A high-speed camera is a device capable of capturing moving images with exposures of less than 1/1,000 second or frame rates in excess of 250 fps. It is used for recording fast-moving objects as photographic images onto a storage medium. After recording, the images stored on the medium can be played back in

slow motion Slow motion (commonly abbreviated as slo-mo or slow-mo) is an effect in film-making whereby time appears to be slowed down. It was invented by the Austrian priest August Musger in the early 20th century. This can be accomplished through the use ...

. Early high-speed cameras used film to record the high-speed events, but were superseded by entirely electronic devices using either a

charge-coupled device A charge-coupled device (CCD) is an integrated circuit containing an array of linked, or coupled, capacitors. Under the control of an external circuit, each capacitor can transfer its electric charge to a neighboring capacitor. CCD sensors are a ...

(CCD) or a

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSF ...

active pixel sensor An active-pixel sensor (APS) is an image sensor where each pixel sensor unit cell has a photodetector (typically a pinned photodiode) and one or more active transistors. In a metal–oxide–semiconductor (MOS) active-pixel sensor, MOS field-effec ...

, recording, typically, over 1,000 fps onto

DRAM Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxid ...

, to be played back slowly to study the motion for scientific study of transient phenomena.

Overview

A high-speed camera can be classified as: # A high-speed film camera which records to film, # A high-speed video camera which records to electronic memory, # A high-speed framing camera which records images on multiple image planes or multiple locations on the same image plane (generally film or a network of CCD cameras), # A high-speed streak camera which records a series of line-sized images to film or electronic memory. A normal

motion picture A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...

film is played back at 24

frames per second A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (con ...

, while television uses 25 frames/s (

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

) or 29.97 frames/s (

NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...

). High-speed film cameras can film up to a quarter of a million fps by running the film over a rotating prism or

mirror A mirror or looking glass is an object that reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the im ...

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 second of action can be stretched to more than ten minutes of playback time (super slow motion). High-speed video cameras are widely used for 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 filming a

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 (see automobile safety) or related systems and comp ...

to investigate the effect on the crash dummy passengers and the

automobile A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded ...

. Today, the digital high-speed camera has replaced the film camera used for Vehicle Impact Testing.

Television series A television show – or simply TV show – is any content produced for viewing on a television set which can be broadcast via over-the-air, satellite, or cable, excluding breaking news, advertisements, or trailers that are typically placed be ...

such as ''

MythBusters ''MythBusters'' is a science entertainment television program, developed by Peter Rees and produced by Australia's Beyond Television Productions. The series premiered on the Discovery Channel on January 23, 2003. It was broadcast internation ...

'' and ''

Time Warp Time travel is a common theme in fiction, mainly since the late 19th century, and has been depicted in a variety of media, such as literature, television, film, and advertisements. The concept of time travel by mechanical means was popularized ...

'' often use high-speed cameras to show their tests in slow motion. Saving the recorded high-speed images can be time consuming because , consumer cameras have resolutions up to four megapixels with frame rates of over 1,000 per second which will record at a rate of 11 gigabytes per second. 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 considerably slower. To reduce the storage space required and the time required for people to examine a recording, only the parts of an action which are of interest or relevance can be selected to film. When recording a cyclical process for industrial breakdown analysis, only the relevant part of each cycle is filmed. A problem for high-speed cameras is the needed exposure for the film; very bright light is needed to be able to film at 40,000 fps, sometimes leading to the subject of examination being destroyed because of the heat of the lighting. Monochromatic (black and white) filming is sometimes used to reduce the light intensity required. Even higher speed imaging is possible using specialized electronic

(CCD) imaging systems, which can achieve speeds of over 25 million fps. These cameras, however, still use rotating mirrors, like their older film counterparts. Solid state cameras can achieve speeds of up to 10 million fps. All development in high-speed cameras is now focused on digital video cameras which have many operational and cost benefits over film cameras. In 2010 researchers built a camera exposing each frame for two trillionths of a second (

picoseconds A picosecond (abbreviated as ps) is a unit of time in the International System of Units (SI) equal to 10−12 or (one trillionth) of a second. That is one trillionth, or one millionth of one millionth of a second, or 0.000 000 000 ...

), for an effective frame rate of half a trillion fps (

femto-photography Femto-photography is a technique for recording the propagation of ultrashort pulses of light through a scene at a very high speed (up to 1013 frames per second). A femto-photograph is equivalent to an optical impulse response of a scene and has a ...

). Work supported by research grants in 2009 and 2010. Modern high-speed cameras operate by converting the incident light (

photons A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are Massless particle, massless ...

) into a stream of

electrons The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have n ...

which are then deflected onto a

photoanode A "photoelectrochemical cell" is one of two distinct classes of device. The first produces electrical energy similarly to a dye-sensitized photovoltaic cell, which meets the standard definition of a photovoltaic cell. The second is a photoelec ...

, back into photons, which can then be recorded onto either film or CCD.

Uses in television

*The show ''

'' prominently uses high-speed cameras for measuring speed or height. *''

'' was 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 production A television show – or simply TV show – is any content produced for viewing on a television set which can be broadcast via over-the-air, satellite, or cable, excluding breaking news, advertisements, or trailers that are typically placed be ...

s of many major sporting events for

instant replay Instant replay or action replay is a video reproduction of something that recently occurred which was both shot and broadcast live. The video, having already been shown live, is replayed in order for viewers to see again and analyze what had j ...

s when normal slow motion is not slow enough, such as international

Cricket Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by st ...

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.

Biomechanics Biomechanics is the study of the structure, function and motion of the mechanical aspects of biological systems, at any level from whole organisms to organs, cells and cell organelles, using the methods of mechanics. Biomechanics is a branch of ...

employs such cameras to capture high-speed animal movements, such as

jumping Jumping or leaping is a form of locomotion or movement in which an organism or non-living (e.g., robotics, robotic) mechanical system propels itself through the air along a ballistic trajectory. Jumping can be distinguished from running, gallo ...

by frogs and insects,

suction feeding Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...

in fish, the strikes of

mantis shrimp Mantis shrimp, or stomatopods, are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 340 million years ago. Mantis shrimp typically grow to around in length, ...

, and the aerodynamic study of pigeons' helicopter-like movements 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 not at all. 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 before and after the trigger (determined by frame rate, image size and memory capacity during continuous recording). Most software allows saving 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. The explosion of alkali metals on contact with water has been studied using a high-speed camera. Frame-by-frame analysis of a sodium/potassium alloy exploding in water, combined with molecular dynamic simulations, suggested that the initial expansion may be the result of a

Coulomb explosion In condensed-matter physics, Coulombic explosions are a mechanism for transforming energy in intense electromagnetic fields into atomic motion and are thus useful for controlled destruction of relatively robust molecules. The explosions are a pr ...

and not combustion of hydrogen gas as previously thought. Digital high-speed camera footage has strongly contributed to the understanding of

lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an average ...

when combined with

electric field An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field ...

measuring instrumentation and sensors which can map the propagation of lightning leaders through the detection of

radio waves Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (s ...

generated by this process.

Uses in industry

When moving from reactive maintenance to

predictive maintenance Predictive maintenance techniques are designed to help determine the condition of in-service equipment in order to estimate when maintenance should be performed. This approach promises cost savings over routine or time-based preventive maintena ...

, it is crucial that breakdowns are really understood. One of the basic analysis techniques is to use high-speed cameras in order to characterize events which happen too fast to see, e.g. during production. Similar to use in science, with a pre- or post-triggering capability the camera can simply record continuously as the mechanic waits for the breakdown to happen, following which a trigger signal (internal or external) 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). Some software allows viewing the issues in real time, by displaying only a subset of recorded frames, minimizing file size and watch time issues by eliminating useless frames before or after the sequence of interest. High-speed video cameras are used to augment other industrial technologies such as x-ray radiography. When used with the proper phosphor screen which converts x-rays into visible light, high-speed cameras can be used to capture high-speed x-ray videos of events inside mechanical devices and biological specimens. The imaging speed is mainly limited by the phosphor screen decay rate and intensity gain which has a direct relationship on the camera's exposure. Pulsed x-ray sources limit frame rate and should be properly synchronized with camera frame captures.

Uses in warfare

In 1950 Morton Sultanoff, an engineer for the U.S. Army at Aberdeen Proving ground, invented a super high-speed camera that took frames at one-millionth of a second, and was fast enough to record the shock wave of a small explosion. High Speed digital cameras have been used to study how mines dropped from the air will deploy in near-shore regions, including development of various weapon systems. In 2005 high speed digital cameras with 4 megapixel resolution, recording at 1500 fps, were replacing the 35mm and 70mm high speed film cameras used on tracking mounts on test ranges that capture ballistic intercepts.

References