Photogrammetry
Encyclopedia
Photogrammetry is the practice of determining the geometric properties of objects from photographic images. Photogrammetry is as old as modern photography
and can be dated to the mid-nineteenth century.
In the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane can be determined by measuring their distance on the image, if the scale
(s) of the image is known. This is done by multiplying the measured distance by 1/s.
A more sophisticated technique, called stereophotogrammetry, involves estimating the three-dimensional coordinates
of points on an object. These are determined by measurements made in two or more photographic images taken from different positions (see stereoscopy
). Common points are identified on each image. A line of sight (or ray) can be constructed from the camera location to the point on the object. It is the intersection of these rays (triangulation
) that determines the three-dimensional location of the point. More sophisticated algorithm
s can exploit other information about the scene that is known a priori
, for example symmetries
, in some cases allowing reconstructions of 3D coordinates from only one camera position.
Photogrammetry is used in different fields, such as topographic map
ping, architecture
, engineering
, manufacturing
, quality control
, police
investigation, and geology
, as well as by archaeologists
to quickly produce plans of large or complex sites and by meteorologists as a way to determine the actual wind speed of a tornado
where objective weather data cannot be obtained. It is also used to combine live action
with computer-generated imagery
in movie post-production
; Fight Club
is a good example of the use of photogrammetry in film (details are given in the DVD extras).
Algorithms for photogrammetry typically express the problem as that of minimizing the sum of the squares of a set of errors. This minimization is known as bundle adjustment
and is often performed using the Levenberg–Marquardt algorithm.
and projective geometry
. The data model on the right shows what type of information can go into and come out of photogrammetric methods.
The 3D co-ordinates define the locations of object points in the 3D space. The image co-ordinates define the locations of the object points' images on the film or an electronic imaging device. The exterior orientation of a camera defines its location in space and its view direction. The inner orientation defines the geometric parameters of the imaging process. This is primarily the focal length of the lens, but can also include the description of lens distortions. Further additional observations play an important role: With scale bars, basically a known distance of two points in space, or known fix points, the connection to the basic measuring units is created.
Each of the four main variables can be an input or an output of a photogrammetric method.
Photogrammetry has been defined by the American Society for Photogrammetry and Remote Sensing
(ASPRS) as the art, science, and technology of obtaining reliable information about physical objects and the environment through processes of recording, measuring and interpreting photographic images and patterns of recorded radiant electromagnetic energy and other phenomena.
, laser scanners (using time of flight, triangulation or interferometry), white-light digitizers and any other technique that scans an area and returns x, y, z coordinates for multiple discrete points (commonly called "point clouds"). Photos can clearly define the edges of buildings when the point cloud footprint can not. It is beneficial to incorporate the advantages of both systems and integrate them to create a better product.
A 3D visualization can be created by georeferencing the aerial photos and LiDAR data in the same reference frame, orthorectifying the aerial photos, and then draping the orthorectified images on top of the LiDAR grid. It is also possible to create digital terrain models and thus 3D visualisations using pairs (or multiples) of aerial photographs or satellite (e.g. SPOT satellite imagery). Techniques such as adaptive least squares stereo matching are then used to produce a dense array of correspondences which are transformed through a camera model to produce a dense array of x, y, z data which can be used to produce digital terrain model and orthoimage products. Systems which use these techniques, e.g. the ITG system, were developed in the 1980s and 1990s but have since been supplanted by LiDAR and radar
-based approaches, although these techniques may still be useful in deriving elevation models from old aerial photographs or satellite images.
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
and can be dated to the mid-nineteenth century.
In the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane can be determined by measuring their distance on the image, if the scale
Scale (map)
The scale of a map is defined as the ratio of a distance on the map to the corresponding distance on the ground.If the region of the map is small enough for the curvature of the Earth to be neglected, then the scale may be taken as a constant ratio over the whole map....
(s) of the image is known. This is done by multiplying the measured distance by 1/s.
A more sophisticated technique, called stereophotogrammetry, involves estimating the three-dimensional coordinates
Coordinate system
In geometry, a coordinate system is a system which uses one or more numbers, or coordinates, to uniquely determine the position of a point or other geometric element. The order of the coordinates is significant and they are sometimes identified by their position in an ordered tuple and sometimes by...
of points on an object. These are determined by measurements made in two or more photographic images taken from different positions (see stereoscopy
Stereoscopy
Stereoscopy refers to a technique for creating or enhancing the illusion of depth in an image by presenting two offset images separately to the left and right eye of the viewer. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth...
). Common points are identified on each image. A line of sight (or ray) can be constructed from the camera location to the point on the object. It is the intersection of these rays (triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...
) that determines the three-dimensional location of the point. More sophisticated algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
s can exploit other information about the scene that is known a priori
A priori and a posteriori (philosophy)
The terms a priori and a posteriori are used in philosophy to distinguish two types of knowledge, justifications or arguments...
, for example symmetries
Symmetry
Symmetry generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically pleasing proportionality and balance; such that it reflects beauty or perfection...
, in some cases allowing reconstructions of 3D coordinates from only one camera position.
Photogrammetry is used in different fields, such as topographic map
Topographic map
A topographic map is a type of map characterized by large-scale detail and quantitative representation of relief, usually using contour lines in modern mapping, but historically using a variety of methods. Traditional definitions require a topographic map to show both natural and man-made features...
ping, architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...
, engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, manufacturing
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
, quality control
Quality control
Quality control, or QC for short, is a process by which entities review the quality of all factors involved in production. This approach places an emphasis on three aspects:...
, police
Police
The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...
investigation, and geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
, as well as by archaeologists
Aerial archaeology
Aerial archaeology is the study of archaeological remains by examining them from altitude.The advantages of gaining a good aerial view of the ground had been long appreciated by archaeologists as a high viewpoint permits a better appreciation of fine details and their relationships within the wider...
to quickly produce plans of large or complex sites and by meteorologists as a way to determine the actual wind speed of a tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
where objective weather data cannot be obtained. It is also used to combine live action
Live action
In filmmaking, video production, and other media, the term live action refers to cinematography, videography not produced using animation...
with computer-generated imagery
Computer-generated imagery
Computer-generated imagery is the application of the field of computer graphics or, more specifically, 3D computer graphics to special effects in art, video games, films, television programs, commercials, simulators and simulation generally, and printed media...
in movie post-production
Post-production
Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...
; Fight Club
Fight Club (film)
Fight Club is a 1999 American film based on the 1996 novel of the same name by Chuck Palahniuk. The film was directed by David Fincher and stars Edward Norton, Brad Pitt and Helena Bonham Carter. Norton plays the unnamed protagonist, an "everyman" who is discontented with his white-collar job...
is a good example of the use of photogrammetry in film (details are given in the DVD extras).
Algorithms for photogrammetry typically express the problem as that of minimizing the sum of the squares of a set of errors. This minimization is known as bundle adjustment
Bundle adjustment
Given a set of images depicting a number of 3D points from different viewpoints, bundle adjustment can be defined as the problem of simultaneously refining the 3D coordinates describing the scene geometry as well as the parameters of the relative motion and the optical characteristics of the camera...
and is often performed using the Levenberg–Marquardt algorithm.
Photogrammetric methods
Photogrammetry uses methods from many disciplines, including opticsOptics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
and projective geometry
Projective geometry
In mathematics, projective geometry is the study of geometric properties that are invariant under projective transformations. This means that, compared to elementary geometry, projective geometry has a different setting, projective space, and a selective set of basic geometric concepts...
. The data model on the right shows what type of information can go into and come out of photogrammetric methods.
The 3D co-ordinates define the locations of object points in the 3D space. The image co-ordinates define the locations of the object points' images on the film or an electronic imaging device. The exterior orientation of a camera defines its location in space and its view direction. The inner orientation defines the geometric parameters of the imaging process. This is primarily the focal length of the lens, but can also include the description of lens distortions. Further additional observations play an important role: With scale bars, basically a known distance of two points in space, or known fix points, the connection to the basic measuring units is created.
Each of the four main variables can be an input or an output of a photogrammetric method.
Photogrammetry has been defined by the American Society for Photogrammetry and Remote Sensing
American Society for Photogrammetry and Remote Sensing
The American Society for Photogrammetry and Remote Sensing, or ASPRS is the United States member organization of the International Society for Photogrammetry and Remote Sensing. Founded in 1934, the society is a scientific association serving over 7,000 professional members around the world...
(ASPRS) as the art, science, and technology of obtaining reliable information about physical objects and the environment through processes of recording, measuring and interpreting photographic images and patterns of recorded radiant electromagnetic energy and other phenomena.
Integration
Photogrammetric data with dense range data from scanners complement each other. Photogrammetry is more accurate in the x and y direction while range data is generally more accurate in the z direction. This range data can be supplied by techniques like LiDARLIDAR
LIDAR is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser...
, laser scanners (using time of flight, triangulation or interferometry), white-light digitizers and any other technique that scans an area and returns x, y, z coordinates for multiple discrete points (commonly called "point clouds"). Photos can clearly define the edges of buildings when the point cloud footprint can not. It is beneficial to incorporate the advantages of both systems and integrate them to create a better product.
A 3D visualization can be created by georeferencing the aerial photos and LiDAR data in the same reference frame, orthorectifying the aerial photos, and then draping the orthorectified images on top of the LiDAR grid. It is also possible to create digital terrain models and thus 3D visualisations using pairs (or multiples) of aerial photographs or satellite (e.g. SPOT satellite imagery). Techniques such as adaptive least squares stereo matching are then used to produce a dense array of correspondences which are transformed through a camera model to produce a dense array of x, y, z data which can be used to produce digital terrain model and orthoimage products. Systems which use these techniques, e.g. the ITG system, were developed in the 1980s and 1990s but have since been supplanted by LiDAR and radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
-based approaches, although these techniques may still be useful in deriving elevation models from old aerial photographs or satellite images.
Applications
This method is commonly employed in collision engineering, especially with automobiles. When litigation for accidents occurs and engineers need to determine the exact deformation present in the vehicle, it is common for several years to have passed and the only evidence that remains is crime scene photographs taken by the police. Photogrammetry is used to determine how much the car in question was deformed, which relates to the amount of energy required to produce that deformation. The energy can then be used to determine important information about the crash (such as the velocity at time of impact).Current Suite of Software
| Standalone / Plugin | Specialisation | Automatic modelling | Scalability | Data source | Inception | Vendor / creator | Guide price | Link | ||
|---|---|---|---|---|---|---|---|---|---|---|
| PhotoSculpt | Standalone | 100% | Yes | No, 2 images only | Images | - | Hippolyte Mounier | $99 | http://www.photosculpt.net/ | |
| PhotoModeler | Standalone | 100% | Yes | Yes, multiple images | Images | 1994 | Eos Systems | $1145 | http://www.photomodeler.com | |
| ImageModeler | Standalone | 100% | No | Yes, multiple images | Images | 2009 | Autodesk | Subscription benefit | http://usa.autodesk.com/adsk/servlet/pc/index?id=11390028&siteID=123112 | |
| 3D VIA | Standalone | 100% | No | Yes | Images | Example | Example | Example | http://www.3dvia.com/ | |
| Match Photo | Plugin / feature | 100% | No | Yes, multiple images | Images | - | Example | http://sketchup.google.com/support/bin/answer.py?answer=94919 | ||
| PhotoSketch | - | - | - | - | - | - | Brainstorm Technology LLC | $350 | http://www.brainstormllc.com/ | |
| 3D pup-up | Standalone | 100% | No | Single image | Image | 2005 | Carnegie Mellon University | non commercial | http://www.cs.uiuc.edu/homes/dhoiem/projects/popup/index.html | |
| Yodel | Standalone | 100% | Limited | Yes, multiple images | Images | 2011 | Lidar Pacific Corporation | $499 | http://www.yodel3d.com | |
| VideoTrace | Tethered Beta | 100% | No | Yes, multiple images | Images/Video | 2011 | Australian Center for Visual Technology (AVCT),PunchCard | Beta Tester Only | http://punchcard.com.au/wordpress/ | |
| 123D Catch (Beta) | Standalone | 100% | Yes | Yes, multiple images | Images/Video | 2011 | Autodesk | Free download | http://www.123dapp.com/catch | |
| Hypr3D | Standalone | 100% | Yes | Yes, multiple images | Images/Video | 2010 | Viztu Technologies | Free, web-based | https://www.hypr3d.com/ | |
| ELCOVISION 10 | Standalone/Plugin | 100% | Yes | Yes, multiple images | Images | 1986 | PMS AG / Leica Geosystems | 2000 | http://www.elcovision.com/ | |
| PhotoScan | Standalone/Plugin | 100% | Semi-automatic | Yes, multiple images | Images | 2010 | Ocali, Inc. | $999 | http://www.Tgi3D.com/ |
See also
- 3D data acquisition and object reconstruction3D data acquisition and object reconstruction3D data acquisition and reconstruction is the generation of three dimensional or spatiotemporal models from sensor data. The techniques and theories, generally speaking, work with most or all sensor types including optical, acoustic, laser scanning, radar, thermal, seismic.-Acquisition:Acquisition...
- Aerial surveyAerial surveyAerial survey is a geomatics method of collecting information by using aerial photography, LiDAR or from remote sensing imagery using other bands of the electromagnetic spectrum, such as infrared, gamma, or ultraviolet. It can also refer to the chart or map made by analysing a region from the air...
- Computer visionComputer visionComputer 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...
- Edouard DevilleEdouard DevilleÉdouard-Gaston Daniel Deville was the first to perfect a practical method of photogrammetry, the making of maps based on photography. He was the Surveyor General of Canada and Canada's Director General for the Bureau of Surveys...
- ERDAS IMAGINEERDAS IMAGINEERDAS IMAGINE is a remote sensing application with raster graphics editor capabilities designed by ERDAS for geospatial applications. The latest version is 2010, version 10.1. ERDAS IMAGINE is aimed primarily at geospatial raster data processing and allows the user to prepare, display and enhance...
- GeofotoGeofotoGeofoto is a Croatian company with 260 employees headquartered in Zagreb, Croatia with subsidiaries in Norway, Macedonia, Slovenia, Bolivia, Argentina, United Arab Emirates, Czech Republic and United Kingdom. Its main fields are Geomatics activities such as photogrammetry and geographic information...
- GeoinformaticsGeoinformaticsGeoinformatics is the science and the technology which develops and uses information science infrastructure to address the problems of geography, geosciences and related branches of engineering.-Overview:...
- Geomatics engineeringGeomatics engineeringGeomatics Engineering, Geomatic Engineering, or Geospatial Engineering is a rapidly developing discipline that focuses on spatial information . The location is the primary factor used to integrate a very wide range of data for viewing and analysis...
- Leica Photogrammetry SuiteLeica Photogrammetry SuiteLeica Photogrammetry Suite is a software application for performing photogrammetric operations on imagery and extracting information from imagery...
- Mobile MappingMobile MappingMobile mapping is the process of collecting geospatial data from a mobile vehicle, typically fitted with a range of photographic, radar, laser, LiDAR or any number of remote sensing systems. Such systems are composed of an integrated array of time synchronised navigation sensors and imaging sensors...
- PeriscopePeriscopeA periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle....
- PhotomappingPhotomappingPhotomapping involves the process of drawing a map from a photographic base. “In all likelihood, computer map making, including analogue processing, will have replaced manual map making for well over 90 per cent of all maps".-Principles and Definitions:...
- PhotoModelerPhotoModelerPhotoModeler is a software application that performs image-based modeling and close range photogrammetry – producing 3D models and measurements from photography....
- RangefinderRangefinderA rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure ; others measure distance using trigonometry...
- SOCET SETSOCET SETSOCET SET is a software application that performs functions related to photogrammetry. It is developed and published by BAE Systems. SOCET SET was the first commercial digital photogrammetry software program...
- StereoplotterStereoplotterA stereoplotter uses stereo photographs to determine elevations. It has been the primary method to plot contour lines on topographic maps since the 1930’s...
- SurveyingSurveyingSee Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
- TopoFlightTopoFlightTopoFlight is a three-dimensional flight planning software that was originally conceived by a team of experts in the mapping industry, in use since 2003...
- VideogrammetryVideogrammetryVideogrammetry is a measurement technology in which the three-dimensional coordinates of points on an object are determined by measurements made in two or more video images taken from different angles. Images can be obtained from two cameras which simultaneously view the object or from successive...
External links
- International Society for Photogrammetry and Remote Sensing
- RSPSoc - Remote Sensing and Photogrammetry Society of UK
- American Society for Photogrammetry and Remote Sensing
- A real world example of usage in reconstructing destroyed historical statues by using photographs
- History of Photogrammetry
- World Photogrammetry, the spanish website of photogrammetry for everyone