Langley Park, Perth, Western Australia as seen from a COPTERCAM at 120m

The Georgian terrace of Royal Crescent (Bath, England) from a hot air balloon

London Docklands in the fog from a Eurocopter AS355

Aerial photography is the taking of photographs of the ground from an elevated position. The term usually refers to images in which the camera is not supported by a ground-based structure. Cameras may be hand held or mounted, and photographs may be taken by a photographer, triggered remotely or triggered automatically. Platforms for aerial photography include fixed-wing aircraft, helicopters, multirotor Unmanned Aircraft Systems (UAS), balloons, blimps and dirigibles, rockets, kites, poles, parachutes, and vehicle mounted poles. Aerial photography should not be confused with Air-to-Air Photography, when aircraft serve both as a photo platform and subject.

History []

Honoré Daumier, "Nadar élevant la Photographie à la hauteur de l'Art" (Nadar elevating Photography to Art), published in Le Boulevard, May 25, 1862.

Aerial photography was first practiced by the French photographer and balloonist Gaspard-Félix Tournachon, known as "Nadar", in 1858 over Paris, France.^[1]

'Boston, as the Eagle and the Wild Goose See It'

However, the photographs he produced no longer exist and therefore the earliest surviving aerial photograph is titled 'Boston, as the Eagle and the Wild Goose See It.' Taken by James Wallace Black and Samuel Archer King on October 13, 1860, it depicts Boston from a height of 630m.^[2][3]

The first use of a motion picture camera mounted to a heavier-than-air aircraft took place on April 24, 1909 over Rome in the 3:28 silent film short, Wilbur Wright und seine Flugmaschine.

The first special semiautomatic aerial camera was designed in 1911 by Russian military engineer — Colonel Potte V. F.^[4] This aerial camera was used during World War I.

Aerial photography and panoramic photography were used for civilian mapping, topography and cartography by the US Geological Survey in Alaska before World War I,^[5] and was also developed and expanded by James W. Bagley who left the USGS to join the US Army Corps of Engineers during the war.

The use of aerial photography for military purposes was expanded during World War I by many other aviators such as Fred Zinn. One of the first notable battles was that of Neuve Chapelle.

The first commercial aerial photography company in the UK was Aerofilms Ltd, founded by World War I veterans Francis Wills and Claude Graham White. Wills had served as an Observer with the Royal Naval Air Service during the Great War, and was the driving force behind the expansion of the company from an office and a bathroom (for developing films) in Hendon to a business with major contracts in Africa and Asia as well as in the UK. Co-founder Graham-White was a pioneer aviator who had achieved fame by making the first night flight in 1910. The entire Aerofilms oblique collection, comprising some 1.26 million negatives and 2000 print albums, is now held in the archive of National Monuments Record (England) in Swindon, UK.

Aerial mapping came into use on the battlefronts during World War I. In 1916 the Austro-Hungarian Monarchy made vertical camera axis aerial photos for example above Italy for map-making. (Images can be viewed at: http://www.rsgis.hu/index.php/component/content/article/155 or http://www.rsgis.hu/images/stories/BG_6.jpg) In January 1918, General Allenby used five Australian pilots from No. 1 Squadron AFC to photograph a 624 square miles (1,620 km²) area in Palestine as an aid to correcting and improving maps of the Turkish front. Lieutenants Leonard Taplin, Allan Runciman Brown, H. L. Fraser, Edward Patrick Kenny, and L. W. Rogers photographed a block of land stretching from the Turkish front lines 32 miles (51 km) deep into their rear areas. Beginning 5 January, they flew with a fighter escort to ward off enemy fighters. Using Royal Aircraft Factory BE.12 and Martinsyde airplanes, they not only overcame enemy air attacks, but also bucked 65 mile per hour winds, antiaircraft fire, and malfunctioning equipment to complete their task circa 19 January 1918.^[6]

One of the most successful pioneers of the commercial use of aerial photography was by Sherman Fairchild who started his own aircraft firm Fairchild Aircraft to develop and build specialized aircraft for high altitude aerial survey missions.^[7] One Fairchild aerial survey aircraft in 1935 carried unit that combined two synchronized cameras, and each camera having five six inch lenses with a ten inch lenses and took photos from 23,000 feet. Each photo covered two hundred and twenty five square miles. One of its first government contracts was an aerial survey of New Mexico to study soil erosion.^[8] A year later, Fairchild introduced a better high altitude camera with nine-lens in one unit that could take a photo of 600 square miles with each exposure from 30,000 feet.^[9]

With the advent of inexpensive digital cameras, many people now take candid photographs from commercial aircraft and increasingly from general aviation aircraft on private pleasure flights. The penultimate aerial image mapping resolution world record tilted in Budapest with 1.8 cm spatial resolution. The aerial photo map was taken about Budapest Zoo. The current highest resolution aerial ortho images were also made in Hungary by the same young university research team (Interspect Group) in June 2012. They reached 0.5 cm spatial resolution. Now this is the World's highest resolution aerial image mosaic. It shows a military memorial park near Pákozd town.

The highest resolution aerial ortho image mosaic of the World (details)

Uses of imagery []

Reflection of a hot air balloon, partially obscured by a pier, an example of low-altitude aerial photography

Giza pyramid complex, photographed from Eduard Spelterini's balloon on November 21, 1904

Fogo island aerial shot taken from an Airbus cockpit by the pilot himself

Aerial photography is used in cartography^[10] (particularly in photogrammetric surveys, which are often the basis for topographic maps), land-use planning,^[10] archaeology,^[10] movie production, environmental studies, surveillance, commercial advertising, conveyancing, and artistic projects. In the United States, aerial photographs are used in many Phase I Environmental Site Assessments for property analysis.

Aerial photography platforms []

Radio-controlled aircraft []

Advances in radio controlled models have made it possible for model aircraft to conduct low-altitude aerial photography. This has benefited real-estate advertising, where commercial and residential properties are the photographic subject. Full-size, manned aircraft are prohibited from low flights above populated locations.^[11] Small scale model aircraft offer increased photographic access to these previously restricted areas. Miniature vehicles do not replace full size aircraft, as full size aircraft are capable of longer flight times, higher altitudes, and greater equipment payloads. They are, however, useful in any situation in which a full-scale aircraft would be dangerous to operate. Examples would include the inspection of transformers atop power transmission lines and slow, low-level flight over agricultural fields, both of which can be accomplished by a large-scale radio controlled helicopter. Professional-grade, gyroscopically stabilized camera platforms are available for use under such a model; a large model helicopter with a 26cc gasoline engine can hoist a payload of approximately seven kilograms (15 lbs).

Recent (2006) FAA regulations grounding all commercial RC model flights have been upgraded to require formal FAA certification before permission to fly at any altitude in USA.

In Australia Civil Aviation Safety Regulation 101 (CASR 101)^[12] allows for commercial use of radio control aircraft. Under these regulations radio controlled unmanned aircraft for commercial are referred to as Unmanned Aircraft Systems (UAS), where as radio controlled aircraft for recreational purposes are referred to as model aircraft. Under CASR 101, businesses/persons operating radio controlled aircraft commercially are required to hold an Operator Certificate, just like manned aircraft operators. Pilots of radio controlled aircraft operating commercially are also required to be licenced by the Civil Aviation Safety Authority (CASA).^[13] Whilst a small UAS and model aircraft may actually be identical, unlike model aircraft, a UAS may enter controlled airspace with approval, and operate within close proximity to an aerodrome.

Due to a number of illegal operators in Australia making false claims of being approved, CASA published and maintains of approved UAS operators^[14]

UAS (also known as drones) are hot topics for the media. Numerous stories have been published about approved operators such as COPTERCAM [1] providing aerial photography services too low for manned aircraft, and too high for pole cameras.^[15] According to an article published by the Association for Unmanned Vehicle Systems International (AUVSI),^[16] approved operators like COPTERCAM have become leaders in the aerial photography industry in a relatively short period of time.

Because anything capable of being viewed from a public space is considered outside the realm of privacy in the United States, aerial photography may legally document features and occurrences on private property.^[17]

Multirotor Unmanned Aircraft Systems []

The COPTERCAM 8 aerial camera system

A number of multirotor UAS are purposely built for aerial photography.

ALMA antennas seen from above^[18]

Octocopters (8 rotors)

• Coptercam Aerial Camera System

Hexacopters (6 rotors)

• Aibotix
• Draganflyer

Quadcopters (4 rotors)

• CyberQuad Maxi
• Microdrone

Tricopters (3 rotors)

Multirotors have been the platform of choice for professional aerial photographers because they are mechanically simpler than helicopters, thus reducing the risk of mechanical failure. Correctly built and tuned they also offer less vibration and greater stability.

Multirotors generally have at least 2 rotors, however with the additional rotors, their payload lifting capacity and redundancy increases. If a 6 rotor aircraft loses power to one rotor it will lose yaw control. If an 8 rotor aircraft loses power to 1 rotor, there is negligible effect on control. This is an important design feature because unlike helicopters with a variable pitch rotor, multirotor aircraft do not have the ability to autorotate.

The flight control system consists of an attitude head reference system (AHRS which is generally also found in manned aircraft with autopilots). The gyros, accelerometers, magnetometers allows the flight control system to determine whether it is level, pitched, rolled and what direction it is pointing.

The navigation control system that consists of a GPS and barometer (pressure altimeter) tells the flight control system where it is, how high it is, and where it took off from. The navigation control system is also responsible for telling the flight control system how to hold a position, navigate to a position, and return to its launch location.

The flight control system controls the aircraft by determining which electronic motors need more power and which need less power unto 400 times every second. This is all achieved through software rather than mechanically adjusting control services like in on a plane. This reduces the risk of mechanical failure, however, the flight performance of a multirotor aircraft like the COPTERCAM relies on the quality of the software and the configuration of the system.

The radio control system allows the pilot to control the aircraft using a fly by wire system. The pilots radio control tells the flight control what the pilot wants to do, e.g. move forwards, climb, descend, move right, and the flight control board decides the speed of each motor required to perform the command. The range of the radio control system can vary between 2 km to 10 km depending environmental factors.

A second radio control is used to monitor aircraft performance on a moving map and also allows the co-pilot to put in navigation points and command the aircraft to fly autonomously. The range of the telemetry system can vary from about 5–20 km using standard radio modems, to hundreds of kilometres if the data is routed via the 3G mobile phone network.

Aerial camera systems like the COPTERCAM are also fitted with pan, tilt, roll and 10x zoom cameras which allows the aircraft to record and transmit to the ground and Internet live HD video via either a wireless digital video link of a 3G/4G wireless internet connection.

Types of aerial photographs []

Oblique photographs []

Photographs taken at an angle are called oblique photographs. If they are taken from a low angle earth surface–aircraft, they are called low oblique and photographs taken from a high angle are called high or steep oblique.^[19]

Vertical photographs []

Vertical photographs are taken straight down.^[20] They are mainly used in photogrammetry and image interpretation. Pictures that will be used in photogrammetry are traditionally taken with special large format cameras with calibrated and documented geometric properties.

Combinations []

Aerial photographs are often combined. Depending on their purpose it can be done in several ways, of which a few are listed below.

• Panoramas can be made by stitching several photographs taken with one hand held camera.
• In pictometry five rigidly mounted cameras provide one vertical and four low oblique pictures that can be used together.
• In some digital cameras for aerial photogrammetry images from several imaging elements, sometimes with separate lenses, are geometrically corrected and combined to one image in the camera.

Orthophotos []

Vertical photographs are often used to create orthophotos, alternatively known as orthophotomaps, photographs which have been geometrically "corrected" so as to be usable as a map. In other words, an orthophoto is a simulation of a photograph taken from an infinite distance, looking straight down to nadir. Perspective must obviously be removed, but variations in terrain should also be corrected for. Multiple geometric transformations are applied to the image, depending on the perspective and terrain corrections required on a particular part of the image.

Orthophotos are commonly used in geographic information systems, such as are used by mapping agencies (e.g. Ordnance Survey) to create maps. Once the images have been aligned, or "registered", with known real-world coordinates, they can be widely deployed.

Large sets of orthophotos, typically derived from multiple sources and divided into "tiles" (each typically 256 x 256 pixels in size), are widely used in online map systems such as Google Maps. OpenStreetMap offers the use of similar orthophotos for deriving new map data. Google Earth overlays orthophotos or satellite imagery onto a digital elevation model to simulate 3D landscapes.

Aerial video []

With advancements in video technology, aerial video is becoming more popular. Orthogonal video is shot from aircraft mapping pipelines, crop fields, and other points of interest. Using GPS, video may be embedded with meta data and later synced with a video mapping program.

This "Spatial Multimedia" is the timely union of digital media including still photography, motion video, stereo, panoramic imagery sets, immersive media constructs, audio, and other data with location and date-time information from the GPS and other location designs.

Aerial videos are emerging Spatial Multimedia which can be used for scene understanding and object tracking. The input video is captured by low flying aerial platforms and typically consists of strong parallax from non-ground-plane structures. The integration of digital video, global positioning systems (GPS) and automated image processing will improve the accuracy and cost-effectiveness of data collection and reduction. Several different aerial platforms are under investigation for the data collection.

See also []

• Aerial archaeology
• Aerial landscape art
• Aerial photographers category
• Aerofilms Ltd., the first commercial aerial photography company in the UK, founded in 1919
• Airborne Real-time Cueing Hyperspectral Enhanced Reconnaissance
• Astrocam
• Aviation photography
• Battle of Neuve Chapelle
• Douglas Douglas-Hamilton, 14th Duke of Hamilton 1932 photo flight over Mount Everest
• Fairchild K-20 An early aerial camera
• Federal Aviation Regulations
• Geoinformatics
• Kite aerial photography
• National Monuments Record the public archive of English Heritage, who hold one of the largest collections of aerial photographs of England
• Oracle model photographic rocket
• Pictometry
• Pigeon photography
• Photogrammetry
• Remote sensing
• Satellite imagery
• TopoFlight
• Unmanned aerial vehicle

References []

External links []

• Aerial photography and remote sensing
• Air photo interpretation
• California Coastal Records Project
• Bird's eye view of the Delaware Valley by the Dallin Aerial Survey Company (1924–1941)
• Historic aerial photos of Columbia, South Carolina from the University of South Carolina Library
• Historical Aerial Photographs of New York , Cornell University Library & Cornell Institute for Resource Information Sciences
• National Collection of Aerial Photography The official archive of British Government declassified aerial photography.
• History of Aerial photos by Kite - KAP
• Aerial Photographic Techniques Suitable for Children
• Graber Collection of Florida Aerial Photographs at the University of South Florida