Lensless object scanning holography for diffuse objects

Javier García; Carlos Ferreira; Vicente Micó

doi:10.1117/12.2020564

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13 May 2013 Lensless object scanning holography for diffuse objects

Javier García, Carlos Ferreira, Vicente Micó

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Proceedings Volume 8788, Optical Measurement Systems for Industrial Inspection VIII; 87880D (2013) https://doi.org/10.1117/12.2020564
Event: SPIE Optical Metrology 2013, 2013, Munich, Germany

Abstract

Recently proposed, Lensless Object Scanning Holography (LOSH) is a fully lensless method, capable of improving image quality in digital Fourier holography applied to reflective objects, and involving a very simplified experimental setup. LOSH is based on the recording and digital post-processing of a set of digital lensless Fourier transform holograms which finally results in a synthetic image with improved resolution, field of view (FOV), signal-to-noise ratio (SNR), and depth of field (DOF). In this paper, LOSH is expanded to the case of diffuse-based objects. Now, the speckle can affect the resolution and it will not be a function of only the size of the aperture. The fact of increasing the aperture can produce the decrease of the size of the speckle. Moreover, there is an overlapping of speckles of the successive images. Different kinds of digital processing can be applied to obtain the final synthetic image. Among them, partial coherent processing, arising from the incoherent sum of several sets of images coherently added, provides the best improvement in the resolution and also in the SNR due to partial averaging of the speckles. Experimental results for a diffuse object are presented for different kinds of digital processing.

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Javier García, Carlos Ferreira, and Vicente Micó "Lensless object scanning holography for diffuse objects", Proc. SPIE 8788, Optical Measurement Systems for Industrial Inspection VIII, 87880D (13 May 2013); https://doi.org/10.1117/12.2020564

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