h a l f b a k e r yA riddle wrapped in a mystery inside a rich, flaky crust
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First, check link [smartphone ultrasound]
Now, my idea is to add a gyro sensor to the ultrasound probe, so we know at exactly which angle we got the image. So, If we just sweep the whole area of interest at different angles, can't we construct a 3d image of the "volume" of interest?
One major drawback
will be that the patient will have to lie rock solid to get accurate reconstruction.
smartphone ultrasound
http://blogs.zdnet....mergingtech/?p=1472 couple this with gyro [kamathln, Aug 05 2009]
David Laserscanner
http://www.david-laserscanner.com/ 3d laser scanning for surface modelling of 3d real life objects. [pocmloc, Aug 05 2009]
[link]
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Not just angle, but accurate 3d position needs measured. |
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[pocmioc], what do you suggest we use? |
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"rock solid" wouldn't be necessary, but perhaps a mechanism similar to that on computer mice to measure distance moved, since you'll be applying it on the surface of the skin. |
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Three small transmitters which clip out of the base of the unit, place them orthogannally around the object to be scanned, the handheld unit could triangulate its position from them. Obviously they need to be calibrated, perhaps photographically? I belive that some laser scanners use a similar system. The problem is getting the position and angle of the handheld unit to enough accuracy that the scans dont just jumble up. I like the idea of gyro and accelerometer but could it really be accurate enough? |
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Aah [FT] I had been thinking of moving it though the air. If over skin, then yes a mouse wheel thingy would be great. |
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See link for laser scanner. |
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I think the trick is to use several jointed arms to connect the ultrasound to a fixed point. Then all you need to do is measure all the angles and do some basic math. Gyros and accelerometers will drift too much. 3D ultrasound is baked, but this could be a poor man's version, so (+). |
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[MisterQED] This *is* supposed to be a poor man's version, but more importantly, a *pocket* version. Any remaining distortions could be algorithmically corrected? Any algorithms that you know? |
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The algorithms you are looking for are called Kalman algorithms and they need a lot of processing power to be worked effectively. My new Wii-motion remote needs re-syncing all the time, but thinking about it, the system I suggested could be very portable. Just have a small clamp or rare earth magnet as a base point, then two short telescopic lengths joined by hinges with angle sensors. It should all collapse down to the size of two pens and take little or no power to operate which keeps the overall size down. |
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