| 摘要 |
PURPOSE:To enable the using of a camera apparatus even under the backlight condition in which the sun light is incident on the camera lens by driving a filter means to shield incident light when the back. light condition is detected within a range of an image picked up. CONSTITUTION:When the sun light is incident within an angle thetac in the vertical direction under a normal condition in which a car 5 running ahead is picked up by camera devices 1-4 to display 11, the sun light also is incident within a photodetecting angle thetas almost the same as the angle thetac in the direction so that an output signal 21a of a photodiode 21 increases in level. On the other hand, no incidence occurs within a photodetecting angle thetas2 narrower than the photodetecting angle thetas1 and an output signal 22a of a photodiode 22 will not change in the level and with 21a>22a, a servo motor 24 is driven by a control signal C. As a result, a filter means 23 moves to a driving position L1 from a standby position L0 and shiels the sun shine S to prevent the direct incidence into a sensor 4. Even under such a condititon, as the shielding area does not reach the upper end part of a window W, the vehicle 5 running ahead can be captured to measure a distance R. After the releasing of the backlight condition, the signal C is turned OFF and the means 23 is returned to the position L0 by an energizing force 24, hence back to the normal condition. |
