Sinusoidal Single-Pixel Imaging Based on Fourier Positive–Negative Intensity Correlation

Single-pixel imaging techniques extend the time dimension to reconstruct a target scene in the spatial domain based on single-pixel detectors. Structured light illumination modulates the target scene by utilizing multi-pattern projection, and the reflected or transmitted light is measured by a single-pixel detector as total intensity. To reduce the imaging time and capture high-quality images with a single-pixel imaging technique, orthogonal patterns have been used instead of random patterns in recent years. The most representative among them are Hadamard patterns and Fourier sinusoidal patterns. Here, we present an alternative Fourier single-pixel imaging technique that can reconstruct high-quality images with an intensity correlation algorithm using acquired Fourier positive–negative images. We use the Fourier matrix to generate sinusoidal and phase-shifting sinusoid-modulated structural illumination patterns, which correspond to Fourier negative imaging and positive imaging, respectively. The proposed technique can obtain two centrosymmetric images in the intermediate imaging course. A high-quality image is reconstructed by applying intensity correlation to the negative and positive images for phase compensation. We performed simulations and experiments, which obtained high-quality images, demonstrating the feasibility of the methods. The proposed technique has the potential to image under sub-sampling conditions.

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Gradient-Descent-like Ghost Imaging

Sensors ◽

10.3390/s21227559 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7559

Author(s):

Wen-Kai Yu ◽

Chen-Xi Zhu ◽

Ya-Xin Li ◽

Shuo-Fei Wang ◽

Chong Cao

Keyword(s):

Artificial Intelligence ◽

Image Quality ◽

Gradient Descent ◽

Imaging Technique ◽

Optimal Solution ◽

Imaging Method ◽

Ghost Imaging ◽

High Quality ◽

Intensity Correlation ◽

Optical Imaging Technique

Ghost imaging is an indirect optical imaging technique, which retrieves object information by calculating the intensity correlation between reference and bucket signals. However, in existing correlation functions, a high number of measurements is required to acquire a satisfied performance, and the increase in measurement number only leads to limited improvement in image quality. Here, inspired by the gradient descent idea that is widely used in artificial intelligence, we propose a gradient-descent-like ghost imaging method to recursively move towards the optimal solution of the preset objective function, which can efficiently reconstruct high-quality images. The feasibility of this technique has been demonstrated in both numerical simulation and optical experiments, where the image quality is greatly improved within finite steps. Since the correlation function in the iterative formula is replaceable, this technique offers more possibilities for image reconstruction of ghost imaging.

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Computational Ghost Imaging with Single Pixel Detector and Scattering Light Illumination

The Review of Laser Engineering ◽

10.2184/lsj.41.12_996 ◽

2013 ◽

Vol 41 (12) ◽

pp. 996

Author(s):

Kouichi NITTA

Keyword(s):

Light Illumination ◽

Pixel Detector ◽

Ghost Imaging ◽

Scattering Light ◽

Single Pixel

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Efficient Fourier Single-Pixel Imaging with Gaussian Random Sampling

Photonics ◽

10.3390/photonics8080319 ◽

2021 ◽

Vol 8 (8) ◽

pp. 319

Author(s):

Ziheng Qiu ◽

Xinyi Guo ◽

Tian’ao Lu ◽

Pan Qi ◽

Zibang Zhang ◽

...

Keyword(s):

Fourier Coefficients ◽

Fourier Spectrum ◽

Spatial Information ◽

Imaging Techniques ◽

Gaussian Function ◽

Sampling Strategy ◽

Acquisition Time ◽

Pixel Detector ◽

Structured Illumination ◽

Single Pixel

Fourier single-pixel imaging (FSI) is a branch of single-pixel imaging techniques. It allows any image to be reconstructed by acquiring its Fourier spectrum by using a single-pixel detector. FSI uses Fourier basis patterns for structured illumination or structured detection to acquire the Fourier spectrum of image. However, the spatial resolution of the reconstructed image mainly depends on the number of Fourier coefficients sampled. The reconstruction of a high-resolution image typically requires a number of Fourier coefficients to be sampled. Consequently, a large number of single-pixel measurements lead to a long data acquisition time, resulting in imaging of a dynamic scene challenging. Here we propose a new sampling strategy for FSI. It allows FSI to reconstruct a clear and sharp image with a reduced number of measurements. The key to the proposed sampling strategy is to perform a density-varying sampling in the Fourier space and, more importantly, the density with respect to the importance of Fourier coefficients is subject to a one-dimensional Gaussian function. The final image is reconstructed from the undersampled Fourier spectrum through compressive sensing. We experimentally demonstrate the proposed method is able to reconstruct a sharp and clear image of 256 × 256 pixels with a sampling ratio of 10%. The proposed method enables fast single-pixel imaging and provides a new approach for efficient spatial information acquisition.

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Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽

10.3390/s21134554 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4554

Author(s):

Ralph-Alexandru Erdelyi ◽

Virgil-Florin Duma ◽

Cosmin Sinescu ◽

George Mihai Dobre ◽

Adrian Bradu ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Radiation Dose ◽

Imaging Techniques ◽

Image Resolution ◽

Optical Coherence ◽

X Rays ◽

High Quality ◽

X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

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Design and Synthesis of Luminescent Lanthanide-Based Bimodal Nanoprobes for Dual Magnetic Resonance (MR) and Optical Imaging

Nanomaterials ◽

10.3390/nano11020354 ◽

2021 ◽

Vol 11 (2) ◽

pp. 354

Author(s):

Walid Mnasri ◽

Mahsa Parvizian ◽

Souad Ammar-Merah

Keyword(s):

Magnetic Resonance ◽

Optical Imaging ◽

Imaging Technique ◽

Imaging Techniques ◽

Design And Synthesis ◽

Bimodal Imaging ◽

Successive Image ◽

Complete Set ◽

Magnetic Resonance Imaging Mri ◽

Physical And Chemical

Current biomedical imaging techniques are crucial for the diagnosis of various diseases. Each imaging technique uses specific probes that, although each one has its own merits, do not encompass all the functionalities required for comprehensive imaging (sensitivity, non-invasiveness, etc.). Bimodal imaging methods are therefore rapidly becoming an important topic in advanced healthcare. This bimodality can be achieved by successive image acquisitions involving different and independent probes, one for each mode, with the risk of artifacts. It can be also achieved simultaneously by using a single probe combining a complete set of physical and chemical characteristics, in order to record complementary views of the same biological object at the same time. In this scenario, and focusing on bimodal magnetic resonance imaging (MRI) and optical imaging (OI), probes can be engineered by the attachment, more or less covalently, of a contrast agent (CA) to an organic or inorganic dye, or by designing single objects containing both the optical emitter and MRI-active dipole. If in the first type of system, there is frequent concern that at some point the dye may dissociate from the magnetic dipole, it may not in the second type. This review aims to present a summary of current activity relating to this kind of dual probes, with a special emphasis on lanthanide-based luminescent nano-objects.

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Colour imaging with single-pixel detectors

Nature Photonics ◽

10.1038/nphoton.2013.325 ◽

2013 ◽

Vol 7 (12) ◽

pp. 943-943 ◽

Cited By ~ 2

Author(s):

Noriaki Horiuchi

Keyword(s):

Pixel Detectors ◽

Single Pixel

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Subpixel resolution in CdTe Timepix3 pixel detectors

Journal of Synchrotron Radiation ◽

10.1107/s1600577518013838 ◽

2018 ◽

Vol 25 (6) ◽

pp. 1650-1657 ◽

Cited By ~ 5

Author(s):

Mohamad Khalil ◽

Erik Schou Dreier ◽

Jan Kehres ◽

Jan Jakubek ◽

Ulrik Lund Olsen

Keyword(s):

Single Photon ◽

Weighted Average ◽

European Synchrotron Radiation Facility ◽

Time Of Arrival ◽

Pixel Detector ◽

Step Size ◽

X Ray ◽

Pixel Detectors ◽

Individual Photon ◽

Subpixel Resolution

Timepix3 (256 × 256 pixels with a pitch of 55 µm) is a hybrid-pixel-detector readout chip that implements a data-driven architecture and is capable of simultaneous time-of-arrival (ToA) and energy (ToT: time-over-threshold) measurements. The ToA information allows the unambiguous identification of pixel clusters belonging to the same X-ray interaction, which allows for full one-by-one detection of photons. The weighted mean of the pixel clusters can be used to measure the subpixel position of an X-ray interaction. An experiment was performed at the European Synchrotron Radiation Facility in Grenoble, France, using a 5 µm × 5 µm pencil beam to scan a CdTe-ADVAPIX-Timepix3 pixel (55 µm × 55 µm) at 8 × 8 matrix positions with a step size of 5 µm. The head-on scan was carried out at four monochromatic energies: 24, 35, 70 and 120 keV. The subpixel position of every single photon in the beam was constructed using the weighted average of the charge spread of single interactions. Then the subpixel position of the total beam was found by calculating the mean position of all photons. This was carried out for all points in the 8 × 8 matrix of beam positions within a single pixel. The optimum conditions for the subpixel measurements are presented with regards to the cluster sizes and beam subpixel position, and the improvement of this technique is evaluated (using the charge sharing of each individual photon to achieve subpixel resolution) versus alternative techniques which compare the intensity ratio between pixels. The best result is achieved at 120 keV, where a beam step of 4.4 µm ± 0.86 µm was measured.

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Political Imaging Techniques Carried Out by Baitul Muslimin Indonesia (BASUMI) in Increasing Public Political Support for PDI Perjuangan Medan City

Budapest International Research and Critics Institute (BIRCI-Journal) Humanities and Social Sciences ◽

10.33258/birci.v2i3.403 ◽

2019 ◽

Vol 2 (3) ◽

pp. 164-174

Author(s):

Sutarto Sutarto ◽

Suwardi Lubis ◽

Katimin Katimin

Keyword(s):

Social Services ◽

Social Service ◽

Imaging Technique ◽

Imaging Techniques ◽

Political Support ◽

The Political ◽

Good Image ◽

The People ◽

Service Activities ◽

Community Trust

BAMUSI is a new breakthrough for PDI Perjuangan to restore the negative stigmatization directed at PDI Perjuangan so far. BAMUSI is here to build a good image of PDI Perjuangan which has only been buzzing and narrating as a national and religious based party. BAMUSI will make a movement towards Islamic understanding that is rahmatan lil 'alamin bagi for the nation. Political imaging techniques carried out by BAMUSI in increasing the political support of the people of PDI Perjuangan Medan, namely to carry out social services: Social service activities carried out by BAMUSI Medan City is an accurate strategy in approaching and touching the hearts of Medan people in fostering community trust. Delivering Assistance: The political imaging technique carried out by BAMUSI Medan City in increasing community political support for PDI Perjuangan is by channeling aid.

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