npr op• Data kinds: image2d → image2d
• Call: import fullseye as fs; fs.ledger.hatch_field(image, spacing_px=8.0, sigma=2.0, levels=3, cross_deg=90.0) (implementation को सीधे call करना हो तो import printpath; printpath.hatch_field(image, spacing_px=8.0, sigma=2.0, levels=3, cross_deg=90.0), registry से लेना हो तो opsprintpath.get("hatch_field"))
चित्र का अनुसरण करने वाली cross-hatching — दिशा structure tensor से।
> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।
The stroke direction is the local structure orientation (the existing structure_tensor_orientation: strokes run *along* edges, not across them), and the number of superposed hatch layers comes from the tone — one layer for a light grey, up to *levels* for a dark one, each rotated by *cross_deg*.
★Why this earns its place: the direction is checkable against a picture whose orientation is known by construction (a sine grating at 30° must give strokes at 30°), and the tone is checkable by blurring the result. The usual NPR routine offers neither.
Returns an image2d: 1 = paper, 0 = ink.
Raises ValueError: spacing below 2 px; levels below 1; non-positive sigma; a non-finite or oversized image.
Limits: a single orientation per pixel, so crossings and junctions (where the structure tensor is isotropic) get an arbitrary but locally smooth direction — the coherence, not the orientation, is what says whether to trust it.
• Sample data catalog (DL URL / license) — 2-D के लिए skimage.data (BSD/public) + synthetic, 3-D के लिए real data sources (Stanford/PDS आदि) के DL URL।
• Operators का स्रोत और संदर्भ — इस op family के मूल research/methods के स्रोत।
• Algorithm का मानक स्रोत (लेखक, वर्ष) और उपयोग ऊपर की family usage guide में दिए गए हैं।
• poc_beats_fringes_and_screens — py -3.11 examples/poc_beats_fringes_and_screens.py
image2d को input के रूप में लेते हैं)stipple_points_from_image · stipple_energy · stroke_tone_error · halftone_screen · engrave_lines · mosaic_tiles_sites · mosaic_tiles_render · print_layer_defect_map
npr)halftone_screen · halftone_moire_period · engrave_lines · mosaic_tiles_sites · mosaic_tiles_render
*Provenance: printpath.py — PRINTPATH operator registry. यह per-op note tools/opdocs.py md से अपने-आप generate होता है (हाथ से edit न करें)।*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.