The dynamics of spherical laser-induced cavitation bubbles in water is investigated by plasma photography, time-resolved shadowgraphs and sensitive single-shot probe beam scattering that portrays the ...transition from initial nonlinear to late linear oscillations. The frequency of late oscillations yields the bubble's gas content. Numerical simulations with an extended Gilmore model using plasma size as input and oscillation times as fit parameter provide insights into experimentally not accessible bubble parameters and shock wave emission. Model extensions include a term covering the initial shock-driven acceleration of the bubble wall, an automated method determining shock front position and pressure decay and a complete energy balance for the partitioning of absorbed laser energy into vaporization, bubble and shock wave energy and dissipation through viscosity and condensation. These tools are used for analysing a scattering signal covering 102 oscillation cycles from a bubble with 36 μm maximum radius produced by a plasma with 1550 K average temperature. Predicted bubble wall velocities during expansion agree well with experimental data. Upon first collapse, most energy was stored in the compressed liquid around the bubble and radiated away acoustically. The collapsed bubble contained more vapour than gas and had a pressure of 13.5 GPa. The decay of the rebound shock wave pressure with radius r was initially $\mathrm{\ \propto }{r^{ - 1.8}}$, and energy dissipation at the shock front heated the liquid near the bubble wall to temperatures above the superheat limit. The shock-induced temperature rise reduces damping during late bubble oscillations. Damping in first collapse increases significantly for small bubbles with less than 10 μm radius.
Diabetic retinopathy (DR) is a sight‐threatening complication of diabetes mellitus (DM) and it contributes substantially to the burden of disease globally. During the last decades, the development of ...multiple imaging modalities to evaluate DR, combined with emerging treatment possibilities, has led to the implementation of large‐scale screening programmes resulting in improved prevention of vision loss. However, not all patients are able to participate in such programmes and not all are at equal risk of DR development and progression. In this review, we discuss the relevance of the currently available imaging modalities for the evaluation of DR: colour fundus photography (CFP), ultrawide‐field photography (UWFP), fundus fluorescein angiography (FFA), optical coherence tomography (OCT), OCT angiography (OCTA) and functional testing. Furthermore, we suggest where a particular imaging technique of DR may aid the evaluation of the disease in different clinical settings. Combining information from various imaging modalities may enable the design of more personalized care including the initiation of treatment and understanding the progression of disease more adequately.
As the visual component of contemporary media has overtaken the verbal, visual reportage has established a unique and extremely significant role in 21st-century culture. Julianne Newton has prepared ...this comprehensive analysis of the development of the role of visual reportage as a critical player in the evolution of our understanding of ourselves, others, and the world. The Burden of Visual Truth offers a first assessment of the role of visual journalism within the context of the complex, cross-disciplinary pool of literature and ideas required for synthesis. Newton approaches the subject matter from several perspectives, examining the theoretical and ideological bases for visual truth, particularly as conveyed by the news media, and applying relevant research on photojournalism and reality imagery to contemporary newspaper, broadcast, and internet professional practice. She extends visual communication theory by proposing an ecology of the visual for 21st century life and developing a typology of human visual behavior. Scholars in visual studies, media studies, journalism, nonverbal communication, cultural history, and psychology will find this analysis invaluable as a comprehensive base for studying reality imaging and human visual behavior. The volume also is appropriate for journalism and media studies coursework at the undergraduate and graduate levels. With its conclusions about the future of visual reportage, The Burden of Visual Truth also will be compelling reading for journalism and mass communication professionals concerned with improving media credibility and maintaining a significant course for journalism in the 21st century. For all who seek to understand the role of visual media in the formation of their views of the world and of their own identities, this volume is a must-read.
To define the social interactions of a photographer and the portrayed artist as friendship is a recurring topos in art. However, only in some instances can the photographic portrait fulfill the ...concrete visibility represented in romantic paintings. Do the attributes of portraiture of a friend remain as unspecified as the hope for authenticity and intimacy ascribed to the term friendship?
•Violent offenders may attempt to conceal physical evidence using fire.•Bloodstains situated within the hot layers of a fire can be concealed by soot.•Longer wavelengths reduce the relative optical ...density of overlaying soot.•Reflected infrared photography may visualise latent bloodstains cover by soot.
Bloodstain evidence is an element of crime scene investigation often found at scenes involving violence. Setting fire to the scene is a method sometimes used by offenders of crime in an attempt to conceal evidence. Fire often produces thick soot as a by-product of the combustion and has the potential to cover bloodstain patterns rendering them latent. There is limited published material offering a method of detecting bloodstains hidden beneath dense soot deposits caused by fire. This project employed a modified digital single-lens reflex (SLR) camera to investigate the application of reflected infrared photography to detect latent bloodstain evidence beneath varying deposited overlaying soot densities. The potential of this technique was examined by photographing blood samples beneath soot from a scaled fire simulation. A qualitative evaluation was completed by comparing images taken of a series of samples using both reflected infrared and standard visible light photography and corroborated with quantitative image analysis to support the findings. Results indicate that infrared photography can reveal latent bloodstains beneath a dense layer of soot in excess of ρ2.3 (550nm) density with substantial clarity. The success of this technique is dependent on specific optical and specimen parameters. These parameters include (i) the reflective properties of the background surface, (ii) the spectral absorption properties of blood and (iii) the ability of infrared wavelengths to transmit through the soot layer. Reflected infrared photography may provide crime scene examiners with a specialised field recording method that is easily executed and non-destructive to assist in visualising and locating latent bloodstain patterns beneath dense layers of soot.
Holography of today is a broad field developed in the meeting between optics and the digital world of computers. A hologram usually contains more or different information on the observed scene than a ...regular image of the same scene. The development of the field has been accelerated lately due to the improvement of digital cameras, computers, light sources, and spatial light modulators. As a multidisciplinary area, holography connects experts in electro-optical engineering, image processing, and computer algorithms. More experts are needed when holography is utilized in various applications such as microscopy, industrial inspection, biomedicine, and entertainment. This book provides an overview of the world of holography from the aspect of concepts, system architectures, and applications.
Aerial photography is a long-range, non-contact method of target detection technology that enables qualitative or quantitative analysis of the target. However, aerial photography images generally ...have certain chromatic aberration and color distortion. Therefore, effective segmentation of aerial images can further enhance the feature information and reduce the computational difficulty for subsequent image processing. In this paper, we propose an improved version of Golden Jackal Optimization, which is dubbed Helper Mechanism Based Golden Jackal Optimization (HGJO), to apply multilevel threshold segmentation to aerial images. The proposed method uses opposition-based learning to boost population diversity. And a new approach to calculate the prey escape energy is proposed to improve the convergence speed of the algorithm. In addition, the Cauchy distribution is introduced to adjust the original update scheme to enhance the exploration capability of the algorithm. Finally, a novel "helper mechanism" is designed to improve the performance for escape the local optima. To demonstrate the effectiveness of the proposed algorithm, we use the CEC2022 benchmark function test suite to perform comparison experiments. the HGJO is compared with the original GJO and five classical meta-heuristics. The experimental results show that HGJO is able to achieve competitive results in the benchmark test set. Finally, all of the algorithms are applied to the experiments of variable threshold segmentation of aerial images, and the results show that the aerial photography images segmented by HGJO beat the others. Noteworthy, the source code of HGJO is publicly available at https://github.com/Vang-z/HGJO.
This article describes the institutionalisation of Brazilian photography in the late 1970s and early 1980s in the context of the other events relating to photography in Latin American countries. This ...process has close links with the first two Latin American Colloquia of Photography held in Mexico City in 1978 and 1981. These Colloquia promoted the creation of connections between Brazilian photographers and photographic institutions and those in Spanish-speaking Latin America. They also made it possible to bring European and North American institutional photographic experiences to Latin America, and helped to disseminate a version of Latin American photography in Europe, one that was based on a socially engaged documentary, the genre which was showcased and foregrounded at the Colloquia.
