The strain dependence of the free-exciton resonance energies in AlN epilayers is presented and the values are analyzed using an appropriate Hamiltonian assuming equibiaxial stress for the wurtzite crystal structure in order to obtain valence band parameters. Based on the results, we study the strain dependence of the valence band ordering, optical transition probability, and free-exciton binding energy. As a result of these calculations, the following strain-free values are obtained for the energy gap, averaged dielectric constants, and ordinary and extraordinary dielectric constants: Eg=6.095 eV at T=11 K, ϵ=7.87, ϵ⊥=7.33, and ϵ∥=8.45, respectively. A brief discussion of the valence band ordering in bulk AlxGa1−xN is also presented.

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Free space detection is one of the techniques for constructing safe driving support and autonomous driving. In this paper, we focus on narrow roads and describe the free space detection algorithm for constructing a narrow road driving support system. By installing the stereo camera in front of the vehicle, it is possible to perform object recognition and distance measurement without other external sensors. The installation position of the camera and the pitch angle of the camera are also used for detection of free space. The evaluation method is performed by comparing the detection result image with the previously prepared correct answer image. We are considering two kinds of evaluation methods based on the area and contour of free space.

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