An evaluation value which includes at least one of a luminance and {TAIL ~ a high frequency component} of the images obtained by {HEAD ~ the imaging units} at the predetermined time interval is calculated 
An evaluation value which includes at least one of a luminance and { TAIL ~ a high frequency component } of the images obtained by { HEAD ~ the imaging units } at the predetermined time interval is calculated
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH