Electronic speckle pattern interferometry (ESPI), also known as TV Holography, is a technique which uses laser light, together with video detection, recording and processing to visualise static and dynamic displacements of components with optically rough surfaces. The visualisation is in the form of fringes on the image where each fringe normally represents a displacement of half a wavelength of the light used (i.e. quarter of a micrometre or so).
ESPI can be used for stress and strain measurement, vibration mode analysis and nondestructive testing.
ESPI is similar to holographic interferometry in many ways, but there are also significant differences between the two techniques.
Read more about Electronic Speckle Pattern Interferometry: How ESPI Works
Famous quotes containing the words electronic, speckle and/or pattern:
“Sometimes, because of its immediacy, television produces a kind of electronic parable. Berlin, for instance, on the day the Wall was opened. Rostropovich was playing his cello by the Wall that no longer cast a shadow, and a million East Berliners were thronging to the West to shop with an allowance given them by West German banks! At that moment the whole world saw how materialism had lost its awesome historic power and become a shopping list.”
—John Berger (b. 1926)
“Leaves chase warm buses, speckle statued air,
Pile up in corners, fetch out vague broomed men
Through mists at morning.”
—Philip Larkin (1922–1986)
“It is just possible that the tensions in a novel of murder are the simplest and yet most complete pattern of the tensions on which we live in this generation.”
—Raymond Chandler (1888–1959)