Naomi,
On Jan 23, 2006, at 9:01 AM, Naomi Barth wrote:
> hi
> I apologise if these questions have been answered before, but I
> currently
> have two questions about Image J that I need help with.
> 1) After converting a 8-bit image to a txt file. How do I know what
> numbers of the file correspond to what pixel from the image? And
> when a
> stack of image has been converted how can I tell which numbers are
> from
> which image of the stack? I need to compare every pixel to every
> other
> pixel once it has been converted to binary, but I need to know what
> vector I
> used to compare them with, so I need x, y, and z components for
> every pixel,
> and currently I am unsure about how the txt file is set up.
>
Why would you want to convert an 8 bit image to text? The only thing
you get from that is the ability to read values in a text editor.
The file will be MUCH larger and no tools will work on it. I don't
know what you are doing, but even so, the best advice I can give you
is to leave it 8 bit. Any operation you could do in text, you can do
in 8 bit.
As for stack operations: in ImageJ each image in a stack is available
using an index. There is really no confusion once you get started.
You can call that image index z if you wish.
>
> 2) How do you set a threshold value for turning an 8-bit image into a
> binary one. I need to be able to set a threshold and then see
> what it
> looks like. I have a two-phased material that I want to be shown
> only in
> black and white, but I want to make sure that the threshold that I
> am using
> is correct, so I need to able to see it. Eventually the threshold
> value
> will be used in a script that will convert a stacked txt file into
> binary.
>
In ImageJ, try the Image->Adjust->Threshold command (shift-cmd-T on a
Mac). That allows you to interactively set a threshold.
> Thank you very much
> -Naomi Barth
You're welcome very much,
duane