By what means do I carry out the geometric calibration of the objectives at the microscope?
 
  Depending on the microscope type, you need an object micrometer for transmitted light, reflected light or for stereo microscopes. You can find such object micrometers in the Sales Packages for Microscope Accessories.
 
For the calibration itself, you have to set the object micrometer with all its possible combinations of objective and zoom factor (in case of fixed TV adaptors, this is only one value) and, after that, carry out the calibration according to Chapter 5 of the Operating Instructions. In case of cameras with non-square pixels, you have to carry out the calibration in X- and Y-direction.
   
What measurement error of the interactive measurement in the TV image do I have to expect?
 
  The following factors influence the measurement error:
- Error of the object micrometer (between 0.5% and 1%)
- Local resolution of the sensor
- Optic reproduction (magnification/reduction) of the object on the sensor
- Mistakes of the user during calibration and measurement (drawing mistakes)

The typical measurement error in case of careful work is between 1% and 2%.
By the so called sub-pixel measurement via grey level profiles (e.g. by the function Profile or the Option MeanProfile), you can also achieve a very high measurement precision of the interactive measurement with IQ EasyMeasure® (better than 1%). You can find more information in an application report in the download area.