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Optical Engineering

Laser-based projectile speed measurement system
Author(s): R. C. Kalonia; Gautam Mitra; Amond Kumar; R. K. Varma; Manpreet Singh; V. S. Sethi
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Paper Abstract

The design and construction of a system to accurately determine the speed of a projectile (bullet) by measuring the time of flight between two parallel laser screens is described. Each screen is formed by a laser source and a set of prisms. At the detection end of each of the screens, a collector lens focuses the incident laser light beam onto a photodetector. The collector lens and detector are kept in a recess so that no stray or ambient light falls on the photodetector. Whenever a projectile crosses either of the screens, the corresponding photodetector senses the event, due to partial or full obscuration of the incident energy. An electronic circuit is used to accurately record the time when the projectile crosses each screen, and the time interval gives the time of flight. The distance between the screens being known, the velocity is displayed on a computer screen. Because a single collimated beam of light generates the entire optical curtain, the reduction in incident energy at the photodetector plane is independent of the entry point of the projectile into the screen. Due to the baffling of the photodetector from ambient light, the optical screens can be used at indoor or outdoor ranges equally effectively.

Paper Details

Date Published: 1 April 2007
PDF: 6 pages
Opt. Eng. 46(4) 044303 doi: 10.1117/1.2720825
Published in: Optical Engineering Volume 46, Issue 4
Show Author Affiliations
R. C. Kalonia, Government of India (India)
Gautam Mitra, Government of India (India)
Amond Kumar, Government of India (India)
R. K. Varma, Terminal Ballistics Research Lab. (India)
Manpreet Singh, Terminal Ballistics Research Lab. (India)
V. S. Sethi, Government of India (India)


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