The earth-atmosphere stray light can lower contrast ratio and SNR of spatial optical remote sensors, or even fail the system at certain conditions. Errors in the calculation of the stray light illuminance based on point source are very large, for the satellite’s altitude is only several hundred kilometers and far less than the radius of the earth. This paper proposed a stray light illuminance c...

We measured r.m.s. contrast sensitivity as a function of retinal illuminance at various spatial frequencies within 3-37 deg of eccentricity in the nasal visual field. In dim light contrast sensitivity increased in proportion to the square root of retinal illuminance obeying the DeVries-Rose law but in bright light contrast sensitivity was independent of luminance following Weber's law. Critical...

An experiment in a mock-up office space gave occupants control over dimmable lighting circuits after a day working under pseudo-random lighting conditions. Data analysis indicated that the lighting experienced during the day influenced the changes in lighting made at the end of the day. Occupants chose to reduce screen glare if any existed. Even after allowing for the effect of glare, desktop i...

A theory is presented to analyze images of anisotropic fine-scale surfaces. We investigate the estimates of illuminance flow by using structure tensors. For anisotropic surfaces, both the gradient-based and the Hessian-based tensors will yield deviations from the true illumination orientation. Our theory predicts this deviation. To show the use of this theory, an algorithm is derived that uses ...

BACKGROUND Alcohol-related driving accidents and fatalities occur most frequently at nighttime and at dawn, that is, a mesopic lighting condition in which visual processing depends on both rod and cone photoreceptors. The temporal functions of the rod and cone pathways are critical for driving in this lighting condition. However, how alcohol influences the temporal functions in the rod and cone...

Fluorescent lamp luminaires with multilayer polarizer panels produce partially polarized light*, which can increase the contrast of a visual task under some viewing conditions. In principle, a decrease in illuminance can accompany an increase in task contrast without affecting visual performance. Because a reduction in illuminance implies a reduction in the electric power used for lighting, mul...

This reserch proposes a method to provide an appropriate illuminance and color temperature in an office lighting environment for individual workers. For the control algorithm, based on the optimization method called Simulated Annealing (SA), a method including a neighborhood design mechanism for the design variables instead of a temperature parameter was used. In addition, for changes in the lu...

Current office lighting recommendations stress the importance of vertical surface illumination over horizontal desktop illumination for VDT work, where the occupant is primarily in a “heads up” position. We investigated this recommendation by creating two very different lighting conditions in two workstations in a mock-up open-plan office space. One workstation was provided with conventional, d...

The NIST candela is maintained via standard photometers which have shown long-term stability better than 0.1% per year. The detector-based method has allowed us to reduce the uncertainties of calibrations and to expand the range of calibration capabilities. There have been several new developments in photometry at NIST. A high-illuminance calibration facility has been developed. Four temperatur...