Signal-to-noise properties of correlation plenoptic imaging with chaotic light

Abstract

Correlation Plenoptic Imaging (CPI) is a novel imaging technique, that exploits the correlations between the intensity fluctuations of light to perform the typical tasks of plenoptic imaging (namely, refocusing out-of-focus parts of the scene, extending the depth of field, and performing 3D reconstruction), without entailing a loss of spatial resolution. Here, we consider two different CPI schemes based on chaotic light, both employing ghost imaging: the first one to image the object, the second one to image the focusing element. We characterize their noise properties in terms of the signalto-noise ratio (SNR) and compare their performances. We find that the SNR can be significantly higher and easier to control in the second CPI scheme, involving standard imaging of the object; under adequate conditions, this scheme enables reducing by one order of magnitude the number of frames for achieving the same SNR.

Classical Ghost Imaging: A Comparative Study of Algorithmic Performances for Image Reconstruction in Prospect of Plenoptic Imaging

“…A different approach to the singular value decomposition might solve the stability issue of PGI, confirming what has been observed in the literature [21]. Theoretical analysis reported in several papers (e. g. [36], [37]) predicts that the SNR proportionally increases with the square root of the number of frames. To check whether this applies to our results, we fitted the SNR curves with a function of the type f (x) = Ax 0.5 + B (see the exemplary fit in Fig.…”

“…[31], where the authors use a source with a wide spectral range in combination with a spectrometer to acquire multiple images at once. Different setups to realize the scheme have been compared in [32], one of them is depicted in Fig. 2.…”

“…If z A = z B the target is in focus and Detector D A images the speckle field in the object plane. Any plane for which the focusing condition is not fulfilled can be refocused in post processing using the following, refocusing equation [10], [32]:…”

Towards Quantum 3D Imaging Devices

“…Interestingly, recent studies have shown that, in the case of chaotic light illumination, the plenoptic properties of the correlation function do not need to rely strictly on ghost imaging: correlations can be measured between any two planes where ordinary images (see Figure 1b) are formed [35]. This discovery has led to the intriguing result that the SNR of CPI improves when ghost imaging of the object is replaced by standard imaging [40]. In particular, excellent noise performances are expected in the case of images of birefringent objects placed between crossed polarizers.…”

“…The accuracy of the correlation function estimate (4) increases with the number of frames like N f [40]. However, increasing N f also linearly extends the total acquisition time T. Therefore, the combination of (1) fast and low-noise sensors, (2) methods to extract a good quality signal from smaller number of frames, and (3) tools for efficient data transfer and elaboration, is crucial in order to speed-up the acquisition process and make the CPI technology ready for real-world applications.…”