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3.31. Change the spatial calibration of a dataset

Each objective on the Volocity acquisition system should be calibrated using a stage graticule. More information on how to do this with Volocity Acquisition may be found on page 151 of the Volocity User Guide

Providing the correct calibration (microns per pixel) is known, then this can be manually entered.

1. Select the image sequence
2. Go to the Edit menu and select Properties...
3. Change the µm/pixel (X) and (Y) as required. By default the µm/pixel (Z) is the physical step size but can be changed to account for spherical aberration.

The µm/pixel in X and Y can be calculated from the camera's pixel size and magnification:

µm/pixel = camera pixel size µm/ (lens magnification*intermediate magnification)

For instance if you are using an Orca AG with a 63x lens and a 0.63x reduction c-mount

The pixel size of the Orca AG is 6.45µm in both X and Y therefore

6.45/(63*0.63) = 0.163

These values could then be entered into the µm/pixel X and Y. However it is best practice to perform the calibration with a stage graticule as this will ensure the calibration is accurate.