Clustering
Clustering =Unsupervised learning
technique
Groups data points into clusters based
on similarity
Popular Clustering Methods:
K-Means Clustering
Hierarchical Clustering
DBSCAN (Density-Based Spatial
Clustering of Applications with Noise)
3.
K-Means Clustering:
Dividesdata into k clusters
Assumes spherical clusters
Sensitive to outliers
Needs to predefine k
4.
Hierarchical Clustering:
Buildsa hierarchy of clusters (tree-like
structure)
Agglomerative (bottom-up) or Divisive (top-
down)
Good for small datasets
Computationally expensive for large data
5.
What is DBSCAN?
Density-Based Spatial Clustering of Applications with Noise
Groups together points that are closely packed (high
density)
Separates low-density regions (noise/outliers)
Key Concepts in DBSCAN
Epsilon (ε): Radius to search for neighbors
MinPts: Minimum number of points to form a dense
region
Points classified as:
Core Points (dense enough)
Border Points (less dense, but close)
Noise Points (outliers)
8.
Why DBSCAN?
Real-worlddata isn't always spherical or
even!
Clusters of arbitrary shape can exist
No need to predefine number of
clusters (unlike k-means)
Can detect outliers (noise)
9.
DBSCAN Advantages
Canfind clusters of arbitrary shape
No need to specify number of
clusters
Robust to outliers
Works well with spatial data
Efficient for Large Datasets
10.
DBSCAN Disadvantages
Hardto choose good ε and MinPts
Struggles with clusters of varying
densities
Performance drops on high-
dimensional data
11.
DBSCAN in SpaceRobotics
and Terrain Mapping
🚀 Used in NASA/ESA space missions for 3D mapping using
LiDAR or stereo vision.
🧠 Clusters 3D point cloud data to identify terrain features:
Rocks, cliffs, craters (non-spherical shapes).
🤖 Supports autonomous navigation of rovers by segmenting
obstacles and traversable paths.
🌌 Ideal for unstructured, noisy environments like Mars or the
Moon.
12.
Research on DBSCANwith
Point Cloud Data
📚 Efficient Clustering of LiDAR Data for 3D Object Detection -
IEEE Paper using DBSCAN for 3D object detection from LiDAR
data.
📚 DBSCAN in SLAM (Simultaneous Localization and Mapping) -
Improves mapping precision by filtering noise in point clouds.
🌕 Lunar/Martian Terrain Segmentation - DBSCAN helps classify
terrain types and supports hazard detection and mission
planning.