tb_dynsys_correlation_dimension — 2D typed op

• 数据种类:points → feature

• 调用:fullseye.apply(img, "tb_dynsys_correlation_dimension", a=0.5, b=0.5)(2-D 的模型是一张图 + 两个标量旋钮 a,b∈[0,1])

tb_dynsys_correlation_dimension: input → output

*图为在 128×128 合成输入上实际运行的输出。左为输入,右为输出。点云以俯视散点显示(亮度 = z),一维序列为折线,体数据为沿 z 的最大值投影,视频为中间帧,复数图像为幅值;无法成像的返回值直接显示数值。*

扫描旋钮 a(0.1 / 0.5 / 0.9,另一旋钮取默认):

▸ tb_dynsys_correlation_dimension: 旋钮 a 扫描 (文档网站)

*旋钮 b 不改变输出(实测: 0.1 / 0.5 / 0.9 相同)。*

阶段(前置算子 → 本算子,从左到右):

▸ tb_dynsys_correlation_dimension: 处理阶段 (文档网站)

用法

Grassberger–Procaccia 关联维数 —— log C(r) 的斜率。

> 以下的详细说明为原文 —— 摘要与标题已翻译。

C(r) is the fraction of point pairs closer than r; for a self-similar set it grows like r**D, and *D* is read off the straight part of the log-log plot (fitted on the middle 60 % of the radii, where the curve is free of the small-r noise floor and the large-r saturation).

★Why this earns its place: unlike box counting it needs no grid, and its answers are known for simple sets — a circle gives 1, a filled square 2, a Cantor set log2/log3 = 0.6309. It measures a different quantity from the existing fractal_dimension (box counting), so the two are an independent pair rather than two names for one number.

Returns a measurement: the fitted dimension.

Raises ValueError: fewer than 32 points; not a 2-D array; non-finite input; a degenerate cloud (every point identical); a radius range that leaves no pairs.

Limits: sub-sampled to *max_points* (pairs grow quadratically). ★The dominant error is not the sub-sampling but the radius window: the default range is the 1st-25th percentile of pair distances, and on a *bounded* set its upper end runs into the boundary, where C(r) saturates and flattens the slope. Measured on a unit square (true D = 2): 1.879 with the default window and 1.873 / 1.879 / 1.871 at 400 / 1,500 / 3,000 points —— more points do not help; narrowing the window to r_lo=0.01, r_hi=0.1 gives 1.947 and 0.002 / 0.05 gives 2.050. Pass *r_lo* / *r_hi* explicitly when the answer matters, and report the window with the number.

Typed bridge of the math op dynsys_correlation_dimension into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. a drives n_radii (default 24); b is unused.

参考(示例数据、文献)

• 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。

在 Studio 中试试

下面的程序已确认可以运行(与图相同的输入)。在 Studio 帮助中,此块会变成按钮,可当场加载并运行。

img_to_points 0.50 0.50
tb_dynsys_correlation_dimension 0.50 0.50

▸ 载入此流水线  ·  载入并运行

可运行的示例(实际调用该算子并已验证的样例)

下面的示例调用的是底层账本算子 dynsys_correlation_dimension。此桥接算子只是把同一实现适配为 fn(v, a, b) 约定,行为完全相同(只是调用形式不同)。

• poc_what_a_picture_cannot_check — py -3.11 examples/poc_what_a_picture_cannot_check.py

类型可衔接的下一个算子(可接受 feature 作为输入)

identity · feature_to_img

同类别(typed)

tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal · tb_voxel_grid_downsample


*Provenance: ops.py — 2D 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.