What does the field of computer visoin deal with?
Automatic extractoin of “meaningful” information from images and videos
What is the “meaningful” information?
semantic informatino
which class belongs parts to the image to?
geometric information
3D structure, horizon, etc.
What is the difference between computer vision and computer graphics?
inverse problems
computer vision:
take images and create model
computer graphics:
take model and create images
What is multi-view geometry?
field studying relationship between
cameras
3D struture
image features
when there are feature correspondences between images taken from varying viewpoints
-> image features usually points or lines
What are camera position, camera pose and camera trajectory?
Camera position:
absolute position of camera
camera pose:
rotation and translation
-> between cameras…
camrea trajectory:
line connecting different cameras…
What is visual odometry?
process of incrementally estimating the pose of the vehicle
by examining the chagnes that motion induces on the images of its onboard cameras
What is VSLAM?
visual odometry + loop detecoin & closure
-> VO affected by noise
SLAM guarantees global consistency
What is SFM?
structure from motion
more general than SLAM
-> works from unordered image sets (i.e. internet-sourced images…)
What is the high-level flow chart of VO/VSLAM/SFM?
image pair
feature detection
feature matching/tracking
camera pose estimation
3D reconstructoin
local optimization
How does feature detection and macthing/tracking look for example?
Why do we need local optimization?
we got the image correspondance
we found out about the camera poses
from these, we reconstructed a 3D point cloud
=> but might be unsatisfactory…
=> need to simultaneously optimize camera poses (i.e. absolute) and the point cloud itself…
=> so called bundle adjustment
Last changeda year ago