Browsing All Posts filed under »Softwares«

Optimal Triangulation for Tuning Keypoint Co-ordinates

October 11, 2017


Given a set of correct keypoint matches and a fundamental matrix, to optimize the coordinates of these key points such that they satisfy the epipolar constraint. A point (x,y) on the left image (pose: [I|0]) and (x’,y’) on the right image (pose: [R|t]). These points are undistorted and in normalized image coordinates. Having known the pose […]

Image Keypoint Descriptors and Matching

August 17, 2017


[GitHub] Extracting keypoints from images, usually, corner points etc is usually the first step for geometric methods in computer vision. A typical workflow is: keypoints are extracted from images (SIFT, SURF, ORB etc.). At these keypoints descriptors are extracted (SURF, ORB etc). Usually a 32D vector at each keypoint. The nearest neighbor search is performed to […]

HowTo – Pose Graph Bundle Adjustment

April 29, 2017


SLAM (Simultaneous Localization and Mapping) is one of the important practical areas in computer vision / robotics / image based modelling community. A SLAM system typically consists of a) odometry estimator (relative pose estimator), b) Bundle adjustment module, c) sensor fusion module (for visual-inertial system), d) mapping module. While there are several excellent resources, refer […]

Vision Controlled Quadcopter Flight

December 9, 2015


Just completed (8th Dec, 2015) the Aerial Robotics course in HKUST (ELEC6910P) by Prof. SHEN Shaojie (my PhD supervisor). Most of the course credit were on the completion of the projects. Course TAs were Su Kunyue and Yang Zhengfei. My project partners were Sun Lin and Sun Ting The projects eventually connected together to make a vision […]

Color Consistency from Multiple-View Images

September 17, 2015


Abstract In this paper we address the problem of multiview color consistency. We propose to use a graph model of 3d positions obtained using matched dense feature points. We define an energy functional on this model which captures relationship of the colors across views while also imposing a smoothness cost to obtain optimal colors for the 3d […]

Direct Edge Alignment (D-EA)

September 14, 2015


Abstract There has been a paradigm shifting trend towards feature-less methods due to their elegant formulation, accuracy and ever increasing computational power. In this work, we present a direct edge alignment approach for 6-DOF tracking. We argue that photo-consistency based methods are plagued by a much smaller convergence basin and are extremely sensitive to noise, changing illumination […]

Photometric Stereo

May 10, 2014


Project Summary A fixed object is observed with a fixed camera under different light direction. See figure below for the setup. The aim of the project is to infer depth model from these set of images.   Acknowledgement This project is a part of the Computer Vision course (COMP 5421) during spring 2014. The project […]