BSplineFitting (with Python interface)

Fitting cubic spline curve to 2d points

Introduction

This is an implementation of paper "Fitting B-spline Curves to Point Clouds by Curvature-Based Squared Distance Minimization".

Link to the paper: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/12/Fitting-B-spline-Curves-to-Point-Clouds-by-Curvature-Based-Squared-Distance-Minimization.pdf

The input is a set of 2d points, the output are control points of a close cubic spline curve.

1. Input file: a file that contains n rows and each row reprents a point with x y positions.
2. Output files: a file with the control points of the output curve; and a file with sampling points of the output file.

Build instructions

This project depends on two code librarie:

1. Download Eigen e.g. 3.3.7 from http://eigen.tuxfamily.org/index.php?title=Main_Page, build and install the project into the dir EIGEN_DIR
2. Download and extract ANN e.g. 1.1.2 to ANN_DIR from https://www.cs.umd.edu/~mount/ANN/ cd to the dir, and build: make linux-g++ for linux (call make without parameters to see the build targets for different platforms).
3. Build the main project with cmake, set the cache variables EIGEN_DIR and ANN_DIR properly.
4. Build the python interface by navigating the py_interface dir in the build folder e.g. python setup.py install.

Python example:

import pysplfit
# Input point cloud in row-major format.
input = [0, 0, 0, 1, 1, 0, 1, 1]
# The control points and the contour in the same format. Only the first parameter is mandatory.
# alpha: curvature coeff, beta: curve length coeff, epsilon: stopping condition
fit_contorls, fit_contour = pysplfit.fit(input, controlnum=8, maxiternum=5, alpha=0.0025, beta=0.006, epsilon=0.002)

# see the demo.py

Building and Running

Tested on Linux, however the original repo this code forked from targeted Windows...

I use cmake to configure and generate project files.

Main Files

drawResult.m: a simple .m file to visulize the input and output

core/cubic_b_spline.h: a class encode the cubic b spline

core/spline_curve_fitting.h:

read_write_asc.h: a simple class that reads/writes files