In
computer graphics
Computer graphics deals with generating images with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, cell phone and computer displays, and many specialized applications. A great de ...
and
computer vision
Computer vision is an interdisciplinary scientific field that deals with how computers can gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to understand and automate tasks that the hum ...
, 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.
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
The light field is a vector function that describes the amount of light flowing in every direction through every point in space. The space of all possible ''light rays'' is given by the five-dimensional plenoptic function, and the magnitude of each ...
which is a parametrisation of the
light field
The light field is a vector function that describes the amount of light flowing in every direction through every point in space. The space of all possible '' light rays'' is given by the five-dimensional plenoptic function, and the magnitude of ea ...
. 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 wavelength
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
morphing
Morphing is a special effect in motion pictures and animations that changes (or morphs) one image or shape into another through a seamless transition. Traditionally such a depiction would be achieved through dissolving techniques on film. Since ...
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-consistency In 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. Most voxel coloring or space carving techniques ...
check
See also
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View synthesis
View synthesis aims to create new views of a specific subject starting from a number of pictures taken from given point of views.
Currently a study branch of Computer Science Research, Vision Research and Artificial Intelligence fields are involve ...
*
3D reconstruction
In computer vision and computer graphics, 3D reconstruction is the process of capturing the shape and appearance of real objects.
This process can be accomplished either by active or passive methods. If the model is allowed to change its shape i ...
*
Structure from motion
Structure from motion (SfM) is a photogrammetric range imaging technique for estimating three-dimensional structures from two-dimensional image sequences that may be coupled with local motion signals. It is studied in the fields of computer visio ...
References
External links
* Quan, Long. ''Image-based modeling''. Springer Science & Business Media, 2010
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{{Computer graphics
Computer graphics
Applications of computer vision
3D imaging