Posted by
Divakar Ramachandran-2 on
Feb 11, 2014; 1:50am
URL: http://imagej.273.s1.nabble.com/calculate-magnification-tp5006474p5006488.html
On Tuesday 11 February 2014 06:47 AM, Glen MacDonald wrote:
> Open the image in Fiji and disable any spatial calibration (Analyze>Set Scale). draw a line across the 3 mm object with the straight line tool. You have 2 options- Measure the length (Analyze>Set Measurements>Perimeter [gives length on straight lines]) and divide # pixels/3 mm for pixels/mm; or go back to Set Scale and enter the known distance. This can be set for future images through Image> Properies…
> Note that saving files as jpeg or tiff will often throw away the spatial calibration.
In my experience, saving as TIFF preserves scale information, though
only for reading through ImageJ.
Divakar
> Another option for measuring the diameter is to download the FWHM macro.
> For more info, Help>ImageJ Documentation
> Glen
> 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
> (206) 616-4156
>
[hidden email]
>
>
>
>
>
>
>
> On Feb 10, 2014, at 8:39 AM, xlancelot <
[hidden email]> wrote:
>
>> Hi everybody,
>>
>> i would like to calculate the magnification of my image
>>
>> i took an image of a mark with actual size 3 mm using my webcam
>>
>> image resolution is 1600x1200 and the webcam is using 2 MP cmos sensor
>>
>> now how can i calculate the magnification between the mark real size and the
>> mark shown form the image ?
>>
>> sorry for my bad english
>>
>> thank you
>>
>>
>>
>> --
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