Re: Optical Density Support for 16 bit?

Posted by Wayne Rasband on Oct 18, 2006; 3:52pm
URL: http://imagej.273.s1.nabble.com/Optical-Density-Support-for-16-bit-tp3701204p3701205.html

The Analyze>Calibrate command in ImageJ 1.38a, due next week, will
support 16-bit images.

The precision of values generated by the "List", "Save" and "Copy"
options in plot windows created by the Calibrate and Plot Profile
commands is determined by the "Decimal Places" field in the Analyze>Set
Measurements dialog box.

-wayne


  On Oct 17, 2006, at 1:05 PM, Yeske, Ben S AMRDEC/Dynetics wrote:

> I need to Calibrate a 16-bit image using Polynomial curve fitting.
>
> When I try to do this, an error message pops up and displays "
> Calibration of 16-bit images, except with straight  line functions, is
> currently not supported."
>
> So I went into the Source code for Calibrator.class and commented out
> the lines:
>
>             if (function>0 && is16Bits) {
>                 IJ.error("Calibrate", "Calibration of 16-bit images,
> except with straight\nline functions, is currently not supported.");
>                 return;
>             }
>
> I tried again to calibrate my image.   This seemed to work correctly.  
> I
> was wondering what is the reason behind 16-bit images not being
> supported by Calibrate Image.
>
> The only bad thing that I noticed, was that when displaying the
> calibrated values in the List file, there was not enough precision
> displayed for my needs after a certain point.  The List box seemed to
> have a different format display for rows below a certain level.
> However,
> this was only a display problem, as when Measure was performed, the
> correct answer was given.
>
> Below is a partial List of Data:
>
> 0 -4.8661383E-4
> 257 -4.3279023E-4
> 514 -3.7735427E-4
> 771 -3.2030593E-4
> 1028 -2.616452E-4
> 1285 -2.0137212E-4
> 1542 -1.3948667E-4
> 1799 -7.598884E-5
> 2056 -1.0878654E-5
> 2313 5.5843906E-5
> 2570 1.2417883E-4
> 2827 1.9412613E-4
> 3084 2.6568578E-4
> 3341 3.3885782E-4
> 3598 4.1364224E-4
> 3855 4.90039E-4
> 4112 5.6804816E-4
> 4369 6.4766966E-4
> 4626 7.289036E-4
> 4883 8.117498E-4
> 5140 8.962084E-4
> 5397 9.822794E-4
> 5654 0.001                           At this point there is not enough
> precision....
> 5911 0.001
> 6168 0.001
> 6425 0.001
> 6682 0.001
> 6939 0.002
> 7196 0.002
> 7453 0.002
> 7710 0.002
> 7967 0.002
> 8224 0.002
> 8481 0.002
> 8738 0.002
> 8995 0.002
> 9252 0.002
> 9509 0.003
> 9766 0.003
> 10023 0.003
> 10280 0.003
>
> Ben
>