What is the Best Lab Apparatus for Measuring Volume of Irregular Objects?

[saplingg]

Could anyone recommend a piece of lab apparatus which will measure the volume of an irregular object? I cannot use displacement of water as the object will compress under pressure and I suspect submerging the object in water will give a different displacement from the actual volume at 1 atm.

Ideally I would use something that could measure volume optically... Anybody know of an apparatus which does that?

 

[berkeman]

If you know its density, you could just weigh it.

Otherwise, you could use a 3-D digitizing device to digitize its outline. I've seen them in the past, but will have to do a quick search to see if I can find one. It's like a wand mounted on an articulated arm with rotary and linear encoders to pick up where the tip of the wand is.

I don't think you'll be able to do it optically in the general case. If your object is always convex, then you could probably do it optically with a laser grid projected on the object, and a TV camera picking up the image as you rotate it.

 

[berkeman]

Wow, I just did a google search on 3D Digitizer, and got a bzillion hits. Here's one:

http://3ddigitalcorp.com/escan.htm

They do it optically. And here's an article about doing it with a wand:

http://lear.inrialpes.fr/people/triggs/events/iccv03/cdrom/demos/aritaki.pdf

 

[saplingg]

Thanks a lot! that's just what i needed.