Optical scanning endoscope via a single multimode optical fiber

Optical endoscopy has become an essential diagnostic and therapeutic approach in modern biomedicine for directly observing organs and tissues deep inside the human body,enabling non-invasive,rapid diagnosis and treatment.Optical fiber endoscopy is highly competitive among various endoscopic imaging techniques due to its high flexibility,compact structure,excellent resolution,and resistance to electromagnetic interference.Over the past decade,endoscopes based on a single multimode optical fiber(MMF)have attracted widespread research interest due to their potential to significantly reduce the footprint of optical fiber endoscopes and enhance imaging capabilities.In comparison with other imaging principles of MMF endoscopes,the scanning imaging method based on the wavefront shaping technique is highly developed and provides benefits including excellent imaging contrast,broad applicability to complex imaging scenarios,and good compatibility with various well-established scanning imaging modalities.In this review,various technical routes to achieve light focusing through MMF and procedures to conduct the scanning imaging of MMF endoscopes are introduced.The advancements in imaging performance enhancements,integrations of various imaging modalities with MMF scanning endoscopes,and applications are summarized.Challenges specific to this endoscopic imaging technology are analyzed,and potential remedies and avenues for future developments are discussed.

Monitoring slope deformation using a 3-D laser image scanning system: a case study

An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and processing methods are illus-trated. The point cloud results are analyzed in detail. The rescale range analysis method was used to analyze the deformation char-acteristics of the slope. The results show that the trend of slope displacement is stable and that the degree of landslide danger is low. This work indicates that 3-D laser image scanning can supply multi-parameter, high precision real time data over long distances. These data can be used to study the distortion of the slope quickly and accurately.

A scanning distortion correction method based on Ⅹ-Y galvanometer Lidar system

Aiming at the problem of scanning distortion in X-Y galvanometer light detecting and ranging(Lidar) scanning system,we propose a method of image scanning distortion correction with controllable driving voltage compensation.Firstly,the geometrical optics vectors model is established to explain the principle of pincushion distortion in the galvanometer scanning system,and the simulation result of scanning trajectory is consistent with experiments.The linear relationship between the driving voltage and the scanning angle of the galvanometer is verified.Secondly,the relationship between the deflection angle of the galvanometer and the scanning trajectory and the driving voltage is deduced respectively,and an image scanning correction algorithm with controllable driving voltage compensation is obtained.The simulation experiment results of the proposed method show that the root-mean-square error(RMSE) and the corresponding curve between the scan value and the actual value at different distances,have a good correction effect for the pincushion distortion.Finally,the X-Y galvanometer scanning Lidar system is established to obtain undistorted two-dimensional scanned image and it can be applied to the three-dimensional Lidar scanning system in the actual experiments,which further demonstrates the feasibility and practicability of our method.

Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update

Adaptive optics scanning laser ophthalmoscopy（AOSLO） has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics（AO） and AO-SLO. Then it compares AO-SLO with conventional imaging methods（fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography） and other AO techniques（adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherence tomography）. Furthermore, an update of current research situation in AO-SLO is made based on different fundus structures as photoreceptors（cones and rods）, fundus vessels, retinal pigment epithelium layer, retinal nerve fiber layer, ganglion cell layer and lamina cribrosa. Finally, this review indicates possible research directions of AO-SLO in future.

Volumetric measurement techniques for assessment of cutaneous neurofibromas:A review

Cutaneous neurofibroma(cNF)is a prevalent clinical manifestation of neurofibromatosis type 1,significantly affecting the well-being and quality of life of the affected individuals.The adoption of reliable and reproducible volumetric measurement techniques is essential for precisely evaluating tumor burden and plays a critical role in the development of effective treatments for cNF.This study focuses on widely used volumetric measurement techniques,including vernier calipers,ultrasound,computed tomography,magnetic resonance imaging,and three-dimensional scanning imaging.It outlines the merits and drawbacks of each technique in assessing the cNF load,providing an overview of their current applications and ongoing research advancements in this domain.

FEATURE EXTRACTION OF BONES AND SKIN BASED ON ULTRASONIC SCANNING

In the prosthetic socket design, aimed at the high cost and radiation deficiency caused by CT scanning which is a routine technique to obtain the cross-sectional image of the residual limb, a new ultrasonic scanning method is developed to acquire the bones and skin contours of the residual limb. Using a pig fore-leg as the scanning object, an overlapping algorithm is designed to reconstruct the 2D cross-sectional image, the contours of the bone and skin are extracted using edge detection algorithm and the 3D model of the pig fore-leg is reconstructed by using reverse engineering technology. The results of checking the accuracy of the image by scanning a cylinder work pieces show that the extracted contours of the cylinder are quite close to the standard circumference. So it is feasible to get the contours of bones and skin by ultrasonic scanning. The ultrasonic scanning system featuring no radiation and low cost is a kind of new means of cross section scanning for medical images.

Compact and effective photon-resolved image scanning microscope

Fluorescence confocal laser-scanning microscopy(LSM)is one of the most popular tools for life science research.This popularity is expected to grow thanks to single-photon array detectors tailored for LSM.These detectors offer unique single-photon spatiotemporal information,opening new perspectives for gentle and quantitative superresolution imaging.However,a flawless recording of this information poses significant challenges for the microscope data acquisition(DAQ)system.We present a DAQ module based on the digital frequency domain principle,able to record essential spatial and temporal features of photons.We use this module to extend the capabilities of established imaging techniques based on single-photon avalanche diode(SPAD)array detectors,such as fluorescence lifetime image scanning microscopy.Furthermore,we use the module to introduce a robust multispecies approach encoding the fluorophore excitation spectra in the time domain.Finally,we combine time-resolved stimulated emission depletion microscopy with image scanning microscopy,boosting spatial resolution.Our results demonstrate how a conventional fluorescence laser scanning microscope can transform into a simple,information-rich,superresolved imaging system with the simple addition of a SPAD array detector with a tailored data acquisition system.We expected a blooming of advanced single-photon imaging techniques,which effectively harness all the sample information encoded in each photon.

Highly specific characterization and discrimination of monosodium urate crystals in gouty arthritis based on aggregation-induced emission luminogens

Existing technologies used to detect monosodium urate(MSU)crystals for gout diagnosis are not ideal due to their low sensitivity and complexity of operation.The purpose of this study was to explore whether aggregation-induced emission luminogens(AIEgens)can be used for highly specific imaging of MSU crystals to assist in the diagnosis of gout.First,we developed a series of luminogens(i.e.,tetraphenyl ethylene(TPE)-NH_(2),TPE-2NH_(2),TPE-4NH_(2),TPE-COOH,TPE-2COOH,TPE-4COOH,and TPE-Ketoalkyne),each of which was then evenly mixed with MSU crystals.Next,optimal fluorescence imaging of each of the luminogens was characterized by a confocal laser scanning microscope(CLSM).This approach was used for imaging standard samples of MSU,hydroxyapatite(HAP)crystals,and mixed samples with 1:1 mass ratio of MSU/HAP.We also imaged samples from mouse models of acute gouty arthritis,HAP deposition disease,and comorbidities of interest.Subsequently,CLSM imaging results were compared with those of compensated polarized light microscopy,and we assessed the biosafety of TPE-Ketoalkyne in the RAW264.7 cell line.Finally,CLSM time series and three-dimensional imaging were performed on MSU crystal samples from human gouty synovial fluid and tophi.As a promising candidate for MSU crystal labeling,TPE-Ketoalkyne was found to detect MSU crystals accurately and rapidly in standard samples,animal samples,and human samples,and could precisely distinguish gout from HAP deposition disease.This work demonstrates that TPE-Ketoalkyne is suitable for highly specific and timely imaging of MSU crystals in gouty arthritis and may facilitate future research on MSU crystal-related diseases.

Improving Yolo5 for Real-Time Detection of Small Targets in Side Scan Sonar Images

Side scan sonar(SSS)is an important means to detect and locate seafloor targets.Autonomous underwater vehicles(AUVs)carrying SSS stay near the seafloor to obtain high-resolution images and provide the outline of the target for observers.The target feature information of an SSS image is similar to the background information,and a small target has less pixel information;therefore,accu-rately identifying and locating small targets in SSS images is challenging.We collect the SSS images of iron metal balls(with a diameter of 1m)and rocks to solve the problem of target misclassification.Thus,the dataset contains two types of targets,namely,‘ball’and‘rock’.With the aim to enable AUVs to accurately and automatically identify small underwater targets in SSS images,this study designs a multisize parallel convolution module embedded in state-of-the-art Yolo5.An attention mechanism transformer and a convolutional block attention module are also introduced to compare their contributions to small target detection accuracy.The performance of the proposed method is further evaluated by taking the lightweight networks Mobilenet3 and Shufflenet2 as the backbone network of Yolo5.This study focuses on the performance of convolutional neural networks for the detection of small targets in SSS images,while another comparison experiment is carried out using traditional HOG+SVM to highlight the neural network’s ability.This study aims to improve the detection accuracy while ensuring the model efficiency to meet the real-time working requirements of AUV target detection.

Advances in the Theory of Conjugation for Reflecting Prisms in China

The achievements made in China in the field of the theory of conjugation for reflecting prisms are outlined which mainly includes 6 theorems, 2 corollaries, over 30 formulae, 4 matric operators, 20 characteristic parameters, a new principle for dassification, and a new system of graphical tabulation for reflecting prisms. As an approach to developing the theory, an imaginary physical model called 'rigid body's kinematics model' has been creatively initiated to simulate the real physical phenomena of both image formation and image motion for reflecting prisms. Such a method of treatment has been successfully making the evolving theory more complete, more systematic, more generalized, and unique as well.

First-principles Study on Geometric and Electronic Structures of Si（111）-√7× √3-In Surface Reconstruction

In order to determine the structures of Si（111）-√7 √3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calculations. Their scanning tunneling microscopic images and work functions are simulated and compared with experimental results. In this way, the hex-H3＇ and rect-T1 models are identified as the experimental configurations for the hexagonal and rectangular types, respectively. The structural evolution mechanism of the In/Si（lll） surface with indium coverage around 1.0 monolayer is discussed. The 4×1 and -√7× √3 phases are suggested to have two different types of evolution mechanisms, consistent with experimental results.

Optimized Deep Learning-Inspired Model for the Diagnosis and Prediction of COVID-19

Detecting COVID-19 cases as early as possible became a critical issue that must be addressed to avoid the pandemic’s additional spread and early provide the appropriate treatment to the affected patients.This study aimed to develop a COVID-19 diagnosis and prediction(AIMDP)model that could identify patients with COVID-19 and distinguish it from other viral pneumonia signs detected in chest computed tomography(CT)scans.The proposed system uses convolutional neural networks(CNNs)as a deep learning technology to process hundreds of CT chest scan images and speeds up COVID-19 case prediction to facilitate its containment.We employed the whale optimization algorithm(WOA)to select the most relevant patient signs.A set of experiments validated AIMDP performance.It demonstrated the superiority of AIMDP in terms of the area under the curve-receiver operating characteristic(AUC-ROC)curve,positive predictive value(PPV),negative predictive rate(NPR)and negative predictive value(NPV).AIMDP was applied to a dataset of hundreds of real data and CT images,and it was found to achieve 96%AUC for diagnosing COVID-19 and 98%for overall accuracy.The results showed the promising performance of AIMDP for diagnosing COVID-19 when compared to other recent diagnosing and predicting models.

Bimorph deformable mirror based adaptive optics scanning laser ophthalmoscope for retina imaging in vivo

A bimorph deformable mirror （DM） with a large stroke of more than 30 μm using 35 actuators is presented and characterized for an adaptive optics （AO） confocal scanning laser ophthalmoscope application. Facilitated with a Shack-Hartmann wavefront sensor, the bimorph DM-based AO operates closed-loop AO corrections for hu- man eyes and reduces wavefront aberrations in most eyes to below 0.1 μm rms. Results from living eyes, including one exhibiting ~5D of myopia and ~2D of astigmatism along with notable high-order aberrations, reveal a prac- tical efficient aberration correction and demonstrate a great benefit for retina imaging, including improving resolution, increasing brightness, and enhancing the contrast of images.

Evaluation of Sub-microstructure in Concrete with Low Water-binder Ratio by SEM-BSE Image Analysis

The coarse pore system, interfacial transition zone （ITZ） between aggregate and paste matrix and volume fraction of unhydrated cement in concrete （w/c=0.3） containing mineral admixtures were quantitatively characterized by the scanning electron microscope-backscattered electron （SEM-BSE） image analysis technique. The experimental results show that compound addition of slag and fly ash decreases the coarse porosity from 10.17% to 3.74% and the threshold diameter of coarse pore size from 345 μm to 105 μm compared with concrete （w/c=0.30） without mineral admixtures; Moreover with compound addition of fly ash and slag, the volume proportion of unhydrated cement in paste matrix is reduced by 30%, the maximum amount of coarse pores in the ITZ between aggregate and paste decreases from 13.11% to 5.57% and the thickness of ITZ is reduced by 37% , compared with concrete without mineral admixtures.

Direct Imaging of Molecular Orbitals of Metal Phthalocyanines on Metal Surfaces with an O2-Functionalized Tip of a Scanning Tunneling Microscope

High-resolution scanning tunneling microscope images of iron phthalocyanine and zinc phthalocyanine molecules on Au（111） have been obtained using a functionalized tip of a scanning tunneling microscope （STM）, and show rich intramolecular features that are not observed using clean tips. Ab initio density functional theory calculations and extended Huckel theory calculations revealed that the imaging of detailed electronic states is due specifically to the decoration of the STM tip with O2. The detailed structures are differentiated only when interacting with the highly directional orbitals of the oxygen molecules adsorbed on a truncated, [111]-oriented tungsten tip. Our results indicate a method for increasing the resolution in generic scans and thus, have potential applications in fundamental research based on high-resolution electronic states of molecules on metals, concerning, for example, chemical reactions, and catalysis mechanisms.

Comparison of TMI and AMSR-E sea surface temperatures with Argo near-surface temperatures over the global oceans

Satellite-derived sea surface temperatures（SSTs） from the tropical rainfall measuring mission（TRMM）microwave imager（TMI） and the advanced microwave scanning radiometer for the earth observing system（AMSR-E） were compared with non-pumped near-surface temperatures（NSTs） obtained from Argo profiling floats over the global oceans. Factors that might cause temperature differences were examined, including wind speed, columnar water vapor, liquid cloud water, and geographic location. The results show that both TMI and AMSR-E SSTs are highly correlated with the Argo NSTs; however, at low wind speeds, they are on average warmer than the Argo NSTs. The TMI performs slightly better than the AMSR-E at low wind speeds, whereas the TMI SST retrievals might be poorly calibrated at high wind speeds. The temperature differences indicate a warm bias of the TMI/AMSR-E when columnar water vapor is low, which can indicate that neither TMI nor AMSR-E SSTs are well calibrated at high latitudes. The SST in the Kuroshio Extension region has higher variability than in the Kuroshio region. The variability of the temperature difference between the satellite-retrieved SSTs and the Argo NSTs is lower in the Kuroshio Extension during spring. At low wind speeds, neither TMI nor AMSR-E SSTs are well calibrated, although the TMI performs better than the AMSR-E.

Application of SPECT Combined with CT and MRI in Malignant Tumors Clinical Value in the Diagnosis of Bone Metastasis

Introduction: Bone is the most common site of hematogenous metastasis of malignant tumors. Patients with bone metastasis can have a series of bone related adverse events, which seriously affect the quality of life and survival time of patients. Imaging examination is the main means of clinical diagnosis and evaluation of bone metastasis. Aim of the Work: To evaluate the value of single-photon emission computerized tomography (SPECT) combined with CT and MRI in the diagnosis of bone metastasis of malignant tumors. Subjects and Methods: Eighty patients with bone metastasis from malignant tumors who were admitted to Affiliated Hospital of Chengde Medical College were selected from March 2019 to June 2021. They underwent bone scan with SPECT imaging, CT and MRI separately. The distribution of bone metastasis from primary tumors as well as efficacy of the above three detection methods for bone metastasis was analyzed. Results: A total of 464 lesions were detected by SPECT and CT in the same scanning field, with SPECT detection rate of 92.5% (429/464) and CT detection rate of 77.8% (361/464) (P P P P Conclusion: SPECT may be the preferred screening modality for uspected bone metastases, and when combined with CT and MRI, it can clarify the regional distribution of bone metastasis from malignant tumors and improve the sensitivity, specificity and accuracy of diagnosis with high clinical significance.

Feature Extraction of Sectorial Scan Image of Thick-Walled Electron Beam Welding Seam Based on Principal Component Analysis

A feature extraction method was proposed to sectorial scan image of Ti-6Al-4V electron beam welding seam based on principal component analysis to solve problem of high-dimensional data resulting in timeconsuming in defect recognition. Seven features were extracted from the image and represented 87. 3% information of the original data. Both the extracted features and the original data were used to train support vector machine model to assess the feature extraction performance in two aspects: recognition accuracy and training time. The results show that using the extracted features the recognition accuracy of pore,crack,lack of fusion and lack of penetration are 93%,90.7%,94.7% and 89.3%,respectively,which is slightly higher than those using the original data. The training time of the models using the extracted features is extremely reduced comparing with those using the original data.

An improved method to distinguish between scanned and rasterized document images

Office automation （OA） has evolved with the development of computer science,improving staff efficiency.Unstructured information processing is an important aspect of OA; therefore,in this paper,we propose an efficient method for distinguishing scanned and rasterized document images which can be used in this process.To ensure the efficiency and precision of our method,two steps are included：rapid processing and classification using noise features.In the first step,color,skew,and isolated noise features are used to identify the source of the images.In the second step,noise features are extracted from the input image and a support vector machine （SVM） classifier is used for classification.Our experiments show that our method has high precision and speed for distinguishing scanned and rasterized document images.

Arterial phase of biphase enhancement spiral CT in diagnosis of small hepatocellular carcinoma

Objectives: To evaluate the value of the arterial phase(AP) of biphase enhanced spiral CT(SCT) in the di-agnosis of small HCC and to investigate the criteria,initial time, ending time and duration of AP.Methods: From May 1995 to March 1999, patients withsmall HCC proved surgically and pathologically in-cluding 49 patients (n=53) in group A, 148 (n=186) ingroup B and 52 (n=52) in group C were collected.Biphase dynamic enhanced SCT scans were performedin all patients of the three groups and additional sin-gle-level dynamic scans only done in the group C. Thedetectability, diagnostic accuracy of lesions and en-hancement of the lesions in AP were analyzed statisti-cally. In addition, the initial time, ending time andduration of AP were measured.Results: The results of the group A showed the de-tectability of small HCC was 88.68% in AP and90.57% in both phases, higher than those by ultra-sound. Markedly enhanced lesions in AP accounted for76% and 78% in the groups B and C respectively. Theinitial time, ending time and duration of AP measuredon single-level dynamic scans were 16.9s, 39.6s and22.7s on average respectively.Conclusions: The biphase dynamic SCT especially itsarterial phase appears to be very valuable in diagnosingsmall HCCs. In light of short duration of AP, under-standing and strict control of AP is obviously impera-tive.