29 lines
1.2 KiB
Markdown
29 lines
1.2 KiB
Markdown
# Mutual Crop
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Align two images using FFT cross-correlation and crop both to their overlapping region. Useful for comparing images acquired at different times or with slight position offsets. Equivalent to Gwyddion's mcrop.c module.
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## Inputs
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| Name | Type | Required | Description |
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|------|------|----------|-------------|
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| field_a | DATA_FIELD | Yes | First input field |
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| field_b | DATA_FIELD | Yes | Second input field |
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## Outputs
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| Name | Type | Description |
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|------|------|-------------|
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| cropped_a | DATA_FIELD | Field A cropped to the overlapping region |
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| cropped_b | DATA_FIELD | Field B cropped to the overlapping region |
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## Controls
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This node has no user-adjustable controls. Alignment is fully automatic.
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## Notes
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- Both fields are zero-padded to a common shape, mean-subtracted, and cross-correlated in the frequency domain to find the optimal shift.
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- The overlap region is computed from the detected shift; both output fields are cropped to identical pixel dimensions.
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- If no valid overlap is found (e.g. completely non-overlapping images), the original fields are returned unchanged.
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- Physical dimensions (xreal, yreal) of the outputs are updated to reflect the cropped size using field_a's pixel spacing.
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