Image calibrations in PFE and PI

[Probeman]

In order to ensure that our beam scan imaging aligns properly with our stage coordinates, we need to calibrate our scan coils for several magnifications (ideally two magnifications per scan coil range). This means for each chosen magnification, we need to determine the scan rotation to ensure orthogonality with our stage and the X and Y scan extents in microns.

As many of you know there are two methods for image calibration in Probe for EPMA and Probe Image.

1. The two point calibration method which is accessed from the Acquire! Imaging window, using the small "@" button as described here:

https://probesoftware.com/smf/index.php?topic=329.0

This method can be entirely performed in Probe for EPMA and is accomplished by first ensuring that the image is orthogonal to the stage by utilizing a linear feature on your sample holder, then finding two points on an approximate diagonal on the image and your sample using the light optics.

2. The three point calibration method utilized in CalcImage by acquiring a stage map and multiple beam scan images in Probe Image which rely on finding three points which are located on both images as described here:

https://probesoftware.com/smf/index.php?topic=396.0

The advantage of this method is that it can work on any sample with visible features and automatically compensates for beam scan rotation.

How do you calibrate your beam scan images in order to ensure that the images are accurate in stage coordinates?

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[Ben Buse]

I used to always use the 3 point in Probe for Epma, but the problem was the samples where different heights so the incorporation of z wasn't helpful - (i.e. not dealing with a uniform slope) - therefore I switched to using the 2 point calibration

[John Donovan]

I used to always use the 3 point in Probe for Epma, but the problem was the samples where different heights so the incorporation of z wasn't helpful - (i.e. not dealing with a uniform slope) - therefore I switched to using the 2 point calibration

This image/beam scan calibration topic has nothing to do with Z stage motion.

By the "three point method in Probe for EPMA" do you mean the fiducial method in the Automate! window?  If so, that's a different calibration situation specific to the navigation of sample mounts. See Karsten's tutorial on this:

https://probesoftware.com/smf/index.php?topic=405.0

Here we are speaking of the beam scan to stage calibration method.  That is, what the X and Y extents (and scan rotation) are for different magnification values.