07 Apr

von Mises-Fisher distributions in machine learning

Tsang-Kai Chang

In our previous paper, we investigate the consensus problem with von Mises distribution. We want to extend our analysis to more general distributions, in particular the von Mises-Fisher (vMF) distribution over hyperspheres. In fact, vMF distributions are used in some machine learning algorithms. I...

04 Feb

Comparison between optimization based and EM based SLAM

Tsang-Kai Chang

error.pdf result_2.pdf I implemented the EM based SLAM algorithms. However, in a visual inertial system, we can to take care of other realistic issues besides the theoretical algorithm itself. It will be insightful to compare the optimization based algorithm, since it has been developed for a wh...

13 Jan

Finish optimization-based SLAM and start working on EM SLAM

Tsang-Kai Chang

Optimization-based SLAM From the pre-optimization (blue line) to the post-optimization (orange line), we can see that the optimization method enables the loop closure effect. The key improvement lies in the better computer vision techniques by discarding possibly erroneous keypoints. Also, the...

14 Dec

Nonlinear least squares optimization in SLAM

Tsang-Kai Chang

Previously, I finished the feature matching and id assignment in the SLAM frontend. Last week, I combine the result with the preintegrated IMU data to formulate an optimization problem. Initial values I initialize the landmark position by triangulate two frames. The selection of these two points...

07 Dec

SLAM frontend overview

Tsang-Kai Chang

okvis is a visual odometry. Therefore, the feature matching only occurs within short time window, and the feature matching that enables loop closure is not provided. The following is the overview as well as the result of the feature matching that I implemented. Keyframe selection This part relie...

30 Nov

Research plan for Dec. 2020

Tsang-Kai Chang

After surveying several SLAM and visual odometry implementation, I decided to work on okvis with monocular camera setting. I will run an nonlinear optimization on the output of the visual odometry system, which can be regarded as global bundle adjustment with IMU constraints. The output of visua...

26 Oct

Some lessons from implementing optimization over SO(3)

Tsang-Kai Chang

For 3D navigation systems, representing the orientation is always annoying. After going through several painful learning and debugging processes, I share some lessons that I learned. The quaterion parameterization There are several ways to represent a 3d orientation. In real system, everyone pre...

19 Oct

Overview of okvis

Tsang-Kai Chang

It took me a while to really understand the structure of the okvis SLAM system. In order to prevent from studying its structure all over again, it is better for me to put down what I understand so far. The main goal of this post is to bridge the gap between the theoretical understanding and the so...

12 Oct

Dead reckoning results from preintegrated IMU data

Tsang-Kai Chang

I implemented the preintegration techniques from this paper. In order to implement the preintegration, the underlying optmization problem structure is also change. To be precise, previously, we optimize all the IMU data point, but now we only optimize the keyframe. The trajectory plot show t...

23 Sep

Combining SLAM frontend and backend

Tsang-Kai Chang

The SLAM frontend, in my definition, finds the features in the image and assigns the same landmark id to matched images. The overall SLAM performance relies on the quality of observation file provided by the frontend, as well as the optimization problem established by the backend. Frontend The...

Search

Popular Tags

foray origami robots blimp ducky vr edg SLAM computer vision computational design roco slam Origami rocolib arduino RoCo design Robot Compiler simulation Motion Planning autonomy edg-model mesh reinforcement learning; multi-agent; mean-field; logics create; kalman filter; motors imu friction mesh network tank esp32 networking contacts multi-agent pushing auxetic machine learning dynamics esp now visual processing wireless control communication webapp pcbs structure ROCO i2c path planning cars Robotica reinforcement learning computer skill openmv test motor dataset visual DARPA odometry Battery surface structure power consumption dash port-arrays modeling origami paper frequency diversity semantic infrastructure auxetics feedback gondola machine vision Consensus bistable auxetic controller gestural intuition mixed reality unit cell robot crawler gestural interface open house network create; kalman filter; EM; refactoring 4-wheeled darpa; create; icra2021 apriltags lidar logic control FORAY perception Quantum Information crazyflie 433mhz optimization propeller Foray structures sensors environmental design radio DER Kullback-Leibler Divergence lasercutter tutorial von Mises Fisher Distribution IR simulink legs project management localization distributed optimization blynk Auxetics painlessmesh experiment results offline reinforcement learning exam research proposal altimeter thrust PCB sensor fusion gate or webots multi-agent path planning UAV RL integration test arnhold joystick balloon test vision processing pushing problem modeling contacts mesh networking motor configuration nodemcu swarm object detection fusionbot ros2 rviz2 gazebo conference matlab arduino nano decentralized surfaces keyboard IROS Integrated Demo throughput peripheral device paper review reinforcement learning; motorized boats Writing slam; paper review rhino Short Post range distance surp origami robot nylon pvdf elastic polymers plastic hot plates reinforcement learning; multi-agent; mean-field; game theory; mean field; reinforcement learning current reinforcement learning; multi-agent; Xbee Zigbee robot compiler spi contact neural network dynamic modeling quasi-static modeling edg-examples Kalman Filter port-array von Mises Fisher von Mises-Fisher literature review multipack car Zero Elastic Energy modes swarm control solar cars system ID serial monitor edg-ide Discrete Elastic Rods ceres debug Consensus Algorithms coriolis force dynamic model proposal wtf deep learning pdms interpolation wireless signal strength reinforcement learning; multi-agent; decentralized misc reinforcement learning; multi-agent; mean-field; stationary demo video flytrap papers steering structured field pivoting differential power detectionrate color shape edg-refactoring pain python vision Machine Learning Q-Learning Model-Free release conferences quasi-static pushing liquid crystal elastomer nonholonomic systems iot grant feedback-controlled controls trajectory optimization surface contact Characterization tool ML multi-agent path finding Liquid Crystal Elastomers Learning kinematic_model reservoir computing 2.4 GHz concept 433 MHz Bayesian Network creative Computer skill internal silicone integrated system instance segmentation marginal cost pricing bootstrapping Bayesian networks ensemble methods offline Rl hardware manipulation COVID 19 paper cutter ESP32 kalman filter; multi-robot state space delta tolling buoyancy chiral square unit cell pressure distribution model prediction thrust configuration grid fabrication firmware protobuf #activecapturingmechanism #claw 3D-CHESS; kalman filter boxboat tracking model-based RL von Mises Distribution slam; flowchart; spring-mass 3D-CHESS; 433 rssi signal strength multirobot system writing in-situ design buoyancy equations boat deployment cell cameras der newton's method Barycenter Euler-Bernoulli beam sma-based actuator game theory Bessel functions von Mises-Fisher Distributions ide HDL board design battery current sensor ZMP center of friction Multi-Agent Systems code balloon semantic segmentation MIMO communications ICRA ICML guassian processes probabilistic neural networks graph generators MBRL batch learning ros edg-compiler multirobot optitrack adaptive control motor driver submission DNN kalman filtering point cloud 2.4ghz latency scenic codesign presentations machine training preliminary exam multiple devices inkscape material multi-object tracking ICLR Python actuation catching mechanism integration flapping color_segmentation lab_data result segmentation on multiple object and centers finding competition prelab multiple blimps pid defender Synthesizable Radio 3d printing kalman filter motor distribution barometer detection lift force depth estimation cad solidworks design tool pixracer pixhawk ardupilot flight controller regression fly test sensor selection