31 August 2007

Polhemus Patriot

Polhemus PATRIOT is a cost-effective solution for 6 Degree-Of-Freedom (DOF) tracking and 3D digitizing. Patriot can accommodate a wide array of indoor applications such as head tracking, biomechanical analysis and computer graphics to cursor control and stereotaxic localization. PATRIOT includes a system electronics unit (SEU), a power supply, one sensor and one source. However, it is possible to expand the system’s capabilities simply by adding an additional sensor or an optional stylus. Measuring in at only 6.75 by 6.25 by 1.75 inches (LWH), the electronics unit is compact for easy installation in any environment. PATRIOT interfaces with the host computer via RS-232 or USB 1.1 and it's fully compatible with Windows® XP, Windows 2000 and Linux®. The source and sensor contain electromagnetic coils enclosed in plastic shells. The source emits magnetic fields, which are detected by the sensor. The sensor’s position and orientation are precisely measured as it is moved. Because the sensor is completely passive, it's safe for use in any application.

PATRIOT provides dynamic, real-time measurements of position (X, Y and Z Cartesian coordinates) and orientation (azimuth, elevation and roll). PATRIOT can update data continuously, discretely (point by point), or incrementally. With the optional stylus, you can trace the outline of a physical object or collect polygon facets and get pinpoint accuracy of unlimited X, Y and Z data points. PATRIOT offers low latency and high stability to ensure precise, uninterrupted tracking at all times. It boasts an update rate of 60Hz per sensor and has a range of five feet, resolution of 0.0015 inch and 0.1 degree, and static accuracy of 0.1 inch RMS for the X, Y, Z position and .75 degrees RMS for orientation. Latency is less than 18 milliseconds for both sensors simultaneously.

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27 August 2007

Sensor-based Mixed Reality

During June and July 2007, I have co-supervised with members of the Cogent research group and the department of Creative Computing, a research project regarding a mixed reality audio-visual visualisation and localisation interface. The project has been developed over a six-week period by three students and operates within a room which is equipped with fixed-location wireless sensing devices called gumstix. These nodes are multi-modal although the system makes use of the microphone only. The main objective of the project is to display a 3D representations of the audio data contained inside the room blended with 3D information. The overall architecture of the sensor-based MR interface is presented below.

This project has been designed to test at least some aspects of the mixed reality presentation system, using easily available sensors and display devices. MR presentation of the sound field occurs within a 3D computer model of the room in which the sensors are located. It can take a variety of forms from a sound 'mist' to 'objects' representing the sound, which hang in space. Computer-vision registration is achieved through the capabilities of ARTag and ARToolKit and the best available marker is selected using confidence levels. Finally, in terms of localisation, the sensors calculate the location of a sound before drawing the object in 3D space.

More information and a demo video of this work can be found at:

21 August 2007

3D Mouse Navigation

3Dconnexion has made powerful 3D navigation accessible and affordable for architects, artists, students and anyone else who wants to enjoy the 3D experience. In particular, 3Dconnexion devices are ideal sensors for navigation into virtual and augmented reality environments, mainly because they provide intuitive manipulation in six degrees-of-freedom. A characteristic example is SpaceNavigator™ which is shown below.

3Dconnexion's SpaceNavigator™ is a very cheap solution to 3D navigation. It works with more than 100 of today's most popular and powerful 3D applications and it is ideal for Google Earth version 4 and Google SketchUp. An alternative and a bit more expensive solution is SpacePilot which is illustrated below.

The 3Dconnexion SpacePilot, connects the users to the 3D design process in a different way that the standard mouse does. Its optical sensor technology and ergonomic design combine to deliver unprecedented control and fewer distractions. The SpacePilot may be used in user’s non-dominant hand to position, rotate, pan and zoom a model in one single, fluid motion. It can be also used in conjunction with the standard mouse w to simultaneously edit the model or select menu items.

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01 August 2007

OQO model 2 Handheld PC

OQO model 2 is another ultra mobile computer (it is the main rival of the SONY VAIO UX model) which is ideal for a number of everyday applications including navigation and wayfinding, location-based services as well as many more. The model 2 comes standard with WiFi 802.11a/b/g and Bluetooth 2.0 technology, 60GB hard drive, 5-inch Wide VGA LCD display and a 1.2GHz or a 1.5GHz VIA C7M ULV processor with integrated graphics chipset.

The OQO model 2 includes a keyboard that features a track stick mouse pointer for precise cursor movement with your thumb and dedicated zoom keys for quickly changing screen magnification that allow full interactivity while zoomed, and support 1000x600 and 1200x720 interpolated modes. The main flaws of the model 2 are that it lacks a digital camera which is nowadays a standard feature with any mobile devices (smartphones, PDAs and other handhelds) and there is no built-in memory card reader.

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