Apparatuses and methods for self-position calculation of a vehicle using a light projector and a camera

A self-position calculating apparatus includes: a light projector projecting a patterned light beam onto a road surface around a vehicle; and a camera capturing an image of the road surface including an area onto which the patterned light beam is projected. The apparatus calculates an orientation angle of the vehicle from a position of the patterned light beam, and calculate an amount of change in orientation based on temporal changes in multiple feature points on the road surface. The apparatus calculates current position and orientation angle by adding the amount of change to initial position and orientation angle. If a condition under which the multiple feature points are detected does not satisfy a first criterion, the apparatus sets the current position at that time and the orientation angle at the initial position and orientation, and starts adding the amount of change to the initial position and orientation angle.