post op• 数据种类:image2d → image2d
• 调用: import fullseye as fs; fs.ledger.dither(img, levels=2, method='ordered', matrix_size=4)(要直接调用实现,import gfx2d; gfx2d.dither(img, levels=2, method='ordered', matrix_size=4);从台账取用则 opsgfx2d.get("dither"))
在保持局部均值的前提下,把每通道量化到 levels 个取值。
> 以下的详细说明为原文 —— 摘要与标题已翻译。
method:
• "ordered" — Bayer threshold matrix of side matrix_size (a power of two, 2..16). The mean error has a closed-form bound: for a uniform patch the output mean is within 0.5 / (matrix_size**2 * (levels-1)) of the input, because the fraction of thresholds crossed is the input fraction rounded to the nearest 1/matrix_size**2. At the defaults (4, 2 levels) the bound is 0.03125; the suite checks it holds for 101 grey levels x 3 matrix sizes, with zero violations.
• "floyd_steinberg" — error diffusion with the 7/3/5/1 sixteenths of Floyd & Steinberg 1976, serial and directional.
Which method preserves the mean better depends on the image, and this docstring will not pretend otherwise. Measured on a 128-step horizontal
ramp: ordered is exact (0.0) at 2, 3 and 4 levels and drifts to 1.1e-3 at 8 levels, while Floyd-Steinberg is 7.3e-4 at 2 levels and improves to 4.1e-5 at 16. Ordered wins where the level lattice divides the ramp, error diffusion wins where it does not.
Accepts (H, W) or (H, W, 3|4); an alpha channel is quantised too, because a dithered sprite with a smooth alpha is exactly the case that motivates this.
Output values lie on the lattice k / (levels - 1).
• 示例数据目录(下载 URL / 许可证) —— 2-D 用 skimage.data(BSD/公有领域)加合成图,3-D 给出真实数据源(Stanford/PDS 等)的下载 URL。
• 算子来历与参考文献 —— 该算子族所依据的研究/方法出处。
• 算法的正典(作者、年份)与用途见上面的族使用指南。
• gfx2d_scene — py -3.11 examples/gfx2d_scene.py
image2d 作为输入)shadow_cast_2d · raw_black_level · raw_dead_pixel_mask · raw_dead_pixel_correct · lens_shading_gain · lens_shading_correct · raw_apply_gains · raw_demosaic_bilinear
post)bloom · vignette · chromatic_aberration · film_grain · color_lut · color_grade · palette_quantize
*Provenance: gfx2d.py — GFX2D 算子登记表。本条目由 tools/opdocs.py md 自动生成(请勿手工编辑)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.