The camera captures an image of a surrounding environment of a work vehicle and outputs image data indicative of the image. The shape sensor measures a three-dimensional shape of the surrounding environment and outputs 3D shape data indicative of the three-dimensional shape. A controller acquires the image data and the 3D shape data. The controller generates a three-dimensional projection model based on the 3D shape data. The three-dimensional projection model portrays the three-dimensional shape of the surrounding environment. The image is projected onto the three-dimensional projection model based on the image data, thereby generating display image data that represents a display image of the surrounding environment of the work vehicle.