PARTIAL IMAGE GENERATING DEVICE, STORAGE MEDIUM STORING COMPUTER PROGRAM FOR PARTIAL IMAGE GENERATION AND PARTIAL IMAGE GENERATING METHOD

A partial image generating device has a processor configured to generate a partial image from an image in which the environment surrounding a vehicle has been photographed using an imaging device provided in the vehicle, and to assess whether or not the road represented in the image is straight. The processor is configured so that, when it has been assessed that the road represented in the image is straight, it generates a partial image by cutting out a first region in the image that is estimated to contain the road, based on the vanishing point of the road, and when it has assessed that the road represented in the image is not straight, it generates a partial image by cutting out a second region in the image determined based on the type of the vehicle.