| 摘要 |
<p>The system controller (20) of a navigation device (1) acquires an image of the periphery of a traffic light using a camera (14) mounted on the vehicle. The system controller (20) also stores a first brightness comparable to the minimum brightness value for each pixel in a subject range (Rtag) on the basis of a plurality of images (Im) acquired during a subject period (Ttag) when the vehicle is in a stationary state. The system controller (20) furthermore calculates, for each of the pixels, the difference between the first brightness value and a brightness value based on at least one image (Im) from amongst a plurality of images (Im) acquired during or immediately after the subject period (Ttag). The system controller (20) then recognizes the type of illuminated signal on the basis of a shape formed by pixels for which the brightness value difference is equal to or greater than a predetermined threshold value.</p> |
