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:
“Ideally, advertising aims at the goal of a programmed harmony among all human impulses and aspirations and endeavors. Using handicraft methods, it stretches out toward the ultimate electronic goal of a collective consciousness.”
—Marshall McLuhan (1911–1980)
“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 may be tempting to focus on the fact that, even among those who support equality, men’s involvement as fathers remains a far distance from what most women want and most children need. Yet it is also important to acknowledge how far and how fast many men have moved towards a pattern that not long ago virtually all men considered anathema.”
—Katherine Gerson (20th century)