threshold questions

Posted by Johannes Breu on Aug 05, 2008; 8:14am
URL: http://imagej.273.s1.nabble.com/threshold-questions-tp3695457.html

Hello,

I have 2 threshold questions:

1) I threshold images, convert them into mask (8 bit image) an multiply
them. The product I measure  by Measurement. While doing the multiplication
I have the choice between an 32 bit image and no 32 bit image. What is the
advantage of a 32 bit image?
I always thought one pixel is multiplied by another pixel (same location) so
the product is 1 or 0. Why should this change the bit format (form 8 to 32)?

2) If I threshold an image by using the menu the image is different from my
macro. So I am a bit worried how to control and check for the conditions.
For instance my macro is like this:

setThreshold(1000,4095);
// run ("Threshold...");
run ("Convert to mask");

If its done via the menu automatically
setAutoThreshold ();
// run("Threshold");
is done (according to the Macro recorder).
If I use the set command successively it looks different from the macro.
Even if I do a reset step before. So I am irritated how to find the right
threshold if I am not able to translate the procedure (done via the menu)
into macro conditions.


Thanks
Johannes