chart_white_balance plugin (Re: measuring color in ImageJ)

[Melissa Amarello]

Hi,
Thanks for the response!  The chart_white_balance plugin looks like
exactly what I need.  Unfortunately I cannot find any instructions for
how to use it.  I downloaded it into my plugins folder and it appears
in ImageJ, but that is as far as I got.  Have you used this plugin?
Is there a readme file or manual somewhere that I am missing?

thanks,
melissa

Melissa Amarello
National Science Foundation Fellow
Arizona State University (Fall 2009)
http://www.public.asu.edu/~mamarell



On Wed, Aug 12, 2009 at 1:20 AM, Joachim
Wesner<[hidden email]> wrote:

> Hi Melissa,
>
> as far as I can see, the kind of calibration you are refering too in the
> link is not about colors at all!
> (I.e. about defining what combination of RGB values represent "true gray")
>
> That calibration in the link is about compensating nonlinear detector
> behaviour (i.e. a double light intensity
> does not read as twice the number) Yes, it will alos not change the image,
> but when you read out the pixels
> with the cursor, an extra number in brackets should appear that indicates
> the calibrated intensity.
>
> What about this plugin ??
>
> http://imagejdocu.tudor.lu/doku.php?id=plugin:color:chart_white_balance:start
>
>
> or Landinis "Color Correct" plugin on that page:
>
> http://www.dentistry.bham.ac.uk/landinig/software/software.html
>
> Cheers
>
> Mit freundlichen Grüßen / Best regards
>
> Joachim Wesner
>
>
>
>
>
>             Melissa Amarello
>             <melissa.amarello
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>             12.08.2009 03:07
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> Hi,
> I am a graduate student studying coloration in a rattlesnake (or I
> hope to).  I would like to use ImageJ, with a standardized color card
> (X-Rite ColorChecker Card) to estimate reflectance in digital photos.
> I have tried using the calibrate function following instructions here:
>  http://imagejdocu.tudor.lu/doku.php?id=gui:analyze:calibrate
> In greater detail:
> I open my jpg image in IJ, which contains the snake whose
> color/reflectance I want to measure and the color card
> I select an area within each grayscale step on the color card and use
> the measure tool to record mean gray values
> In "Analyze - Calibrate", I enter the actual mean gray values in the
> right column (corresponding to the measured values on the left)
> I pick a function (usually polynomial) and click ok.
>
> However, after accepting the calibration function, the image does not
> seem to have changed?  I use the color picker to measure color in the
> color card and it still says the original, incorrect gray values.
> What am I doing wrong?  Is there a better tutorial for the calibrate
> function than the one linked above?  Can I use ImageJ to calibrate a
> color photo?
>
> thanks,
> melissa
>
> Melissa Amarello
> National Science Foundation Fellow
> Arizona State University (Fall 2009)
> http://www.public.asu.edu/~mamarell
>
>
>
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