interpolation for millimeters

[Tony Shepherd]

I have an image where the pixels have real-world dimensions, representing
0.57mm per pixel in x and y directions.

I need to create a new image from this, with pixel values as they would be
at every 1.0 mm in each direction. Some kind of interpolation for re-gridding

Does anyone have a plugin / code that can do this?

Thanks

[Joachim Wesner]

Hi Tony,

I don´t understand, do you actually want to apply any changes to the pixel
values (make a new image that has LOWER resolution, i.e. less pixels in x
any total)

-> Image/Adjust/Size or Image/Scale in the latter case you can directly
input your sacle factor of 0.57/1

OR do you want to simply changes the "scaling to reale world coordinates"
in the image (NO change to pixel values)

-> Image/Properties....

Joachim

ImageJ Interest Group <[hidden email]> schrieb am 25.04.2008 12:58:15:

> I have an image where the pixels have real-world dimensions, representing
> 0.57mm per pixel in x and y directions.
>
> I need to create a new image from this, with pixel values as they would
be
> at every 1.0 mm in each direction. Some kind of interpolation for
re-gridding
>
> Does anyone have a plugin / code that can do this?
>
> Thanks


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[ctrueden]

Hi Tony,

This kind of problem is exactly what the VisAD Java class library for
visualization of numerical data (http://www.ssec.wisc.edu/~billh/visad.html)
was designed to solve. It would take a small amount of coding on your part
-- take a look at the FlatField's resample method. If you decide to go this
route and need further assistance, I would be happy to help.

-Curtis

On Fri, Apr 25, 2008 at 5:58 AM, Tony Shepherd <[hidden email]>
wrote:

> I have an image where the pixels have real-world dimensions, representing
> 0.57mm per pixel in x and y directions.
>
> I need to create a new image from this, with pixel values as they would be
> at every 1.0 mm in each direction. Some kind of interpolation for
> re-gridding
>
> Does anyone have a plugin / code that can do this?
>
> Thanks
>

[Justin McGrath]

Isn't this called resampling, which involves, but it not the same as,
interpolation? I learned the math behind this years ago and promptly forgot
it, so I can't describe how to do it.  However, I think that IrfanView (
http://www.irfanview.com/) has this capability.  Choose
Image->Resize/Resample.  To get a spacing of 1mm, multiply your original
pixel dimensions by 0.57.

The window (called Resample filter in IrfanView) affects the results
somewhat.  Lanzcos is popular, but Burger Wilhelm on the list recently
recommended Mitchell-Netravali over Lanzcos.

One day I might break out my text and try to put this into ImageJ, but I'm
not really a programmer and I'm not a signal processing expert by any means,
so perhaps it's a job more suited to someone else.

Justin

On Fri, Apr 25, 2008 at 9:09 AM, Curtis Rueden <[hidden email]> wrote:

> Hi Tony,
>
> This kind of problem is exactly what the VisAD Java class library for
> visualization of numerical data (
> http://www.ssec.wisc.edu/~billh/visad.html<http://www.ssec.wisc.edu/%7Ebillh/visad.html>
> )
> was designed to solve. It would take a small amount of coding on your part
> -- take a look at the FlatField's resample method. If you decide to go this
> route and need further assistance, I would be happy to help.
>
> -Curtis
>
> On Fri, Apr 25, 2008 at 5:58 AM, Tony Shepherd <[hidden email]
> >
> wrote:
>
> > I have an image where the pixels have real-world dimensions, representing
> > 0.57mm per pixel in x and y directions.
> >
> > I need to create a new image from this, with pixel values as they would
> be
> > at every 1.0 mm in each direction. Some kind of interpolation for
> > re-gridding
> >
> > Does anyone have a plugin / code that can do this?
> >
> > Thanks
> >
>