Week 3 Flashcards
what is the split and merge algorithm?
a recursive algorithm to extract line segments from points
what is the input of the split in a split merge algorithm?
A list of points
what is the output of the split in a split merge algorithm?
List of segments (pair of points)
what is the parameters of the split in a split merge algorithm?
Threshold distance
what is the input of the merge in a split merge algorithm?
List of segments (pair of points)
what is the output of the merge in a split merge algorithm?
List of segments (pair of points)
what are the parameters of the merge in a split merge algorithm?
Threshold angle
what type of sensor is a camera
a passive sensor that captures light reflected from objects
what does a camera measure?
angles
what type of information does a camera provide?
2D information of a 3D world
how can a 360 degree view be obtained from a camera?
by adding mirrors
what are the pros of cameras?
-Cheap and small
-lots of information
-well-known and commonly used
-Libraries with algorithms (OpenCV)
what are the cons of cameras?
-Lots of data
-require calibration
-lighting and colour consistency
what is a pixel?
a picture element is the smallest element of an image
how are greyscale images represented?
by 2D arrays of pixel values (0 = black, 255 = white)
what is computer vision?
a field of artificial intelligence (AI) enabling computers to derive information from images, videos and other inputs
when is computer vision used for images?
when we are only interested in parts of an image it can be used to identify objects and find relations
what is Odometry?
the use of data from motion sensors to estimate change in position over time
where is Odometry used?
in passive sensors that measure the velocity of a robot’s wheels
what are the pros of odometry?
-included in many motors
-provides position information
-can be combined with laser (ICP)
what are the cons of odometry?
-errors grow (systematic)
-dependency on accelerations, weight distribution, floor type…
-heading direction ‘lost’ after a few metres
what is a kinect 3D camera?
-RGB camera, infrared camera and infrared laser emitter
-provides 3D distance information
-range of 0.5-5 meters
what are the pros of a kinect 3D camera?
-cheap
-allows 3D reconstruction of a scene
-high resolution
-Point Cloud Library (PCL) to process the data
what are the cons of a Kinect 3D camera?
-indoor use only
-lots of data (computation)
