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Consent has gained an increasing innportance in both health care policy and practice. Research in this subject has focused on information needs of patients (McKeague and Windsor, 2003), and their understanding of information (Turner and Williams 2002). There has been little or no consideration as to how the health professional interactionally seeks the patients consent.

Research on information processing in neuronal networks may lead to a better understanding of many brain diseases and disorders and could inform potential future treatments. It may also lead to the development of more intelligent electronic technology. To understand how the brain processes information we need to study the patterns of action potentials (APs) in a neuronal network over the long-term. The aim of this project, therefore, is to develop an optical system to both detect and stimulate APs in a small neuronal network. A closed-loop system has been developed that consists of a signal detection tool (a camera system), a signal analysis tool (a real-time computer) and a signal delivery tool (a spatially modulated light source). The conventional techniques for measuring APs, using patch clamp electrodes or multi electrode arrays for example, are limited by the spatial extent, or the spatial resolution, that can be achieved. Alternatively, optical imaging systems can be used to monitor APs. Imaging systems can achieve high-resolution across a wide field-of-view. To record network-wide neuronal activity a high- speed camera is necessary. Ideally imaging needs to be performed continuously over long periods of time. However, continuous high-speed imaging is typically not possible using commercially available systems due to restrictions in bandwidth.

Optical Coherence Tomography (OCT) is a powerful imaging technology in biomedical research and medicine. It enables in situ. 3D visualization of tissue structure and pathology, without the need. to excise the tissue and resolution approaching that of histology. OCT has had the most clinical impact in ophthalmology, where it provides structural and quantit ative informat ion that cannot be obtained by any other modality. The objective of the work presented in this thesis was the development of new imaging methods and optical devices to progress the OCT technology in t erms of its versatility, as well as to improve on parameters such as resolution, wavelength availability, integration effort and reliability. One of the most desired features in high resolution imaging is the display of simultaneously generated confocal images. The implementation of a confocal channel at the core of an OCT with quasi-simultaneous display of both images is demonstrated by synchronous optical switching of the power in the reference arm of the interferometer with the scanner determining the line in the final raster. The 1.0-1.1 11m region of the optical spectrum emerged as an attractive option compared to the standard 700-900 nm region, due to increased penetration beyond the retina, into the choroid, and reduced scat tering. Therefore, in this thesis, two novel optical sources based on fiber optic technology at 1 micrometer have been researched, assembled and tested: (a) a broadband ASE source based on combination of Yb-doped and Nd-doped silica fibers . The source emits at a cent ral wavelength of 1060 nm with a full-width-halfmaximum exceeding 70 nrn and 20 m\V output power; and (b) a swept fiber laser source emitting at 1065 nm central wavelength, with :::::l 50 nm tuning range and 40 m Woutput average power. A simple solution to linearize the sweeping in wavenumber (optical frequency), as required for image rendering, is demonstrated. The two prototype sources have been packaged and their performances validated in fully func tional OCT systems.

Optical imaging is becoming a method of choice in applications where high resolution images are required non-invasively. Optical imaging technologies are capable of representing the internal structure of the sample investigated across a range of spatial scales. In this project, we worked on two optical imaging systems, including the optical coherence tomography (OCT) and confocal microscopy (CM). Similar to every other imaging system, optical imaging systems have limitations mainly due to scattering and noise. Four separate limitation factors of imaging, including the speckle noise, intensity decay due to tissue absorption, aberrations, and point spread function (PSF) distortion are investigated in this thesis and a number of algorithms are devised to reduce their impact so an enhanced image is achieved. The hardware of the imaging systems is also modified to improve their performances. We have developed two speckle reduction algorithms based on artificial neural network (ANN) and temporal compounding methods. The algorithms are tested successfully on varieties of skin images, retina, larynx, human teeth and also drosophila images with the view to improve the signal-to-noise ratio (SNR) and contrast. An attenuation compensation algorithm is designed based on Beer- Lambert law using a novel skin layer detection method. The algorithm is successfully tested on in-vivo OCT skin images of human fingertip. For aberration correction, a sensor-less adaptive optics system is studied along with a blind optimization algorithm. Three optimization algorithms are tested effectively on a CM system; simulated annealing, genetic algorithm and particle swarm optimization. To eliminate the effect of the distortion of the PSF of the OCT system, a deconvolution technique with Lucy-Richardson algorithm is used. The PSF of the OCT system is estimated from images of a specially designed phantom. The algorithm is successfully evaluated using OCT images of healthy tissue including dorsal skin of hand, basaloid eyelid skin, skin of fingertip, and basaloid larynx tissues. Compared to the original images, the improved images are less blurred with higher contrast. We improve a dynamic focus (DF-) OCT system operated at 830 nm to be able to image at 1300 nm wavelength. Different tissues of skin, larynx, eyelid, and several phantoms are imaged by this system.

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