Operation support system, vehicle, and method for estimating three-dimensional object area

Camera images at times (t1 and t2) are acquired from a camera installed on a vehicle, and the camera images are converted to bird's-eye images at the times (t1 and t2). A plurality of feature points are extracted from the camera image at the time (t1) and the movement vectors of the respective feature points between first and second camera images are detected. Then, the respective feature points and the respective movement vectors are mapped onto a bird's-eye image coordinate plane. Two or more feature points on the bird's-eye images are permitted to be targets, the positions and the movement vectors of the target feature points are applied to an equation of constraint which ground surface feature points have to satisfy, thereby discriminating whether the target feature points are the ground surface feature points. Then, from position information and movement vector information on the two or more feature points discriminated to be the ground surface feature points, movement information on the vehicle is obtained and used for taking the difference between the bird's-eye images at the times (t1 and t2) to estimate a three-dimensional object area.