PubMed · 48239
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J Marshall. 1975-04-24. Methods of contraception.. https://pubmed.ncbi.nlm.nih.gov/48239/
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In today's health service, doctors cannot avoid teaching or lectures. Visual aids are an important part of any successful presentation. Adequate overheads and slides can be easily made using ordinary office equipment and simple cameras. Modern computers and laser printers are also an exciting medium for producing visual aids. Nevertheless, if the talk is to achieve its purpose, good pictures must be presented in the correct way, along with an absorbing commentary. Both these aspects of presentation technique require careful preparation, but are seldom taught to medical students or junior staff as a necessary tool for their future work as doctors.
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Image enhancement as an aid for the visually impaired may improve visibility of TV programs and provide portable visual aid. This paper describes the current techniques for image enhancement and their underlying models. The limitations of the various techniques and of potential methods of implementation are high-lighted. Initial work in this area was based on a linear model. The finite dynamic range available in the video display and contamination of the enhanced image by high spatial frequency noise limited the model's usefulness. I propose a method to address some limitations of the original model that considers the nonlinear response of the visual system and requires enhancement of subthreshold spatial information only. This modification may increase the dynamic range available by decreasing the range previously used by the linear models to enhance visible details. However, for the modified technique to be most effective, the enhancement has to be continuously tuned, based on the patient's visual loss and the spatial frequency content of the displayed images. The implications of these limitations for the potential implementation in TV are discussed. Implementation of an image-enhancing visual aid in a head-mounted, binocular, full-field, virtual vision device may cause substantial difficulties. Patient adaptation may be difficult due to head movement and interaction of the vestibular system response with the head-mounted display. An alternate, bioptic design is proposed in which the display is positioned above or below the line of sight to be examined intermittently, possibly in a freeze-frame mode. Such implementation is also likely to be less expensive, enabling more users access to the device.