Overview¶

pyransac is a general-purpose random sample consensus (RANSAC) framework written in Python. You can use it to remove outliers from your data sets given a data model to which you expect your data to fit. For convenience, some data models (such as a 2D straight line) are already provided. However, you are free to define your own data models.

Installation¶

You can install pyransac using pip with the following command:

$ python3 -m pip install pyransac

Getting Started¶

After installing pyransac, all you need to do is create a data model definition (or use one of the built in models) and specify the RANSAC algorithm parameters. From there you can call the find_inliers function and pass in your data, model, and parameters. The function will return a list of your inliers.

Example Program¶

The following is a simple example of filtering data against a 2D line model.

import pyransac
from pyransac import line2d

# Create data
inliers = [line2d.Point2D(x, x) for x in range(0, 10)]
outliers = [line2d.Point2D(x ** 2, x + 10) for x in range(0, 5)]
data = inliers + outliers

# Specify our RANSAC parameters
params = pyransac.RansacParams(samples=2,
                               iterations=10,
                               confidence=0.999,
                               threshold=1)

# Create our model object
model = line2d.Line2D()

# Get the inliers
inliers = pyransac.find_inliers(points=data,
                                model=model,
                                params=params)

# Compare the data sets
print(data)
print(inliers)

Custom Data Models¶

All data models are derived from the Model base class. This class defines an interface consisting of two functions: make_model and calc_error. The make_model function generates a data model from a set of data points. The calc_error function calculates the error between a data point and the generated model. See the Model reference for more information.

You can define custom data models by extending the Model class. pyransac provides the following built-in data models:

Line2D — a 2-dimensional line model

Table of Contents¶

Reference