Selective edge enhancement in three-dimensional vortex imaging with incoherent light

Abstract

We demonstrate a new imaging method enabling a selective edge contrast enhancement of three-dimensional amplitude objects with spatially incoherent light. The imaging process is achieved in a spiral modification of Fresnel incoherent correlation holography and uses a vortex impulse response function. The correlation recordings of the object are acquired in a one-way interferometer with the wavefront division carried out by a spatial light modulator. Two different methods based on applying a helical reference wave in the hologram recording and a digital spiral phase modulation in image reconstruction are proposed for edge enhancement of amplitude objects. Results of both isotropic and anisotropic spiral imaging are demonstrated in experiments using an LED as an incoherent source of light.

Three-Dimensional Imaging by Self-Reference Single-Channel Digital Incoherent Holography

“…Since its introduction in 2007 [31], FINCH has earned the attention of several research groups around the world [8], [9], [12], [32]–[48]. This may be attributed to many contributing factors, including the simple working principle of FINCH, its common-path single channel design and, most importantly, its ability to record the complete 3D information of spatially incoherent objects.…”

“…Moreover, using holograms, it is possible to image objects covered by scattering medium [8], [9], or by absorbing obstacles [10], [11]. Additionally, digital holography can be used for certain tasks of image processing, such as edge enhancement [12], [13]. Finally, some holographic imagers have been proved quite efficient for sectioning a general 3D scene [14], [15].…”

Incoherent digital holography with phase-only spatial light modulators

“…Other tasks, besides holographic imaging, have been successfully demonstrated including an anisotropic edge contrast enhancement of 3-D objects, achieved by displaying special phase patterns on the SLM in order to create a point-spread function with a vortex structure. 41 An accurate axial localization of the point-like objects has been accomplished by the same group using digital processing performed on a FINCH-like hologram. 42 It is out of the scope of this article to present every variation and application of FINCH or its closed systems.…”

Violation of the Lagrange invariant in an optical imaging system

“…The FINCH system was initially proposed to overcome the "incoherent property" of partially coherent light [3,4] and was studied extensively [5][6][7][8][9][10]. We find, with intrinsic special characteristics, that this system has the potential to break the Lagrange invariant.…”

“…In addition, insufficient overlap of two interference waves, observed commonly in FINCH, is eliminated in this simplified system. A more efficient method to solve this problem was recently reported [13].…”