Re: Image transform

Posted by Gabriel Landini on
URL: http://imagej.273.s1.nabble.com/Image-transform-tp3703413p3703427.html

On Friday 03 March 2006 15:40, Liu, Dongfang (NIH/NIAID) [E] wrote:
> I am using a non-calibrated image. I don't know how to calibrate a image
> and what is function of this calibration? You mean the spatial calibration?

Yes. The result is the coordinates in your image.
If you have a calibrated image (you do this by going to Image>Properties and
set the width and height of you pixels.)

> In our system, we use the 10.35 microns pixel size of CCD and
> 100*objective. So I think of the pixel size of image is 100nm/pixel.

And not other optics in between? Is it a microscope? if so, it is very likely
that there are other correcting lenses in between.

I can't tell if your calculation is correct. You need to put a known sized
object under your imaging system and see how many pixels it spans. Then you
estimate the size of your pixels dividing the known size of your object by
the number of pixels it occupies.

The XM and YM coordinates are relative to the image coordinates. Since the
resolution of the image is given in pixels, there is no advantage in
calculating the coordinates in calibrated units. The result is not any more
accurate than in pixel units.

Cheers,

Gabriel