In Front DI, infrared light is shined at the screen from above the touch surface. A diffuser is placed on top (preferred) or on bottom of the touch surface.  When a finger or object touches the surface, a shadow is created under the object and seen by an infrared camera below the surface. This method is what the MTmini uses, but without the need for infrared light (since there is no visual display to remove). The MTbiggie also uses this technique. An image is displayed by using a projector connected to a computer pointed towards the projection material.

Parts List

• Clear, Sturdy Surface (Glass, Acrylic, Polycarbonate, Plexiglas, etc.)
• Infrared Lighting (The Sun, Infrared LEDs, Infrared Illuminator, Ambient Light/Lamps, etc.)
• Diffuser/Projection

In Rear DI, infrared light is shined at the screen from below the touch surface. A diffuser is placed on top (preferred) or on bottom of the touch surface.  When a finger or object touches the surface, the infrared light hits the object and is reflected downward and seen by an infrared camera below the surface. Depending on the diffuser, this method can also detect hovering objects, hands, and fingers above the surface. An image is displayed by using a projector connected to a computer pointed towards the projection material.

Parts List

• Clear, Sturdy Surface (Glass, Acrylic, Polycarbonate, Plexiglass, etc.)
• Infrared Lighting (Infrared LEDs, Infrared Cluster Illuminator, Infrared Lamp, etc.)
• Diffuser/Projection Surface (Vellum, Mylar, Lee Filter, other, etc.) – For

In FTIR, infrared light is placed and directed into the edges (sides) of an acrylic panel. The light is trapped within the acrylic by a phenomena called “total internal reflection”. When a finger touches the acrylic surface, the infrared light is “frustrated” causing the light to escape internal reflection and scatter downwards where it is seen by an infrared camera (modified webcam).

A silicone rubber layer is often used as a “compliant surface” to help improve dragging and sensitivity of the device. When touching bare acrylic, one must press hard or have oily fingers in order to frustrate the light and the projection material must be under the acrylic (which is not ideal). With a complaint surface (like silicone rubber),

Overview

Community Core Vision (CCV for short) is the software used to build multitouch surfaces,the MTmini and the MTbiggie.

CCV, is an open-source computer vision framework for multitouch and other emerging interaction types. I co-founded and developed CCV for Google Summer of Code in 2008. It has since been downloaded over 250,000 times and utilized by companies, researchers, and hobbyists around the world. Community Core Vision is currently maintained by the NUI Group community.

System Requirements

• Hardware:
  • Pentium 4+ (Recommended Core 2 Duo+)
  • 512MB+ RAM (Recommended 1024+)
  • Web Camera (for live interaction)

• Software:
  • Windows:
    • Quicktime
    • VS2005 Redist x86
  • Mac:
    • Quicktime
  • Linux:
    • libpoco

CCV Download Link

• Main Website: http://ccv.nuigroup.com
• Alternative Link 1: http://nuicode.com/projects/ccv/files
• Alternative Links 2

[download id=”3926″]

[download

For testing and fun, several demo and complete applications can be downloaded in flash (swf) format. The following guide shows how to run the applications using your touch surface and Community Core Vision.

Requirements

• Flash Player Projector – This is a flash player that runs outside of your browser
• FLOSC (CCV 1.1 and below only)
• Java 6+ is required for running FLOSC (CCV 1.1 and below only)

Flash Demo Application Setup

1. Download some flash demos. You can find the nuigroup (MTmini video) flash example clients here and some of my own applications here.

• If you’re using CCV 1.2+, skip to step 4.
• If you use an older version of CCV,version 1.1 or below, and

In order to track fingers or objects, CCV first needs to be configured. The goal is to have a final tracked image that has white blobs coming from fingers or objects placed on the touch surface (with no background noise or false blobs visible or tracked). In order to reach this goal, various image filter sliders are adjusted. By following the steps below, a final tracked image with clear and distinct blobs should be achievable (like the one you see on the picture below). The default settings may not be ideal, and I advise you to play with each slider to understand how it works.

CCV Diagram Overview

1. Source image – Displays the raw video image from either camera or