes. I’ve got less wrong strings in this mode and the detection runs faster. You can set it to false, to use the original method.
• The outside parts of the video are cropped, to reduce image noise. By providing a markerGuide the user knows where to hold the marker.
• The data from the onQrDecodeComplete event is compared with the data from a previous event as a way of extra error correction.

The user interface uses the minimalcomps by Keith Peters (bit-101) and the Hi-Res! stats by Mr. Doob.

Example (Flash Player 10 or higher)

Generate a QRcode and print it out.
You need a webcam and give Flashplayer access to the camera to see the example below :

Used resources

• Introduction of QR Code Reader Library
• QRCodeReader library (Libspark)
• Max 2008 develop – Be here pixels by Mario Klingemann (interesting lecture)
• Automated Threshold & Edge Detection

Download : ReadQrSimple – source code

If you have suggestions for more improvements, please give your feedback in the comments.

Blob Detection test by samkeene :

Click here to view the embedded video.

Max Meinders made a good description of all the processing steps involved in Blob tracking :
Max Meinders – videotracking.

Face detection

OpenCV also supports the recognition of special characteristics in an image and use those as a blob. Face detection a tecnique to recognize things that look like a face in an image. It doesn’t recognize a certain face ( although thats possible, see Image recognition ), but it detects facial features.

Face Detection with Processing by Pedro Amado

Click here to view the embedded video.

Face detection works with classifiers. You can learn the computer characteristics of an object. So OpenCV can detect other objects as well, as long you have a classifier file for it.

Keywords : Haar Classifier, Viola Jones object detection framework, cascade classifiers.

Tomek made a nice example where he tracks faces in the ‘Black and White’ video of Michael Jackson in realtime in Flash ( you can tried it yourself to with a webcam ) : Machines are looking for Michael Jackson.

Below an example of the difference filter in the OpenCV library for Processing. You can do the same in Flash with the Difference Blendmode.

Click here to view the embedded video.

You can move objects to area’s where most of the motion is happening, like in the Pong example of Ostrich : Ostrich two cursors example

Or you can make some hotspots in your image and check the amount of motion in those. A nice example to get the idea is the webcam piano from Memo Akten (implemented in Quartz Composer and Processing) :

Click here to view the embedded video.

Or you can do other creative things with it (video by WTF? by OK Go, example code in Processing by Memo Akten) :

Click here to view the embedded video.

Code examples and tutorials

If you only want to detect if there is a certain amount of motion in front of a webcam, you can use the activityHandler and activityLevel parameters in Flash. See my example on bitmap filters where i use it the apply a red filter when there is movement :
Flash AS3 : Apply bitmap filters to a webcam image