We analyze the channel properties of a nonline-of-sight (NLOS) ceiling-to-device and device-to-device visible light communication systems by considering various receivers' orientation and variable fields of view (FOVs). Analyses based on the recursive indoor channel model show that for a particular transmitter configuration, the pure NLOS path can offer higher 3-dB channel bandwidth (up to 14 MHz) compared with the link with LOS and NLOS components. We also show how the receiver rotation (orientation) influences the probability of receiving signals via the NLOS path compared with the LOS and NLOS paths. Moreover, based on the experimental campaign, we demonstrate that shadowing observed at the receiver due to people’s movement results in decreased received power level (up to 1.8 dB), thus resulting in reshaping of the probability density function of received power.
Color grading of archive films is a very particular task in the process of their restoration. The ultimate goal of color grading here is to achieve the same look of the movie as intended at the time of its first presentation. The role of the expert restorer, expert group and a digital colorist in this complicated process is to find the optimal settings of the digital color grading system so that the resulting image look is as close as possible to the estimate of the original reference release print adjusted by the expert group of cinematographers. A methodology for subjective assessment of perceived differences between the outcomes of color grading is introduced, and results of a subjective study are presented. Techniques for objective assessment of perceived differences are discussed, and their performance is evaluated using ground truth obtained from the subjective experiment. In particular, a solution based on calibrated digital single-lens reflex camera and subsequent analysis of image features captured from the projection screen is described. The system based on our previous work is further developed so that it can be used for the analysis of projected images. It allows assessing color differences in these images and predict their impact on the perceived difference in image look.
Remote Telescope System 2nd version (RTS2) is an open source project aimed at developing a software environment
to control a fully robotic observatory. RTS2 consists of various components, which communicate via
an ASCII based protocol. As the protocol was from the beginning designed as an observatory control system,
it provides some unique features, which are hard to find in the other communication systems. These features
include advanced synchronisation mechanisms and strategies for setting variables. This presentation describes
the protocol and its unique features. It also assesses protocol performance, and provides examples how the RTS2
library can be used to quickly build an observatory control system.
We present a novel design of an all-sky 4096×4096 pixels camera devoted to continuous observations of the sky.
A prototype camera is running at the BOOTES-1 astronomical station in Huelva (Spain) since December 2002
and a second one is working at the BOOTES-2 station in Málaga (Spain) since July 2004. Scientific applications
are the search for simultaneous optical emission associated to gamma-ray bursts, study of meteor showers, and
determination of possible areas for meteorite recovery from the reconstruction of fireball trajectories. This last
application requires that at least two such devices for simultaneously recording the sky at distance of the order
of ~ 100 km. Fifteen GRB error boxes (13 for long/soft events and 2 for short/hard GRBs) have been imaged
simultaneously to the gamma-ray emission, but no optical emission has been detected. Bright fireballs have been
also recorded, allowing the determination of trajectories, as in the case of the fireball of 30 July 2005. This device
is a very promising instrument for continuous recording of the night sky with moderate angular resolution and
limiting magnitude (up to R ~ 10).
BIRCAM is a near-infrared (0.8-2.5um) cryogenic camera based on a 1Kx1K HgCdTe array. It was designed for - and
is now mounted at - one of the Nasmyth foci of the fast-slewing 0.6 m BOOTES-IR telescope at the Sierra Nevada
Observatory (OSN) in Spain. The primary science mission is prompt Gamma Ray-Burst afterglow research, with an
implied demand for extremely time-efficient operation. We describe the challenges of installing a heavy camera on a
small high-speed telescope, of integrating the dithering mechanism, the filterwheel, and the array itself into a high-efficiency
instrument, the design of the software to meet the requirements.