Posted by
Melissa Amarello on
Aug 12, 2009; 1:07am
URL: http://imagej.273.s1.nabble.com/measuring-color-in-ImageJ-tp3691452.html
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:calibrateIn 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