Posted by
Michael Schmid on
Mar 28, 2015; 7:53pm
URL: http://imagej.273.s1.nabble.com/Problems-using-the-FFT-Bandpass-Filter-tp5012174p5012234.html
On Fri, March 27, 2015 23:44, Hening Bettermann wrote:
>
> I have in the meantime tried to read some of the documentation, but
> without being able to extract much of use for my purpose.
> Strange enough, if I first convert to RGB stack (Image > Color > Stack to
> RGB), then convert to 32 bit grayscale (Image > Type > 32 bit), then
> export as TIF and open that in Preview, I see an inverted image, not just
> black.
> Regardless, trying to run Process > FFT > Bandpass Filter, still gives me
> the memory error. - Which operating system and version do you use? How
> much RAM do you have/allocated to ImageJ?
> Mine is Mac 10.9.5, and I have 16 GB of RAM, 12 allocated to ImageJ.
>
Hi Henning,
(1) There is hardly any software apart from ImageJ that can read 32-bit
TIFFs (Preview on OS X 10.6 can't, but it does not complain that it can't
read it).
For exporting, you have to convert to 8 or 16 bits (make sure that the
display range in Adjust Brightness&Contrast is reasonable and 'Scale when
converting' is checked in Options>Conversions). All tiff readers can
handle 8 bits, a few programs can also handle 16 bits.
Preview on OS X 10.6 can read 16-bit tiffs, but many 16-bit TIFFs appear
black or almost black in Preview because it assumes that the grayscale
range from black to white is 0-65535, i.e., all 16 bits are used. Many
16-bit tiffs don't actually use the full dynamic range possible with 16
bits.
(2) I have never seen a memory error with Bandpass Filter, using Macs with
mostly OSX 10.5 or 10.6, Java 1.6. 2-8 GB of RAM, and 640 MB-2 GB limit
for ImageJ. Typically, I have rather small images, however.
For 4096x4096 pixels, about 1 GB is needed.
Michael
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