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Illumination Variance In Video Processing
Doctor of Philosophy and was awarded by Brunel University LondonInthisthesiswefocusontheimpactofilluminationchangesinvideoand we discuss how we can minimize the impact of illumination variance in video processing systems. Identifyingandremovingshadowsautomaticallyisaverywellestablished and an important topic in image and video processing. Having shadowless image data would benefit many other systems such as video surveillance, tracking and object recognition algorithms. Anovelapproachtoautomaticallydetectandremoveshadowsispresented in this paper. This new method is based on the observation that, owing to the relative movement of the sun, the length and position of a shadow changes linearly over a relatively long period of time in outdoor environments,wecanconvenientlydistinguishashadowfromotherdark regions in an input video. Then we can identify the Reference Shadow as the one with the highest confidence of the mentioned linear changes. Once one shadow is detected, the rest of the shadow can also be identifiedandremoved. Wehaveprovidedmanyexperimentsandourmethod is fully capable of detecting and removing the shadows of stationary and moving objects. Additionally we have explained how reference shadows can be used to detect textures that reflect the light and shiny materials such as metal, glass and water. ..
An investigation into textile applications of thermochromic pigments
Methods were developed for application of thermochromic pigments to textiles, based
on printing and extrusion, for both leuco dye based and cholesteric liquid crystal
thermochromics. The leuco dye based thermochromics were assessed in terms of heat
stability, binder optimization and colour saturation using an instrumental colour
measurement system. Enhancement of lightfastness of leuco dye based thermochromics
was carried out using UV absorbers, HALS and antioxidants as additives. A
comparative study was also carried out between printing and extrusion application
methods. A colour measurement system with the facility for temperature variation was
constructed using two traditional components – a reflectance spectrophotometer and a
controllable hot stage. The dynamic colour change of leuco dye based thermochromics
with temperature was assessed. The liquid crystals were assessed with temperature for
their additive colour mixing properties by layering them over each other. They were
also assessed in terms of aspects of applications, such as differences in the over-layering
sequence and colour hysteresis on heating and cooling. The results were evaluated not
only to provide a scientific understanding of the performance but also to provide useful
information from a creative designer’s point of view.
The research carried out as described in this thesis has established an improved
understanding of the application methods for leuco dye based and liquid crystal
thermochromic pigments for optimum performance. The availability and selection of
colours achievable with liquid crystal thermochromics have been widened significantly
by the improved understanding of the colours derived from over-layered liquid crystals.
It is anticipated that this research will broaden the potential for use of leuco dye based
and liquid crystal thermochromics in textiles, especially in the fields of functional
textiles and creative design