vx_phase — VX `gradient` op

• Data kinds: image2d × image2d → image2d

• Call: import fullseye as fs; fs.ledger.vx_phase(gx, gy, *, mapping) (to call the implementation directly, import vxcore; vxcore.vx_phase(gx, gy, *, mapping); from the registry, opsvx.get("vx_phase"))

Usage

Gradient phase (Section 3.41): shifts ϕ = atan2(gy, gx) into 0 ≤ ϕ < 2π and maps it to 0–255 (REQ-0364). Output U8.

*mapping* (required): the specification does not state the rounding of the mapping. "floor" = ⌊ϕ·256/(2π)⌋ (0 ≤ value ≤ 255 holds automatically), "round" = ⌊ϕ·256/(2π) + 0.5⌋ mod 256 (just below 2π wraps to 0). Pixels with gx = gy = 0 get ϕ = 0 by the atan2 convention.

Raises ValueError: not a 2-D S16 / shapes differ / mapping not in the list.

Detailed usage guide

• openvx_ports family guide

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.

Runnable examples (verified samples that actually call this op)

• (none yet)

Ops the type connects to (they accept `image2d` as input)

vx_sobel3x3 · vx_magnitude · vx_table_lookup · vx_histogram · vx_nonmax_suppression · vx_warp_affine · vx_warp_perspective · vx_remap

Same category (`gradient`)

vx_sobel3x3 · vx_magnitude

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

vx_phase — VX gradient op