Correlation Plenoptic Imaging

Abstract

Plenoptic imaging is a promising optical modality that simultaneously captures the location and the propagation direction of light in order to enable three-dimensional imaging in a single shot. However, in standard plenoptic imaging systems, the maximum spatial and angular resolutions are fundamentally linked; thereby, the maximum achievable depth of field is inversely proportional to the spatial resolution. We propose to take advantage of the second-order correlation properties of light to overcome this fundamental limitation. In this Letter, we demonstrate that the correlation in both momentum and position of chaotic light leads to the enhanced refocusing power of correlation plenoptic imaging with respect to standard plenoptic imaging.

Correlation Plenoptic Imaging With Entangled Photons

“…In fact, the maximum achievable depth of focus of the proposed CPI scheme is the result of the increased depth of focus of coherent ghost imaging, with respect to incoherent ghost imaging. This can be better understood by considering the origin of both the out-of-focus and the refocused image: The first one is obtained by integrating the out-of-focus coherent image (Equations (10), (15), or (18)) over the whole sensor S b , exactly as it would do a bucket detector of standard ghost imaging; the second one is obtained by integrating, over the same sensor S b , the rescaled version of such out-of-focus coherent image, as indicated in Equation (20). Now, as shown in Figure 5, the out-of-focus coherent image is a projection of the focused image (hence, it is either enlarged or reduced with respect to it) as seen by the viewpoint defined by the specific value of ρ b .…”

“…Such rescaling is formally identical to the one employed both in standard plenoptic imaging [5] and in correlation plenoptic imaging with chaotic light [18,19]. Similar to standard plenoptic imaging, the signal to noise ratio of the refocused image can be improved by integrating the result of Equation (19) over the whole sensor array ρ b , thus employing light coming from the whole light source:…”

Exploring plenoptic properties of correlation imaging with chaotic light

“…Recently, a new plenoptic scheme, based on correlated light sources and second-order correlation measurements, has been proposed for overcoming this fundamental limit; the scheme was named Correlation Plenoptic Imaging (CPI) and was demonstrated both for chaotic light [32,33] and entangled photon pairs [34]. Exploiting spatio-temporal correlation properties of light, spatial and directional detection can be performed on two distinct sensors: one sensor captures the high-resolution "ghost" image of the object [35][36][37][38][39], while the other one detects an image of the focusing element, which enables to reconstruct the path of light in the setup, as in a standard plenoptic device.…”

“…Exploiting spatio-temporal correlation properties of light, spatial and directional detection can be performed on two distinct sensors: one sensor captures the high-resolution "ghost" image of the object [35][36][37][38][39], while the other one detects an image of the focusing element, which enables to reconstruct the path of light in the setup, as in a standard plenoptic device. From a practical point of view, the relation between the spatial (N x ) and the angular (N u ) pixels per line, at fixed N tot , becomes linear rather than hyperbolic: N x + N u = N tot [32]. Such a novel approach to plenoptic imaging aims at keeping the advantages of the conventional approach without renouncing to diffraction-limited resolution, thus fostering promising practical applications.…”

Plenoptic x-ray microscopy

“…A plenoptic camera captures both the intensity and direction of light-rays and uses arrays of micro-lenses to collect multiple views of the same scene in a single image [10][11][12][13][14] . Optical microscopy 15 and correlation imaging 16 with plenoptic cameras is also possible. Extension of plenoptic imaging to x-ray range is cumbersome and has not yet been presented.…”