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Photo finish

Photo finish

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A photo finish occurs in a sport
A Sport is all forms of physical activity which, through casual or organised participation, aim to use, maintain or improve physical fitness and provide entertainment to participants. Sport may be competitive, where a winner or winners can be identified by objective means, and may require a degree...

ing race
A sport race is a competition of speed, against an objective criterion, usually a clock or to a specific point. The competitors in a race try to complete a given task in the shortest amount of time...

, when two (or more) competitors cross the finishing line at near the same time. As the naked eye
Naked eye
The naked eye is a figure of speech referring to human visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"...

 may not be able to discriminate between which of the competitors crossed the line first, a strip photo, a series of rapidly triggered photograph
A photograph is an image created by light falling on a light-sensitive surface, usually photographic film or an electronic imager such as a CCD or a CMOS chip. Most photographs are created using a camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of...

s, or a video taken at the finish line may be used for a more accurate check. Nowadays, the photographs may be digital. A digital photo finish camera uses a 1-D array sensor to take sequential images of the finish line. Since only a single line of the CCD is read out at a time, the frame rates can be very high (up to 10,000 frames per second). Unlike a film based photo finish, there is no delay from developing the film, and the photo finish is available immediately. They may be triggered by a laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 or photovoltaic means.

Historically, a hand cranked strip photograph was taken at the finishing line. Today, finish-line photos are still used in nearly every modern racing sport. Although some sports use electronic equipment to track the racers during a race, a photo is considered the most important evidence in selecting the winner. However, they may be examined only when a race is close or when a record
World record
A world record is usually the best global performance ever recorded and verified in a specific skill or sport. The book Guinness World Records collates and publishes notable records of all types, from first and best to worst human achievements, to extremes in the natural world and beyond...

 has been broken, however are often used to give official times for events. An alternative is the use of manual touch pads to register a time by the athletes themselves, such as in competitive swimming.


In athletics, races have to be timed accurately to hundredths (or even thousandths
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....

) of a second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

. A battery of electronic devices are installed in high-profile events (such as the Olympic Games
Olympic Games
The Olympic Games is a major international event featuring summer and winter sports, in which thousands of athletes participate in a variety of competitions. The Olympic Games have come to be regarded as the world’s foremost sports competition where more than 200 nations participate...

) to ensure that accurate timings are given swiftly both to the spectators and to the officials.

At the finish line, photocells and digital camera
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...

s are used to establish the placings. Sometimes, in a race as fast as the 100 m sprint, all eight athletes can be separated by less than half a second. It is not uncommon for two athletes to have exactly the same time recorded without there being a deadheat.

The 2008 Summer Olympics
2008 Summer Olympics
The 2008 Summer Olympics, officially known as the Games of the XXIX Olympiad, was a major international multi-sport event that took place in Beijing, China, from August 8 to August 24, 2008. A total of 11,028 athletes from 204 National Olympic Committees competed in 28 sports and 302 events...

 saw the introduction of some of the fastest timekeeping equipment yet, with cameras that take photographs 3000 times a second (compared to 1996
1996 Summer Olympics
The 1996 Summer Olympics of Atlanta, officially known as the Games of the XXVI Olympiad and unofficially known as the Centennial Olympics, was an international multi-sport event which was celebrated in 1996 in Atlanta, Georgia, United States....

, which were 1,000 times per second).

Horse racing

In horse racing
Horse racing
Horse racing is an equestrian sport that has a long history. Archaeological records indicate that horse racing occurred in ancient Babylon, Syria, and Egypt. Both chariot and mounted horse racing were events in the ancient Greek Olympics by 648 BC...

, a factor known as a dead heat
Tie (draw)
To tie or draw is to finish a competition with identical or inconclusive results. The word "tie" is usually used in North America for sports such as American football. "Draw" is usually used in the United Kingdom, Ireland and the Commonwealth of Nations and it is usually used for sports such as...

 can occur, when two — or possibly more — horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

s cross the finish line at exactly the same time. Photo finishes determine accurately where the horses were at the time of finish. Stewards at the racetrack usually put up PHOTO status on the races during these photo finishes; the status of objection
Objection may refer to:* Objection , a motion during a trial to disallow a witness's testimony or other evidence* Objection , used in informal logic and argument mapping** Inference objection, a special case of the above...

 or inquiry
An inquiry is any process that has the aim of augmenting knowledge, resolving doubt, or solving a problem. A theory of inquiry is an account of the various types of inquiry and a treatment of the ways that each type of inquiry achieves its aim.-Deduction:...

 can also trigger if other horses or jockeys somehow interfered in the horse rankings and can factor in Dead Heats. The most notable dead heat was in the 1989 Hambletonian Stakes, with both Park Avenue Joe and Probe finishing in a dead heat. A photo finish decided the winner of the 2005 running of the Japan Cup
Japan Cup
The is the most prestigious horse race run in Japan. It is contested at the end of November at Tokyo Racecourse in Fuchu, Tokyo at a distance of 2400 meters over the grass. With a purse of ¥476 million , the Japan Cup is one of the richest races in the world.The Japan Cup is an invitational event...

, which was given to Alkaseed, narrowly defeating Heart's Cry. And in 2011 with new digital technology recording vision at 10,000 frames per second, Duneden was declared a winner over REd Cadeaux in the $6 million Melbourne Cup.

Types of photographs

There are two methods for creating a photo finish. The most common method uses a special slit camera, which produces a panoramic film strip
A panorama is any wide-angle view or representation of a physical space, whether in painting, drawing, photography, film/video, or a three-dimensional model....

. This camera uses a single vertical slit instead of 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...

, and the film is advanced continuously at a similar speed to the racers' images. This creates a 'virtual view' of the positions of each racer as they crossed the finish line, from the side without motion blur
Motion blur
Motion blur is the apparent streaking of rapidly moving objects in a still image or a sequence of images such as a movie or animation. It results when the image being recorded changes during the recording of a single frame, either due to rapid movement or long exposure.- Photography :When a camera...

. Racers may appear compressed in this view based on the difference in the speed that the film is turning relative to their movement speed. Still objects at the finish line are imaged as streaks. Slit-scan photography
Slit-scan photography
The slit-scan photography technique is a photographic and cinematographic process where a moveable slide, into which a slit has been cut, is inserted between the camera and the subject to be photographed.-Use in cinematography:...

 is similar, however the camera moves rather than the subject.

The second method for creating this strip involves combining individual photographs. A high speed camera or a movie camera
Movie camera
The movie camera is a type of photographic camera which takes a rapid sequence of photographs on strips of film which was very popular for private use in the last century until its successor, the video camera, replaced it...

 is used to take a continuous series of partial frame photos at a fast rate, while leaving no blank space between the cells.

With all methods, time markings along the bottom of the photo can be used to find the exact crossing time of any racer, or simply used to compare their finishing positions along the strip.

Cultural references

  • In the TV series Futurama
    Futurama is an American animated science fiction sitcom created by Matt Groening and developed by Groening and David X. Cohen for the Fox Broadcasting Company. The series follows the adventures of a late 20th-century New York City pizza delivery boy, Philip J...

    , the episode "The Luck of the Fryrish
    The Luck of the Fryrish
    "The Luck of the Fryrish" is the fourth episode in season three of Futurama. It originally aired in North America on March 11, 2001.-Plot:...

    " starts with several horse races, one of which the finish is measured by an electron microscope
    Electron microscope
    An electron microscope is a type of microscope that uses a beam of electrons to illuminate the specimen and produce a magnified image. Electron microscopes have a greater resolving power than a light-powered optical microscope, because electrons have wavelengths about 100,000 times shorter than...

    , and the difference between the two lead horses is apparently measured in quark
    A quark is an elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as color confinement, quarks are never directly...

    s. Professor Farnsworth angrily tears up his ticket after protesting "You changed the outcome by measuring it!," a reference to the observer effect
    Observer effect (physics)
    In physics, the term observer effect refers to changes that the act of observation will make on the phenomenon being observed. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner...


External links and references