how to read pixel resolution in a .tiif image

[Chiara Magliaro]

Hi all,

i have some .tiff images obtained by a optical microscopy. As you all know,
thanks to the tiff tag, we can read some important information about the
image saved in .tiff after the microscopy acquisition.
So i downloaded MetaData and Tiff Tag. but i can't know the x and y
resolution of the pixel...i want to know, in fact, the dimension (in
micrometers) of a single pixel. how can i do?
Thanks you all, and best regards

Chiara Magliaro

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ImageJ mailing list: http://imagej.nih.gov/ij/list.html

[Vivek Saraswat-2]

Hi,
I think that is governed by image's PPI (Pixels per Inch). So inverse of
this would give you the length of one pixel in inches

And as far as i know pixels are square shaped, so both x and y dimensions
of a pixels would remain the same

*Vivek Saraswat*
*Pre-final year Undergraduate*
*Department of Materials Science and Engineering*
*IIT Bombay, India*
*[phone]*




On 12 December 2012 15:38, Chiara Magliaro
<[hidden email]>wrote:

> Hi all,
>
> i have some .tiff images obtained by a optical microscopy. As you all know,
> thanks to the tiff tag, we can read some important information about the
> image saved in .tiff after the microscopy acquisition.
> So i downloaded MetaData and Tiff Tag. but i can't know the x and y
> resolution of the pixel...i want to know, in fact, the dimension (in
> micrometers) of a single pixel. how can i do?
> Thanks you all, and best regards
>
> Chiara Magliaro
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

--
ImageJ mailing list: http://imagej.nih.gov/ij/list.html

[Glen MacDonald-2]

The XResolution and YResolution in the TIFF format refers to the point spacing for printing or display, by default. this has nothing to do with the spatial calibration of the imaging system.   The allowable TIFF units for these tags are 'none' (points per pixel) or 'Inches' or 'cm'.   Some acquisition software will write the pixel dimensions in the information tag, others will write to the XResolution and YResolution tags, but using inches or cm - these need to be converted to microns.  In ImageJ you simply type 'microns' to replace the inches or cm in the Image>Properties window.  

Most proprietary software will save the spatial calibration, in microns or nanometers, in their own special tag.  If your tiffs are the default format from a commercial system, or use the OME-TIFF, the calibration tag probably can be read with the LOCI plugin for ImageJ.   If these images are exported from a proprietary file format, they may still have the scale written to a proprietary tag, and LOCI should be able find it.  But, you would be best to open the original proprietary file format with LOCI.  

Your other option is to collect images of a stage micrometer using the same optical settings.

Regards
Glen MacDonald
        Core for Communication Research
Virginia Merrill Bloedel Hearing Research Center
        Cellular Morphology Core
Center on Human Development and Disability
Box 357923
University of Washington
Seattle, WA 98195-7923  USA
[phone]
[hidden email]
[hidden email]





On Dec 12, 2012, at 2:08 AM, Chiara Magliaro <[hidden email]> wrote:

> Hi all,
>
> i have some .tiff images obtained by a optical microscopy. As you all know,
> thanks to the tiff tag, we can read some important information about the
> image saved in .tiff after the microscopy acquisition.
> So i downloaded MetaData and Tiff Tag. but i can't know the x and y
> resolution of the pixel...i want to know, in fact, the dimension (in
> micrometers) of a single pixel. how can i do?
> Thanks you all, and best regards
>
> Chiara Magliaro
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html

--
ImageJ mailing list: http://imagej.nih.gov/ij/list.html