Thickness of paper

Hi...Can anyone suggest a method of finding the thickness of paper in the link below http://tinypic.com/r/30dfrbl/7

[Fangjun Jiang]

Using MATLAB?

[Gova ReDDy]

yes.......

Answer 1

[Walter Roberson]

No. The same image has no scale indicators, so no absolute measurements are possible.

The sheet of paper to the left curves away from the camera, and is never shown edge-on, so we cannot determine its thickness.

There is something semi-vertical in the center, but we cannot tell if it is a single sheet or multiple sheets.

If you knew the mechanical properties of the paper, and knew the local force of gravity, and knew the temperature and humidity, then if we assume that the curve of the sheet on the left is due to the action of gravity and that the sheet is resisting gravity by way of its mechanical stiffness (which, in the case of wood pulp or similar materials would be affected by humidity and possibly temperature), then it might be possible to estimate the thickness of the sheet by measuring the curvature of the sheet in the image: for any one composition and environmental condition combination, the thicker the sheet, the less it would curve.

[Fangjun Jiang]

Good lecture, Prof. Roberson!

[Walter Roberson]

Please -- my proper title is Scientific Numerologist and Analyst of Fundamental Uncertainties.

Answer 2

[the cyclist]

estimatedThickness = 1; % Arbitrary units

[Walter Roberson]

Heh. ;-)

Answer 3

[Image Analyst]

Well it looks just like a piece of paper I have here. Believe it or not I have a micrometer here (it's true) and I measure my paper at 0.04 inches. So I think your paper must be the same thickness. If you don't believe me then prove it by providing something - some extra information to disprove what I said.

[Walter Roberson]

Dang -- my micrometer is on my desk at home! (it's true)

[Walter Roberson]

Your paper is probably .0038", which would be "20 pound" paper.

[Walter Roberson]

Closest I was able to get with mine was 0.0042 minus an indeterminate zeroing error that could be as high as 0.001.

http://www.practicalmachinist.com/vb/antique-machinery-history/slocomb-micrometer-repair-185226/