将闭合曲线拟合到一组噪声点

fitting closed curve to a set of noisy points

这是我的数据集,我想在其中拟合一条闭合曲线,就像

array([[ 0.3 , -0.05],
       [ 0.35, -0.05],
       [ 0.4 , -0.05],
       [ 0.45, -0.05],
       [ 0.5 , -0.05],
       [ 0.55, -0.05],
       [ 0.6 , -0.05],
       [ 0.65, -0.05],
       [ 0.7 , -0.05],
       [ 0.75, -0.05],
       [ 0.8 , -0.05],
       [ 0.85, -0.05],
       [ 0.9 , -0.05],
       [ 0.95, -0.05],
       [ 1.  , -0.05],
       [ 1.05, -0.05],
       [ 1.1 , -0.05],
       [ 1.15, -0.05],
       [ 1.2 , -0.05],
       [ 1.25, -0.05],
       [ 1.3 , -0.05],
       [ 1.35, -0.05],
       [ 1.4 , -0.05],
       [ 1.45, -0.05],
       [ 1.5 , -0.05],
       [ 1.55, -0.05],
       [ 1.6 , -0.05],
       [ 1.65, -0.05],
       [ 1.7 , -0.05],
       [ 1.75, -0.05],
       [ 1.8 , -0.05],
       [ 0.  , -0.1 ],
       [ 0.05, -0.1 ],
       [ 0.  , -0.15],
       [ 2.1 , -0.15],
       [ 2.15, -0.15],
       [ 0.  , -0.2 ],
       [ 2.1 , -0.2 ],
       [ 2.15, -0.2 ],
       [ 2.2 , -0.2 ],
       [ 2.2 , -0.25],
       [ 2.35, -0.35],
       [-0.15, -0.4 ],
       [ 2.35, -0.4 ],
       [-0.15, -0.45],
       [ 2.35, -0.45],
       [ 2.4 , -0.45],
       [ 2.35, -0.5 ],
       [ 2.4 , -0.5 ],
       [ 2.4 , -0.55],
       [-0.25, -0.6 ],
       [-0.2 , -0.6 ],
       [ 2.4 , -0.6 ],
       [ 2.45, -0.6 ],
       [-0.4 , -0.65],
       [ 2.45, -0.65],
       [-0.4 , -0.7 ],
       [ 2.45, -0.7 ],
       [ 2.5 , -0.7 ],
       [ 2.45, -0.75],
       [ 2.45, -0.8 ],
       [-0.5 , -0.85],
       [ 2.45, -0.85],
       [ 2.5 , -0.85],
       [-0.5 , -0.9 ],
       [ 2.45, -0.9 ],
       [ 2.5 , -0.9 ],
       [-0.5 , -0.95],
       [ 2.5 , -0.95],
       [-0.5 , -1.  ],
       [ 2.5 , -1.  ],
       [-0.5 , -1.05],
       [-0.45, -1.05],
       [ 2.5 , -1.05],
       [-0.5 , -1.1 ],
       [-0.45, -1.1 ],
       [ 2.5 , -1.1 ],
       [ 2.55, -1.1 ],
       [-0.5 , -1.15],
       [-0.45, -1.15],
       [ 2.5 , -1.15],
       [ 2.55, -1.15],
       [-0.5 , -1.2 ],
       [-0.45, -1.2 ],
       [ 2.5 , -1.2 ],
       [ 2.55, -1.2 ],
       [-0.45, -1.25],
       [ 2.55, -1.25],
       [-0.45, -1.3 ],
       [ 2.55, -1.3 ],
       [-0.45, -1.35],
       [ 2.55, -1.35],
       [-0.45, -1.4 ],
       [ 2.55, -1.4 ],
       [-0.45, -1.45],
       [-0.4 , -1.45],
       [ 2.55, -1.45],
       [-0.45, -1.5 ],
       [-0.4 , -1.5 ],
       [ 2.6 , -1.5 ],
       [-0.45, -1.55],
       [-0.4 , -1.55],
       [ 2.6 , -1.55],
       [-0.45, -1.6 ],
       [-0.4 , -1.6 ],
       [ 2.6 , -1.6 ],
       [-0.45, -1.65],
       [-0.4 , -1.65],
       [ 2.6 , -1.65],
       [-0.45, -1.7 ],
       [-0.4 , -1.7 ],
       [ 2.6 , -1.7 ],
       [-0.4 , -1.75],
       [ 2.55, -1.75],
       [-0.4 , -1.8 ],
       [ 2.55, -1.8 ],
       [-0.45, -1.85],
       [-0.4 , -1.85],
       [ 2.55, -1.85],
       [-0.45, -1.9 ],
       [-0.4 , -1.9 ],
       [-0.4 , -1.95],
       [-0.4 , -2.  ],
       [-0.35, -2.  ],
       [-0.4 , -2.05],
       [-0.35, -2.05],
       [ 2.5 , -2.05],
       [ 2.55, -2.05],
       [-0.35, -2.1 ],
       [ 2.5 , -2.1 ],
       [ 2.55, -2.1 ],
       [-0.35, -2.15],
       [ 2.5 , -2.15],
       [ 2.55, -2.15],
       [-0.4 , -2.2 ],
       [-0.35, -2.2 ],
       [ 2.5 , -2.2 ],
       [-0.4 , -2.25],
       [-0.35, -2.25],
       [-0.35, -2.3 ],
       [ 2.45, -2.3 ],
       [-0.3 , -2.35],
       [ 2.45, -2.35],
       [-0.3 , -2.4 ],
       [-0.3 , -2.45],
       [-0.2 , -2.6 ],
       [ 2.05, -2.6 ],
       [ 2.2 , -2.6 ],
       [ 2.25, -2.6 ],
       [ 2.1 , -2.65],
       [-0.15, -2.7 ],
       [-0.05, -2.75],
       [ 0.  , -2.75],
       [ 0.05, -2.75],
       [ 0.1 , -2.75],
       [ 0.15, -2.75],
       [-0.05, -2.8 ],
       [ 0.  , -2.8 ],
       [ 0.05, -2.8 ],
       [ 0.1 , -2.8 ],
       [ 1.1 , -2.8 ],
       [ 1.15, -2.8 ],
       [ 1.2 , -2.8 ],
       [ 1.25, -2.8 ],
       [ 1.3 , -2.8 ],
       [ 1.35, -2.8 ],
       [ 1.4 , -2.8 ],
       [ 1.45, -2.8 ],
       [ 1.5 , -2.8 ],
       [ 1.55, -2.8 ],
       [ 1.6 , -2.8 ],
       [ 1.65, -2.8 ],
       [ 1.7 , -2.8 ],
       [ 1.75, -2.8 ],
       [ 1.8 , -2.8 ],
       [ 0.7 , -2.85],
       [ 0.75, -2.85],
       [ 0.8 , -2.85],
       [ 0.85, -2.85],
       [ 0.9 , -2.85],
       [ 0.95, -2.85],
       [ 1.  , -2.85],
       [ 1.05, -2.85]])

这是可视化数据集:

但是,无论我如何对数组进行排序,这些都是我得到的结果。

我提出了一些关于我的数据集的问题,但不知道如何处理它们:

  1. 许多 x 和 y 值不是一一对应的
  2. 点未按相邻顺序排序

因此,如果我的假设是正确的,那么主要问题将是如何按照 splprep 方法起作用的顺序对数组进行排序?如果没有,我将非常感谢任何能帮助我解决问题的解决方案!

[更新]感谢@michael-szczesny的回复我得到了一个满意的结果

您可以将数据平移到原点并按复角排序。

设置数据

import numpy as np
import matplotlib.pyplot as plt
from scipy.interpolate import splprep, splev

x = np.array(
      [[-0.50, -1.20],
       [-0.50, -1.15],
       [-0.50, -1.10],
       [-0.50, -1.05],
       [-0.50, -1.00],
       [-0.50, -0.95],
       [-0.50, -0.90],
       [-0.50, -0.85],
       [-0.45, -1.90],
       [-0.45, -1.85],
       [-0.45, -1.70],
       [-0.45, -1.65],
       [-0.45, -1.60],
       [-0.45, -1.55],
       [-0.45, -1.50],
       [-0.45, -1.45],
       [-0.45, -1.40],
       [-0.45, -1.35],
       [-0.45, -1.30],
       [-0.45, -1.25],
       [-0.45, -1.20],
       [-0.45, -1.15],
       [-0.45, -1.10],
       [-0.45, -1.05],
       [-0.40, -2.25],
       [-0.40, -2.20],
       [-0.40, -2.05],
       [-0.40, -2.00],
       [-0.40, -1.95],
       [-0.40, -1.90],
       [-0.40, -1.85],
       [-0.40, -1.80],
       [-0.40, -1.75],
       [-0.40, -1.70],
       [-0.40, -1.65],
       [-0.40, -1.60],
       [-0.40, -1.55],
       [-0.40, -1.50],
       [-0.40, -1.45],
       [-0.40, -0.70],
       [-0.40, -0.65],
       [-0.35, -2.30],
       [-0.35, -2.25],
       [-0.35, -2.20],
       [-0.35, -2.15],
       [-0.35, -2.10],
       [-0.35, -2.05],
       [-0.35, -2.00],
       [-0.30, -2.45],
       [-0.30, -2.40],
       [-0.30, -2.35],
       [-0.25, -0.60],
       [-0.20, -2.60],
       [-0.20, -0.60],
       [-0.15, -2.70],
       [-0.15, -0.45],
       [-0.15, -0.40],
       [-0.05, -2.80],
       [-0.05, -2.75],
       [0.00, -2.80],
       [0.00, -2.75],
       [0.00, -0.20],
       [0.00, -0.15],
       [0.00, -0.10],
       [0.05, -2.80],
       [0.05, -2.75],
       [0.05, -0.10],
       [0.10, -2.80],
       [0.10, -2.75],
       [0.15, -2.75],
       [0.30, -0.05],
       [0.35, -0.05],
       [0.40, -0.05],
       [0.45, -0.05],
       [0.50, -0.05],
       [0.55, -0.05],
       [0.60, -0.05],
       [0.65, -0.05],
       [0.70, -2.85],
       [0.70, -0.05],
       [0.75, -2.85],
       [0.75, -0.05],
       [0.80, -2.85],
       [0.80, -0.05],
       [0.85, -2.85],
       [0.85, -0.05],
       [0.90, -2.85],
       [0.90, -0.05],
       [0.95, -2.85],
       [0.95, -0.05],
       [1.00, -2.85],
       [1.00, -0.05],
       [1.05, -2.85],
       [1.05, -0.05],
       [1.10, -2.80],
       [1.10, -0.05],
       [1.15, -2.80],
       [1.15, -0.05],
       [1.20, -2.80],
       [1.20, -0.05],
       [1.25, -2.80],
       [1.25, -0.05],
       [1.30, -2.80],
       [1.30, -0.05],
       [1.35, -2.80],
       [1.35, -0.05],
       [1.40, -2.80],
       [1.40, -0.05],
       [1.45, -2.80],
       [1.45, -0.05],
       [1.50, -2.80],
       [1.50, -0.05],
       [1.55, -2.80],
       [1.55, -0.05],
       [1.60, -2.80],
       [1.60, -0.05],
       [1.65, -2.80],
       [1.65, -0.05],
       [1.70, -2.80],
       [1.70, -0.05],
       [1.75, -2.80],
       [1.75, -0.05],
       [1.80, -2.80],
       [1.80, -0.05],
       [2.05, -2.60],
       [2.10, -2.65],
       [2.10, -0.20],
       [2.10, -0.15],
       [2.15, -0.20],
       [2.15, -0.15],
       [2.20, -2.60],
       [2.20, -0.25],
       [2.20, -0.20],
       [2.25, -2.60],
       [2.35, -0.50],
       [2.35, -0.45],
       [2.35, -0.40],
       [2.35, -0.35],
       [2.40, -0.60],
       [2.40, -0.55],
       [2.40, -0.50],
       [2.40, -0.45],
       [2.45, -2.35],
       [2.45, -2.30],
       [2.45, -0.90],
       [2.45, -0.85],
       [2.45, -0.80],
       [2.45, -0.75],
       [2.45, -0.70],
       [2.45, -0.65],
       [2.45, -0.60],
       [2.50, -2.20],
       [2.50, -2.15],
       [2.50, -2.10],
       [2.50, -2.05],
       [2.50, -1.20],
       [2.50, -1.15],
       [2.50, -1.10],
       [2.50, -1.05],
       [2.50, -1.00],
       [2.50, -0.95],
       [2.50, -0.90],
       [2.50, -0.85],
       [2.50, -0.70],
       [2.55, -2.15],
       [2.55, -2.10],
       [2.55, -2.05],
       [2.55, -1.85],
       [2.55, -1.80],
       [2.55, -1.75],
       [2.55, -1.45],
       [2.55, -1.40],
       [2.55, -1.35],
       [2.55, -1.30],
       [2.55, -1.25],
       [2.55, -1.20],
       [2.55, -1.15],
       [2.55, -1.10],
       [2.60, -1.70],
       [2.60, -1.65],
       [2.60, -1.60],
       [2.60, -1.55],
       [2.60, -1.50]])

使用 np.angle((xs[:,0] + 1j*xs[:,1])) 将您的数据转换为复数坐标,并使用它对您的数据进行排序。

xs = (x - x.mean(0))
x_sort = xs[np.angle((xs[:,0] + 1j*xs[:,1])).argsort()]

现在您可以 (code by @rth) 以正确的顺序排列您的数据。

# plot from  as mentioned in the question
tck, u = splprep(x_sort.T, u=None, s=0.0, per=1) 
u_new = np.linspace(u.min(), u.max(), 1000)
x_new, y_new = splev(u_new, tck, der=0)

plt.figure(figsize=(10,10))
plt.plot(x_sort[:,0], x_sort[:,1], 'ro')
plt.plot(x_new, y_new, 'b--');

输出: