To determine the visual range of, in particular, a driver in a motor vehicle, a contrast, c) is measured from at least two measuring positions of a measuring device situated at different distances from the object, and the ratio of the measured contrast values is converted to a visual range, using the difference of the distances of the measuring positions from the object. The shower body is disposed with a root waterway, several diversion waterways and an outlet cover unit, each diversion waterway is disposed with an electromagnetic valve to control the on-off thereof. The irradiation control unit makes the irradiation nozzle scan in a diluting manner the particle beam onto a predetermined area in the irradiation subject, in a predetermined period after a time point when emission is switched from ON to OFF, or in a period from the time point when emission is switched from ON to OFF to a time point when the particle beam is cut off. The upper surface of the cam member supporting member has a first upper surface portion on a first plane and a second lower surface portion in a different substantially parallel second plane such that the first and second cam members slide in offset planes on the upper surface to fire the fasteners. Exemplary processing performed by such matched systems includes discrete transforms, such as the discrete Fourier transform, the discrete cosine transform and the discrete wavelet transform.