ARTag : SDK demonstrating AR

Demo AR Programs using ARTag

There are four main programs demonstrating AR (augmented reality) using ARTag; , <3d_augmentations>, and . The first two have two versions, one with “_usb.exe” for most cameras such as USB webcams, and the second “_dragonfly.exe” is for the Point Grey Dragonfly camera from Point Grey Research (www.ptgrey.com) often used in university labs that gives better performance and was used by myself in ARTag development.

1. The program uses the “base0” image and just draws a few graphics primitives and a textured logo image relative to the marker array, its purpose is to be a simple example for people programming with the SDK.

2. The <3d_augmentations> demo is more interesting, it was used to create the images at the first page of this document. This program uses the “base0” array, and the individual toolbars. To save space in the download, and for permission reasons, only 5 models are provided in the demo and SDK download; fish, Chihuahua, car, frog, and can of asparagus model.

If you run this application, aim the camera at the base0 and toolbar arrays and you should see 3D virtual objects rendered relative to them.
Fiala (2004) has developed new system called ARTag was inspired by ARToolkit. ARTag was taking advantage of the increased computing processing power available. ARTag uses more complex image processing and digital symbol processing to achieve a higher reliability and immunity to lighting

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Camera Resolution : Setting Resolution Problems

Camera Resolution: Bigger = Better Performance, Setting Resolution Problems

The larger the input camera image is, the smaller the markers can be and still be detected, and the less the JPEG artefacts will disturb the detection. Unfortunately the OpenCV cvcam interface that was used in these demos is not able to properly set the camera resolution, it usually defaults to a lower resolution such as 160x120 or 320x240.

The camera resolution should not be confused with the resolution of the graphics window, the demo program window can be 640x480 when the camera resolution is only 160x120. The picture of the background will just appear grainer and more pixelated. The system will work better if the camera can be set to a higher resolution.

Some users have found that if they run another program where you can set the camera resolution first, then it will run with a higher resolution when you run the ARTag demos. For some, the programs downloaded from http://www.shrinkwrapvb.com/ezvidcap.htm seem to do the trick on some computers.

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