High speed camera
Encyclopedia
A high speed camera is a device used for recording fast moving objects as a photographic image(s) onto a storage media. After recording, the images stored on the media can be played back in slow-motion
. Early high speed cameras used film to record the high speed events but today, high speed cameras are entirely electronic using either a charge-coupled device
(CCD) or a CMOS
active pixel sensor
, recording typically over 1000 frames per second into DRAM
and playing slowly images back to study the motion for scientific study of transient phenomena. A high speed camera can be classified as (1) a high speed film camera that records to film, (2) a high speed framing camera that records a short burst of images to film/digital still camera, a high speed streak camera that records to film/digital memory or (3) a high speed video camera recording to digital memory.
A normal motion picture
is filmed and played back at 24 frames per second, while television uses 25 frames/s (PAL
) or 29.97 frames/s (NTSC
). High speed cameras can film up to a quarter of a million frames per second by running the film over a rotating prism
or mirror
instead of using a shutter
, thus reducing the need for stopping and starting the film behind a shutter which would tear the film stock at such speeds. Using this technique one can stretch one second to more than ten minutes of playback time (super slow motion). The fastest cameras are generally in use in scientific research, military test and evaluation, and industry. Examples of industrial applications are filming a manufacturing line to better tune the machine, or in the car industry the crash test
ing to better document the crash and what happens to the automobile
and passengers during a crash. Today, the digital high speed camera has replaced the film camera used for Vehicle Impact Testing. Television series such as MythBusters
and Time Warp
often use high speed cameras to show their tests in slow motion. Saving the recorded high speed images can be time consuming because the newest cameras today have resolutions up to four megapixels at record rates over 1000 frames per second which means in one second, you will have over 11 gigabytes of image data. Technologically, these cameras are very advanced yet, saving images requires use of slower standard video-computer interfaces. While recording is very fast, saving images is considerable slower. The fastest high speed camera has the ability to take pictures at a speed of 200 million frames per second.
One of the solutions to drive down the recorded data, or to minimize the required time to look at the images, is to pre-select the interesting parts of what is interesting enough to film. During industrial breakdown analysis, cyclical filming focuses only on that part of the cycle which is interesting.
A problem for high speed cameras is the needed exposure
for the film, so one needs very bright light to be able to film at forty thousand frames per second sometimes leading to the subject of examination being destroyed because of the heat of the lighting.
Monochromatic filming (black/white) is sometimes used to reduce the required amount of light.
Even higher speed imaging is possible using specialized electronic charge-coupled device
(CCD) imaging systems which can achieve speeds of up to or in excess of 25 million frames per second. All development in high speed cameras is now focused on digital video cameras which have many operational and cost benefits over film cameras.
Recent advances in the form of image converter devices are able to provide temporal resolutions of less than fifty picoseconds, equivalent to over 20,000,000,000 (twenty billion) frames per second. These instruments operate by converting the incident light (consisting of photons) into a stream of electrons which are then deflected onto a photoanode, back into photons, which can then be recorded onto either film or CCD.
employs such cameras to capture high-speed animal movements, such as jumping
in frogs and insects, suction feeding in fish, and the strikes of mantis shrimp
, using motion analysis
of the resulting sequences from one or more cameras to characterize the motion in either 2-D or 3-D.
The move from film to digital technology has greatly reduced the difficulty in use of these technologies with unpredictable behaviors, specifically via the use of continuous recording and post-triggering. With film high-speed cameras, an investigator must start the film then attempt to entice the animal to perform the behavior in the short time before the film runs out, resulting in many useless sequences where the animal behaves too late or refuses. In modern digital high-speed cameras, the camera can simply record continuously as the investigator attempts to elicit the behavior, following which a trigger button will stop the recording and allow the investigator to save a given time interval prior to the trigger (determined by frame rate, image size and memory capacity during continuous recording). Most software allows saving only a subset of recorded frames, minimizing file size issues by eliminating useless frames before or after the sequence of interest. Such triggering can also be used to synchronize recording across multiple cameras.
Slow motion
Slow motion is an effect in film-making whereby time appears to be slowed down. It was invented by the Austrian priest August Musger....
. Early high speed cameras used film to record the high speed events but today, high speed cameras are entirely electronic using either a charge-coupled device
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
(CCD) or a CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
active pixel sensor
Active pixel sensor
An active-pixel sensor is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web...
, recording typically over 1000 frames per second into DRAM
Dram
Dram or DRAM may refer to:As a unit of measure:* Dram , an imperial unit of mass and volume* Armenian dram, a monetary unit* Dirham, a unit of currency in several Arab nationsOther uses:...
and playing slowly images back to study the motion for scientific study of transient phenomena. A high speed camera can be classified as (1) a high speed film camera that records to film, (2) a high speed framing camera that records a short burst of images to film/digital still camera, a high speed streak camera that records to film/digital memory or (3) a high speed video camera recording to digital memory.
A normal motion picture
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
is filmed and played back at 24 frames per second, while television uses 25 frames/s (PAL
PAL
PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
) or 29.97 frames/s (NTSC
NTSC
NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
). High speed cameras can film up to a quarter of a million frames per second by running the film over a rotating prism
Prism (optics)
In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use...
or mirror
Mirror
A mirror is an object that reflects light or sound in a way that preserves much of its original quality prior to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection...
instead of using a shutter
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...
, thus reducing the need for stopping and starting the film behind a shutter which would tear the film stock at such speeds. Using this technique one can stretch one second to more than ten minutes of playback time (super slow motion). The fastest cameras are generally in use in scientific research, military test and evaluation, and industry. Examples of industrial applications are filming a manufacturing line to better tune the machine, or in the car industry the crash test
Crash test
A crash test is a form of destructive testing usually performed in order to ensure safe design standards in crashworthiness and crash compatibility for various modes of transportation or related systems and components.- Types :...
ing to better document the crash and what happens to the automobile
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
and passengers during a crash. Today, the digital high speed camera has replaced the film camera used for Vehicle Impact Testing. Television series such as MythBusters
MythBusters
MythBusters is a science entertainment TV program created and produced by Beyond Television Productions for the Discovery Channel. The series is screened by numerous international broadcasters, including Discovery Channel Australia, Discovery Channel Latin America, Discovery Channel Canada, Quest...
and Time Warp
Time Warp (TV series)
Time Warp was a popular science-themed television program produced for the Discovery Channel in the United States, in which Jeff Lieberman, an MIT scientist, teacher, and artist, along with high speed camera expert Matt Kearney, turn their high speed camera on everyday occurrences and singular...
often use high speed cameras to show their tests in slow motion. Saving the recorded high speed images can be time consuming because the newest cameras today have resolutions up to four megapixels at record rates over 1000 frames per second which means in one second, you will have over 11 gigabytes of image data. Technologically, these cameras are very advanced yet, saving images requires use of slower standard video-computer interfaces. While recording is very fast, saving images is considerable slower. The fastest high speed camera has the ability to take pictures at a speed of 200 million frames per second.
One of the solutions to drive down the recorded data, or to minimize the required time to look at the images, is to pre-select the interesting parts of what is interesting enough to film. During industrial breakdown analysis, cyclical filming focuses only on that part of the cycle which is interesting.
A problem for high speed cameras is the needed exposure
Exposure (photography)
In photography, exposure is the total amount of light allowed to fall on the photographic medium during the process of taking a photograph. Exposure is measured in lux seconds, and can be computed from exposure value and scene luminance over a specified area.In photographic jargon, an exposure...
for the film, so one needs very bright light to be able to film at forty thousand frames per second sometimes leading to the subject of examination being destroyed because of the heat of the lighting.
Monochromatic filming (black/white) is sometimes used to reduce the required amount of light.
Even higher speed imaging is possible using specialized electronic charge-coupled device
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
(CCD) imaging systems which can achieve speeds of up to or in excess of 25 million frames per second. All development in high speed cameras is now focused on digital video cameras which have many operational and cost benefits over film cameras.
Recent advances in the form of image converter devices are able to provide temporal resolutions of less than fifty picoseconds, equivalent to over 20,000,000,000 (twenty billion) frames per second. These instruments operate by converting the incident light (consisting of photons) into a stream of electrons which are then deflected onto a photoanode, back into photons, which can then be recorded onto either film or CCD.
Uses in television
- The show MythbustersMythBustersMythBusters is a science entertainment TV program created and produced by Beyond Television Productions for the Discovery Channel. The series is screened by numerous international broadcasters, including Discovery Channel Australia, Discovery Channel Latin America, Discovery Channel Canada, Quest...
prominently uses high speed cameras for measuring speed or height. - Time WarpTime Warp (TV series)Time Warp was a popular science-themed television program produced for the Discovery Channel in the United States, in which Jeff Lieberman, an MIT scientist, teacher, and artist, along with high speed camera expert Matt Kearney, turn their high speed camera on everyday occurrences and singular...
is centered around the use of High-Speed cameras to slow things down that are usually too fast to see with the naked eye. - High-speed cameras are frequently used in television productions of many major sporting events for slow motionSlow motionSlow motion is an effect in film-making whereby time appears to be slowed down. It was invented by the Austrian priest August Musger....
instant replayInstant replayInstant replay is the replaying of video footage of an event or incident very soon after it has occurred. In television broadcasting of sports events, instant replay is often used during live broadcast, to show a passage of play which was important or remarkable, or which was unclear on first...
s when normal slow motion is not slow enough, such as international CricketCricketCricket is a bat-and-ball game played between two teams of 11 players on an oval-shaped field, at the centre of which is a rectangular 22-yard long pitch. One team bats, trying to score as many runs as possible while the other team bowls and fields, trying to dismiss the batsmen and thus limit the...
matches.
Uses in science
High-speed cameras are frequently used in science in order to characterize events which happen too fast for traditional film speeds. BiomechanicsBiomechanics
Biomechanics is the application of mechanical principles to biological systems, such as humans, animals, plants, organs, and cells. Perhaps one of the best definitions was provided by Herbert Hatze in 1974: "Biomechanics is the study of the structure and function of biological systems by means of...
employs such cameras to capture high-speed animal movements, such as jumping
Jumping
Jumping or leaping is a form of locomotion or movement in which an organism or non-living mechanical system propels itself through the air along a ballistic trajectory...
in frogs and insects, suction feeding in fish, and the strikes of mantis shrimp
Mantis shrimp
Mantis shrimp or stomatopods are marine crustaceans, the members of the order Stomatopoda. They are neither shrimp nor mantids, but receive their name purely from the physical resemblance to both the terrestrial praying mantis and the shrimp. They may reach in length, although exceptional cases of...
, using motion analysis
Motion analysis
Motion analysis is a topic in computer vision, image processing, and machine vision that studies methods and applications in which two or more consecutive images from an image sequences, e.g., produced by a video camera, are processed to produce information based on the apparent motion in the images...
of the resulting sequences from one or more cameras to characterize the motion in either 2-D or 3-D.
The move from film to digital technology has greatly reduced the difficulty in use of these technologies with unpredictable behaviors, specifically via the use of continuous recording and post-triggering. With film high-speed cameras, an investigator must start the film then attempt to entice the animal to perform the behavior in the short time before the film runs out, resulting in many useless sequences where the animal behaves too late or refuses. In modern digital high-speed cameras, the camera can simply record continuously as the investigator attempts to elicit the behavior, following which a trigger button will stop the recording and allow the investigator to save a given time interval prior to the trigger (determined by frame rate, image size and memory capacity during continuous recording). Most software allows saving only a subset of recorded frames, minimizing file size issues by eliminating useless frames before or after the sequence of interest. Such triggering can also be used to synchronize recording across multiple cameras.