An X-Ray detector based on CMOS imaging sensors has recently been developed for dental practice application. The X-Ray
detector has an inherited fixed pattern noise, as well as other temporal noise due to the CMOS sensor. In order to
offer a quality image for dental diagnostics, the X-Ray image must be processed and corrected prior to displaying for
customer use. The X-Ray detector noise has been studied and characterized. Three X-Ray devices are used in the
investigation. Both an X-Ray source and a green visual LED light source are used to determine the magnitude of X-Ray
photon shot noise. Two sets of images, a single-flood image and a 20-averaged image, are studied to characterize the
photon response non-uniformity noise. The investigation shows that the device has different noise sources, with fixed
pattern noise and X-Ray photon shot noise being the dominant noise sources of the device. Separating these noises from
each other helps to improve image quality by reducing or even eliminating some noise components.
The goal of the investigation was to develop experimental techniques for measuring the spectra, pressure and gas temperature of transient optical emission from the detonation of exotic materials in a vented chamber. The measurands are important in characterizing the performance of the materials and in optimization of the mechanical and chemical design. A dual branch multi-channel spectrograph was constructed and calibrated to measure both the time- resolved spectral radiation and total spectral energy from the detonation process. An optical trigger system was designed to synchronize the data acquisition system with the detonation of the exotic materials. Fiber optics were used to isolate the spectrography from the vibration of the detonation and to facilitate the optical alignment of the spectrograph. A quartz pressure transducer and charge amplifier were used to obtain the chamber pressure. The indication of gas temperature was calculated on the basis of temperature calibration and the obtained spectral data. A total of twenty different types of materials were tested. The lifetime of the radiation from the detonation of these materials ranged from 600 microseconds to 1.5 milliseconds, and the wavelength ranged from 400 to 1200 nanometers. The radiation was a continuum superimposed by the lines and bands. The gas temperature derived from the measurements was found to be from 2000 to 3000 degrees Kelvin. The experimental techniques developed for this investigation have proved helpful in comparing the performance of the existing materials and for the design of additional materials.
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.