Showing posts with label augmented reality. Show all posts
Showing posts with label augmented reality. Show all posts

Wednesday, April 23, 2008

3D Object Modeling Using Spatial and Pictographic Gestures

Summary:

Nishino et al. designed a 3D object modeling system that uses stereoscopic glasses, CyberGloves, and polhemus trackers.

The system allows the creation of superellipsoids that can have smooth or squarish parameters. These primitive shapes can be bent, stretched, twisted, and merged with other shapes. Hand postures control these actions, such as grasping and pointing. Virtual hands are displayed on a 200-inch arched screen, along with the object, in stereoscopic mode. The virtual hands allow the user to easily see where they can touch and modify the 3D model.

The authors tested the system by having users attempt two types of objects: symmetric and asymmetric. The symmetric object was a bottle, and the asymmetric object was a teapot.
Creation of the objects took up to 120 minutes. The size of the stored objects was much less than a competing program, Open Inventor.


Discussion:

For a paper in 1998, this was a pretty advanced system and seemed to offer some benefits over other systems. I would have liked to have seen feedback from the users, though, since I'm not sure how hard the system is to use.

Monday, February 25, 2008

Computer Vision-Based Gesture Recognition For An Augmented Realtiy Interface

Summary:

Storring et al. from Aalborg University created an augmented reality system to create a "less obtrusive and more intuitive" interface.

The gestures used in the system are the mapped to the hand signs for 0-6, i.e. no fist, index finger, index and middle, etc. This gesture set can be recognizable in a 2D plane with a camera. In order for these gestures to work, the hand needs to be segmented from the image. The authors use normalized RGB values, called chromaticities, to minimize the variance of the color intensity. The distributions for the background and skin chromaticities are found and are modeled as 2D Gaussians. The hands are assumed to be a minimum number and maximum number of pixels.

Gestures are found by counting the number of fingers. A polar transformation counts the number of spikes (fingers) on currently shown on the hand. Click gestures can be found by checking the bounding box width of the hand between the regular index finger gesture and a "thumb click" addition.


Discussion:

For a system that is supposed to be less obtrusive and more intuitive than current interfaces, virtual reality with unintuitive gestures does not seem like a good solution. Using "finger numbers" is a poor choice, and having a gigantic head-mounted display with cameras is probably less comfortable than looking at a computer screen. Furthermore, if the authors are focusing on using head equipment, why not just use gloves to increase the gesture possibilities?