National Repository of Grey Literature 42 records found  beginprevious14 - 23nextend  jump to record: Search took 0.00 seconds. 
Content-based Image Search
Talaš, Josef ; Surynek, Pavel (advisor) ; Děchtěrenko, Filip (referee)
This work aims at content-based image search. Different approaches to this type of search are investigated. The main focus of the thesis is special category of content-based image search called sketch-based image search. The most important descriptor types used for image feature extraction in image search are analyzed. Main contribution of the thesis to this research area is a new feature extraction method based on sketch-based image search. This method is implemented together with search interface. The method was evaluated by three test persons. The testing results show promising properties of new method and suggest further possible improve-ments. Powered by TCPDF (www.tcpdf.org)
Bayesian models of eye movements
Lux, Erik ; Děchtěrenko, Filip (advisor) ; Toth, Peter Gabriel (referee)
Attention allows us to monitor objects or regions of visual space and extract information from them to use for report or storage. Classical theories of attention assumed a single focus of selection but many everyday activities, such as playing video games, suggest otherwise. Nonetheless, the underlying mechanism which can explain the ability to divide attention has not been well established. Numerous attempts have been made in order to clarify divided attention, including analytical strategies as well as methods working with visual phenomena, even more sophisticated predictors incorporating information about past selection decisions. Virtually all the attempts approach this problem by constructing a simplified model of attention. In this study, we develop a version of the existing Bayesian framework to propose such models, and evaluate their ability to generate eye movement trajectories. For the comparison of models, we use the eye movement trajectories generated by several analytical strategies. We measure the...
Bayesian models of eye movements
Lux, Erik ; Děchtěrenko, Filip (advisor) ; Toth, Peter Gabriel (referee)
Attention allows us to monitor objects or regions of visual space and extract information from them to use for report or storage. Classical theories of attention assumed a single focus of selection but many everyday activities, such as playing video games, suggest otherwise. Nonetheless, the underlying mechanism which can explain the ability to divide attention has not been well established. Numerous attempts have been made in order to clarify divided attention, including analytical strategies as well as methods working with visual phenomena, even more sophisticated predictors incorporating information about past selection decisions. Virtually all the attempts approach this problem by constructing a simplified model of attention. In this study, we develop a version of the existing Bayesian framework to propose such models, and evaluate their ability to generate eye movement trajectories. For the comparison of models, we use the eye movement trajectories generated by several analytical strategies. We measure the similarity between...
The Focusing of Mental Attention During Sexual Intercourse and the Ability to Achieve Orgasm in Women
Hůtová, Lucie ; Weiss, Petr (advisor) ; Děchtěrenko, Filip (referee)
The present thesis focuses on the relationship between cognitive distractions and female ability to achieve orgasm and female sexual function. The theoretical part summarises current knowledge about female sexual response, the ability to achieve orgasm and explains the concept of cognitive distractions in the context of the spectatoring theory and cognitive interference. The empirical part is split into two phases. First one describes the process of creation, pilot measurements and psychometric evaluation of own measuring tool, Cognitive distractions questionnaire (Dotazník kognitivních distraktorů, DKD). It presents three independent subscales - sexual behavior (DKD-S), negative body image (DKD- B) and bad timing (DKD-C). All subscales were evauated via confirmatory factorial analysis and showed good reliability. The second phase was designed as an explorative correlation study. It focused on finding a relationship between distractions of each subscale of DKD and female ability to achieve orgasm, which was measured with Female Sexual Function Index (FSFI, Rosen et al., 2000). Data was collected via a snowball method with an online questionnaire. Sample consisted of 352 women in the age between 18 and 56 years. Spearman correlation indicated a negative relationship between distractions of sexual...
Pareidolia and its evolutionary significance
Grégr, Richard ; Tureček, Petr (advisor) ; Děchtěrenko, Filip (referee)
In our everyday lives, we come across situations where we might get the impression of seeing characters in the clouds, or faces in moon crates. We think that we found a pattern that we can use to beat a slot-machine, that the constellation of the stars influences us, that we hear voices in background noise, or hear tones in it. All these examples are instances of a phenomenon called apophenia. In other words, apophenia denotes situations where we make a pattern recognition error. A special case of apophenia, in which our brains make the error during the immediate sensory information processing, is called pareidolia. Today there is no unified opinion about the definition of apophenia and pareidolia. This thesis is concerned with the findings about pareidolia, whether it is a product of an evolutionary effort to minimize losses and pattern overfitting. Furthermore, it clarifies apophenia with pareidolia as a special case, and offers a more detailed look at face pareidolia; how our brain processes information about faces, differences between the sexes in propensity to face recognition, and a possible explanation of its evolutionary origin. Key words: pareidolia, apophenia, error management, psychotism, perception
Detection of dynamic Gabor patches in 1/f noise
Šerý, Martin ; Děchtěrenko, Filip (advisor) ; Pilát, Martin (referee)
Research focusing on static scenes with static objects is omitting the time factor from real life examples we are trying to study. Can we say that a lifeguard looking for a drowning man is using the same brain processes that were observed in the laboratory for static scenes? We can conclude that a static scene is a big simplification of the task itself. The aim of this thesis is to prepare a tool which would allow researching dynamic scenes and thus broadening the possibilities of visual detection tasks at hand. Along the tool we also present a couple of simplified examples with which we would like to demonstrate the utilization of the tool. All concluding with a final experiment in which we will try to detect masked patterns in a noisy environment. 1
Visual Memory in the perception of prototypical scenes
Děchtěrenko, Filip ; Lukavský, Jiří (advisor) ; Kulišťák, Petr (referee)
To be able to operate in the world around us, we need to store visual information for further processing. Since we are able to memorize a vast array of visual scenes (photographs of the outside world), it is still an open question of how we represent these scenes in memory. Research shows that perception and memory for visual scenes is a complex problem that requires contribution from many subfields of vision science. In this work we focused on the visual scene memory on the creation of perceptual prototypes. Using convolutional neural networks, we defined the similarity of scenes in the scene space, which we used in two experiments. In the first experiment, we validated this space using a paradigm for detecting an odd scene. In the second experiment, using the Deese-Roediger-McDermott paradigm, we verified the creation of false memories and thus visual prototypes. The results show that people intuitively understand the scene space (Experiment 1) and that a visual prototype is created even in the case of the complex stimuli such as scenes. The results have wide application either for machine evaluation of image similarities or for visual memory research.
Analysis of the robustness of the psychometric functions
Myšička, Pavel ; Děchtěrenko, Filip (advisor) ; Pilát, Martin (referee)
Psychophysics offers a wide range of experimental techniques to study human percep- tion and often uses mathematical models to do so. Psychometrical function is a formal model of the relationship between intensity of stimulus and perception, that is used by psychophysics to model experimental data. There are various types of psychometric functions used in psychophysical practice. So far it is unknown whether use of different psychometric functions in model experiment data can influence the results of experiment. The goal of this work is to explore differences between commonly used psychometric func- tions, prove if there are any differences between their ability to estimate psychometric data and if these differences are big enough so that researchers should pay attention to choice of psychometric function. 1
Perceptual learning and Ideal Bayesian obsever in visual search task
Němeček, Viktor ; Děchtěrenko, Filip (advisor) ; Pilát, Martin (referee)
Searching for objects in a complex environment is an activity we do many times each day. Najemnik and Geisler (2005; 2008; 2009) showed in their work that people do not perform optimally, and devised multiple ideal observer models for one particular visual search task. In this thesis we tried to show that if people get feedback from one of the ideal observer models, they learn to solve the task better during a given amount of trials than they would without the feedback. We were unable to prove any nontrivial result with statistical significance due to a small sample size, but the data suggests that the feedback indeed has a positive effect on the learning, and that the continuation of the research is justified. An iOS application necessary for the experiment was created as a part of the thesis. Aside from the experiment itself, one can also use it to play a visual search testing game. 1
Relationships among characteristics perceived from photos of faces
Machová, Kamila ; Flegr, Jaroslav (advisor) ; Děchtěrenko, Filip (referee)
Estimating others characteristics from facial cues plays an important role in our everyday lives. People usually agree in these estimates well and many of these estimates correlate. Majority studies consider one or few character- istics only and their respondents usually are in narrow ranges of ages. This study is partly based on rating of 13 characteristics of 80 men's and women's faces by respondents of various ages. These data were originally collected within yet unpublished study of Jaroslav Flegr, Amy E. Blum and Šebastian Kroupa. In this study I most strikingly found out that: i) older respondents of both genders rates photos of women as more attractive, ii) respondents spend more time by rating faces considered by themselves as more attractive or nice, iii) men rate people with different eye color as more attractive and women rate others with the same eye color as nicer, iv) preferences computed by two methods do not differ much. 1

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1 Dechtěrenko, F.
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