Re: AND function

Posted by Florian Ulrich on Jul 14, 2005; 2:03pm
URL: http://imagej.273.s1.nabble.com/AND-function-tp3705233p3705238.html

Ups, thanks,

just discovered that myself as well... now, I am curious: on which type of
images and for which kind of analysis would you then use the AND function?
What is the significance of the AND function to your images?

All the best,

Florian

> Hi,
>
> On Thu, 14 Jul 2005, Florian Ulrich wrote:
>
>> to find colocalization, I am comparing two 8-bit channels with the AND
>> function. I thought, it would calculate like
>>
>> first channel value 128
>> second channel value 180
>> AND operation gives 128
>>
>> or
>>
>> first channel value 110
>> second channel value 55
>> AND operation gives 55
>>
>> etc.
>>
>> However, imagej sometimes does that, but also sometimes yields different
>> values for the AND function. How can that be? I am using imagej version
>> 1.33u on 8-bit tif images gained from a Leica confocal microscope.
>
> You calculate the Boolean AND function, which means that each pixel's
> value is interpreted as a dual number, i.e. 128 = dual(10000000), and 55 =
> dual(110111). The AND function calculates the minimum *per digit*, i.e.
> 128 AND 55 = 0.
>
> What you probably want is the Minimum function.
>
> Hth,
> Dscho
>
>