Abstract

In digital holography and holographic interferometry, refocusing to the correct image plane can be challenging and may be obtained by various metrics. This paper proposes a digital refocus approach utilizing the linear relationship between in-plane speckle motion and defocus as a response to an induced phase gradient. The theory based on cross-correlations between pairs of intensity images reconstructed at different distances from the recording plane is discussed. Two simple metrics, based on the cross-correlation properties of the reconstructed speckle images, are proposed and evaluated utilizing both simulations and experiments. Experiments exhibit similar trends in which the estimate of the correct reconstruction distance differs by a small amount between the two metrics. The difference is found less than 1% in the estimate of the true reconstruction distance. The results show that either metric is able to yield a sufficient reconstruction distance for the reconstruction of the image plane.

© 2024 Optica Publishing Group

Quality assessment of refocus criteria for particle imaging in digital off-axis holography

Soumaya Kara Mohammed, Larbi Bouamama, Derradji Bahloul, and Pascal Picart
Appl. Opt. 56(13) F158-F166 (2017)

Decorrelation and anti-correlation from defocus in digital holographic interferometry

Erwan Meteyer, Charles Pezerat, and Pascal Picart
J. Opt. Soc. Am. A 40(4) B33-B46 (2023)

Modeling of speckle decorrelation in digital Fresnel holographic interferometry

Erwan Meteyer, Felix Foucart, Charles Pezerat, and Pascal Picart
Opt. Express 29(22) 36180-36200 (2021)

Extension of refocus depth range in digital holographic microscopy

Ming Tang, Zhi Yuan Tang, Xin Qiao, Kai Qi Lang, Yi Sun, and Xiao Ping Wang
Appl. Opt. 59(28) 8540-8552 (2020)

Improving the quality of phase maps in phase object digital holographic interferometry by finding the right reconstruction distance

Eva-Lena Johansson, Lars Benckert, and Mikael Sjödahl
Appl. Opt. 47(1) 1-8 (2008)