Exposure Targeting Set-up for MSI-T for Four holes¶

A good way to improve the throughput if there are multiple holes visible in a hl image is to target all four holes.

We can set up for 4 holes with this more challenging example:

About this image:¶

This image shows the edge of the grid bar. The intensity at edge of the grid bar has a mean around 20 while the rest has a mean around 45. The four holes are reasonably centered.

Leginon/Exposure Targeting/Template>¶

• Cross correlation works better than phase correlation in this case because the hole does not have sharp edge and not perfectly round.
• Adjust the value to fill the mean before correlation to minimize the correlation along the edge of grid bar.
• Invert template for correlation if needed.

Leginon/Exposure Targeting/Threshold>¶

• Fairly easy to set.
  

Leginon/Exposure Targeting/Blobs>¶

• Allow more blobs than the intended 4.
• Use border to eliminate those too close to the edge.
  

Leginon/Exposure Targeting/Lattice>¶

• Similar to that in Hole Targeting/Lattice step.
  • Make measurement of the lattice distance
  • Estimate the reference intensity for ice thickness filter.
    

Leginon/Exposure Targeting/Acquisition>¶

• Set up focus template but DO NOT eliminate focus targets using ice thickness criteria. This works because Leginon (3.1 and above) will automatically choose the center most focus target.