J. Eur. Opt. Society-Rapid Publ. 2026, 22, 15 Ó The Author( s), published by EDP Sciences, 2026 https:// doi. org / 10.1051 / jeos / 2026006 Available online at: https:// jeos. edpsciences. org
Recent Advances on Optics and Photonics 2026 Guest editors: Manuel Filipe P. C. M. Costa, Rogerio Nogueira and Alessandro Fantoni
RESEARCH ARTICLE
Journal of the European Optical Society-Rapid Publications Lensless hypercentric imaging using digital holography
Claas Falldorf 1,*
, Beñat Gutiérrez-Cañas Pazos 1, 2, and Ralf B. Bergmann 1, 2
1 BIAS – Bremer Institut für Angewandte Strahltechnik, Klagenfurter Str. 5, 28359 Bremen, Germany 2 Universität Bremen, Fachbereich 01: Physik / Elektrotechnik and MAPEX Center for Materials and Processes, 28359 Bremen, Germany
Received 5 December 2025 / Accepted 20 January 2026
Abstract. Hypercentric imaging is a powerful imaging modality that allows for the inspection of a specimen and its sides in the same recording. Typically, hypercentric imaging involves special lens objectives, which are bulky and limit the use of interferometric methods. To overcome this, we introduce lensless hypercentric imaging utilizing digital holography. We show, that the same hologram can be used to render various digital image perspectives, depending on the size and the position of a virtual aperture. We describe the perspective imaging model in detail and present experimental results, which proof the main concept and exemplarily show the dependence of the image perspective from the position of the aperture. To the best of our knowledge, this is the first time that lensless hypercentric imaging was realized. The results combine the benefits of lensless digital holography with the hypercentric imaging modality, thereby opening a path to a new class of inspection systems.
Keywords: Lensless imaging, Digital holography, Hypercentric imaging, Perspective imaging.
1 Introduction
Hypercentric imaging is a convenient imaging modality for optical inspection [ 1 ]. It allows for the investigation of an entire specimen from only one observation direction. However, the corresponding lens objectives are heavy and bulky. They also typically have a very short imaging distance and a large numerical aperture on the image side. This impedes the application of interferometric methods, because it is difficult to superpose the object wave with a reference wave in front of the camera sensor.
A potential solution of this problem could be to avoid the lens and to establish a lensless hypercentric imaging scheme. In this publication we show, that digital holography [ 2 ] is a suitable candidate to achieve this. In digital holography, no lens is required [ 3 – 5 ]. Instead, light scattered from the object is superposed with a coherent reference wave. The recorded interference pattern is referred to as the digital hologram. From the digital hologram, the image of the object can be numerically obtained by solving the Rayleigh – Sommerfeld diffraction integral. Since no lens is involved, the image plane can be freely selected in the digital imaging process, thus digital holography facilitates lensless volumetric imaging [ 6, 7 ], unusual imaging geometries like sideways lensless imaging( SLIM) [ 8 ] and enhanced depth of focus [ 9 ]. An additional advantage of this approach is that the hologram can be modified prior to the imaging
* Corresponding author: Falldorf @ bias. de process through numerical reconstruction. For example, the effect of lenses and apertures located in arbitrary planes can be added [ 10 ], and multiple holograms can be combined to form a synthetic aperture for enhanced image resolution [ 11 ] or speckle noise reduction [ 12, 13 ]. Likewise, the same digital hologram may be used for various imaging perspectives, such as multiple observation directions for example [ 14 ]. Because of the above mentioned benefits, digital holography has gained large attention in recent years in the fields of biomedical imaging [ 15 – 17 ] and industrial inspection [ 18 – 20 ].
In lens based imaging systems, the hypercentric perspective is obtained by a small aperture located between the back focal plane and the image plane [ 1 ]. The small diameter of the aperture generates ray-like wave fields, which results in an image with large depth of field. Within this imaging geometry, the positioning of the aperture creates the typical perspective distortion, with object parts further away being imaged larger than those nearby.
Here, we introduce the particularly intriguing case of lensless hypercentric imaging using digital holography. We achieve this by introducing a virtual aperture into the holographic reconstruction process, which has a similar effect like the small aperture in the lens based case. The details of the scheme will be outlined and explained in Section 2. Interestingly, hypercentricity is obtained by reducing the amount of information. This shows again, that a hologram contains a large amount of different perspectives [ 14 ], which can be addressed by proper filtering.
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