m1_measure_thresh — 2D `measure1d` op

• Data kinds: image → feature

• Call: fullseye.apply(img, "m1_measure_thresh", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

• HALCON equivalent: measure_thresh (the HALCON reference is a useful guide to its meaning and parameters)

m1_measure_thresh: input → output

*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*

Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):

▸ m1_measure_thresh: knob a sweep (docs site)

Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):

▸ m1_measure_thresh: knob b sweep (docs site)

Usage

Counts how many times the brightness profile crosses a specified level along a caliper line through the centre (equivalent to HALCON measure_thresh: extracts points with a specific gray value along a rectangle/arc).

a is the line orientation (theta = a*pi), b the grey-value threshold level (0 to 1, used as-is). Returns as the feature (integer value) the number of times the raw profile (no smoothing) crosses this level. 0.0 if the line does not hit the image.

Detailed usage guide

• gallery2d_contour_measure family guide

Background guides (the physics and conventions behind this op)

• measurement_uncertainty — Measurement uncertainty and calibration — what it takes to claim you are measuring

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Try it in Studio

The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.

m1_measure_thresh 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_contour_measure — py -3.11 examples/gallery2d_contour_measure.py

Ops the type connects to (they accept `feature` as input)

identity · feature_to_img

Same category (`measure1d`)

m1_measure_projection · m1_measure_pos · m1_measure_pairs · m1_fuzzy_measure_pos

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

m1_measure_thresh — 2D measure1d op