To obtain uniform power distribution on the ATR prism for biomedical spectroscopy system, the power intensity mapping on the prism is precisely measured by using a newly developed probing technique. It is found that the distribution of QCL based system is less uniform than that of the FT-IR based system due to the high coherency of the laser beam. To homogenize the distribution, a lens is introduced to diffuse the light and the incident beam is inclined to increase the number of reflections in the prism. As a result, we confirmed that the measurement error of in-vivo experiments is suppressed.
Information about the polarization of light is valuable because it contains information about the light source
illuminating an object, the illumination angle, and the object material. However, polarization information strongly
depends on the direction of the light source, and it is difficult to use a polarization image with various recognition
algorithms outdoors because the angle of the sun varies. We propose an image enhancement method for utilizing
polarization information in many such situations where the light source is not fixed. We take two approaches to
overcome this problem. First, we compute an image that is the combination of a polarization image and the
corresponding brightness image. Because of the angle of the light source, the polarization contains no information
about some scenes. Therefore, it is difficult to use only polarization information in any scene for applications such as
object detection. However, if we use a combination of a polarization image and a brightness image, the brightness
image can complement the lack of scene information. The second approach is finding features that depend less on
the direction of the light source. We propose a method for extracting scene features based on a calculation of the
reflection model including polarization effects. A polarization camera that has micro-polarizers on each pixel of the
image sensor was built and used for capturing images. We discuss examples that demonstrate the improved visibility
of objects by applying our proposed method to, e.g., the visibility of lane markers on wet roads.
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