Image-Based Modeling And Rendering
Encyclopedia
In computer graphics
and computer vision
, image-based modeling and rendering (IBMR) methods rely on a set of two-dimensional images of a scene to generate a three-dimensional model and then render
some novel views of this scene.
The traditional approach of computer graphics has been used to create a geometric model in 3D and try to reproject it onto a two-dimensional image. Computer vision, conversely, is mostly focused on detecting, grouping, and extracting features (edges, faces, etc.) present in a given picture and then trying to interpret them as three-dimensional clues. Image-based modeling and rendering allows the use of multiple two-dimensional images in order to generate directly novel two-dimensional images, skipping the manual modeling stage.
. The plenoptic function describes the light rays contained in a given volume. It can be represented with seven dimensions: a ray is defined by its position
, its orientation 
, its wave length 
and its time 
: 
. IBMR methods try to approximate the plenoptic function to render a novel set of two-dimensional images from another. Given the high dimensionality of this function, practical methods place constraints on the parameters in order to reduce this number (typically to 2 to 4).
Computer graphics
Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....
and computer vision
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...
, image-based modeling and rendering (IBMR) methods rely on a set of two-dimensional images of a scene to generate a three-dimensional model and then render
Rendering (computer graphics)
Rendering is the process of generating an image from a model , by means of computer programs. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene...
some novel views of this scene.
The traditional approach of computer graphics has been used to create a geometric model in 3D and try to reproject it onto a two-dimensional image. Computer vision, conversely, is mostly focused on detecting, grouping, and extracting features (edges, faces, etc.) present in a given picture and then trying to interpret them as three-dimensional clues. Image-based modeling and rendering allows the use of multiple two-dimensional images in order to generate directly novel two-dimensional images, skipping the manual modeling stage.
Light modeling
Instead of considering only the physical model of a solid, IBMR methods usually focus more on light modeling. The fundamental concept behind IBMR is the plenoptic illumination function which is a parametrisation of the light fieldLight field
The light field is a function that describes the amount of light faring in every direction through every point in space. Michael Faraday was the first to propose that light should be interpreted as a field, much like the magnetic fields on which he had been working for several years...
. The plenoptic function describes the light rays contained in a given volume. It can be represented with seven dimensions: a ray is defined by its position
, its orientation , its wave length and its time : . IBMR methods try to approximate the plenoptic function to render a novel set of two-dimensional images from another. Given the high dimensionality of this function, practical methods place constraints on the parameters in order to reduce this number (typically to 2 to 4).IBMR methods and algorithms
- View morphingMorphingMorphing is a special effect in motion pictures and animations that changes one image into another through a seamless transition. Most often it is used to depict one person turning into another through technological means or as part of a fantasy or surreal sequence. Traditionally such a depiction...
generates a transition between images - Panoramic imaging renders panoramas using image mosaics of individual still images
- Lumigraph relies on a dense sampling of a scene
- Space carving generates a 3D model based on a photo-consistencyPhoto-consistencyIn computer vision Photo-consistency determines whether a given voxel is occupied. A voxel is considered to be photo consistent when its color appears to be similar to all the cameras that can see it...
check
External links
- Mixed Reality Toolkit (MRT) - University College LondonUniversity College LondonUniversity College London is a public research university located in London, United Kingdom and the oldest and largest constituent college of the federal University of London...
- insight3d - open source image-based 3d modeling software