We manufactured a far infrared ray (FIR) heater that uses natural zeolite as the radiation body, and conducted active thermography to heat the body surface with this FIR heater. We also evaluated the possible application for breast cancer inspection by examining eight subjects with breast cancer using this system. From the results of the thermal image and histogram analysis, we found that the temperature of the tumor region was higher than the normal tissue region in six out of eight subjects just before heating, and after heating for 1 or 2 minutes. Also, the dTs/dTr property was different from the tumor and blood vessel regions after heating for 1 or 2 minutes. This may become an important criterion in discriminating between tumor and blood vessel regions automatically in thermal images.
We propose adopting total revealing power to evaluate the visibility of obstacles dropped on the road in tunnels. Total revealing power is a combination of silhouette vision and reversed silhouette vision. To evaluate visibility under conditions of total revealing power, we surveyed relationship the revealing power and the reflection factor of an obstacle dropped on the road surface of an expressway. We also carried out experimental observations to determine the relationship between road surface luminance and luminance contrast to achieve a correct perception rate of 75% with silhouette vision and reversed silhouette vision. Results show that the visibility of an obstacle dropped on the road depends on the road surface luminance, in spite of the vertical illuminance. We found that total revealing power is effective in estimating visibility of an obstacle dropped on the road. This is because such than assumed in previous obstacles usually have a higher reflectance factor by Smith.
We propose a measurement method for evaluating space brightness by measuring border luminance as it is very important for architectural design to assess space brightness quantitatively. Border luminance is the transition point of the color appearance mode. It is where natural object color mode changes to unnatural object color mode. Our previous work showed that the border luminance stays the same regardless of measuring position, if the room is uniformly illuminated. In such conditions, the border luminance is mainly determined by the illuminance and configuration of the interior's reflectance. We measured the border luminance at various positions in a non-uniformly illuminated room to examine how border luminances are distributed. Our results show that the illuminance distribution is not significant in determining the border luminance, but the distance between the measurement position and the wall, which might be used as the main cue for a subject to recognize the illumination of the room, is important. We also found that additivity law holds for border luminance. This rule is very useful for practical lighting design. For example, the border luminance of a room illuminated by two or more lights can be estimated from the border luminances under each single light.
A new color-difference formula based on uniform color-difference space presented. CIELAB color space that was revised seemed to create an equal color difference between the adjacent hue lines or chroma lines on the Munsell system. Weighting functions for a new chroma scale and new hue-difference scale adjust the distance in uniform space to the perceived color-difference magnitude of the Munsell system. We called this uniform space a uniform color-difference space. We determined the total color-difference between two color samples with the weighting factor corresponding to the location of the color samples in uniform color-difference space. The Relationships between the total color-difference used in the new formula and the perceived magnitude were performs analyzed through visual perception data sets. The new formula is better than CIELAB, CIE94, and CIEDE2000.