An ECU of a night vision system stores small obtained images of
provisional targets as six templates depending on the distance from
infrared cameras, and selects one of the templates depending on the
distance up to an actual object. Using the selected template, the ECU
performs template matching on images obtained by the infrared cameras,
and calculates coordinates of the inspection target. The ECU compares the
calculated coordinates of the inspection target and stored reference
coordinates with each other, and determines mounted angles of the
infrared cameras.