| 摘要 |
PROBLEM TO BE SOLVED: To reduce a hardware load to determine whether there is a need to change a target value of a brightness sensor corresponding to a layout change of an area to be irradiated, and to enable early exchange of the target value. SOLUTION: An illumination control system 1 is provided with a light source 2, a brightness sensor 4 and an illumination control device 5. The illumination control device 5 controls an on-off duty ratio of the light source 2 corresponding to a detected value of the brightness sensor detecting brightness of the area to be irradiated. A control part 51 of the illumination control device 5 obtains a detected value of the brightness sensor 4 and feedback controls the duty ratio so that a mean value of the detected values in a period more than a pulse period of the light source 2 gets closer to the target value. A calculation part 54 finds a differential detected value which is a difference of the detected values between that in an on-state and that in an off-state of the light source 2. When an absolute difference value between the differential detected value and the reference value is more than the threshold value, a judging part 55 determines that the target value is necessary to be changed. COPYRIGHT: (C)2011,JPO&INPIT |
