3D reconstruction
Encyclopedia
See Iterative reconstruction
for 3D reconstruction in Medical imaging
.
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 we allow the model to change its shape in time, we talk about non-rigid or spatio-temporal reconstruction.
A simple example of a mechanical method would use a depth gauge to measure a distance to a rotating object put on a turntable.
More applicable radiometric methods emit radiance
towards the object and then measure its reflected part. Examples range from moving light sources, colored visible light, time-of-flight lasers to microwaves or ultrasound
. See 3D scanning for more details.
to measure the radiance reflected or emitted by the object's surface to infer its 3D structure
.
Typically, the sensor is an image sensor
in a camera
sensitive to visible light and the input to the method is a set of digital images (one, two or more) or video
. In this case we talk about image-based reconstruction and the output is a 3D photography.
Iterative reconstruction
Iterative reconstruction refers to iterative algorithms used to reconstruct 2D and 3D images in certain imaging techniques.For example, in computed tomography an image must be reconstructed from projections of an object...
for 3D reconstruction in Medical imaging
Medical imaging
Medical imaging is the technique and process used to create images of the human body for clinical purposes or medical science...
.
In 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...
and computer graphics
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....
, 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 we allow the model to change its shape in time, we talk about non-rigid or spatio-temporal reconstruction.
Active methods
These methods actively interfere with the reconstructed object, either mechanically or radiometrically.A simple example of a mechanical method would use a depth gauge to measure a distance to a rotating object put on a turntable.
More applicable radiometric methods emit radiance
Radiance
Radiance and spectral radiance are radiometric measures that describe the amount of radiation such as light or radiant heat that passes through or is emitted from a particular area, and falls within a given solid angle in a specified direction. They are used to characterize both emission from...
towards the object and then measure its reflected part. Examples range from moving light sources, colored visible light, time-of-flight lasers to microwaves or ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
. See 3D scanning for more details.
Passive methods
Passive methods of 3D reconstruction do not interfere with the reconstructed object, they only use a sensorSensor
A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...
to measure the radiance reflected or emitted by the object's surface to infer its 3D structure
Structure
Structure is a fundamental, tangible or intangible notion referring to the recognition, observation, nature, and permanence of patterns and relationships of entities. This notion may itself be an object, such as a built structure, or an attribute, such as the structure of society...
.
Typically, the sensor is an image sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...
in a camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
sensitive to visible light and the input to the method is a set of digital images (one, two or more) or video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
. In this case we talk about image-based reconstruction and the output is a 3D photography.