Efficient single-pixel imaging encrypted transmission based on 3D Arnold transformation

Single-pixel imaging(SPI)can transform 2D or 3D image data into 1D light signals,which offers promising prospects for image compression and transmission.However,during data communication these light signals in public channels will easily draw the attention of eavesdroppers.Here,we introduce an efficient encryption method for SPI data transmission that uses the 3D Arnold transformation to directly disrupt 1D single-pixel light signals and utilizes the elliptic curve encryption algorithm for key transmission.This encryption scheme immediately employs Hadamard patterns to illuminate the scene and then utilizes the 3D Arnold transformation to permutate the 1D light signal of single-pixel detection.Then the transformation parameters serve as the secret key,while the security of key exchange is guaranteed by an elliptic curve-based key exchange mechanism.Compared with existing encryption schemes,both computer simulations and optical experiments have been conducted to demonstrate that the proposed technique not only enhances the security of encryption but also eliminates the need for complicated pattern scrambling rules.Additionally,this approach solves the problem of secure key transmission,thus ensuring the security of information and the quality of the decrypted images.

Complex-amplitude Fourier single-pixel imaging via coherent structured illumination

We propose a method of complex-amplitude Fourier single-pixel imaging(CFSI)with coherent structured illumination to acquire both the amplitude and phase of an object.In the proposed method,an object is illustrated by a series of coherent structured light fields,which are generated by a phase-only spatial light modulator,the complex Fourier spectrum of the object can be acquired sequentially by a single-pixel photodetector.Then the desired complex-amplitude image can be retrieved directly by applying an inverse Fourier transform.We experimentally implemented this CFSI with several different types of objects.The experimental results show that the proposed method provides a promising complex-amplitude imaging approach with high quality and a stable configuration.Thus,it might find broad applications in optical metrology and biomedical science.

Resolution-enhanced single-pixel imaging using the Hadamard transform matrix

We propose a single-pixel imaging(SPI)method to achieve a higher-resolution image via the Hadamard transform matrix.Unlike traditional SPI schemes,this new method recovers images by correlating single-pixel signals with synchronized transformed patterns of Hadamard bases that are actually projected onto the digital micromirror device.Each transform pattern is obtained through the inverse Fourier transform of the pattern acquired by Gaussian filtering of each Hadamard basis in the frequency domain.The proposed scheme is based on a typical SPI experimental setup and does not add any hardware complexity,enabling the transformation of Hadamard matrices and image reconstruction through data processing alone.Therefore,this approach could be considered as an alternative option for achieving fast SPI in a diffraction-limited imaging system,without the need for additional hardware.

Fast Fourier single-pixel imaging based on Sierra–Lite dithering algorithm

The single-pixel imaging(SPI) technique is able to capture two-dimensional(2 D) images without conventional array sensors by using a photodiode. As a novel scheme, Fourier single-pixel imaging(FSI) has been proven capable of reconstructing high-quality images. Due to the fact that the Fourier basis patterns(also known as grayscale sinusoidal patterns)cannot be well displayed on the digital micromirror device(DMD), a fast FSI system is proposed to solve this problem by binarizing Fourier pattern through a dithering algorithm. However, the traditional dithering algorithm leads to low quality as the extra noise is inevitably induced in the reconstructed images. In this paper, we report a better dithering algorithm to binarize Fourier pattern, which utilizes the Sierra–Lite kernel function by a serpentine scanning method. Numerical simulation and experiment demonstrate that the proposed algorithm is able to achieve higher quality under different sampling ratios.

Measurable speckle gradation Hadamard single-pixel imaging

The array spatial light field is an effective means for improving imaging speed in single-pixel imaging.However,distinguishing the intensity values of each sub-light field in the array spatial light field requires the help of the array detector or the time-consuming deep-learning algorithm.Aiming at this problem,we propose measurable speckle gradation Hadamard single-pixel imaging(MSG-HSI),which makes most of the refresh mechanism of the device generate the Hadamard speckle patterns and the high sampling rate of the bucket detector and is capable of measuring the light intensity fluctuation of the array spatial light field only by a simple bucket detector.The numerical and experimental results indicate that data acquisition in MSG-HSI is 4 times faster than in traditional Hadamard single-pixel imaging.Moreover,imaging quality in MSG-HSI can be further improved by image stitching technology.Our approach may open a new perspective for single-pixel imaging to improve imaging speed.

Enhancing the ability of single-pixel imaging against the source's energy fluctuation by complementary detection

The source's energy fluctuation has a great effect on the quality of single-pixel imaging(SPI).When the method of complementary detection is introduced into an SPI camera system and the echo signal is corrected with the summation of the light intensities recorded by two complementary detectors,we demonstrate,by both experiments and simulations,that complementary single-pixel imaging(CSPI)is robust to the source's energy fluctuation.The superiority of the CSPI structure is also discussed in comparison with previous SPI via signal monitoring.

Vibration measurement with frequency modulation single-pixel imaging

Single-pixel imaging can reconstruct the image of the object when the light traveling from the object to the detector is scattered or distorted.Most single-pixel imaging methods only obtain distribution of transmittance or reflectivity of the object.Some methods can obtain extra information,such as color and polarization information.However,there is no method that can get the vibration information when the object is vibrating during the measurement.Vibration information is very important,because unexpected vibration often means the occurrence of abnormal conditions.In this Letter,we introduce a method to obtain vibration information with the frequency modulation single-pixel imaging method.This method uses a light source with a special pattern to illuminate the object and analyzes the frequency of the total light intensity signal transmitted or reflected by the object.Compared to other single-pixel imaging methods,frequency modulation single-pixel imaging can obtain vibration information and maintain high signal-to-noise ratio and has potential on finding out hidden facilities under construction or instruments in work.

A detail-enhanced sampling strategy in Hadamard single-pixel imaging

Hadamard single-pixel imaging is an appealing imaging technique due to its features of low hardware complexity and industrial cost.To improve imaging efficiency,many studies have focused on sorting Hadamard patterns to obtain reliable reconstructed images with very few samples.In this study,we propose an efficient Hadamard basis sampling strategy that employs an exponential probability function to sample Hadamard patterns in a direction with high energy concentration of the Hadamard spectrum.We used the compressed-sensing algorithm for image reconstruction.The simulation and experimental results show that this sampling strategy can reconstruct object reliably and preserves the edge and details of images.

A synthetic diagnostics platform for microwave imaging diagnostics in tokamaks

Interpreting experimental diagnostics data in tokamaks,while considering non-ideal effects,is challenging due to the complexity of plasmas.To address this challenge,a general synthetic diagnostics(GSD)platform has been established that facilitates microwave imaging reflectometry and electron cyclotron emission imaging.This platform utilizes plasma profiles as input and incorporates the finite-difference time domain,ray tracing and the radiative transfer equation to calculate the propagation of plasma spontaneous radiation and the external electromagnetic field in plasmas.Benchmark tests for classical cases have been conducted to verify the accuracy of every core module in the GSD platform.Finally,2D imaging of a typical electron temperature distribution is reproduced by this platform and the results are consistent with the given real experimental data.This platform also has the potential to be extended to 3D electromagnetic field simulations and other microwave diagnostics such as cross-polarization scattering.

Self-confocal NIR-II fluorescence microscopy for multifunctional in vivo imaging

Fluorescence imaging in the second near-infrared window(NIR-II,900–1880 nm)with less scattering background in biological tissues has been combined with the confocal microscopic system for achieving deep in vivo imaging with high spatial resolution.However,the traditional NIR-IIfluorescence confocal microscope with separate excitation focus and detection pinhole makes it possess low confocal e±ciency,as well as di±cultly to adjust.Two types of upgraded NIR-IIfluorescence confocal microscopes,sharing the same pinhole by excitation and emission focus,leading to higher confocal e±ciency,are built in this work.One type is-ber-pinhole-based confocal microscope applicable to CW laser excitation.It is constructed forfluorescence intensity imaging with large depth,high stabilization and low cost,which could replace multiphotonfluorescence microscopy in some applications(e.g.,cerebrovascular and hepatocellular imaging).The other type is air-pinhole-based confocal microscope applicable to femtosecond(fs)laser excitation.It can be employed not only for NIR-IIfluorescence intensity imaging,but also for multi-channelfluorescence lifetime imaging to recognize different structures with similarfluorescence spectrum.Moreover,it can be facilely combined with multiphotonfluorescence microscopy.A single fs pulsed laser is utilized to achieve up-conversion(visible multiphotonfluorescence)and down-conversion(NIR-II one-photonfluorescence)excitation simultaneously,extending imaging spectral channels,and thus facilitates multi-structure and multi-functional observation.

Microwave-induced thermoacoustic elastic imaging:A simulation study

Microwave-induced thermoacoustic imaging(MTI)has the advantages of high resolution,high contrast,non-ionization,and non-invasive.Recently,MTI was used in the¯eld of breast cancer screening.In this paper,based on the¯nite element method(FEM)and COMSOL Multiphysics software,a three-dimensional breast cancer model suitable for exploring the MTI process is proposed to investigate the in°uence of Young's modulus(YM)of breast cancer tissue on MTI.It is found that the process of electromagnetic heating and initial pressure generation of the entire breast tissue is earlier in time than the thermal expansion process.Besides,compared with normal breast tissue,tumor tissue has a greater temperature rise,displacement,and pressure rise.In particular,YM of the tumor is related to the speed of thermal expansion.In particular,the larger the YM of the tumor is,the higher the heating and contraction frequency is,and the greater the maximum pressure is.Di®erent Young's moduli correspond to di®erent thermoacoustic signal spectra.In MTI,this study can be used to judge di®erent degrees of breast cancer based on elastic imaging.In addition,this study is helpful in exploring the possibility of microwave-induced thermoacoustic elastic imaging(MTAE).

Topic highlight on texture and color enhancement imaging in gastrointestinal diseases

Olympus Corporation developed texture and color enhancement imaging(TXI)as a novel image-enhancing endoscopic technique.This topic highlights a series of hot-topic articles that investigated the efficacy of TXI for gastrointestinal disease identification in the clinical setting.A randomized controlled trial demonstrated improvements in the colorectal adenoma detection rate(ADR)and the mean number of adenomas per procedure(MAP)of TXI compared with those of white-light imaging(WLI)observation(58.7%vs 42.7%,adjusted relative risk 1.35,95%CI:1.17-1.56;1.36 vs 0.89,adjusted incident risk ratio 1.48,95%CI:1.22-1.80,respectively).A cross-over study also showed that the colorectal MAP and ADR in TXI were higher than those in WLI(1.5 vs 1.0,adjusted odds ratio 1.4,95%CI:1.2-1.6;58.2%vs 46.8%,1.5,1.0-2.3,respectively).A randomized controlled trial demonstrated non-inferiority of TXI to narrow-band imaging in the colorectal mean number of adenomas and sessile serrated lesions per procedure(0.29 vs 0.30,difference for non-inferiority-0.01,95%CI:-0.10 to 0.08).A cohort study found that scoring for ulcerative colitis severity using TXI could predict relapse of ulcerative colitis.A cross-sectional study found that TXI improved the gastric cancer detection rate compared to WLI(0.71%vs 0.29%).A cross-sectional study revealed that the sensitivity and accuracy for active Helicobacter pylori gastritis in TXI were higher than those of WLI(69.2%vs 52.5%and 85.3%vs 78.7%,res-pectively).In conclusion,TXI can improve gastrointestinal lesion detection and qualitative diagnosis.Therefore,further studies on the efficacy of TXI in clinical practice are required.

Five-view three-dimensional reconstructionfor ultrafast dynamic imaging of pulsedradiation sources

Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights intothe generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of thepulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are oftenavailable for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete datamay introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction methodusing cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. Weaugment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have beencarried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns betweenadjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstructionresults and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.

Activatable fluorescent probes for imaging and diagnosis of rheumatoid arthritis

Rheumatoid arthritis(RA)is a systemic autoimmune disease that is primarily manifested as synovitis and polyarticular opacity and typically leads to serious joint damage and irreversible disability,thus adversely affecting locomotion ability and life quality.Consequently,good prognosis heavily relies on the early diagnosis and effective therapeutic monitoring of RA.Activatable fluorescent probes play vital roles in the detection and imaging of biomarkers for disease diagnosis and in vivo imaging.Herein,we review the fluorescent probes developed for the detection and imaging of RA biomarkers,namely reactive oxygen/nitrogen species(hypochlorous acid,peroxynitrite,hydroxyl radical,nitroxyl),pH,and cysteine,and address the related challenges and prospects to inspire the design of novel fluorescent probes and the improvement of their performance in RA studies.

Two-photon live imaging of direct glia-to-neuron conversion in the mouse cortex

Over the past decade,a growing number of studies have reported transcription factor-based in situ reprogramming that can directly conve rt endogenous glial cells into functional neurons as an alternative approach for n euro regeneration in the adult mammalian central ne rvous system.Howeve r,many questions remain regarding how a terminally differentiated glial cell can transform into a delicate neuron that forms part of the intricate brain circuitry.In addition,concerns have recently been raised around the absence of astrocyte-to-neuron conversion in astrocytic lineage-tra cing mice.In this study,we employed repetitive two-photon imaging to continuously capture the in situ astrocyte-to-neuron conversion process following ecto pic expression of the neural transcription factor NeuroD1 in both prolife rating reactive astrocytes and lineage-tra ced astrocytes in the mouse cortex.Time-lapse imaging over several wee ks revealed the ste p-by-step transition from a typical astrocyte with numero us short,tapered branches to a typical neuro n with a few long neurites and dynamic growth cones that actively explored the local environment.In addition,these lineage-converting cells were able to migrate ra dially or to ngentially to relocate to suitable positions.Furthermore,two-photon Ca2+imaging and patch-clamp recordings confirmed that the newly generated neuro ns exhibited synchronous calcium signals,repetitive action potentials,and spontaneous synaptic responses,suggesting that they had made functional synaptic connections within local neural circuits.In conclusion,we directly visualized the step-by-step lineage conversion process from astrocytes to functional neurons in vivo and unambiguously demonstrated that adult mammalian brains are highly plastic with respect to their potential for neuro regeneration and neural circuit reconstruction.

Investigating the relationship between intracranial atherosclerotic plaque remodelling and diabetes using high-resolution vessel wall imaging

BACKGROUND Intracranial atherosclerosis,a leading cause of stroke,involves arterial plaque formation.This study explores the link between plaque remodelling patterns and diabetes using high-resolution vessel wall imaging(HR-VWI).AIM To investigate the factors of intracranial atherosclerotic remodelling patterns and the relationship between intracranial atherosclerotic remodelling and diabetes mellitus using HR-VWI.METHODS Ninety-four patients diagnosed with middle cerebral artery or basilar artery INTRODUCTION Intracranial atherosclerotic disease is one of the main causes of ischaemic stroke in the world,accounting for approx-imately 10%of transient ischaemic attacks and 30%-50%of ischaemic strokes[1].It is the most common factor among Asian people[2].The adaptive changes in the structure and function of blood vessels that can adapt to changes in the internal and external environment are called vascular remodelling,which is a common and important pathological mechanism in atherosclerotic diseases,and the remodelling mode of atherosclerotic plaques is closely related to the occurrence of stroke.Positive remodelling(PR)is an outwards compensatory remodelling where the arterial wall grows outwards in an attempt to maintain a constant lumen diameter.For a long time,it was believed that the degree of stenosis can accurately reflect the risk of ischaemic stroke[3-5].Previous studies have revealed that lesions without significant luminal stenosis can also lead to acute events[6,7],as summarized in a recent meta-analysis study in which approximately 50%of acute/subacute ischaemic events were due to this type of lesion[6].Research[8,9]has pointed out that the PR of plaques is more dangerous and more likely to cause acute ischaemic stroke.Previous studies[10-13]have found that there are specific vascular remodelling phenomena in the coronary and carotid arteries of diabetic patients.However,due to the deep location and small lumen of intracranial arteries and limitations of imaging techniques,the relationship between intracranial arterial remodelling and diabetes is still unclear.In recent years,with the development of magnetic resonance technology and the emergence of high-resolution(HR)vascular wall imaging,a clear and multidimensional display of the intracranial vascular wall has been achieved.Therefore,in this study,HR wall imaging(HR-VWI)was used to display the remodelling characteristics of bilateral middle cerebral arteries and basilar arteries and to explore the factors of intracranial vascular remodelling and its relationship with diabetes.

Imaging plate scanners calibration and the attenuation behavior of imaging plate signals

Based on previously reported work, we propose a new method for calibrating image plate(IP) scanners, offering greater flexibility and convenience, which can be extended to the calibration tasks of various scanner models. This method was applied to calibrate the sensitivity of a GE Typhoon FLA 7000 scanner. Additionally, we performed a calibration of the spontaneous signal attenuation behavior for BAS-MS, BAS-SR, and BAS-TR type IPs under the 20±1℃ environmental conditions, and observed significant signal carrier diffusion behavior in BAS-MS IP. The calibration results lay a foundation for further research on the interaction between ultra-short, ultra-intense lasers and matter.

Comparison of Microwave Imaging Algorithms for Short-Range Scenarios

Three dimensional(3-D)imaging algorithms with irregular planar multiple-input-multiple-output(MIMO)arrays are discussed and compared with each other.Based on the same MIMO array,a modified back projection algorithm(MBPA)is accordingly proposed and four imaging algorithms are used for comparison,back-projection method(BP),back-projection one in time domain(BP-TD),modified back-projection one and fast Fourier transform(FFT)-based MIMO range migration algorithm(FFT-based MIMO RMA).All of the algorithms have been implemented in practical application scenarios by use of the proposed imaging system.Back to the practical applications,MIMO array-based imaging system with wide-bandwidth properties provides an efficient tool to detect objects hidden behind a wall.An MIMO imaging radar system,composed of a vector network analyzer(VNA),a set of switches,and an array of Vivaldi antennas,have been designed,fabricated,and tested.Then,these algorithms have been applied to measured data collected in different scenarios constituted by five metallic spheres in the absence and in the presence of a wall between the antennas and the targets in simulation and pliers in free space for experimental test.Finally,the focusing properties and time consumption of the above algorithms are compared.

Recent Research Advances in Imaging of Prostate Cancer

Imaging study plays a crucial role in the diagnosis of prostate cancer. As early screening and management of prostate cancer has evolved over the past decade, research is now focusing on how to detect clinically significant prostate cancer and avoid overdiagnosis accurately. This article provides an overview of recent advances in imaging in prostate cancer diagnosis, including new ultrasound imaging techniques, positron emission computed tomography, multiparametric magnetic resonance imaging, and emerging areas such as imaging histology, by systematically reviewing and summarizing the existing literature.

Application value of indocyanine green fluorescence imaging in guiding sentinel lymph node biopsy diagnosis of gastric cancer: Meta-analysis

BACKGROUND Gastric cancer is a common malignant tumor of the digestive system worldwide,and its early diagnosis is crucial to improve the survival rate of patients.Indocyanine green fluorescence imaging(ICG-FI),as a new imaging technology,has shown potential application prospects in oncology surgery.The meta-analysis to study the application value of ICG-FI in the diagnosis of gastric cancer sentinel lymph node biopsy is helpful to comprehensively evaluate the clinical effect of this technology and provide more reliable guidance for clinical practice.AIM To assess the diagnostic efficacy of optical imaging in conjunction with indocya-nine green(ICG)-guided sentinel lymph node(SLN)biopsy for gastric cancer.METHODS Electronic databases such as PubMed,Embase,Medline,Web of Science,and the Cochrane Library were searched for prospective diagnostic tests of optical imaging combined with ICG-guided SLN biopsy.Stata 12.0 software was used for analysis by combining the"bivariable mixed effect model"with the"midas"command.The true positive value,false positive value,false negative value,true negative value,and other information from the included literature were extracted.A literature quality assessment map was drawn to describe the overall quality of the included literature.A forest plot was used for heterogeneity analysis,and P<0.01 was considered to indicate statistical significance.A funnel plot was used to assess publication bias,and P<0.1 was considered to indicate statistical significance.The summary receiver operating characteristic(SROC)curve was used to calculate the area under the curve(AUC)to determine the diagnostic accuracy.If there was interstudy heterogeneity(I2>50%),meta-regression analysis and subgroup analysis were performed.analysis were performed.RESULTS Optical imaging involves two methods:Near-infrared(NIR)imaging and fluorescence imaging.A combination of optical imaging and ICG-guided SLN biopsy was useful for diagnosis.The positive likelihood ratio was 30.39(95%CI:0.92-1.00),the sensitivity was 0.95(95%CI:0.82-0.99),and the specificity was 1.00(95%CI:0.92-1.00).The negative likelihood ratio was 0.05(95%CI:0.01-0.20),the diagnostic odds ratio was 225.54(95%CI:88.81-572.77),and the SROC AUC was 1.00(95%CI:The crucial values were sensitivity=0.95(95%CI:0.82-0.99)and specificity=1.00(95%CI:0.92-1.00).The Deeks method revealed that the"diagnostic odds ratio"funnel plot of SLN biopsy for gastric cancer was significantly asymmetrical(P=0.01),suggesting significant publication bias.Further meta-subgroup analysis revealed that,compared with fluorescence imaging,NIR imaging had greater sensitivity(0.98 vs 0.73).Compared with optical imaging immediately after ICG injection,optical imaging after 20 minutes obtained greater sensitivity(0.98 vs 0.70).Compared with that of patients with an average SLN detection number<4,the sensitivity of patients with a SLN detection number≥4 was greater(0.96 vs 0.68).Compared with hematoxylin-eosin(HE)staining,immunohistochemical(+HE)staining showed greater sensitivity(0.99 vs 0.84).Compared with subserous injection of ICG,submucosal injection achieved greater sensitivity(0.98 vs 0.40).Compared with 5 g/L ICG,0.5 and 0.05 g/L ICG had greater sensitivity(0.98 vs 0.83),and cT1 stage had greater sensitivity(0.96 vs 0.72)than cT2 to cT3 clinical stage.Compared with that of patients≤26,the sensitivity of patients>26 was greater(0.96 vs 0.65).Compared with the literature published before 2010,the sensitivity of the literature published after 2010 was greater(0.97 vs 0.81),and the differences were statistically significant(all P<0.05).CONCLUSION For the diagnosis of stomach cancer,optical imaging in conjunction with ICG-guided SLN biopsy is a therapeut-ically viable approach,especially for early gastric cancer.The concentration of ICG used in the SLN biopsy of gastric cancer may be too high.Moreover,NIR imaging is better than fluorescence imaging and may obtain higher sensitivity.