Compound Letters Research Articles

Prerequisites for Learning Cued Speech in Tamil Language among Individuals with Hearing Impairment

A study was conducted to assess the prerequisite skills for learning Cued Speech in Tamil language among 45 individuals with hearing impairment in the Coimbatore district of Tamil Nadu, India. Purposive sampling method was followed to select the participants. A questionnaire was developed by the authors which included three domains: a) Awareness on Tamil speech sounds, b) Skill to identify the mouth shape for Tamil speech sounds, and c) Skill to form compound letters. Data was gathered and collected through administering the questionnaire and analysed qualitatively and quantitatively. The findings of the study suggested that the individuals were poor achievers in identifying the speech sounds vital for linguistic performance and effective communication. The study recommends exposure to Tamil speech sounds, their formations, and following Mouth shape, which will help to learn the cued speech effectively to enhance the verbal communication skills of individuals with hearing impairment.

Navon letters and composite faces: same or different processing mechanisms?

Navon letters and composite faces are two fascinating demonstrations of hierarchical organization in perception. Many researchers believe that the two types of stimuli and their associated tasks gauge comparable holistic mechanisms. This belief is so common that the two paradigms are now being applied in tandem to measure impaired holistic processing in prosopagnosic patients. But are Navon letters and composite faces processed in a similar fashion? In the present study we take a closer look at their apparent affinity. We gain novel insights into their underlying mechanisms by fitting parameters of the linear ballistic accumulator (LBA) model to empirical correct and incorrect response times (RTs). The results reveal major differences in processing between the two tasks. We conclude that despite the presence of a compelling surface similarity, Navon compound letters and composite faces tap into separate psychological processes.

Spatial cognition in glaucoma: Constricted field of view weakens the perception of global configurations

ABSTRACT We tested whether the global precedence effect shifts towards local precedence when the visual field is reduced by glaucoma. Fifteen patients, 15 age-matched and 15 young controls were presented with compound letters and asked to recognize a target letter occurring randomly at the global (target-large) or at the local (target-small) level. Small stimuli elicited a global precedence effect in all three groups with shorter response times for target-large than for target-small but accuracy was at chance for target-small in patients. Large stimuli produced a shift towards a local precedence effect with shorter response times for target-small than for target-large in all three groups but accuracy was at chance for target-large in patients. The results suggest that glaucoma impairs perception at different spatial scales. The recognition of small letters in the fovea is affected by crowding. The recognition of global configurations is impaired by reduced sensitivity in the peripheral visual field.

An Efficient Deep Learning Model with Interrelated Tagging Prototype with Segmentation for Telugu Optical Character Recognition

More than 66 million people in India speak Telugu, a language that dates back thousands of years and is widely spoken in South India. There has not been much progress reported on the advancement of Telugu text Optical Character Recognition (OCR) systems. Telugu characters can be composed of many symbols joined together. OCR is the process of turning a document image into a text-editable one that may be used in other applications. It saves a great deal of time and effort by not having to start from scratch each time. There are hundreds of thousands of different combinations of modifiers and consonants when writing compound letters. Symbols joined to one another form a compound character. Since there are so many output classes in Telugu, there’s a lot of interclass variation. Additionally, there are not any Telugu OCR systems that take use of recent breakthroughs in deep learning, which prompted us to create our own. When used in conjunction with a word processor, an OCR system has a significant impact on real-world applications. In a Telugu OCR system, we offer two ways to improve symbol or glyph segmentation. When it comes to Telugu OCR, the ability to recognise that Telugu text is crucial. In a picture, connected components are collections of identical pixels that are connected to one another by either 4- or 8-pixel connectivity. These connected components are known as glyphs in Telugu. In the proposed research, an efficient deep learning model with Interrelated Tagging Prototype with Segmentation for Telugu Text Recognition (ITP-STTR) is introduced. The proposed model is compared with the existing model and the results exhibit that the proposed model’s performance in text recognition is high.

Typical visual processing of Navon-style compound letters and compound arrows in developmental prosopagnosia

Typical visual processing of Navon-style compound letters and compound arrows in developmental prosopagnosia

Forest Before Trees: Letter Stimulus and Sex Modulate Global Precedence in Visual Perception.

The global precedence effect (GPE), originally referring to processing hierarchical visual stimuli composed of letters, is characterised by both global advantage and global interference. We present herein a study of how this effect is modulated by the variables letter and sex. The Navon task, using the letters “H” and “S,” was administered to 78 males and 168 females (69 follicular women, 52 luteal women, and 47 hormonal contraceptive users). No interaction occurred between the letter and sex variables, but significant main effects arose from each of these. Reaction times (RTs) revealed that the letter “H” was identified more rapidly in the congruent condition both in the global and the local task, and the letter “S” in the incongruent condition for the local task. Also, although RTs showed a GPE in both males and females, males displayed shorter reaction times in both global and local tasks. Furthermore, luteal women showed higher d’ index (discrimination sensitivity) in the congruent condition for the local task than both follicular women and hormonal contraceptive users, as well as longer exploration time of the irrelevant level during the global task than males. We conclude that, according to the linear periodicity law, the GPE is enhanced for compound letters with straight vs. curved strokes, whereas it is stronger in males than in females. Relevantly, luteal phase of the menstrual cycle seems to tilt women to rely on finer grained information, thus exhibiting an analytical processing style in global/local visual processing.

Global and local mechanisms of perception of “compound letters”

This study describes an algorithm of temporal interaction of spatial mechanisms for global and local analysis in recognition of “compound letters” by second-grade students including some with speech disorders. A method of “compound letters” was used that models some properties of reading without line-by-line text scanning. Large “compound letters” are composed of small letters. Large “compound letters” are congruent if they are composed of the same letters; otherwise, they are incongruent. The test subject was asked to recognize either a large (global task) or a small (local task) letter in the “compound letter” and press the corresponding button. The number of correct/incorrect responses and the reaction time were registered. The responses of second-grade students with and without speech disorders were compared. The percentage of correct responses in recognition of large and small, congruent and incongruent letters was identical, but the response times were different for these groups of test subjects. The temporal properties of interaction of vision system channels that are responsible for local and global analysis during text recognition and speech production were assumed to be important.

The global precedence effect in English and Korean native speakers with Roman, Korean Hangul and Thai compound letters

The aim was to investigate whether native English speakers (Experiment 1) and native Korean speakers (Experiment 2) processed familiar letters in an analytic manner in comparison to unfamiliar letters or symbols. Participants performed a two-alternative-forced-choice identification task with Roman, Korean Hangul and Thai Navon compound letters (large letters made up of small letters). The English speakers were familiar with Roman script but not Korean or Thai, whereas the Korean speakers were familiar with Korean and Roman script but not Thai. The global precedence effect (GPE), an indication of holistic processing, is characterised by a global advantage (global processing is faster than local processing) and asymmetric congruence (global processing interferes with the processing of local features). Based on previous research, it was predicted that there would be a global precedence effect for unfamiliar but not familiar letters.Results from the English speakers did not support this prediction as we found a GPE for familiar Roman as well as unfamiliar Thai letters but not for unfamiliar Korean letters. In contrast, for the Korean speakers, we found support for the prediction as we found a GPE for Thai letters but not for familiar Korean and Roman letters. Based on this evidence, we propose that the Koreans are processing Korean and Roman letters in a more analytic manner than the English native speakers for Roman script. Due to the characteristics of Korean Hangul, Korean readers may be processing letters in a more analytic manner than the English readers.

Do we always see the forest before the trees? The global precedence effect in English native speakers with Roman and Thai Navon letters

Event Abstract Back to Event Do we always see the forest before the trees? The global precedence effect in English native speakers with Roman and Thai Navon letters Rebecca Watts1* and Heather Winskel2 1 Southern Cross University, Psychology, School of Health and Human Sciences 2 Department of Psychological Science, School of Health and Human Sciences, Southern Cross University, Australia Aim: Reading acquisition is a prerequisite of functioning in modern day existence as we live in a data driven society. Paying attention to the bigger picture is an evolutionary survival response achieved via a global processing mechanism in human cognition. This level of attention can be problematic when children are learning to read or are dyslexic, as reading requires local and analytic processing to focus on the letters that make up a word. The study investigated if priming moderates global and local processing in English speakers with Roman and Thai Navon compound letters. The purpose of this study was to investigate whether global and local priming could moderate English speaker’s processing of Roman and Thai Navon letters. The Global Precedence Effect (GPE) is evidence of holistic processing, characterized by a global advantage (faster responses at the global level) and asymmetric congruence (global to local interference). Based on previous research, it was predicted that there would be a global precedence effect for the face priming condition but not the letter priming condition. Method: Forty-six native English speakers living in Australia (18 males, 28 females) were subjected to a priming task, either a face sorting (global priming condition) or letter identification (local priming condition) task, prior to participating in the Navon experiment. Results: The results revealed a robust GPE in both priming conditions revealing that the native English speakers were processing Roman and Thai Navon letters in a more holistic manner. Conclusion: The priming conditions did not have an influence on local/global processing of the Navon letters. In fact, a robust GPE was found for both familiar Roman letters and unfamiliar Thai letters. Even though the letters were presented in central vision and were in a font size typical for reading, a GPE still emerged for the Roman letters. Keywords: holistic processing, Global precedence effect, Roman letters, Thai letters, Navon compound letters, reading, global advantage Conference: 15th Annual Psychology Honours Research Conference , Coffs Harbour, Australia, 4 Oct - 5 Oct, 2018. Presentation Type: Research Topic: Abstract for 15th Annual Psychology Honours Research Conference Citation: Watts R and Winskel H (2019). Do we always see the forest before the trees? The global precedence effect in English native speakers with Roman and Thai Navon letters. Front. Psychol. Conference Abstract: 15th Annual Psychology Honours Research Conference . doi: 10.3389/conf.fpsyg.2018.74.00037 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Sep 2018; Published Online: 27 Sep 2019. * Correspondence: Ms. Rebecca Watts, Southern Cross University, Psychology, School of Health and Human Sciences, Coffs Harbour, r.watts.14@student.scu.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Rebecca Watts Heather Winskel Google Rebecca Watts Heather Winskel Google Scholar Rebecca Watts Heather Winskel PubMed Rebecca Watts Heather Winskel Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Attentional selection of levels within hierarchically organized figures is mediated by object-files.

Objects frequently have a hierarchical organization (tree-branch-leaf). How do we select the level to be attended? This has been explored with compound letters: a global letter built from local letters. One explanation, backed by much empirical support, is that attentional competition is biased toward certain spatial frequency (SF) bands across all locations and objects (a SF filter). This view assumes that the global and local letters are carried respectively by low and high SF bands, and that the bias can persist over time. Here we advocate a complementary view in which perception of hierarchical level is determined by how we represent letters in object-files. Although many properties bound to an object-file (i.e., position, color, even shape) can mutate without affecting its persistence over time, we posit that same object-file cannot be used to store information from different hierarchical levels. Thus, selection of level would be independent from locations but not from the way objects are represented at each moment. These views were contrasted via an attentional blink paradigm that presented letters within compound figures, but only one level at a time. Attending to two letters in rapid succession was easier if they were at the same-compared to different-levels, as predicted by both accounts. However, only the object-file account was able to explain why it was easier to report two targets on the same moving object compared to the same targets on distinct objects. The interference of different masks on target recognition was also easier to predict by the object-file account than by an SF filter. The methods introduced here allowed us to investigate attention to hierarchical levels and to object-files within the same empirical framework. The data suggests that SF information is used to structure the internal organization of object representations, a process understood best by integrating object-file theory with previous models of hierarchical perception.

Same, same — but different: On the use of Navon derived measures of global/local processing in studies of face processing

Some studies have reported a significant correlation between face discrimination/recognition ability and indexes of global/local processing derived from the Navon paradigm. Other studies, however, have failed to find such a relationship. In this paper we examine three aspects related to the Navon paradigm that may have contributed to this discrepancy but which have been largely neglected: (i) the use of different types of compound stimuli across studies, (ii) differences between studies in the type of index derived from the Navon paradigm, and (iii) the reliability of these indexes. In a Navon experiment comparing performance with compound letters and compound shapes in normal participants, we find little consistency both within and across participants in how they perform with these stimulus types, despite the fact that both stimulus types give rise to the typical effects. In addition we find that many of the Navon derived indexes of global/local effects used in studies examining face processing have low reliability and do not measure the same aspects of global/local processing. Echoing the results from the normal participants, we also find little consistency in how a congenital prosopagnosic performs in the Navon paradigm. With compound letters, she responds much faster to local than to global aspects of the stimuli; a pattern not seen in a single of the normal participants. With compound shapes, however, she exhibits no such abnormality. These findings question the validity of the conclusions in studies relating Navon derived indexes of global/local processing to face processing.

Displaying All Bangla Compound Letters & Alphabets By 32- Segment

Different approaches have been proposed for representing Bangla and English alphabets and numerals by segment display. But there is no complete and accurate scheme has been done yet for Bangla compound letters. The focus of our paper is on all compound letters to represent by 32 segments. By these 32 segments, we also represent all Bengali and English numerals and alphabets. Accurate recognition of compound characters is difficult due to their complex shapes. In this paper we try to present total 97 compound letters in simpler look. This proposed design performs well for complex-shaped compound characters, which were confusing to the existing methods.

3P2-P05 自閉症スペクトラム障害における部分的情報処理バイアスの計算論的モデル(脳・神経・認知ロボティクス)

It is known that people with Autism Spectrum Disorders (ASD) have a bias for local information processing, whereas normally developing people exhibit a global bias. This study examines its underlying mechanism inspired by an evidence from neuroscience studies. Our hypothesis is that an imbalance between excitation and inhibition neurons modifies a threshold for neural activities and thus changes a bias for local or global information. We employed a hierarchical neural network called neocognitron to examine the influence of the excitation/inhibition balance on the recognition of hierarchical compound letters (i.e., a global/large letter consisting of local/small letters). Our experiments demonstrated that hyper inhibitory connections made the network recognize a local letter better than a global letter, whereas a proper excitation/inhibition balance produced an opposite result. This empirically supports our hypothesis that the excitation/inhibition imbalance is a cause of a local processing bias in ASD.

An Open Source Tesseract based Tool for Extracting Text from Images with Application in Braille Translation for the Visually Impaired

Many valuable paper documents are usually scanned and kept as images for backup. Extracting text from the images is quite helpful and thus a need for some tool for this extraction is always there. One of the important applications of this tool is its use in Braille Translation. Braille has been the primary writing and reading system used by the visually impaired since the 19 th century. This application that extracts text from images and then converts it to Braille will prove to be quite useful for converting old valuable documents or books into Braille format. In this paper the complete methodology used for the extraction of texts from scanned images and for the translation of texts to Braille is presented. The scanned images are initially pre-processed and converted to grayscale and then passed through an adaptive threshold function for conversion to binary image. Then it is sent for Recognition using Google’s powerful Tesseract recognition engine which is considered to be the best Open Source OCR Engine currently available. The generated text is then post-processed using a spell checking API JOrtho for removing the errors in the previous step. The final corrected text is then translated to a six dot cell Braille format using a set of rules provided by www.iceb.org. The translation to Braille includes conversion of numbers, alphabets, symbols and compound letters. The translated text can then be saved for printing the document later or for sending it to a Refreshable Braille Display.

Identity but not size information in working memory biases attentional selection in hierarchical forms

Participants held the size of a cue in working memory and looked for a target letter across local and global levels of hierarchical, compound letters. There was no effect of whether the cue size matched the size of the local or global letter, even when the size memory task was made difficult. The null effect of cue size was also found under priming conditions, when size had to be identified but not held in memory. Although cue size did not affect subsequent selection in these experiments, cue identity did. There were effects of size, however, on the magnitude of cueing effects, irrespective of whether targets were at the local or global level. The data are discussed in terms of the effects of overlap between the contents of WM and the attentional set for targets, and the role of focused and distributed attention on selection. Critically, the data run counter to the idea that local and global stimuli are selected by opening an “attentional window” of a particular size in working memory and matching this to the target letter.

Working memory, perceptual priming, and the perception of hierarchical forms: Opposite effects of priming and working memory without memory refreshing

Previous research has shown that stimuli held in working memory (WM) can influence spatial attention. Using Navon stimuli, we explored whether and how items in WM affect the perception of visual targets at local and global levels in compound letters. Participants looked for a target letter presented at a local or global level while holding a regular block letter as a memory item. An effect of holding the target's identity in WM was found. When memory items and targets were the same, performance was better than in a neutral condition when the memory item did not appear in the hierarchical letter (a benefit from valid cuing). When the memory item matched the distractor in the hierarchical stimulus, performance was worse than in the neutral baseline (a cost on invalid trials). These effects were greatest when the WM cue matched the global level of the hierarchical stimulus, suggesting that WM biases attention to the global level of form. Interestingly, in a no-memory priming condition, target perception was faster in the invalid condition than in the neutral baseline, reversing the effect in the WM condition. A further control experiment ruled out the effects of WM being due to participants' refreshing their memory from the hierarchical stimulus display. The data show that information in WM biases the selection of hierarchical forms, whereas priming does not. Priming alters the perceptual processing of repeated stimuli without biasing attention.

Self-construal priming modulates the scope of visual attention

Although it is well documented that cultures influence basic cognitive processes such as attention, the underlying mechanisms remain unclear. We tested the hypothesis that self-concepts that characterize people from different cultures mediate the variation of visual attention. After being primed with self-construals that emphasize the Eastern interdependent self or the Western independent self, Chinese participants were asked to discriminate a central target letter flanked by compatible or incompatible stimuli (Experiment 1) or global/local letters in a compound stimulus (Experiment 2). Experiment 1 showed that, while responses were slower to the incompatible than to the compatible stimuli, this flanker compatibility effect was increased by the interdependent relative to the independent self-construal priming. Experiment 2 showed that the interdependent-self priming resulted in faster responses to the global than to the local targets in compound letters whereas a reverse pattern was observed in the independent-self priming condition. The results provide evidence for dynamics of the scope of visual attention as a function of self-construal priming that switches self-concept toward the interdependent or independent styles in Chinese.

The role of parietal cortex in global/local processing of hierarchical stimuli: a transcranial magnetic stimulation study

We studied whether the posterior parietal cortex contributes both to focus attention on one level and to switch attention between global and local levels of compound letters across trials. After 1 Hz repeated transcranial magnetic stimulation was applied to the left, right posterior parietal cortex, and the precentral gyrus, participants identified global and local target letters. We found that repeated transcranial magnetic stimulation over the left posterior parietal cortex resulted in faster global than local responses but did not affect global-to-local interference and the level-repetition effect. The results suggest that the neural mechanism underlying focusing attention on one level of compound stimuli is distinct from that mediating switching attention between global and local levels across trials.

Global perception depends on coherent work of bilateral visual cortices: Transcranial magnetic stimulation (TMS) studies

Previous research suggests that the right and left hemispheres dominate global and local perception of hierarchical patterns, respectively. The current work examined whether global perception of hierarchical stimuli requires coherent work of bilateral visual cortices using transcranial magnetic stimulation (TMS). Subjects discriminated global or local properties of compound letters in Experiment 1. Reaction times were recorded when single-pulse real TMS or sham TMS was delivered over the left or right visual cortex. While a global precedence effect (i.e., faster responses to global than local targets and stronger global-to-local interference than the reverse) was observed, TMS decreased global-to-local interference whereas increased local-to-global interference. Experiment 2 ruled out the possibility that the effects observed in Experiment 1 resulted from perceptual learning. Experiment 3 used compound shapes and observed TMS effect similar to that in Experiment 1. Moreover, TMS also slowed global RTs whereas speeded up local RTs in Experiment 3. Finally, the TMS effects observed in Experiments 1 and 3 did not differ between the conditions when TMS was applied over the left and right hemispheres. The results support a coherence hypothesis that global perception of compound stimuli depends upon the coherent work of bilateral visual cortices.

Neural correlates of within-level and across-level attention to multiple compound stimuli

Event-related potentials (ERPs) were recorded to investigate the neural mechanisms of attention to the same or different levels of two compound letters presented concurrently in the left and right visual fields, respectively. Relative to the condition when attention was allocated to the global level of one compound stimulus and the local level of another one (across-level attention), attention to the same level of the two compound stimuli (within-level attention) increased an early positivity between 100 and 140 ms (P1) over the occipito-parietal cortex. A long-latency positivity between 320 and 560 ms (P3) over the central–parietal area was also increased in the within-level relative to across-level attention conditions. The ERP results suggest that, relative to across-level attention, within-level attention to multiple compound stimuli facilitates both early sensory-perceptual processing and late process of stimulus evaluation and identification in hierarchical analysis.