Transformation of environment map by changing the captured position in a cuboidal room

Abstract

In this paper, we consider the use of an environment map as a photographic support tool for understanding the condition of surrounding light. It is well known that an environment map should be captured at a position directly above the target object. However, this is not always possible. Therefore, we developed a practical transformation method for an environment map that was captured from a different position. The proposed method is effective in an indoor scene where the direction of a light source differs significantly depending on the captured position. A mapping for a rectangular parallelepiped (cuboid), and perspective information estimated from a corner position of a room is used to calculate the transformed environment map at the target position. The method was applied to the transformation for an actual room, and it was verified that the transformed environment map almost corresponds to the ground truth of the environment map captured at the target position.