Lemonade


Zach Davis, Haewon Kang, Will Wolcott



 

Interaction

 

A 3D accelerometer severs as the interaction between Lemonade and the user. The XSENS MT9 measures the force of gravity relative to the orientation of the sensor. By adjusting the pitch, roll, or yaw of the MT9, different parameters of video are changed in real time.


Video Processing

Live video is streamed from a camera in the interaction space. Raw pixel information is converted into an openGL scene based on intensity values. The method in which the scene interpolates pixel values, depth of scene, and color ranges are parameters controled by the MT9. The camera outputs 24-bit RGB values at 15 frames per second to a computer for processing on software.


Installation The video picture is reversed from the camera view. This is implimented to give the user a feeling of looking back at him or herself. Lemonade was designed to have the user be the focus of the camera, hand-held interaction, and video processing.


MT9 Development

 

The XSENS MT9 offers C++ libraries for Windows and Linux. Because the project concept was developed in Max/MSP and Jitter, the first goal was to create a method for reading data from the sensors to to a Max external. The MT9ori.cpp was created in C++ to interface with Max/MSP in Windows XP.

MT9ori.mxe is an external for Max/MSP. Once loaded in Max, a new object named "MT9ori" can be created in a patch window.

The MT9ori object has one input and three outputs. The outputs of the Max object are the MT9's measured orientation: pitch, roll and yaw. Rolling over each output reveals which output corresponds to which dimension of orientation. A "bang" signal is required for the input, usually applied with a "metro" metronome to receive streaming orientation measurements. Upon each bang signal to the MT9ori, pitch, roll and yaw are outputed in the form of integer values -180 to 180.

Once a bang is sent to MT9ori, the object queries the MT9 device for its current orientation and sends the responce to the three output channels. While a metronome of bangs can be set at any frame rate, the MT9 samples at a maximum of approxamately 100 frames per second.

Upon startup, the MT9ori object looks for the MT9 on serial port 1. Status and error messages can be viewed in Max's dialog window. When Max quits, MT9ori shuts down the MT9 data stream and power.

The MT9 was found to have a high enough data refresh rate to handle video applications. The code successfully developed for Max/MSP was adapted to Lemonade's C++ application.


Lemonade Development  

Lemonade was developed for Windows XP or 2000. It uses MIcrosoft's DirectShow to capture video and openGL libraries for the visualization output. Lemonade first opens the video stream and outputs it to the screen. Selecting "Start Video Processing" from the menu opens the openGL scene. If the MT9 is plugged into a serial port, it is initializes and begins output of orientation information.


Download

Lemonade.exe v1.0 for Windows XP and 2000

Lemonade Source Code - C++ and Visual Studio .NET project files

MT9 c++ & Max/MSP Interface files

Install and Instructions README rtf file