Posted by
Herbie on
URL: http://imagej.273.s1.nabble.com/Find-missing-spots-in-a-grid-of-spots-tp5019879p5019973.html
Good day,
concerning the rotation I determined an angle of 0.9 degrees for the
provided sample image.
What I did for this analysis is:
1. "Process >> FFT >> FFT Options... >> Raw power spectrum + Do forward
transform"
2. Make a selection for the resulting power spectrum:
"Edit >> Selection >> Specify >> 255, 255, 512, 512, Oval + Constrain
circle + Centered"
3. Run plugin "Slice_Integrals" available from here
<<
http://www.gluender.de/Miscellanea/MiscTexts/UtilitiesText.html>
with parameters "Number of Angles = 402, Slice Interpolation = Bicubic"
The resulting graph gives you the distribution of power in the
Fourier-spectrum as a function of the angle.
For the sample image I get 119.10 degrees that, modulo 60 degrees, gives
a rotation of 0.9 degrees.
Regards
Herbie
:::::::::::::::::::::::::::::::::
Am 31.01.18 um 15:53 schrieb ard:
> Hi Gabriel,
> Unless I grossly misunderstand you, I'm afraid that is not exactly what we
> are after, as we are after the perfect grid with all missing dots put back
> in and stray blobs removed. This grid is generated by drawing circles in an
> empty window, by the way.
> Imagine a perfect honeycomb (hexagonal) with a dot on every corner and a dot
> in the center of each honeycomb cell. Now erase all edges so only the dots
> are left. Then randomly remove some dots. Now degrade each remaining dot a
> random number of pixels around the perimeter. Then shift and rotate the
> whole image across an arbitrary distance and angle < 30 degrees. Add noise.
> Invert the image. Add noise again.
>
> In the cleaned-up image below, which is only 1 degree off vertical, there
> are two dots missing (3rd column 9th row and 4th column 8th row; near the
> latter is a strayblob, not a dot). Both the missing dots and the stray blob
> could easily be identified by an X- and Y projection. Analyze Particles,
> with the proper size and circularity will find the most dots correctly, but
> of course it will not find the missing dots and it is confused by the stray
> dots too.
>
> We are asked to indicate which dot(s) have vanished and which are not dots
> but blobs, so as to generate the 'perfect' honeycomb dot pattern again.
>
> <
http://imagej.1557.x6.nabble.com/file/t188556/dots.gif>
>
>
>
>
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http://imagej.nih.gov/ij/list.html>
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