Questions about strain and orientation mapping

[sbachu6812]

Thanks very much for creating the very useful py4DSTEM package. I have a few questions about strain mapping and ACOM routines:

1. I acquire my 4DSTEM data for strain mapping using C2 20 aperture (0.6 mrad semi convergence angle and 2.3 nm probe size FWHM). So, I see diffraction spots instead of disks. When I set template = None in the disk detection step during the data processing, the code is not detecting any spots at all. Should I change any of the filtering arguments such as minAbsoluteIntensity or minRelativeIntensity or subpixel when using template = None?

2. I use the same CL and C2 aperture for all my experiments. So, I created one probe template by collecting a quick dataset from vacuum and use the same to detect spots for all my datasets. As of now, I saved the probe template as a tif image and load it back as kernel and pass it to template. Is it ok to do that? Or, is there a better way to save the probe template and reuse it?

3. For ACOM routine, if my dataset has 2 polycrystalline materials, say W and Cu, in the field of view, how do I go about it? Do I run the ACOM routine for the entire dataset twice, one for each material? Also, that will give me separate orientation maps of Cu and W. Is there a way to combine them into one composite map?

4. For ACOM routine of one material, after I get the orientation map, is there a way to measure the grain sizes? Are you planning to add that routine in the future? I am just curious.

py4DSTEM version: 14.9
Python version: 3.11.4