ScanSlicer/docs/parameters.md

Parameter Reference

This page documents the detection parameters defined in scanslicer/params.py (AutoslicerParams.SPECS).

Notes

• All values are integer-backed.
• Some parameters are context-sensitive and only apply to specific detection modes.
• Internal safeguards:
  • aspect_ratio_max is clamped to be >= aspect_ratio_min
  • canny_high is clamped to be >= canny_low

Choice Parameters

• detect_pipeline
  • 0: Threshold pipeline
  • 1: Canny pipeline
• bw_method (threshold pipeline only)
  • 0: Simple threshold
  • 1: Adaptive Gaussian threshold
  • 2: Otsu threshold
• invert_mode
  • 0: Auto (try normal polarity, then inverted fallback)
  • 1: Off (normal polarity only)
  • 2: On (force inverted polarity)
• morph_op
  • 0: None
  • 1: Dilate
  • 2: Erode
  • 3: Open
  • 4: Close

Full Table

Parameter	Default	Range	Step	Used In	Effect
detect_pipeline	0	0..1	1	global	Select threshold or Canny detection pipeline.
clahe_clip	0	0..40	1	preprocessing	CLAHE contrast boost (0 disables). Effective clip limit is value/10.
gaussian	0	0..100	1	preprocessing	Gaussian blur kernel size (0 disables). Even values are bumped to odd.
bw_method	0	0..2	1	threshold pipeline	Selects Simple, Adaptive Gaussian, or Otsu thresholding.
bw_thresh	210	0..255	5	threshold+simple	Binary threshold cutoff.
bw_gauss	64	0..1000	2	threshold+adaptive	Adaptive block size basis. Converted to odd and at least 3.
bw_adaptive_c	2	-20..20	1	threshold+adaptive	Adaptive threshold subtraction constant.
canny_low	50	0..255	5	Canny pipeline	Lower Canny hysteresis threshold.
canny_high	150	0..255	5	Canny pipeline	Upper Canny hysteresis threshold.
invert_mode	0	0..2	1	global	Controls polarity inversion behavior before contour extraction.
morph_op	1	0..4	1	global	Morphological operation on mask/edges.
contour_approx_pct	0	0..50	1	contour extraction	Polygon approximation epsilon percentage (value/1000).
bbox_min_size	2	0..100	1	contour filtering	Minimum candidate area as % of full image area.
bbox_max_size	90	1..100	1	contour filtering	Maximum candidate area as % of full image area.
bbox_fill_thresh	10	0..100	1	contour filtering	Minimum contour fill ratio within min-area box (%).
expected_count	0	0..20	1	scoring/autotune	Expected number of photos (0 means auto/unbounded heuristics).
aspect_ratio_min	100	100..1000	5	contour filtering	Minimum long/short aspect ratio, scaled by x100.
aspect_ratio_max	400	100..1000	5	contour filtering	Maximum long/short aspect ratio, scaled by x100.
border_ignore	0	0..20	1	contour filtering	Ignore candidates touching image edges within this margin (%).
iou_merge_thresh	30	0..100	1	contour dedup	Merge overlap threshold as IoU percentage.
dilate_kernel	30	0..500	1	morphology	Morph kernel size for selected morph operation (0 disables morphology).

Advanced Parameters in UI

The UI can hide/show advanced controls. Advanced set:

• detect_pipeline
• clahe_clip
• gaussian
• bw_adaptive_c
• invert_mode
• contour_approx_pct
• bbox_max_size
• aspect_ratio_min
• aspect_ratio_max
• border_ignore
• iou_merge_thresh

Practical Tuning Guidance

• Too many tiny false positives:
  • Increase bbox_min_size
  • Increase bbox_fill_thresh
  • Increase iou_merge_thresh
• Missed photos:
  • Lower bbox_min_size
  • Broaden aspect_ratio_min/max
  • Try detect_pipeline=1 (Canny)
  • Try invert_mode=2
• Border/frame artifacts:
  • Increase border_ignore
  • Switch morphology operation/kernel
• Uneven illumination:
  • Use adaptive mode (bw_method=1)
  • Enable modest clahe_clip