Re: 3D projections

Posted by Knecht, David on
URL: http://imagej.273.s1.nabble.com/3D-projections-tp5023114p5023122.html

The problem is that confocal data is rarely cubic voxels.  They are nearly always much larger in z and x-y.  In the case of the data I was analyzing they were 0.06 x 0.06 x 0.5 µm and that is not unusual.  So you would expect to see the side on projection as a smear given you are looking through elongated voxels.  Dave

Dr. David Knecht
Professor, Department of Molecular and Cell Biology
University of Connecticut
91 N. Eagleville Rd.
U-3125
Storrs, CT 06269-3125
860-486-2200

On Mar 31, 2020, at 1:37 PM, Herbie <[hidden email]<mailto:[hidden email]>> wrote:

*Message sent from a system outside of UConn.*


Good day Kenneth,

thanks for your reply!

"Now...why doesn't the same logic apply to image "planes"?"

With a stack of voxel-size 1x1x1 and when I use "Reslice..." (e.g.
Rotate 90deg), I'm quite happy with the result.

Not sure what's the original problem...

Regards

Herbie

:::::::::::::::::::::::::::::::::::::::::::
Am 31.03.20 um 18:38 schrieb Kenneth Sloan:
Understood.  Now...why doesn't the same logic apply to image "planes"?
--
Kenneth Sloan
[hidden email]<mailto:[hidden email]> <mailto:[hidden email]>
Vision is the art of seeing what is invisible to others.

Begin forwarded message:

From: Herbie <[hidden email]<mailto:[hidden email]> <mailto:[hidden email]>>

Subject: Re: 3D projections

Date: March 31, 2020 at 05:37:15 CDT

To: [hidden email]<mailto:[hidden email]> <mailto:[hidden email]>

Reply-To: [hidden email]<mailto:[hidden email]> <mailto:[hidden email]>


"ImageJ does not treat PIXELS as infinitely small in x and y [...]"

If you would, which were correct, you wouldn't see anything.
Therefore and in general, the cheapest interpolation is applied:
Little squares or rectangles of constant value(s).
Actually, such block images are incorrect as well, because the correct
interpolation is a totally different one that is much more costly and
cannot be realized by common display technology.

Regards

Herbie

:::::::::::::::::::::::::::::::::::::::::::
Am 30.03.20 um 23:49 schrieb Kenneth Sloan:
This has always confused me.  After all, ImageJ does not treat PIXELS
as infinitely small in x and y - so why should it consider  VOXELS to
be infinitely thin in z (but with finite  width and height)?
--
Kenneth Sloan
[hidden email]<mailto:[hidden email]> <mailto:[hidden email]>
Vision is the art of seeing what is invisible to others.
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