Hi Michael,
in Process>Binary>Options you can set the distance map (EDM) to 16 or 32 bits (float).
By the way, you have to make sure that you set whether you have a black background or not (also in Process>Binary>Options); otherwise your short macro may create the distance map outside the circle.
Don't be astonished if the distance map maximum of your circle is not exactly 350 but 349.3 or so; that's because of the rough borders due to pixel quantization.
Michael
________________________________________________________________
On Feb 3, 2012, at 17:15, Michael Ellis wrote:
> Dear IMageJ group,
>
> I am writing a macro that attempts to create the largest circular region of interest that can be contained within the current region of interest. I am using the Distance Map function but have hit a limitation in that the Distance Map created is an 8 bit image and therefore the maximum distance that can be stored in the map is 255.
>
> This can be shown with the script below. Since the original region is a circle (radius 350), the distance map ought to be a radial gradient going from 0 at the edge to a maximum value of 350 at the centre of the circle, however the since actual result is capped to an unsigned 8 bit quantity, there is a large flat circular area that is uniformly 255.
>
> Any suggestions?
>
> Is it possible to specify that the distance map be 16 bit?
>
> newImage("Test", "8-bit White", 800, 800, 1);
> run("Specify...", "width=700 height=700 x=400 y=400 oval centered");
> run("Clear Outside");
> run("Fill", "slice");
> run("Select All");
> run("Distance Map");
>
> Thanks in advance for any suggestions.
>
> Michael Ellis
> www.dsuk.biz
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