visual contrast
Recently Published Documents


TOTAL DOCUMENTS

376
(FIVE YEARS 84)

H-INDEX

32
(FIVE YEARS 4)

2022 ◽  
Vol 6 (1) ◽  
pp. V9

A contrast-enhancing lesion in the left temporal lobe of a 72-year-old woman was biopsied and diagnosed as glioblastoma. Near-infrared (NIR)–labeled epidermal growth factor receptor (EGFR) antibody, panitumumab-IRDye800, was infused 52 hours before craniotomy without pretreatment. Tumor fluorescence was detected through intact dura, and the visual contrast between disease and peritumoral healthy brain was enhanced after tumor exposure. Residual cancerous tissue was identified with strong fluorescence in resection cavity after en bloc tumor removal. Minimal fluorescence remained in the final wound bed, likely from nonenhancing tumor. Fluorescence was heterogeneously distributed at the infiltrative margin in resected tumor pieces imaged ex vivo. Postoperative MRI confirmed gross-total resection. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21201


2021 ◽  
Vol 15 ◽  
Author(s):  
Irina Shoshina ◽  
Inna Zelenskaya ◽  
Valeriia Karpinskaia ◽  
Yuri Shilov ◽  
Elena Tomilovskaya

The aim of this work was to study the sensitivity of the visual system in 5-day “dry” immersion with a course of high-frequency electromyostimulation (HFEMS) and without it. “Dry” immersion (DI) is one of the most effective models of microgravity. DI reproduces three basic effects of weightlessness: physical inactivity, support withdrawal and elimination of the vertical vascular gradient. The “dry” immersion included in the use of special waterproof and highly elastic fabric on of immersion in a liquid similar in density to the tissues of the human body. The sensitivity of the visual system was assessed by measuring contrast sensitivity and magnitude of the Müller-Lyer illusion. The visual contrast sensitivity was measured in the spatial frequency range from 0.4 to 10.0 cycles/degree. The strength of visual illusion was assessed by means of motor response using “tracking.” Measurements were carried out before the start of immersion, on the 1st, 3rd, 5th days of DI, and after its completion. Under conditions of “dry” immersion without HFEMS, upon the transition from gravity to microgravity conditions (BG and DI1) we observed significant differences in contrast sensitivity in the low spatial frequency range, whereas in the experiment with HFEMS—in the medium spatial frequency range. In the experiment without HFEMS, the Müller-Lyer illusion in microgravity conditions was absent, while in the experiment using HFEMS it was significantly above zero at all stages. Thus, we obtained only limited evidence in favor of the hypothesis of a possible compensating effect of HFEMS on changes in visual sensitivity upon the transition from gravity to microgravity conditions and vice versa. The study is a pilot and requires further research on the effect of HFEMS on visual sensitivity.


2021 ◽  
Vol 02 (02) ◽  
Author(s):  
Nur Farhana Fadzil ◽  
◽  
Siti Amira Othman ◽  

Qai’lullah or napping is a phenomenon that is widely practiced in the world. Islam advocates mid-day napping as it is primarily practiced by the Prophet Muhammad (pbuh). Scientists and scholars also acknowledge the benefits beyond this practice after various research and studies done. Hence, this article emphasizes topic of sleep in Islamic insight, their stages of sleeps according to Quran and the practiced of Qai’lullah or mid-day napping. The high-energy blue light exposure from the natural source, Sun and also digital screens reported reduce visual contrast and affect the sharpness and clarity by creating glares lead to mental and physical fatigue. Thus, a short nap in the mid-afternoon helps to boost memory, lift our mood, and improve job performance. The effect associated with qai’lullah are also being reviewed including improved the neurocognitive performance, alertness, recover the loss night sleep and enhanced the quality and increased memory consolidation in people.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ozan E. Eren ◽  
Andreas Straube ◽  
Florian Schöberl ◽  
Ruth Ruscheweyh ◽  
Thomas Eggert ◽  
...  

Abstract Objective Patients with visual snow syndrome (VSS) suffer from a debilitating continuous (“TV noise-like”) visual disturbance. They report problems with vision at night and palinopsia despite normal visual acuity. The underlying pathophysiology of VSS is largely unknown. Currently, it is a clinical diagnosis based on the patient’s history, an objective test is not available. Here, we tested the hypothesis that patients with VSS have an increased threshold for detecting visual contrasts at particular temporal frequencies by measuring dynamic contrast detection-thresholds. Methods Twenty patients with VSS were compared to age-, gender-, migraine- and aura-matched controls in this case-control study. Subjects were shown bars randomly tilted to the left or right, flickering at six different frequencies (15 Hz, 20 Hz, 25 Hz, 30 Hz, 35 Hz, 40 Hz). The contrast threshold (CT) for detection of left or right tilt was measured in a two-alternative adaptive forced-choice procedure (QUEST). The threshold was defined as the Michelson contrast necessary to achieve the correct response in 75% of the cases. Results The CT increased for higher flicker frequencies (ANOVA: main effect frequency: F (5,180) = 942; p < 0.001), with an additional significant frequency*diagnosis interaction (ANOVA: F (5,180) = 5.00; p < 0.001). This interaction effect was due to an increased CT at a flicker frequency of 15 Hz in the VSS cohort (VSS: MC = 1.17%; controls: MC = 0.77%). At the other frequencies, group comparisons revealed no differences. Furthermore, in the VSS cohort we observed an increase of CT with higher age (r = 0.69; p < 0.001), which was not seen in controls (r = 0.30; p = 0.20). Conclusions This study demonstrates a lower visual contrast sensitivity exclusively at 15 Hz in VSS patients and demonstrates frequency-dependent differences in dynamic contrast vision. The peak sensitivities of both parvo- and magnocellular visual pathways are close to a frequency of about 10 Hz. Therefore, this frequency seems to be of crucial importance in everyday life. Thus, it seems plausible that the impairment of contrast sensitivity at 15 Hz might be an important pathophysiological correlate of VSS. Furthermore, the overall age-related decrease in contrast sensitivity only in VSS patients underscores the vulnerability of dynamic contrast detection in VSS patients. Dynamic CT detection seems to be a promising neurophysiological test that may contribute to the diagnosis of VSS.


2021 ◽  
Vol 144 ◽  
pp. 138-145
Author(s):  
Shaynna N. Herrera ◽  
Vance Zemon ◽  
Nadine Revheim ◽  
Gail Silipo ◽  
James Gordon ◽  
...  

2021 ◽  
Author(s):  
◽  
Alexander Love

<p>Historic buildings play an important role in helping shape and characterise a city’s’ urban fabric. They extend beyond purely the aesthetic by enhancing our urban experience through providing a notion of continuity, and, by forming an enduring connection to our past, present, and future. In many instances, extending a historic building’s life that has fallen into a state of dilapidation, and, saving the rich history in which resides within its walls requires a rehabilitative or adaptive approach. Undertaking this process however, can become challenging when there lies an absence of interior documentation for the site. A clear understanding of the current, forsaken state in which the building’s interior has sunken into cannot therefore be established.  The aim of this research is to therefore explore how a rehabilitative approach can be applied to the dilapidated, heritage listed, former Tramway Hotel to rejuvenate its forgotten interiors. By breathing another life into the building’s old bones, it seeks to make it fit for modern purposes once again whilst tangentially retaining the rich history that is housed within its weathered walls. Through the cyclical, reflective, and iterative nature of action research, this research investigates a range of techniques in response to the site’s forgotten interiors. By initially exploring the issue from various avenues, through the cycles of identifying, planning, acting and then critically self-reflecting, the design iterations produced refined in scope to eventuate in the act of strategically inserting, and then shifting newly built elements within the existing structure of the former Tramway Hotel. What was essential throughout the research and was therefore translated into a criterion for the evaluation of each iteration, was the need to add another life to the building, to allow it to persist, to live on without disrupting its historic integrity and character. Through the implementation and direct visual contrast of the newly built elements from historic ones, the developed design response seeks to establish a clear dialogue between the two so that each complements and enhances the other.</p>


2021 ◽  
Author(s):  
◽  
Alexander Love

<p>Historic buildings play an important role in helping shape and characterise a city’s’ urban fabric. They extend beyond purely the aesthetic by enhancing our urban experience through providing a notion of continuity, and, by forming an enduring connection to our past, present, and future. In many instances, extending a historic building’s life that has fallen into a state of dilapidation, and, saving the rich history in which resides within its walls requires a rehabilitative or adaptive approach. Undertaking this process however, can become challenging when there lies an absence of interior documentation for the site. A clear understanding of the current, forsaken state in which the building’s interior has sunken into cannot therefore be established.  The aim of this research is to therefore explore how a rehabilitative approach can be applied to the dilapidated, heritage listed, former Tramway Hotel to rejuvenate its forgotten interiors. By breathing another life into the building’s old bones, it seeks to make it fit for modern purposes once again whilst tangentially retaining the rich history that is housed within its weathered walls. Through the cyclical, reflective, and iterative nature of action research, this research investigates a range of techniques in response to the site’s forgotten interiors. By initially exploring the issue from various avenues, through the cycles of identifying, planning, acting and then critically self-reflecting, the design iterations produced refined in scope to eventuate in the act of strategically inserting, and then shifting newly built elements within the existing structure of the former Tramway Hotel. What was essential throughout the research and was therefore translated into a criterion for the evaluation of each iteration, was the need to add another life to the building, to allow it to persist, to live on without disrupting its historic integrity and character. Through the implementation and direct visual contrast of the newly built elements from historic ones, the developed design response seeks to establish a clear dialogue between the two so that each complements and enhances the other.</p>


2021 ◽  
Vol 38 (5) ◽  
pp. 1345-1351
Author(s):  
Sunkavalli Jaya Prakash ◽  
Manna Sheela Rani Chetty ◽  
Jayalakshmi A

One of the most important processes in image processing is image enhancement, which aims to enhance image contrast and quality of information. Due to the lack of adequate conventional image enhancement and the challenge of mean shift, intelligence-based image enhancement systems are becoming an essential requirement in image processing. This paper proposes a new approach for enhancing low contrast images utilizing a modified measure and integrating a new Chaotic Crow Search (CCS) and Krill Herd (KH) Optimization-based metaheuristic algorithm. Crow Search Algorithm is a cutting-edge meta-heuristic optimization technique. Chaotic maps are incorporated into the Crow Search Method in this work to improve its global optimization. The new Chaotic Crow Search Algorithm depends on chaotic sequences to replace a random location in the search space and the crow's recognition factor. Based on a new fitness function, Krill Herd optimization is utilized to optimize the tunable parameter. The fitness function requires different primary objective functions that use the image's edge, entropy, grey level co-occurrence matrix (GLCM) contrast, and GLCM energy for increased visual, contrast, and other descriptive information. The results proved that the suggested approach outperforms all-new methods in terms of contrast, edge details, and structural similarity, both subjectively and statistically.


Vehicles ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 661-690
Author(s):  
Ane Dalsnes Storsæter ◽  
Kelly Pitera ◽  
Edward McCormack

Road markings are beneficial to human drivers, advanced driver assistance systems (ADAS), and automated driving systems (ADS); on the contrary, snow coverage on roads poses a challenge to all three of these groups with respect to lane detection, as white road markings are difficult to distinguish from snow. Indeed, yellow road markings provide a visual contrast to snow that can increase a human drivers’ visibility. Yet, in spite of this fact, yellow road markings are becoming increasingly rare in Europe due to the high costs of painting and maintaining two road marking colors. More importantly, in conjunction with our increased reliance on automated driving, the question of whether yellow road markings are of value to automatic lane detection functions arises. To answer this question, images from snowy conditions are assessed to see how different representations of colors in images (color spaces) affect the visibility levels of white and yellow road markings. The results presented in this paper suggest that yellow markings provide a certain number of benefits for automated driving, offering recommendations as to what the most appropriate color spaces are for detecting lanes in snowy conditions. To obtain the safest and most cost-efficient roads in the future, both human and automated drivers’ actions must be considered. Road authorities and car manufacturers also have a shared interest in discovering how road infrastructure design, including road marking, can be adapted to support automated driving.


2021 ◽  
Author(s):  
Trevor R Sorrells ◽  
Anjali Pandey ◽  
Adriana Rosas-Villegas ◽  
Leslie B Vosshall

Predatory animals first detect, then pursue, and ultimately capture prey. Sensory cues, including scent emitted by prey, are detected by the predator and used to guide pursuit. Because the pursuit phase can last for extended periods of time, it is critical for predators to persist in the chase even when prey is difficult to detect in a noisy sensory land-scape. It is equally important for predators to abandon pursuit if enough time has elapsed that prey capture is unlikely to occur. We studied prey detection and sustained pursuit in the mosquito Aedes aegypti, a micropredator of humans. These animals first detect hu-mans through sensory cues that are emitted at a distance such as carbon dioxide in breath and odor from skin. As the mosquito approaches a human, additional cues such as body heat and visual contrast signal the promise of a blood meal, which females need to produce eggs. To study how initial prey detection influences the duration of pursuit, we developed optogenetic tools to induce a brief fictive sensation of carbon dioxide and used machine learning-based classification of behavior to investigate how mosquitoes respond to subsequent human cues. We found that a 5-second optogenetic pulse of fictive carbon dioxide induced a persistent behavioral state in female mosquitoes that lasted for more than 10 minutes. This state is highly specific to females searching for a blood meal and was not induced in recently blood-fed females or in males, who do not feed on blood. In males that lack the gene fruitless, which controls persistent social behaviors in other insects, fictive carbon dioxide induced a long-lasting behavior response resembling the predatory state of females. Finally, we show that the persistent state triggered by detection of fictive carbon dioxide enabled females to engorge on a blood meal mimic offered up to 14 minutes after the initial stimulus. Our results demonstrate that a persistent internal state allows female mosquitoes to integrate multiple human sensory cues over long timescales, an ability that is key to their success as an apex micropredator of humans


Sign in / Sign up

Export Citation Format

Share Document