| Table of Contents |
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Summary
| VoCentering | |||||
| Process category | Brief description | Computational demand for typical tomography data (low, medium, high) | Comment(s) | Reference(s) | Common alternative process(es) |
|---|---|---|---|---|---|
| filter | To find an optimal value of CoR automatically. | Reliable method for calculating the center of rotation in parallel-beam tomography | VoCenteringIterative | ||
Parameters
| Code Block | ||
|---|---|---|
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>>> disp -avv
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1) VoCentering(savu.plugins.centering.vo_centering)
A plugin to find the center of rotation per frame
1) preview : []
A slice list of required frames (sinograms) to use in the calulation of the
centre of rotation (this will not reduce the data size for subsequent plugins).
2) start_pixel : None
The approximate centre. If value is None, take the value from .nxs file else set
to image centre.
3) search_area : (-50, 50)
Search area from horizontal approximate centre of the image.
4) in_datasets : []
Create a list of the dataset(s) to process.
5) search_radius : 6
Use for fine searching.
6) ratio : 0.5
The ratio between the size of object and FOV of the camera.
7) out_datasets : ['cor_raw', 'cor_fit']
The default names.
8) datasets_to_populate : []
A list of datasets which require this information.
9) row_drop : 20
Drop lines around vertical center of the mask.
10) step : 0.5
Step of fine searching.
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>>> |
| Item | Parameter name | Parameter format | Example(s) | Comment(s) | |
|---|---|---|---|---|---|
| Parameter value | Effect | ||||
| 1 | preview | ||||
| 2 | start_pixel | An initial estimate for the pixel coordinate of an optimal CoR. | |||
| 3 | search_area | If the value of the search_area parameter is set to the default interval of (-50, 50), then this auto-centring process will attempt to determine an optimal CoR in the (start_pixel - 50, start_pixel + 50) interval. This range of this default search interval (100 pixel) may sometimes prove to be not sufficiently large to capture an optimal CoR, leading to subsequent sub-optimal reconstruction. If the value of CoR determined by VoCentering turns out to coincide with one of the search-interval limits (i. e. either start_pixel - 50 or start_pixel + 50), then this may indicate that this value is not optimal and that the search interval needs to be made larger before proceeding any further. | |||
| 4 | in_datasets | ||||
| 5 | search_radius | ||||
| 6 | ratio | ||||
| 7 | out_datasets | ||||
| 8 | datasets_to_populate | ||||
| 9 | row_drop | ||||
| 10 | step | In pixel units. | |||
Usage
TBC.