Tong's Blog

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[Cheatsheet] Rotation

Quaternion1 Quaternion type Hamilton JPL Components order \(\begin{bmatrix} q_{w} \\ \mathbf{q}_{v} \end{bmatrix}\) \(\begin{bmatrix} \...

Posted by Tong on November 20, 2020

Calibration

Chinese Blog Tools kalibr kalibr allan AprilTag Dynamic Vision Sensor Calibration DVS Calibration Multi Sensor Calibration Extrinsic Calibration IMU Intrisic LiDAR Align ...

Posted by Tong on November 20, 2020

VIO - Preintegration

Motivation1 Once we have IMU measurements, we can integrate them to estimate the orientation, velocity, and position. The IMU measurements can be represented as \[\tilde{\boldsymbol{\omega}}^{\te...

Posted by Tong on October 27, 2020

VIO - Optimization

Convention Basic \[\boldsymbol{\phi}^{\wedge}=[\begin{array}{c} \phi_{1} \\ \phi_{2} \\ \phi_{3} \end{array}]^{\wedge}=[\begin{array}{ccc} 0 & -\phi_{3} & \phi_{2} \\ \phi_{3} & 0 &am...

Posted by Tong on October 26, 2020

VIO - IMU Initialization

Goal The goal of this step is to obtain good initial values for the inertial variables \(\mathcal{X}_{I}=\left[\mathbf{v}_{b_{0}}^{b_{0}}, \mathbf{v}_{b_{1}}^{b_{1}}, \ldots \mathbf{v}_{b_{m}}^...

Posted by Tong on October 26, 2020

Probablistic Depth Estimation

Video-based, Real-Time Multi View Stereo 1 Abstract We investigate the problem of obtaining a dense reconstruction in real-time, from a live video stream. In recent years, Multi-view stereo (MVS)...

Posted by Tong on April 28, 2020

C++ - Nitty Gritty

Rule of Three Rule of three: If you need to explicitly declare either the destructor, copy constructor or copy assignment operator yourself, you probably need to explicitly declare all three of...

Posted by Tong on April 27, 2020

DSO - Null Space

Direct sparse odometry (Chinese) DSO(5)——零空间的计算与推导 (Chinese) DSO零空间与尺度漂移 What is Null Space? A null space is usually defined in combination with a matrix, namely \[\mathbf{H} \math...

Posted by Tong on April 24, 2020

DSO - First Estimates Jacobian

Analysis and Improvement of the Consistency of Extended Kalman Filter Based SLAM 1 Abstract In this work, we study the inconsistency of EKF- based SLAM from the perspective of observability. We a...

Posted by Tong on April 24, 2020

CMVS + PMVS

Yasutaka Furukawa CMVS PMVS OpenMVG to PMVS Application Installation CMVS-PMVS git clone https://github.com/pmoulon/CMVS-PMVS.git cd program mkdir build cd build cmake .....

Posted by Tong on April 19, 2020