Structure from motion
Encyclopedia
In computer vision
structure from motion refers to the process of finding the three-dimensional structure of an object by analyzing local motion signals
over time.
In Vision Science (visual perception), Structure from motion (SfM), refers to the general phenomenon by which humans (and other animals) can recover 3-D structure from the projected 2D (retinal) motion field of a moving object.
Finding structure from motion presents a similar problem as finding structure from stereo vision. In both instances, the correspondence between images and the reconstruction of 3D object needs to be found.
To find correspondence between images, features such as corner points (edges with gradients in multiple directions) need to be tracked from one image to the next. The feature trajectories over time are then used to reconstruct their 3D positions and the camera's motion.
Structure from motion is related to the kinetic depth effect
in perception whereby subjects viewing the shadow cast by a wire frame or other structure in rotation, perceive the full three-dimensional structure of the object, whereas when viewing the shadow of a static object they perceive only its two-dimensional projection. Actually, the terms "kinetic depth effect" and "structure from motion" are usually used indistinctly in the vision science literature.
Computer vision
Computer vision is a field that includes methods for acquiring, processing, analysing, and understanding images and, in general, high-dimensional data from the real world in order to produce numerical or symbolic information, e.g., in the forms of decisions...
structure from motion refers to the process of finding the three-dimensional structure of an object by analyzing local motion signals
Motion perception
Motion perception is the process of inferring the speed and direction of elements in a scene based on visual, vestibular and proprioceptive inputs...
over time.
In Vision Science (visual perception), Structure from motion (SfM), refers to the general phenomenon by which humans (and other animals) can recover 3-D structure from the projected 2D (retinal) motion field of a moving object.
Obtaining 3D information from 2D images
Humans perceive a lot of information about the three-dimensional structure in their environment by moving through it. When the observer moves and the objects around him move, information is obtained from images sensed over time.Finding structure from motion presents a similar problem as finding structure from stereo vision. In both instances, the correspondence between images and the reconstruction of 3D object needs to be found.
To find correspondence between images, features such as corner points (edges with gradients in multiple directions) need to be tracked from one image to the next. The feature trajectories over time are then used to reconstruct their 3D positions and the camera's motion.
Structure from motion is related to the kinetic depth effect
Kinetic depth effect
In visual perception, the kinetic depth effect refers to the phenomenon whereby the three-dimensional structural form of an object can be perceived when the object is moving. In the absence of other visual depth cues, this might be the only perception mechanism available to infer the object's shape...
in perception whereby subjects viewing the shadow cast by a wire frame or other structure in rotation, perceive the full three-dimensional structure of the object, whereas when viewing the shadow of a static object they perceive only its two-dimensional projection. Actually, the terms "kinetic depth effect" and "structure from motion" are usually used indistinctly in the vision science literature.
See also
- Match movingMatch movingIn cinematography, match moving is a visual-effects, cinematic techniques that allows the insertion of computer graphics into live-action footage with correct position, scale, orientation, and motion relative to the photographed objects in the shot...
- Motion fieldMotion fieldIn computer vision the motion field is an ideal representation of 3D motion as it is projected onto a camera image. Given a simplified camera model, each point in the image is the projection of some point in the 3D scene but the position of the projection of a fixed point in space can vary with...
- Epipolar geometryEpipolar geometryEpipolar geometry is the geometry of stereo vision. When two cameras view a 3D scene from two distinct positions, there are a number of geometric relations between the 3D points and their projections onto the 2D images that lead to constraints between the image points...
- Tomasi–Kanade factorization
Structure from Motion software toolboxes
- FIT3D (From Images to 3D) Toolbox by Isaac Esteban
- Structure from Motion toolbox for Matlab by Vincent Rabaud
- Matlab Functions for Multiple View Geometry by Andrew Zissermann
- Structure and Motion Toolkit by Phil Torr
- Non Rigid Structure from Motion in trajectory space by Ijaz Akhter.
- Matlab Code for Non-Rigid Structure from Motion using Factorisation by Lorenzo Torresani Kooni
- Bundler - Structure from Motion for Unordered Photo Collections by Noah Snavely
- Voodoo Camera Tracker: A tool for the integration of virtual and real scenes, by Laboratorium für Informationstechnologie, University of Hannover
- Libmv - A C++ Structure from Motion library