View Full Version : 3D axis system by four points on the human body ?

Pascal Coorevits
12-15-1999, 01:22 AM

I'm assistant at the Ghent University. Currently we are doing research with
the Zebris system. With this system we can measure some points in space via
ultrasound. When we are doing our tests, we have to set the measuring sensor
( what is also our origin of the coordinate axis system) aligned with the
patient, because otherwise we can't say that the angles we measure are for
example in the sagittal plane ( or frontal, or transverse ). What I want to
know is, does anyone have an idea of points on the human body, that are
simply palpable. I need four points on the human body, and with these four
points it must be possible to define an origin with an orthogonal axis
system, where the axes are in the different planes of the body ( i.e.
sagittal, frontal and transverse ). If this is possible with these four
points, we can do a mathematical transformation from the original
coordinate system ( i.e. our measuring sensor ) to the new coordinate system
( i.e. defined by our four points ). If that is possible we don't have to
align the measuring sensor very precisely ( --> less errors ), what means
that our measurements will be measured in the correct planes. I hope I have
expressed me well enough to give a good explanation of our problem and I'm
waiting for your replies ... Thanks in advance !

Greetings from Belgium,

Pascal Coorevits
Ghent University - Faculty of Medicine
Dpt. of Rehabilitation Sciences and Physical Therapy
University Hospital
De Pintelaan 185 - B-9000 Ghent
Tel. : 0032-9-2402632
Fax : 0032-9-2403811

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