A two-dimensional or three-dimensional camera (2) is installed at a lower portion of a tire of self-propelled agricultural working machine (1) so as to image the soil. An image analyzing device (20) is provided to determine the soil condition or obstruction based on the image photographed by the camera. A warning signal is output to driver of self-propelled agricultural working machine by a control unit (21) based on the soil condition analyzed by image analyzing device. Independent claims are included for the following: (1) self-propelled agricultural working machine and (2) device for optical image capturing/analyzing.
