Filtering Algorithms

Filtering algorithms: These algorithms are used to remove noise, outliers, or unwanted points from the point cloud data.

Application of the Lidar point cloud Filtering algorithms

Lidar (Light Detection and Ranging) point cloud filtering algorithms are used to process raw lidar data and remove unwanted or erroneous points, leaving only the points that accurately represent the surface of the target object or environment. These algorithms are critical for many applications, including autonomous vehicles, topographical mapping, urban planning, and forestry management. By removing noise and outliers from the point cloud data, filtering algorithms improve the accuracy and reliability of subsequent analysis, such as object detection, terrain modeling, and classification. Different filtering techniques are used depending on the specific application and lidar sensor characteristics, including range-based, intensity-based, and geometric-based methods.

Here are ten commonly used LiDAR point cloud filtering algorithms along with a brief description and their download URL:

1.Voxel Grid Filter: This filter discretizes the point cloud into voxels and replaces the points within each voxel with their centroid. This reduces the density of the point cloud while preserving its overall structure. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/filters/include/pcl/filters/voxel_grid.h

2.Statistical Outlier Removal: This filter identifies outliers in the point cloud based on the statistical properties of the neighboring points. It removes the points whose distance to their neighbors exceeds a certain threshold. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/filters/include/pcl/filters/statistical_outlier_removal.h

3.Radius Outlier Removal: This filter removes the points that have fewer than a certain number of neighbors within a given radius. It can remove noise points as well as spurious points that are far away from the main structure of the point cloud. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/filters/include/pcl/filters/radius_outlier_removal.h

4.Pass Through Filter: This filter removes the points that fall outside a given range of values along a specified axis. It can be used to extract a subset of the point cloud that lies within a certain region of interest. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/filters/include/pcl/filters/passthrough.h

5.Conditional Removal Filter: This filter removes the points that satisfy a given set of conditions on their properties. It can be used to extract specific features or remove noise from the point cloud. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/filters/include/pcl/filters/conditional_removal.h

6.Moving Least Squares Filter: This filter fits a smooth surface to the point cloud using a weighted least squares algorithm. It can be used to denoise the point cloud and extract features such as normals and curvature. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/surface/include/pcl/surface/mls.h

7.Normal Estimation: This algorithm estimates the surface normals of the point cloud by fitting a plane to the neighboring points. It can be used to compute features such as curvature and orientation. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/features/include/pcl/features/normal_3d.h

8.Curvature Estimation: This algorithm estimates the curvature of the point cloud surface by fitting a quadratic surface to the neighboring points. It can be used to detect sharp edges and other geometric features. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/features/include/pcl/features/curvature.h

9.Euclidean Cluster Extraction: This algorithm groups the points in the point cloud that are close to each other into clusters based on their Euclidean distance. It can be used to segment the point cloud into different objects or regions. Download URL: https://github.com/PointCloudLibrary/pcl/blob/master/segmentation/include/pcl/segmentation/extract_clusters.h

10.Smoothed Voxel Occupancy Filter: This filter voxelizes the point cloud and estimates the occupancy of each voxel using a kernel density estimate. It can be used to generate a 3D occupancy map of the environment. Download URL: https://github.com/ethz-asl/voxblox/blob/master/voxblox_ros/include/voxblox_ros/esdf_server.h