Monday, April 16, 2012


Using Kinect and a Haptic Interface for Implementation of Real-Time Virtual Fixtures
Fredrik Ryd´en, Howard Jay Chizeck, Sina Nia Kosari, Hawkeye King and Blake Hannaford


This paper uses the depth feature of the Kinect camera to create real-time haptic virtual fixtures to aid with robotic surgery.  Essentially, these images serve to give the surgeon an indication of where and where not to cut.  This seems like a really good thing to have available to your surgeon, and it's cool that they are getting results using technology initially intended for video games.  The ability to come up with these virtual fixtures in real-time allows the doctors to compensate for movements and deformations during a surgical procedure.  Normally, these images are produced using a CT scan.  However, it's quite complicated to continuously CT scan during a surgery, so using the Kinect presents a more viable solution.

The haptic forces used in this paper are generated from a point cloud, which is the depth data taken from the Kinect.  This data is sent from the computer attached to the Kinect to a computer that is attached to the haptic device.  What this allows is for the surgeon (or whoever is manning the device) to see the effects that their "touch" will have.  An example given in the paper is that by moving your hand up will force the haptic device to move along with the hand.

While this doesn't directly relate to our project, I feel that it is a good example of the versatility of the Kinect, and how it has a myriad of applications that go beyond video games (such as ours).




Thursday, April 5, 2012

Design a questionnaire

D H Stone

Another not-super-exciting blog, but since we're in the middle of coming up with evaluation material it's probably more useful to me than another hand tracking algorithm.  This paper is on: how to write a useful questionnaire.  It also came out of a medical journal, although I don't think that changes much because the concepts behind making a solid questionnaire are still the same.  Anyway, back on topic:

According to the author, a good questionnaire is "one that works".  Basically, that the respondent's answers can be analyzed without bias, error, or misrepresentation.  While there is not a strict set of rules to follow to achieve this, the author does give a set of guidelines he feels will help you toward this goal.

Questions should be:
* Appropriate - The questions give relevant information.
* Intelligible - The language in the questionnaire is understandable by the respondent.
* Unambiguous - The questions mean the same thing to both the respondent and inquirer.
* Unbiased - Equal chance for all answers, also avoid "Recall Bias" (memory based).
* Omnicompetent - Be able to handle as many responses as possible. (Use 'other' and 'don't know' categories)
* Appropriately coded - Make sure your categories are mutually exclusive.
* Piloted - Questionnaires should always be piloted to check for any errors or other faults.
* Ethical - Get consent, etc. (IRB)

The author also has a step-by-step guide on the actual design of the questionnaire, rather than just theory behind the questions, which should be useful when actually constructing the survey:

(1) Decide what data you need
(2) Select items for inclusion
(3) Design individual questions
(4) Compose wording
(5) Design layout
(6) Think about coding
(7) Prepare first draft and pretest
(8) Pilot and evaluate
(9) Perform survey