The Suitability of Radiance for Calculating Circadian Potential
This research project deals with the suitability of the program Radiance for detailing the spectral qualities of the light received inside a room. More specifically, it asks whether Radiance’s innate RGB algorithm can be used to accurately determine the nonvisual effects of light on viewers in the space, particularly when also considering the view direction of the sensor. It goes on to explore whether there is a simple method to modify the results produced by an RGB-type simulation to more closely match more accurate methods. The experiment compared several simulations, all measured from a viewpoint at the center of rectangular room with a single window on one side. The interior color of the room was varied, while the color cast of the sky and ground remained constant. Eight vertical (facing toward the wall) view directions were simulated. For each color condition and viewpoint, the RGB simulation was compared to three other simulations that represented the spectrum using a different method, averaging the reflectance over three, nine, and twenty-seven spectral intervals between 380 nanometers and 730 nanometers. The Radiance program produced three irradiance values for the RGB and three-interval simulations, nine irradiance values for the nine-interval simulation, and so on, which could then be used with the visual and circadian sensitivity curves to calculate visual lux and circadian lux.
Record created on 2014-09-12, modified on 2016-08-09