813 resultados para VISUAL INSPECTION METHODS


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Methods are presented (1) to partition or decompose a visual scene into the bodies forming it; (2) to position these bodies in three-dimensional space, by combining two scenes that make a stereoscopic pair; (3) to find the regions or zones of a visual scene that belong to its background; (4) to carry out the isolation of objects in (1) when the input has inaccuracies. Running computer programs implement the methods, and many examples illustrate their behavior. The input is a two-dimensional line-drawing of the scene, assumed to contain three-dimensional bodies possessing flat faces (polyhedra); some of them may be partially occluded. Suggestions are made for extending the work to curved objects. Some comparisons are made with human visual perception. The main conclusion is that it is possible to separate a picture or scene into the constituent objects exclusively on the basis of monocular geometric properties (on the basis of pure form); in fact, successful methods are shown.

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Li, Longzhuang, Liu, Yonghuai, Obregon, A., Weatherston, M. Visual Segmentation-Based Data Record Extraction From Web Documents. Proceedings of IEEE International Conference on Information Reuse and Integration, 2007, pp. 502-507. Sponsorship: IEEE

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C.R. Bull, R. Zwiggelaar and R.D. Speller, 'Review of inspection techniques based on the elastic and inelastic scattering of X-rays and their potential in the food and agricultural industry', Journal of Food Engineering 33 (1-2), 167-179 (1997)

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Some WWW image engines allow the user to form a query in terms of text keywords. To build the image index, keywords are extracted heuristically from HTML documents containing each image, and/or from the image URL and file headers. Unfortunately, text-based image engines have merely retro-fitted standard SQL database query methods, and it is difficult to include images cues within such a framework. On the other hand, visual statistics (e.g., color histograms) are often insufficient for helping users find desired images in a vast WWW index. By truly unifying textual and visual statistics, one would expect to get better results than either used separately. In this paper, we propose an approach that allows the combination of visual statistics with textual statistics in the vector space representation commonly used in query by image content systems. Text statistics are captured in vector form using latent semantic indexing (LSI). The LSI index for an HTML document is then associated with each of the images contained therein. Visual statistics (e.g., color, orientedness) are also computed for each image. The LSI and visual statistic vectors are then combined into a single index vector that can be used for content-based search of the resulting image database. By using an integrated approach, we are able to take advantage of possible statistical couplings between the topic of the document (latent semantic content) and the contents of images (visual statistics). This allows improved performance in conducting content-based search. This approach has been implemented in a WWW image search engine prototype.

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The spiking activity of nearby cortical neurons is correlated on both short and long time scales. Understanding this shared variability in firing patterns is critical for appreciating the representation of sensory stimuli in ensembles of neurons, the coincident influences of neurons on common targets, and the functional implications of microcircuitry. Our knowledge about neuronal correlations, however, derives largely from experiments that used different recording methods, analysis techniques, and cortical regions. Here we studied the structure of neuronal correlation in area V4 of alert macaques using recording and analysis procedures designed to match those used previously in primary visual cortex (V1), the major input to V4. We found that the spatial and temporal properties of correlations in V4 were remarkably similar to those of V1, with two notable differences: correlated variability in V4 was approximately one-third the magnitude of that in V1 and synchrony in V4 was less temporally precise than in V1. In both areas, spontaneous activity (measured during fixation while viewing a blank screen) was approximately twice as correlated as visual-evoked activity. The results provide a foundation for understanding how the structure of neuronal correlation differs among brain regions and stages in cortical processing and suggest that it is likely governed by features of neuronal circuits that are shared across the visual cortex.

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Periodic visual stimulation and analysis of the resulting steady-state visual evoked potentials were first introduced over 80 years ago as a means to study visual sensation and perception. From the first single-channel recording of responses to modulated light to the present use of sophisticated digital displays composed of complex visual stimuli and high-density recording arrays, steady-state methods have been applied in a broad range of scientific and applied settings.The purpose of this article is to describe the fundamental stimulation paradigms for steady-state visual evoked potentials and to illustrate these principles through research findings across a range of applications in vision science.

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INTRODUCTION: Adherence to glaucoma medications is essential for successful treatment of the disease but is complex and difficult for many of our patients. Health coaching has been used successfully in the treatment of other chronic diseases. This pilot study explores the use of health coaching for glaucoma care. METHODS: A mixed methods study design was used to assess the health coaching intervention for glaucoma patients. The health coaching intervention consisted of four to six health coaching sessions with a certified health coach via telephone. Quantitative measures included demographic and health information, adherence to glaucoma medications (using the visual analog adherence scale and medication event monitoring system), and an exit survey rating the experience. Qualitative measures included a precoaching health questionnaire, notes made by the coach during the intervention, and an exit interview with the subjects at the end of the study. RESULTS: Four glaucoma patients participated in the study; all derived benefits from the health coaching. Study subjects demonstrated increased glaucoma drop adherence in response to the coaching intervention, in both visual analog scale and medication event monitoring system. Study subjects' qualitative feedback reflected a perceived improvement in both eye and general health self-care. The subjects stated that they would recommend health coaching to friends or family members. CONCLUSION: Health coaching was helpful to the glaucoma patients in this study; it has the potential to improve glaucoma care and overall health.

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Aims: To determine whether or not self reported visual functioning and quality of life in patients with choroidal neovascularisation caused by age related macular degeneration (AMD) is better in those treated with 12 Gy external beam radiotherapy in comparison with untreated subjects. Methods: A multicentre single masked randomised controlled trial of 12 Gy of external beam radiation therapy (EBRT) delivered as 6x2 Gy fractions to the macula of an affected eye versus observation. Patients with AMD, aged 60 years or over, in three UK hospital units, who had subfoveal CNV and a visual acuity equal to or better than 6/60 (logMAR 1.0). Methods: Data from 199 eligible participants who were randomly assigned to 12 Gy teletherapy or observation were available for analysis. Visual function assessment, ophthalmic examination, and fundus fluorescein angiography were undertaken at baseline and at 3, 6, 12, and 24 months after study entry. To assess patient centred outcomes, subjects were asked to complete the Daily Living Tasks Dependent on Vision (DLTV) and the SF-36 questionnaires at baseline, 6, 12, and 24 months after enrolment to the study. Cross sectional and longitudinal analyses were conducted using arm of study as grouping variable. Regression analysis was employed to adjust for the effect of baseline co-variates on outcome at 12 months and 24 months. Results: Both control and treated subjects had significant losses in visual functioning as seen by a progressive decline in mean scores in the four dimensions of the DLTV. There were no statistically significant differences between treatment and control subjects in any of dimensions of the DLTV at 12 months or 24 months after study entry. Regression analysis confirmed that treatment status had no effect on the change in DLTV dimensional scores. Conclusions: The small benefits noted in clinical measures of vision in treated eyes did not translate into better self reported visual functioning in patients who received treatment when compared with the control arm. These findings have implications for the design of future clinical trials and studies.

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Primary Objective: To investigate the utility of using a new method of assessment for deficits in selective visual attention (SVA). Methods and Procedures: An independent groups design compared six participants with brain injuries with six participants from a non-brain injured control group. The Sensomotoric Instruments Eye Movement system with remote eye-tracking device (eye camera), and 2 sets of eight stimuli were employed to determine if the camera would be a sensitive discriminator of SVA in these groups. Main Outcomes and Results: The attention profile displayed by the brain injured group showed that they were slower, made more errors, were less accurate, and more indecisive than the control group. Conclusions: The utility of eye movement analysis as an assessment method was established, with implications for rehabilitation requiring further development. Key words: selective visual attention, eye movement analysis, brain injury

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We present results of a study into the performance of a variety of different image transform-based feature types for speaker-independent visual speech recognition of isolated digits. This includes the first reported use of features extracted using a discrete curvelet transform. The study will show a comparison of some methods for selecting features of each feature type and show the relative benefits of both static and dynamic visual features. The performance of the features will be tested on both clean video data and also video data corrupted in a variety of ways to assess each feature type's robustness to potential real-world conditions. One of the test conditions involves a novel form of video corruption we call jitter which simulates camera and/or head movement during recording.

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OBJECTIVE:
To elucidate the contribution of environmental versus genetic factors to the significant losses in visual function associated with normal aging.
DESIGN:
A classical twin study.
PARTICIPANTS:
Forty-two twin pairs (21 monozygotic and 21 dizygotic; age 57-75 years) with normal visual acuity recruited through the Australian Twin Registry.
METHODS:
Cone function was evaluated by establishing absolute cone contrast thresholds to flicker (4 and 14 Hz) and isoluminant red and blue colors under steady state adaptation. Adaptation dynamics were determined for both cones and rods. Bootstrap resampling was used to return robust intrapair correlations for each parameter.
MAIN OUTCOME MEASURES:
Psychophysical thresholds and adaptational time constants.
RESULTS:
The intrapair correlations for all color and flicker thresholds, as well as cone absolute threshold, were significantly higher in monozygotic compared with dizygotic twin pairs (P<0.05). Rod absolute thresholds (P = 0.28) and rod and cone recovery rate (P = 0.83; P = 0.79, respectively) did not show significant differences between monozygotic and dizygotic twins in their intrapair correlations, indicating that steady-state cone thresholds and flicker thresholds have a marked genetic contribution, in contrast with rod thresholds and adaptive processes, which are influenced more by environmental factors over a lifetime.
CONCLUSIONS:
Genes and the environment contribute differently to important neuronal processes in the retina and the role they may play in the decline in visual function as we age. Consequently, retinal structures involved in rod thresholds and adaptive processes may be responsive to appropriate environmental manipulation. Because the functions tested are commonly impaired in the early stages of age-related macular degeneration, which is known to have a multifactorial etiology, this study supports the view that pathogenic pathways early in the disease may be altered by appropriate environmental intervention.

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The context for this paper is a teacher education program for adult literacy practitioners at Queen’s University Belfast in Northern Ireland. This paper describes and reflects on the use of arts-based approaches to enhance these practitioners’ conceptualizations of literacy, presenting their arts-based responses and their evaluations of the methods and their contrasting definitions of literacy at the start and the end of the course. The discussion raises questions about the inclusion of visual literacy in adult literacy teacher education programmes.

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The effects of three non-antibiotic, antimicrobial agents (taurolidine, chlorhexidine acetate and providone-iodine) on the surface hydrophobicity of the clinical strains Escherichia coli, Staphylococcus saprophyticus, Staphylococcus epidermidis and Candida albicans were examined. Three recognized techniques for hydrophobicity measurements, Bacterial Adherence to Hydrocarbons (BATH), the Salt Aggregation Test (SAT) and Hydrophobic Interaction Chromatography (HIC) were compared. At concentrations reported to interfere with microbial-epithelial cell adherence, all three agents altered the cell surface hydrophobicity. However, these effects failed to exhibit a uniform relationship. Generally, taurolidine and povidone-iodine treatments decreased the hydrophobicity of the strains examined whereas chlorhexidine acetate effects depended upon the micro-organism treated. Subsequently, the exact contribution of altered cell surface hydrophobicity to the reported microbial anti-adherence effects is unclear. Comparison of the three techniques revealed a better correlation between the results obtained with the BATH test and HIC than the results obtained with the BATH and SAT or SAT and HIC. However, these differences may be due to the inaccuracy associated with the visual assessment of results employed by the SAT.

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Age-related macular degeneration (AMD), is the leading cause of blind registration in the Western World among individuals 65 years or older. Early AMD, a clinical state without overt functional loss, is said to be present clinically when yellowish deposits known as drusen and/or alterations of fundus pigmentation are seen in the macular retina. Although the etiopathogenesis of AMD remains uncertain, there is a growing body of evidence in support of the view that cumulative oxidative damage plays a causal role. Appropriate dietary antioxidant supplementation is likely to be beneficial in maintaining visual function in patients with AMD, and preventing or delaying the progression of early AMD to late AMD. The Carotenoids in Age-Related Maculopathy (CARMA) Study is a randomized and double-masked clinical trial of antioxidant supplementation versus placebo in 433 participants with either early AMD features of sufficient severity in at least one eye or any level of AMD in one eye with late AMD (neovascular AMD or central geographic atrophy) in the fellow eye. The aim of the CARMA Study is to investigate whether lutein and zeaxanthin, in combination with co-antioxidants (vitamin C, E, and zinc), has a beneficial effect on visual function and/or prevention of progression from early to late stages of disease. The primary outcome is improved or preserved distance visual acuity at 12 months. Secondary outcomes include improved or preserved interferometric acuity, contrast sensitivity, shape discrimination ability, and change in AMD severity as monitored by fundus photography. This article outlines the CARMA Study design and methodology, including its rationale.

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The Audio/Visual Emotion Challenge and Workshop (AVEC 2011) is the first competition event aimed at comparison of multimedia processing and machine learning methods for automatic audio, visual and audiovisual emotion analysis, with all participants competing under strictly the same conditions. This paper first describes the challenge participation conditions. Next follows the data used – the SEMAINE corpus – and its partitioning into train, development, and test partitions for the challenge with labelling in four dimensions, namely activity, expectation, power, and valence. Further, audio and video baseline features are introduced as well as baseline results that use these features for the three sub-challenges of audio, video, and audiovisual emotion recognition.