Rico贾若童的博客

Robotics - [3D SLAM - 1] Scan Matching

3D Point-Point ICP, 3D Point-Plane ICP, NDT

The Scan Matching Problem When we run scan matching, we usually have two point clouds: a source scan $S_1 = {\mathbf{p}_1, \ldots, \mathbf{p}_n}$ (the new measurement), and a target scan $S_...

Posted by Rico's Nerd Cluster on March 1, 2025

Robotics - [Bugs - 2] SLAM Related Small Bugs

Passing Ptr By Value

⚠️ Beware of Passing Smart Pointers by Value Passing a smart pointer (e.g. std::shared_ptr or boost::shared_ptr) by value is fine when you’re only modifying the object it points to. But if you int...

Posted by Rico's Nerd Cluster on February 1, 2025

Robotics - [Bugs - 1] SLAM Related "Epic Bugs"

G2O Optimization Vertex Updates, Compiler-Specific Bugs, Yaml-cpp

Below is a list of bugs that took me multiple hours, if not days, to troubleshoot and analyze. These are the “epic bugs” that are worth remembering for my career. Epic Bug 1: G2O Optimization Didn...

Posted by Rico's Nerd Cluster on February 1, 2025

[ML] K-Nearest-Neighbor Using Heap With CUDA

KNN (Heap-Based Implementation) Goal: For a query point qqq, find its kkk nearest neighbors from a set of NNN points. Algorithm Idea We use a max-heap of size k. Why a max-heap? The hea...

Posted by Rico's Nerd Cluster on January 9, 2025

[ML] -Point-cloud-compression-2-FPFH-Features

Other Alternatives Chamfer distance Earth Mover’s Distance (EMD) Normal consistency loss Curvature loss Learned feature-space loss (via PointNet / DGCNN embeddings) What is FPFH FPFH...

Posted by Rico's Nerd Cluster on January 8, 2025

Robotics - Spatial Hashing

Spatial Hashing Hash integer coordinates <x,y,z>. A good hash should make small input changes produce very different outputs. 1 2 3 4 5 6 7 std::size_t operator()(const TileKey &k) cons...

Posted by Rico's Nerd Cluster on January 2, 2025

Robotics - A Short Introduction To Underwater Sonar Imaging Cameras

Beam Forming

Sonar Imaging Pipeline Here is a nice introduction to the concept of beam-forming Beam Forming If you have multiple attenae, say each attena is attached to a fixed delay,...

Posted by Rico's Nerd Cluster on December 24, 2024

AI - LLM Applications

Techniques For Using AI Reflection is extremely helpful. “validate this code”, “check instructions for coherence and completeness”; “make this code more concise.” For subjective questions, AI is ...

Posted by Rico's Nerd Cluster on December 22, 2024

Robotics - A Survey On Oil Pipe Inspection Robotics (Revising)

Sonar Imaging, gradian

Non-Destructive Testing Methods American Society for Testing and Materials (ASTM) and American Society of Mechanical Engineers (ASME) develops standards for pipe inspections Ultrasonic Testing...

Posted by Rico's Nerd Cluster on December 20, 2024

Robotics - ROS2 Logging

Logging Level Tweaking

Logging Level Tweaking Programmatic API (in-process) In C++, any rclcpp::Logger can have its level tweaked at runtime: 1 2 3 #include <rclcpp/logger.hpp> auto my_logger = rclc...

Posted by Rico's Nerd Cluster on December 12, 2024

Rico's Nerd Cluster