In this paper we discuss a microprocessor controlled illumination system that covers the visible spectrum. The system uses multiple discrete wavelength LEDs. Uniform intensity illumination is achieved by controlling LED currents with an array of voltage controlled current sources. A highly efficient polycarbonate holographic diffuser is used to improve the uniformity of the distribution. Current control is also used to maintain a spatially and spectrally homogenous illumination. Image analysis techniques are then used to parameterise the recorded scene and provide a figure of merit for the quality of the illumination. Several functions such as contrast, low/high saturation, average brightness and histogram entropy are applied to extract objective quality judgements and to compute an overall quality function. This process is then iterated so as to maximise the image quality against embedded quality function benchmarks.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.