The Design and Evaluation of Multi-Finger Mouse Emulation Techniques

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Authors:
Justin Matejka - Autodesk Research
Tovi Grossman -Autodesk Research
Jessica Lo - Autodesk Research
George Fitzmaurice - Autodesk Research

Summary:
With the increased use of multi-touch tables and screens, it is common for users to want the precision of the mouse from standard computer systems.  The goal of this paper is to find the best technique to for emulating the mouse on large multi-touch devices.  Autodesk Research explores many different avenues for mouse emulation and measures the effectiveness of each.

The study first focuses on the types of mapping for the mouse cursor (direct, offset, scaled absolute, and relative) and on the tracking style used (one finger tracking or two finger tracking.)  It was shown that the offset technique performed the best overall for both large and small targets.

The study then focuses on way to define button distinction.  Some of the styles that they chose to test and implement to specify left, right, and middle mouse buttons are:

• Chording Technique - a single tracking finger with each additional finger representing left, middle, and right buttons as the number of fingers increase.
• Side Technique - tracking is done by the index and ring finger.  The thumb activates the left button, the pinky activates the right button, and the middle finger activates the middle button.
• Distance Technique - a single tracking finger where the relative distances from the tracking finger represent left, middle, and right button trigger points.
• Gesture Technique - a single tracking finger where a thumb tap is the left button, and thumb swipe to the right activates the right button and thumb swipe downward activates the middle button.
• Side+Chording Technique - a single tracking finger where side and chording are combined where the thumb activates the left button, the middle finger activates the right button and the combination of thumb and middle finger activate the middle button.
• Side+Distance Technique - single tracking finger where the left button is activated by the thumb, the middle button is the middle finger and the right button is the index finger.
• Chording+Distance Technique - a single tracking finger that is similar to Side+Chording tracking but where distance determines the button press instead of which side the press occurs on.

From all of these techniques the study found that the Side+Distance Technique is far superior and easier to use out of all of the emulation techniques.  The SDMouse (Side+Distance Mouse) performed equal with physical mouse use.

The study then briefly explores button activation technique (momentary pressing vs. toggle button activation.)  It was found that momentary press is much faster and is the most like the way a physical mouse is used.


Discussion:
I chose to read this paper (a very long and detailed technical paper) because I am very interested in multi-touch table technology and this confronts the input issues head on.  I have read other papers trying to solve this same issue and I believe this one satisfies the need the best.  While I do think the information is very useful, from all of the pictures, videos, and pretending to try it out myself, I find it very uncomfortable to not have something in my hand.  My hand gets cramped easily and it feels more awkward than if I was simply holding something.  They did not address this issue in the paper, but I believe that would be useful future work for these researchers.