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Quantum Imaging
Published in Yanhua Shih, An Introduction to Quantum Optics, 2020
It is necessary to emphasize that the mathematics of the convolution between the aperture function and the point-to-point image-forming function has no difference in any optical imaging systems, including the traditional classic imaging, the ghost imaging of entangled states, and the ghost imaging of thermal field. The differences between different imaging systems come from different mechanisms that produce the point-to-point or point-to-“spot” image-forming function in that particular imaging system. In a classic imaging system, it is the first-order constructive-destructive interference that causes the point-to-point correspondence between the object and image planes, i.e., any radiation which is radiated (or reflected) from a point on the object plane will arrive at an unique point on the image plane. In the lensless ghost imaging system of thermal field, it is the two-photon interference that causes the nonlocal second-order correlation between the object plane and the image plane. Analogous to the ghost image of entangled photon pairs, this natural, non-factorizable, point-to-point image-forming correlation represents a nonlocal interference of a randomly created and randomly paired photons in thermal state: neither photon-one nor photon-two “knows” precisely where to go when they are created at each independent sub-source; however, if one is observed at a point on the object plane, the other one has twice the probability of arriving at a unique corresponding point on the image plane.2
Fourier-transform ghost imaging with polychromatic light
Published in Journal of Modern Optics, 2020
Zhijie Tan, Hong Yu, Shanchu Yang, Ruiguo Zhu, Ronghua Lu, Shensheng Han
Ghost imaging has prospered as a distinct technology which can be achieved with both entangled and classical light [1–6]. Various ghost imaging schemes have been proposed [7–11] and now widely applied to remote sensing, single-pixel camera, spectral camera, super-resolution imaging, x-ray imaging, etc. [12–17]. In 2004, a scheme of lensless Fourier-transform ghost imaging (FGI) and its potential application in x-ray diffraction was proposed theoretically [18]. Then the experimental demonstration of FGI was performed with visible light [19]. However, because it is difficult to obtain correlated x-ray beams, the x-ray FGI experiment has not been successfully carried out until 2016 [20]. In the meantime, x-ray ghost imaging in real space was also realized with synchrotron radiation [21]. Soon, real-space ghost imaging was implemented utilizing laboratory x-ray sources [22,23]. Recently, ghost imaging experiments using x-ray free electron laser [24] and three-dimensional x-ray imaging have also been reported [25].
Towards time-efficient ghost imaging
Published in Journal of Modern Optics, 2020
Valeria Rodríguez-Fajardo, Jonathan Pinnell, Andrew Forbes
Ghost imaging offers an alternative and intriguing image acquisition technique, where the reconstruction of an image is enabled by harnessing the optical correlations between two beams. The image information cannot be retrieved from either beam, but it is revealed from the correlations between them [1]. It was initially demonstrated in the quantum regime for correlations arising from a spontaneous parametric down-conversion (SPDC) process [2,3], and later on expanded to systems with classical correlations [4–6]. In the last two decades, it has been a very active field, owing to its potential in novel imaging modalities, where it provides performance attributes that traditional approaches cannot compete against [7–9]. For instance, it could be especially advantageous for biological imaging, which would benefit from a reduced risk of photo-damage [10] by using low levels of light [11], and non-degenerate photon correlations [12–14]. Many implementations of ghost imaging have been proposed, including computational ghost imaging [15], single-pixel imaging [16,17] and Fourier single-pixel imaging [18,19], and using raster [3] or spatially resolved pattern [20] scanning schemes. Researchers have been interested in probing the technique's spatial resolution [21,22], and have proposed approaches where super-resolution is achievable [23], as well as developed applications from imaging through scattering media [24] and three-dimensional imaging [25] to remote sensing [26].
Noise reduction from two frame speckle-shifting ghost images with morphology algorithms
Published in Journal of Modern Optics, 2019
Sheng Yuan, Xuemei Liu, Xin Zhou, Pibin Bing
Ghost imaging (GI), as an innovative imaging technique, has received increasing attention in recent years. It was initially considered to be caused by quantum entanglement effect (1,2), but later studies have demonstrated that GI can also be realized by a classical light source (3,4). Classical GI employs a series of random phase masks to illuminate an unknown object. For each illumination, the transmitted and reflected light is collected by a single-pixel (or bucket) detector. The random intensity patterns on the object plane are generated by the diffraction of the phase masks and measured by a charge coupled device (CCD) in the reference beam. The desired image is computationally retrieved by correlating the series of single-pixel measurements with the intensity patterns. Computational GI (CGI) replaces the reference beam in the classical GI system with a virtual computational part (5,6). The random phase masks are generated by a computer-controlled spatial light modulator (SLM), and the intensity patterns on the object plane are computed according to the Fresnel transformation. CGI technique simplifies the system of classical GI and avoids the measurement error of distance from SLM to object in an actual optical system.