A compact structured light based otoscope for three dimensional imaging of the tympanic membrane

Three dimensional (3D) imaging of the tympanic membrane (TM) has been carried out using a traditional otoscope equipped with a high-definition webcam, a portable projector and a telecentric optical system. The device allows us to project fringe patterns on the TM and the magnified image is processed using phase shifting algorithms to arrive at a 3D description of the TM. Obtaining a 3D image of the TM can aid in the diagnosis of ear infections such as otitis media with effusion, which is essentially fluid build-up in the middle ear. The high resolution of this device makes it possible examine a computer generated 3D profile for abnormalities in the shape of the eardrum. This adds an additional dimension to the image that can be obtained from a traditional otoscope by allowing visualization of the TM from different perspectives. In this paper, we present the design and construction of this device and details of the imaging processing for recovering the 3D profile of the subject under test. The design of the otoscope is similar to that of the traditional device making it ergonomically compatible and easy to adopt in clinical practice

Comparative anatomy of the mammalian bony cochlea and its ontogenetic development in humans

The cochlea is the organ for sound reception. Mammals place varied functional demands on their sense of hearing to meet the requirements of a broad range of ecological niches and diverse behaviours. However, documenting potentially related adaptations of the cochlea to eco-behavioural traits is difficult due to its complex geometry. The present study aims to determine whether the bony cochlea carries eco-behavioural traits that can be used to contextualize our understanding of the fossil record and evolutionary transitions. This study also includes work on ontogenetic changes since these can yield important insights into evolutionary processes resulting in differences of the adult phenotypes. Advanced techniques in micro-CT imaging, 3D image visualization, geometric morphometrics and statistical methods were used to study morphological variations of the bony cochlea across 45 adult eutherian species. Also, the same set of techniques was used to study 12 human fetal (approximately four to nine months of gestation) cochleae in comparison with five adult cochleae. Results revealed that there was a considerable range of variation in form of the mammalian bony cochlea. Potential links between the bony cochlear morphology and hearing, ecology and behaviour were found. Dimensions of the bony cochlea may be indicative of the eco-behavioural niche that a mammal occupies; e.g., fewer than two spiral turns is associated with obligate marine species. Rodents also showed remarkable variation in the cochlear morphology, more so than any other group of mammals studied, reflecting their diverse eco-behavioural traits. Results from the human developmental study showed that whilst the general coiled shape was achieved at the midgestational age, there was size related morphological change during the postnatal period. The round window size reached mature state prior to birth, by approximately the second trimester, whereas the oval window continued to change in size after birth. The postnatal enlargement may be determined by functional requirements of air-borne hearing, particularly with respect to frequency range and sensitivity

Auditory-visual interaction in computer graphics

Generating high-fidelity images in real-time at reasonable frame rates, still remains one of the main challenges in computer graphics. Furthermore, visuals remain only one of the multiple sensory cues that are required to be delivered simultaneously in a multi-sensory virtual environment. The most frequently used sense, besides vision, in virtual environments and entertainment, is audio. While the rendering community focuses on solving the rendering equation more quickly using various algorithmic and hardware improvements, the exploitation of human limitations to assist in this process remain largely unexplored. Many findings in the research literature prove the existence of physical and psychological limitations of humans, including attentional, perceptual and limitations of the Human Sensory System (HSS). Knowledge of the Human Visual System (HVS) may be exploited in computer graphics to significantly reduce rendering times without the viewer being aware of any resultant image quality difference. Furthermore, cross-modal effects, that is the influence of one sensory input on another, for example sound and visuals, have also recently been shown to have a substantial impact on viewer perception of virtual environment. In this thesis, auditory-visual cross-modal interaction research findings have been investigated and adapted to graphics rendering purposes. The results from five psychophysical experiments, involving 233 participants, showed that, even in the realm of computer graphics, there is a strong relationship between vision and audition in both spatial and temporal domains. The first experiment, investigating the auditory-visual cross-modal interaction within spatial domain, showed that unrelated sound effects reduce perceived rendering quality threshold. In the following experiments, the effect of audio on temporal visual perception was investigated. The results obtained indicate that audio with certain beat rates can be used in order to reduce the amount of rendering required to achieve a perceptual high quality. Furthermore, introducing the sound effect of footsteps to walking animations increased the visual smoothness perception. These results suggest that for certain conditions the number of frames that need to be rendered each second can be reduced, saving valuable computation time, without the viewer being aware of this reduction. This is another step towards a comprehensive understanding of auditory-visual cross-modal interaction and its use in high-fidelity interactive multi-sensory virtual environments

Cochlear models

The intention of the research activity described in this thesis is to contribute to the dynamical theory of the cochlea of the human inner ear. The Science of Hearing, being disseminated in a wide range of frequently independent or unco-ordinated disciplines, is advancing far in the fields of subjective human acoustics, middle ear restorative surgery, medical diagnostic electro-encephalography and cochlear-nucleus-to-thalamus neural communications research. At the same time, exploitation, in auditory research, of the techniques and resources of modern engineering science, which may be particularly appropriately applied to analyses of the peripheral hearing system, has not been manifest to any great degree. It was therefore hoped that a first-principles engineering approach to the subject of cochlear action would demonstrate the need for a mathematical and quantitative type of analysis of the response of this key organ of hearing and also indicate the extent to which cochlear science is at present to be found in a state of disarray. The writer's principal thesis is that a considerably greater potential for discrimination of the frequencies and intensities of pure and complex tones is attributable to the mechanical action of the cochlea than is generally supposed. That thesis will be more fully proven (it is expected) when current research is considerably extended and improved to permit the computation of spatial arrays of cochlear hair cell cilia shearing force patterns and electrical responses. The studies reported herein are relevant and fundamental to this aim and are limited to considerations of the dynamical response of the cochlear partition as a whole. This research has included approximately equal parts of review, physical cochlear model experimentation and mathematical analysis. The first two chapters end sections of most of the other chapters concentrate on defining the system and reviewing the literature. Chapters 3 and 4 estimate the order and ranges of the physical properties of mass and stiffness of the scala media (or cochlear partition), these properties being essential to the subsequent design of both physical and mathematical models of the cochlea in Chapters 5 and 6 respectively. The final chapter adds to the comments in other chapters on the credibility of the physical constants previously deduced in the thesis and tested in the models, the performance of the models, the particular problems clearly requiring further research effort and the relevance of the work to a more complete comprehension of human auditory theory

Pressure Systems Energy Release Protection (Gas Pressurized Systems)

A survey of studies into hazards associated with closed or pressurized system rupture and preliminary guidelines for the performance design of primary, secondary, and protective receptors of these hazards are provided. The hazards discussed in the survey are: blast, fragments, ground motion, heat radiation, biological, and chemical. Performance guidelines for receptors are limited to pressurized systems that contain inert gas. The performance guidelines for protection against the remaining unaddressed degenerative hazards are to be covered in another study

Investigation of biofilms associated with chronic otitis media with effusion and adenoids hypertrophy

Ph. D. ThesisChronic otitis media with effusion (COME) is the most common cause of acquired hearing loss in young children. Bacterial biofilm is an important contributor to the aetiopathogenesis of COME, although conventional culture generally recovers few microorganisms from the middle ear. Extracellular DNA (eDNA) is a key structural component within the matrix of many microbial biofilms including those associated with COME. The aims of this study were to characterise microbial populations associated with COME, and to explore the efficacy of the DNase, NucB, to control in vitro biofilms associated with COME. Methods were established to culture biofilms in vitro and to challenge with NucB. NucB efficiently disrupted biofilms of clinically isolated Staphylococcus aureus strains either alone or in combination with the antibiotic Co-amoxiclav. Concentrations of NucB 100-fold higher than those required for biofilm inhibition had no toxic effects on human epithelial cells. Twenty-seven bacterial species were isolated from middle ear effusion fluids (MEEFs) of 34 patients with COME. Culture-positive MEEFs were increased two-fold following optimisation of the culture methods. Microbiome analysis of MEEFs by 16S rDNA sequencing identified the majority of the cultured species and several additional species. Similar species were also detected by 16S rRNA gene sequencing of microbial DNA from adenoids. The ability of 23 bacterial isolates from MEEF to form biofilm was assessed. Twenty strains formed biofilms, and 16 of these were sensitive to NucB. Imaging analysis showed significant structural alterations in biofilms of the selected COME isolates after NucB treatment. In conclusion, this study has provided further insights into the microbiology of middle ear infections and has shown that many bacteria from this environment are capable of forming biofilms. NucB alone or in combination with antibiotics may potentially be a potent and safe agent to control biofilm-associated conditions including COME.Iraqi Ministry of Higher Education and Scientific Research, Kirkuk Universit