Multi-class classification of pathological myopia based on fundus photography

Pathological myopia(PM)is a severe ocular disease leading to blindness.As a traditional noninvasive diagnostic method,fundus color photography(FCP)is widely used in detecting PM due to its highfidelity and precision.However,manual examination of fundus photographs for PM is time-consuming and prone to high error rates.Existing automated detection technologies have yet to study the detailed classification in diagnosing different stages of PM lesions.In this paper,we proposed an intelligent system which utilized Resnet101 technology to multi-categorically diagnose PM by classifying FCPs with different stages of lesions.The system subdivided different stages of PM into eight subcategories,aiming to enhance the precision and efficiency of the diagnostic process.It achieved an average accuracy rate of 98.86%in detection of PM,with an area under the curve(AUC)of 98.96%.For the eight subcategories of PM,the detection accuracy reached 99.63%,with an AUC of 99.98%.Compared with other widely used multi-class models such as VGG16,Vision Transformer(VIT),EfficientNet,this system demonstrates higher accuracy and AUC.This artificial intelligence system is designed to be easily integrated into existing clinical diagnostic tools,providing an efficient solution for large-scale PM screening.

Warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography

High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high efficiency.However,it faces challenge in dense objects tracking and 3D trajectories reconstruction due to the characteristics of small size and dense distribution of fragment swarm.To address these challenges,this work presents a warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography.Firstly,background difference algorithm is utilized to extract the center and area of each fragment in the image sequence.Subsequently,a multi-object tracking(MOT)algorithm using Kalman filtering and Hungarian optimal assignment is developed to realize real-time and robust trajectories tracking of fragment swarm.To reconstruct 3D motion trajectories,a global stereo trajectories matching strategy is presented,which takes advantages of epipolar constraint and continuity constraint to correctly retrieve stereo correspondence followed by 3D trajectories refinement using polynomial fitting.Finally,the simulation and experimental results demonstrate that the proposed method can accurately track the motion trajectories and reconstruct the spatio-temporal distribution of 1.0×10^(3)fragments in a field of view(FOV)of 3.2 m×2.5 m,and the accuracy of the velocity estimation can achieve 98.6%.

A Systematic Literature Review of Machine Learning and Deep Learning Approaches for Spectral Image Classification in Agricultural Applications Using Aerial Photography

Recently,there has been a notable surge of interest in scientific research regarding spectral images.The potential of these images to revolutionize the digital photography industry,like aerial photography through Unmanned Aerial Vehicles(UAVs),has captured considerable attention.One encouraging aspect is their combination with machine learning and deep learning algorithms,which have demonstrated remarkable outcomes in image classification.As a result of this powerful amalgamation,the adoption of spectral images has experienced exponential growth across various domains,with agriculture being one of the prominent beneficiaries.This paper presents an extensive survey encompassing multispectral and hyperspectral images,focusing on their applications for classification challenges in diverse agricultural areas,including plants,grains,fruits,and vegetables.By meticulously examining primary studies,we delve into the specific agricultural domains where multispectral and hyperspectral images have found practical use.Additionally,our attention is directed towards utilizing machine learning techniques for effectively classifying hyperspectral images within the agricultural context.The findings of our investigation reveal that deep learning and support vector machines have emerged as widely employed methods for hyperspectral image classification in agriculture.Nevertheless,we also shed light on the various issues and limitations of working with spectral images.This comprehensive analysis aims to provide valuable insights into the current state of spectral imaging in agriculture and its potential for future advancements.

Investigating Jet Appearance in Different Background Lights with High-Speed Frame Photography

Shaped charge jet formation process is studied under the conditions of different background lights by means of high speed frame photography. In order to shoot true jet appearance, the glass tube in which jet moves is vacuumized. The experiment results show that observing jet appearance with the double reflecting mirrors system is feasible as long as the vacuum of the glass tube can meet the requirement of experiment.

Problems and improvement strategies of photography education in Colleges and Universities

In recent years, with the development of social economy, college photography education career has been developing rapidly, but at the same time, some problems have appeared. In the construction of photography specialty, a series of problems, such as unreasonable course arrangement, outdated hardware facilities and imperfect teaching software system, are hindering the de-velopment of photography education in universities. Therefore, college educators should seriously sum up the problems existing in college photography education, and carry out photography teaching reasonably and scientifically.

On the Improvement Method of Photography Practice Teaching

Photography teaching is different from general culture teaching.There are obvious differences in teaching methods and teachers' teaching styles.To this end,photography teaching should be innovative,really interested in students,love the photography course,and put photography knowledge into practice.At present,some photography teachers have some problems in the way of explai-ning photography knowledge,which makes it difficult for students to really grasp the practical knowledge of photography,and is not conducive to arousing students' interest in learning. The reason is that photography teachers do not attach importance to practical teaching.

基于线性特征边界线的实景三维动态更新关键技术研究

实景三维中国建设是落实数字中国、平安中国、数字经济战略的重要举措,是新时期国家重要新型基础设施,是服务生态文明建设和经济社会发展的基础支撑。“十四五”以来,各地已经陆续开展了一定规模的实景三维建设项目,积累了不同尺度的实景三维底板数据。如何充分利用已有建设成果,且持续保障实景三维数据的时效性、可用性,已经成为下一个亟需解决的问题。文章针对实景三维数据的场景特征属性,提出一种线性特征边界线的实景三维动态更新和场景融合的方案。基于原有场景数据,将目标更新区域最邻近线性特征边界线作为实际更新范围,对其进行切割、拼接、调色、融合等处理,实现多期实景三维数据的无缝融合。

ValueofDigitalX—RayPhotographyinDiagnosisofCongenitalHeartDisease

目的探讨数字化X线摄影在先天性心脏病诊断中的应用价值。方法收集我院2009-01-01—10-31经数字化X线摄影检查阳性并经临床随访或手术证实的先天性心脏病患者97例,对其临床及影像学资料进行回顾性分析。结果 97例患者中,房间隔缺损46例（47.4%）,动脉导管未闭17例（17.5%）,室间隔缺损13例（13.4%）,法洛四联症5例（5.2%）,肺动脉瓣狭窄3例（3.1%）,镜面右位心4例（4.1%）,右位主动脉弓7例（7.2%）,其他复杂畸形2例（2.1%）。X线表现为：肺血增多、肺血减少及心影形态失常。结论数字化X线摄影准备简单、安全、快捷,禁忌证少,整体感强,同时还是术后随访的重要检查手段,目前仍然能够为先天性心脏病的诊断提供独特和有价值的信息。

Full-field mapping of internal strain distribution in red sandstone specimen under compression using digital volumetric speckle photography and X-ray computed tomography

It is always desirable to know the interior deformation pattern when a rock is subjected to mechanicalload. Few experimental techniques exist that can represent full-field three-dimensional （3D） straindistribution inside a rock specimen. And yet it is crucial that this information is available for fully understandingthe failure mechanism of rocks or other geomaterials. In this study, by using the newlydeveloped digital volumetric speckle photography （DVSP） technique in conjunction with X-ray computedtomography （CT） and taking advantage of natural 3D speckles formed inside the rock due to materialimpurities and voids, we can probe the interior of a rock to map its deformation pattern under load andshed light on its failure mechanism. We apply this technique to the analysis of a red sandstone specimenunder increasing uniaxial compressive load applied incrementally. The full-field 3D displacement fieldsare obtained in the specimen as a function of the load, from which both the volumetric and the deviatoricstrain fields are calculated. Strain localization zones which lead to the eventual failure of the rock areidentified. The results indicate that both shear and tension are contributing factors to the failuremechanism. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

A Model for Estimating Total Forest Coverage with Ground-Based Digital Photography

Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P < 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.

Study on Gardening Photography

Through analyzing the concept,development history and works of gardening photography,unique status and charm of gardening photography in the field of photography art was explored.It was proposed that professional knowledge about gardening disciplines should be grasped,and the shoot targets shouid be fully investigated to present excellent works of gardening photography.In addition,photographers should have strong artistic sense,and be able to grasp the means of expressing image language,so that they will produce works with outstanding themes,proper light,concise composition,harmonious hue color and shadow tone.Sophisticated equipment and post processing skills are also needed.

Analysis of droplet transfer of pulsed MIG welding based on electrical signal and high-speed photography

In order to study how welding parameters affect welding quality and droplet transfer, a synchronous acquisition and analysis system is established to acquire and analyze electrical signal and instantaneous images of droplet transfer simultaneously, which is based on a self-developed soft-switching inverter. On the one hand, welding current and voltage signals are acquired and analyzed by a self-developed dynamic wavelet analyzer. On the other hand, images are filtered and optimized after they are captured by high-speed camera. The results show that instantaneous waveforms and statistical data of electrical signal contribute to make an overall assessment of welding quality, and that optimized high-speed images allow a visual and clear observation of droplet transfer process. The analysis of both waveforms and images leads to a further research on droplet transfer mechanism and provides a basis for precise control of droplet transfer.

Does bird photography affect nest predation and feeding frequency?

Bird photography is a popular and growing form of ecotourism that contributes to the economic growth of local communities,but its disturbance to bird reproduction remains understudied.We worked in a tropical forest of southern China,which has experienced a sharp increase in the number of photographers in recent years.We compared nests that were photographed and those that were not,in their nest predation and parental feeding rates.Including nests of 42 species,the results demonstrate that the predation rate of nests that were not photographed(incubation stage:43.3%of 194 nests;nestling stage:34.5%of 110 nests)was significantly higher than that of photographed ones(incubation:2.4%of 83 nests;nestling:11.1%of 81 nests).Among different nest types,open cup nests in shrub and trees were most affected by photography,in both incubation and nestling stages.Of five factors investigated,including three natural factors(nest stage,structure and position),and two anthropogenic factors(photography and distance to forest edge),only photographic disturbance and nest structure had significant effects(open nests had higher predation).The feeding frequency at nests when photographers were present was not strongly different from when they were not present.Human activity therefore had no negative effects on the birds,but showed a positive effect on their nesting success,in terms of reducing nest predation rates.However,there needs to be further assessment of other aspects of nesting(e.g.,clutch size,duration of nestlings in nests),and other kinds of stress responses(e.g.,hormonal changes),before the total effect of bird photography can be understood.

Computer-Assisted DEM-Based Aero Photography Design

In aerial photography, the primary factor is terrain undulation. However, most of the external aerial photography software used for aerial photography design do not take terrain undulation influence into consideration. Therefore, the design result has comparative randomicity and ＂gaps＂ are expected. An aerial photography design system is developed by analyzing the terrain undulation influence to the design result with DEM data so that the forward overlap and side overlap can be justified according to the block terrain undulation to meet specifications or standards. The data designed by this system is compared with the real flying data. The results show that making use of DEM to assist in aerial photography design can ensure that the designed result fits the real terrain better.

PIV analysis and high-speed photographic observation of cavitating flow field behind circular multi-orifice plates

Based on a self-developed hydrodynamic cavitation device with different geometric parameters for circular multi-orifice plates,turbulence characteristics of cavitating flow behind multi-orifice plates,including the effects of orifice number and orifice layout on longitudinal velocity,turbulence intensity,and Reynolds stress,were measured with the particle image velocimetry(PIV)technique.Flow regimes of the cavitating flow were also observed with high-speed photography.The experimental results showed the following:(1)high-velocity multiple cavitating jets occurred behind the multi-orifice plates,and the cavitating flow fields were characterized by topological structures;(2)the longitudinal velocity at each cross-section exhibited a sawtooth-like distribution close to the multi-orifice plate,and each sawtooth indicated one jet issuing from one orifice;(3)there were similar magnitudes and forms for the longitudinal and vertical turbulence intensities at the same cross-section;(4)the variation in amplitude of Reynolds stress increased with an increase in orifice number;and(5)the cavitation clouds in the flow fields became denser with the increase in orifice number,and the clouds generated by the staggered layout of orifices were greater in number than those generated by the checkerboard-type one for the same orifice number.The experimental results can be used to analyze the mechanism of killing pathogenic microorganisms through hydrodynamic cavitation.

Characteristics of Laser Produced Plasmas Obtained by Fast ICCD Photography, Schlieren Photography and Optical Emission Spectroscopy

Pulsed laser produced plasmas(LPP)are important for industrial applications and fundamental researches,and their complex,multi-physical and cross-chemical processes need to be investigated more comprehensively.In this work,images of the luminous plasma,the spatial density distribution,and the plasma parameters are experimentally investigated by using fast ICCD photography,schlieren photography,and optical emission spectroscopy.Plasmas are produced by a 1 064 nm,15 ns Nd:YAG laser.Free expanding and splitting phenomena are observed in vacuum(at the pressure of about 1×10 3Pa)and air(at the pressure of 20 Pa)using fast photography,respectively.Meanwhile,shock waves formed in the atmospheric laser produced plasma are visualized by schlieren photography.The formation of shock waves is interpreted with the Sedov-Taylor theory,and an averaged expansion velocity about 375 m/s of the shock waves is estimated during 200～1 000 ns.Atmospheric air is found to have significant confinement effects on the plasma expansions compared to that in vacuum or low pressure ambient.Based on the optical emission spectroscopy,after 1 000 ns,at 0.6 mm above the target,the plasma temperature is about 7 800 K and the electron number density is approximately 0.64×1016cm-3.

THE APPLICATION OF FOURIER TRANSFORM IN REGULARIZED SPECKLE PHOTOGRAPHY

Two speckle patterns are recorded using a video cameracorresponding to undisplaced and displaced states into the memory ofa computer. After one pattern is added to another, the displacementof the measured points can be calculated by using the Fouriertransform. The expression of displacement field is deduced fornon-uniform displacement, and as an example, a rotatanle disc istested for illustration. The re- sults prove that the present methodis promising.

On Architectural Photography

Definition of architectural photography and features of the discipline in the new era were introduced. It was proposed that consummate photography and photographic equipment were prerequisites of architectural photography, and architectural photographers had to learn architectural cultures and also intentions of architects. In addition, the ways of shooting should be determined by uses of the photos, and rich photographic languages applied to appreciate the buildings.

A Fundus Photographic Method with Narrow Spectral Band Luminance

We perfected the narrow spectral band fundus photographic system using interference filters at the wavelengths of 417, 478, 500, 530, 547, 570, 589, 607, 628 and 648nm. Tests about the light penetration of filters and exposure of various brand films were made on this system. Studies of the contrast of fundal tissues and structures under the different narrow spectral band light were made on 43 Chinese fellow eyes. The results indicates that the interference filters of 570 nm have the highest light penetr...

Measuring Surface Roughness through the Use of Digital Photography and Image Processing

This paper aims to provide a quantitative method that employs image processing in the assessment of surface roughness based on digital photograph field surveys, as in previous studies employing the outdoor integrated digital photography and image processing (O-IDIP) method. Digital photographs were taken on two different days under contrasting outdoor lighting conditions (overcast versus clear sky). Images were captured mounted on a tripod close up to the surface of a 380-year-old wall located at the University of Oxford Botanic Garden in the City of Oxford, UK. Sampling points were established at regular intervals along the border wall and encompassed sections facing west, north, and east, respectively along the survey. Two photographs were taken with a digital camera at each sampling point, one containing a color chart used to calibrate outdoor lighting conditions across images, which was excluded from the other photographic pair. Histogram-based quantification was performed based on images converted to Lab Color mode. The 10-step calibration procedure presented in this paper required more adjustments of contrast. However, more adjustments were not required under a clear sky. Std Dev L measurements were used to establish categories in a simple 3-point roughness index, namely the surface roughness index (SRI). The results denote that pitting did not affect surface roughness measurements. The study shows that it is possible to use Std Dev L measurements to quantify surface roughness on a comparative basis.