Re: Objects Counter can't find any objects on my screen?

Posted by Thomas Boudier on Dec 08, 2014; 8:10am
URL: http://imagej.273.s1.nabble.com/Objects-Counter-can-t-find-any-objects-on-my-screen-tp5010585p5010835.html

Hi,

It looks to me that your raw pixel value is 32994 (integer) and that
then your calibrated value is 226.0 (float value), so the slope may be
146 and intercept 0 ? Try also to convert your image to 32-bits, I think
it will then use calibrated values as normal values.

Thomas


On 07/12/14 21:26, esumft wrote:

> I am still having trouble with this unfortunately.
>
> However, it appears that on my original stack, these numbers appear to be
> calibrated by the DICOM header. Highlighted in red is the calibrated HU
> value and in brackets, what I assume is the raw pixel value? How can I find
> out how the raw pixel value is scaled?
>
> <http://imagej.1557.x6.nabble.com/file/n5010831/Numbercalibration.png>
>
> I have looked online, and apparently the typical HU calibration function is:
>
>   hu = pixel_value * slope + intercept
>
> But this wouldn't work in this context? It would give:
>
> Pixel value= 1
> Intercept = -1024
>
> HU= 32994*1 - 1024 = 31970 HU
>
> It should be 226 HU. Any idea how I can find out how the number in brackets
> is scaled, please?
>
>
>
> --
> View this message in context: http://imagej.1557.x6.nabble.com/Objects-Counter-can-t-find-any-objects-on-my-screen-tp5010585p5010831.html
> Sent from the ImageJ mailing list archive at Nabble.com.
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

--
   /***************************************************************/
      Thomas Boudier, Associate Professor, UPMC,
      Université Pierre et Marie Curie, Paris, France.
      BioInformatics Institute (BII)/IPAL, Singapore.
/**************************************************************/

--
ImageJ mailing list: http://imagej.nih.gov/ij/list.html