scholarly journals Interactions between luminance steps and luminance textures for boundary segmentation

2021 ◽  
Author(s):  
Christopher DiMattina

ABSTRACTIn natural scenes, two adjacent surfaces may differ in mean luminance without any sharp change in luminance at their boundary, but rather due to different relative proportions of light and dark regions within each surface. We refer to such boundaries as luminance texture boundaries (LTBs), and in this study we investigate interactions between luminance texture boundaries and luminance step boundaries (LSBs) in a segmentation task. Using a simple masking paradigm, we find very little influence of LSB maskers on LTB segmentation thresholds. Similarly, we find only modest effects of LTB maskers on LSB thresholds. By contrast, each kind of boundary strongly masks targets of the same kind. Our data is consistent with the possibility that luminance texture boundaries may be segmented using different mechanisms than those used to segment luminance step boundaries. At the same time, our work also suggests that LTB segmentation is subject to influences from LSBs. We suggest that the relative robustness of LTB segmentation to interference from LSBs may serve the ecologically important role of providing robustness to changes in luminance caused by cast shadows, and we propose future experimental work to investigate this hypothesis.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christopher DiMattina ◽  
Curtis L. Baker

AbstractSegmenting scenes into distinct surfaces is a basic visual perception task, and luminance differences between adjacent surfaces often provide an important segmentation cue. However, mean luminance differences between two surfaces may exist without any sharp change in albedo at their boundary, but rather from differences in the proportion of small light and dark areas within each surface, e.g. texture elements, which we refer to as a luminance texture boundary. Here we investigate the performance of human observers segmenting luminance texture boundaries. We demonstrate that a simple model involving a single stage of filtering cannot explain observer performance, unless it incorporates contrast normalization. Performing additional experiments in which observers segment luminance texture boundaries while ignoring super-imposed luminance step boundaries, we demonstrate that the one-stage model, even with contrast normalization, cannot explain performance. We then present a Filter–Rectify–Filter model positing two cascaded stages of filtering, which fits our data well, and explains observers' ability to segment luminance texture boundary stimuli in the presence of interfering luminance step boundaries. We propose that such computations may be useful for boundary segmentation in natural scenes, where shadows often give rise to luminance step edges which do not correspond to surface boundaries.


2020 ◽  
Author(s):  
Christopher DiMattina ◽  
Curtis L. Baker

ABSTRACTSegmenting scenes into distinct surfaces is a basic visual perception task, and luminance differences between adjacent surfaces often provide an important segmentation cue. However, mean luminance differences between two surfaces may exist without any sharp change in albedo at their boundary, but rather from differences in the proportion of small light and dark areas within each surface, e.g. texture elements, which we refer to as a luminance texture boundary. Here we investigate the performance of human observers segmenting luminance texture boundaries. We demonstrate that a simple model involving a single stage of filtering cannot explain observer performance, unless it incorporates contrast normalization. Performing additional experiments in which observers segment luminance texture boundaries while ignoring super-imposed luminance step boundaries, we demonstrate that the one-stage model, even with contrast normalization, cannot explain performance. We then present a Filter-Rectify-Filter (FRF) model positing two cascaded stages of filtering, which fits our data well, and explains observers’ ability to segment luminance texture boundary stimuli in the presence of interfering luminance step boundaries. We propose that such computations may be useful for boundary segmentation in natural scenes, where shadows often give rise to luminance step edges which do not correspond to surface boundaries.


2019 ◽  
Vol 7 (1) ◽  
pp. 10-18
Author(s):  
Tsvetanka Tsenova

This article focuses on the relationship between literacy methods applied at school and the emergence of serious difficulties in mastering reading and writing skills that shape the developmental dyslexia. The problem was analyzed theoretically and subjected to empirical verification. Experimental work was presented which aims to study the phonological and global reading skills of 4- th grade students with and without dyslexia. Better global reading skills have been demonstrated in all tested children, and this is much more pronounced in those with dyslexia than their peers without disorders. Hence, the need to develop a special, corrective methodology for literacy of students with developmental dyslexia consistent with their psychopathological characteristics.


Author(s):  
Adil Ali Aiyush Al Zeen

ملخص البحث: يعرض هذا البحث موضوع  الخلود في الشعر الجاهلي، ودوره في تكوين شخصية الرجل المثال؛ إذ إن الجاهليين أرَّقَتهم مسألة الفناء، فبحثوا عن الخلود الجسدي وأدركوا أنه لا يمكن تحقيقه، وأمام رفضهم للفناء، اتضح لهم أن الخلود المعنوي هو السبيل الوحيد لبقاء الذكر بعد فناء الجسد، فعمد الرجل المثال في العصر الجاهلي إلى القيام بأفعالٍ حميدةٍ يذكره الشعراء في قصائدهم بها، ويفخر بها هو في أشعاره، كشهرة عنترة بالشجاعة، وحاتم بالكرم، والسموأل بالوفاء. ولإدراكهم أن أفعالهم تلك ستُبْقِي ذكرهم سائر العصور. توصل البحث إلى نماذج من أشعار الجاهليين، ليصل في النهاية إلى أنهم أدركوا أن خلودهم يتحقق معنوياً لا جسدياً. فيظهر لنا - من خلال الشعر – معنى الخلود ومعنى المثال، وإدراكهم لحقيقة الفناء بعد أن لمسوه في أنفسهم وفي مشاهد الطبيعة من حولهم، وطريقتهم في البحث عن الخلود المعنوي، ودور الشعر في تحقيق هذه الغاية. ثم يتبيَّنُ لنا إدراكهم أن الخلود لا يكون إلا من خلال المُثُلِ والقِيَمِ العربية التي كانوا يأتونها ويفخرون بها. الكلمات المفتاحية: الجاهلي - الشعر - الرجل - المثال - الخلود.         Abstract     The paper discusses the topic of immortality in the pre-Islamic period and its role in constructing the character of an ideal man. Since the Arabs before Islam were softened by the issue of death, they dwelled on the topic of immortality though they knew it too well its impossibility. As they rejected mortality, they realized that the abstract immortality is the only way for them to be remembered after the mortality of the body that enticed the ideal man in the pre-historic period to do commendable deeds that other poets would mention them with or he would make it as a virtue in his poems; as ‘Antarah was known for his bravery, Hatim with his generosity and Samuel with his loyalty as they realized that their deeds will be remembered for the rest of the ages. The study highlighted on a number of the Pre-Islamic poems and concluded that those poets realized that their mortality was achievable in a subtle way but not physically. This seems to us- from the poems- the meaning of immortality, idealism and their realization of the meaning of mortality from what they witnessed from the natural scenes that take place around them; the means to immortalize themselves in a subtle way and the role of poems in achieving this aim. We also learned that they themselves were fully aware that immortality is possible only through the Arabic virtues that they so proudly adhered to.   Keywords: Pre-Islamic period, Poem, Man, Ideal, Immortality     Abstrak   Makalah ini membincangkan tema keabadian hidup dalam era Jahiliah dan peranannya dalam membentuk keperibadian manusia ideal. Memandangkan bangsa Arab sebelum Islam mudah dilunakkan dengan isu kematian, mereka tetap mencanangkan tema keabadian walaupun sedar tentang kemustahilan untuk mengelaknya. Apablila mereka cuba menolak kematian, mereka menyedari bahawa keabadian secara abstrak ialah satu-satunya cara untuk mereka diingati selepas kematian dan meninggalkan legasi manusia ideal  dalam era Jahiliah ialah dengan menjadikan ingatan terhadap mereka itu ialah dengan kebaikan apa yang mereka lakukan dalam sebutan penyair-penyair lain ataupun dengan mereka sendiri menyebutnya dalam karya syair mereka sendiri. Demikianlah ‘Antarah dikenali dengan keberaniannya, Hatim dengan kemurahan hatinya, Samuel dengan kesetiaannya kerana kebaikan mereka akan dikenali sehingga bila-bila. Kajian ini menumpukan  kepada beberapa syair Jahiliah dan menyimpulkan bahawa penyair-penyair tersebut menyedari bahawa keabadian mereka boleh dicapai secara halus dan bukan secara fizikal. Kita dapat merumuskan daripada syair-syair tersebut bahawa pernyataan maksud keabadian dan idealisma serta penyerlahan maksud keabadian oleh mereka melalui apa yang mereka lihat berlaku di sekeliling mereka; cara untuk mengabadikan diri mereka ialah dengan melalui syair. Kami juga memperoleh maklumat bahawa mereka juga amat menyedari yang keabadian adalah sesuatu yang dapat dicapai melalui nilai-nilai budaya Arab yang amat mereka banggakan.   Kata kunci: Era jahiliah, Syair, Manusia, Keabadian


2004 ◽  
Vol 14 (02) ◽  
pp. 453-491 ◽  
Author(s):  
EROL BAŞAR ◽  
MURAT ÖZGÖREN ◽  
SIREL KARAKAŞ ◽  
CANAN BAŞAR-EROĞLU

The present report describes the dynamic foundations of long-standing experimental work in the field of oscillatory dynamics in the human and animal brain. It aims to show the role of multiple oscillations in the integrative brain function, memory, and complex perception by a recently introduced conceptional framework: the super-synergy in the whole brain. Results of recent experiments related to the percept of the grandmother-face support our concept of super-synergy in the whole brain in order to explain manifestation of Gestalts and Memory-Stages. This report may also provide new research avenues in macrodynamics of the brain.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Oliver Zimmermann ◽  
Kefei Li ◽  
Myron Zaczkiewicz ◽  
Matthias Graf ◽  
Zhongmin Liu ◽  
...  

The role of C-reactive protein (CRP) in atherosclerosis is controversially discussed. Whereas initial experimental studies suggested a pathogenic role for CRP in atherogenesis, more recent genetic data from Mendelian randomization trials failed to provide evidence for a causative role of CRP in cardiovascular disease. Also, experimental results from laboratories all over the world were indeed contradictory, partly because of species differences in CRP biology and partly because data were not accurately evaluated. Here we summarize the published data from experimental work with mainly human material in order to avoid confusion based on species differences in CRP biology. Experimental work needs to be reevaluated after reconsideration of some traditional rules in research: (1) in order to understand a molecule’s role in disease it may be helpful to be aware of its role in physiology; (2) it is necessary to define the disease entity that experimental CRP research deals with; (3) the scientific consensus is as follows: do not try to prove your hypothesis. Specific CRP inhibition followed by use of CRP inhibitors in controlled clinical trials may be the only way to prove or disprove a causative role for CRP in cardiovascular disease.


1998 ◽  
Vol 526 ◽  
Author(s):  
R. Kubo ◽  
H. Xu ◽  
Y. Yoshino ◽  
M. Okuyama

AbstractBa1-xSrxTiO3 thin films have been deposited on Pt/Ti/SiO2/Si substra by the pulsed ArF laser deposition method. Deposition conditions, such as ambient gas and substrt temperatze, have been optmized to rrxove crystallinepropesty. Fe oelectric p e phasehasbeenobtainod ithe BSTthin filns deposited above 500°C in Q2 gas havingpressure ofabout 13Pa. Using N2O gas instead of O2 gas improved the crystallinity, because highly chemical active oxygen radicals produced due to ultraviolet inadiation of the laser. Doping of Bi ranging around 2% fills of the role of decrease leakage current of BST thin films. Temperature dependence of the dielectric constant (εr) shows a sharp change, peaking aroumd room temperature. The peak point exists below 25°C in the ratio of Ba/Sr=1.1 film, and shills above 50°C in Ba/Sr=5.7 film. When the Ba/Sr ratio is 1.4 the dielectric peak exists near 27°C and is very sharp. The maxinium differentW rate of dielectric constanttversus temperature is the largest in Ba/Sr=1.4 film and is about 100K-1. This value is equivalent to apyroelectric coefficient of 1.8 × 10-7 C/cm2K, which is almost the same as that of LiTaO3 single crystl, a typical pyroelectric material.


1962 ◽  
Vol 30 (3) ◽  
pp. 186-190 ◽  
Author(s):  
H. V. Neher
Keyword(s):  

2021 ◽  
Author(s):  
Julie M. Schneider ◽  
Yi-Lun Weng ◽  
Anqi Hu ◽  
Zhenghan Qi

Statistical learning, the process of tracking distributional information and discovering embedded patterns, is traditionally regarded as a form of implicit learning. However, recent studies proposed that both implicit (attention-independent) and explicit (attention-dependent) learning systems are involved in statistical learning. To understand the role of attention in statistical learning, the current study investigates the cortical processing of prediction errors in speech based on either local or global distributional information. We then ask how these cortical responses relate to statistical learning behavior in a word segmentation task. We found ERP evidence of pre-attentive processing of both the local (mismatching negativity) and global distributional information (late discriminative negativity). However, as speech elements became less frequent and more surprising, some participants showed an involuntary attentional shift, reflected in a P3a response. Individuals who displayed attentive neural tracking of distributional information showed faster learning in a speech statistical learning task. These results provide important neural evidence elucidating the facilitatory role of attention in statistical learning.


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