Publication

Measurement of the coherent transfer function

Theo Lasser
2010
Posters

Abstract

It is important to characterize and quantify the imaging performance of optical coherence tomography (OCT) and especially optical coherence microscopy (OCM) systems for validation and calibration of the setup. We suggest using a simple rubber surface, presented to the setup at different focal positions, to measure the system’s lateral resolution and depth of field. Rubber is a nearly perfect scatterer and produces a fully developed speckle pattern. The speckle size and shape are directly defined by the optical system and its illumination and detection apertures. Analysis of the speckle pattern reveals the system’s coherent transfer function (CTF) and hence the point spread function (PSF) in a straightforward computation.

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https://infoscience.epfl.ch/entities/publication/8e41fb57-0ecc-46a1-a4f5-5878171cc20b

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Theo Lasser
2010
Posters

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/8e41fb57-0ecc-46a1-a4f5-5878171cc20b

About this result

Related concepts (28)

Point spread function

The point spread function (PSF) describes the response of a focused optical imaging system to a point source or point object. A more general term for the PSF is the system's impulse response; the PSF is the impulse response or impulse response function (IRF) of a focused optical imaging system. The PSF in many contexts can be thought of as the extended blob in an image that represents a single point object, that is considered as a spatial impulse. In functional terms, it is the spatial domain version (i.e.

Optical coherence tomography

Optical coherence tomography (OCT) is an imaging technique that uses low-coherence light to capture micrometer-resolution, two- and three-dimensional images from within optical scattering media (e.g., biological tissue). It is used for medical imaging and industrial nondestructive testing (NDT). Optical coherence tomography is based on low-coherence interferometry, typically employing near-infrared light. The use of relatively long wavelength light allows it to penetrate into the scattering medium.

Speckle (interference)

Speckle, speckle pattern, or speckle noise is a granular degrading the as a consequence of interference among wavefronts in coherent imaging systems, such as radar, synthetic aperture radar (SAR), medical ultrasound and optical coherence tomography. Speckle is not external noise; rather, it is an inherent fluctuation in diffuse reflections, because the scatterers are not identical for each cell, and the coherent illumination wave is highly sensitive to small variations in phase changes.

Related publications (10)

Measurement of the coherent transfer function

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