I used the digital camera for microscope DCM35 (350K pixels, USB2.0) to capture some specimens (the software Minisee is included with the camera). The max resolution of the camera is 640x480 and pixel size 8µmx8µm. I used a x10 objective and a x10 ocular on the microscope. I don't know how to calculate the image "distance in pixels" and the "known distance" required in the "Set Scale" dialog box of IMAGEJ 1.38
Hi Hermine,
you will need to create a calibration image: take an image of an object with a known size with the same microscope setting you used for your original image. We typically do this using a calibration slide that shows a known distance, e.g. 100µm.
Here is how you do it:
http://microscopy.berkeley.edu/courses/dib/sections/04IPIII/IJsetscale.html
See also:
http://rsb.info.nih.gov/ij/docs/guide/146-30.html#toc-Subsection-30.8
Hope this helps,
Eszter
Hi Hermine,
you will need to create a calibration image: take an image of an object with a known size with the same microscope setting you used for your original image. We typically do this using a calibration slide that shows a known distance, e.g. 100µm.
Here is how you do it:
http://microscopy.berkeley.edu/courses/dib/sections/04IPIII/IJsetscale.html
See also:
http://rsb.info.nih.gov/ij/docs/guide/146-30.html#toc-Subsection-30.8
Hope this helps,
Eszter
If you prefer, you can also do it in Photoshop, Ruler tool. It measures the distance and if you hold Alt, you can continue the line from the end to another line.
Dear Hermine,
If you don't have a calibration slide by hand you can also use a hemocytometer (http://en.wikipedia.org/wiki/Hemocytometer look this link up for the distances) that is okay for most applications.
Beside pixel size and used lens there might also be a convertion factor by the camera adapter. So a single picture of a Hemocytometer will be the best option. You can than drag a line along i.e. one square to measure the pixel number and use the set scale dialog as suggested by Eszter (the berkeley link). If you are using the set up more often and different lenses you might think about the editing of the microscope scale plug in (http://rsb.info.nih.gov/ij/plugins/microscope-scale.html) that was even easy to me since I do not know anything about Java coding.
Best Soenke
Dear Eszter, Aleksandar and Sönke,
Thank you very much. Your answers were very helpfull.
Best regards
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