Patent ID: 7064311

Claim:
An optical image detector comprising: a light source for controlling illumination in response to an illumination control signal and irradiating light having the controlled illumination onto a subject; an image sensor for detecting a quantity of light reflected from the subject and generating and outputting image signals corresponding to the detected quantity of light; and an image processor for calculating a shutter-on time using the image signals, comparing the calculated shutter-on time with at least one of maximum and minimum shutter-on times, and generating and outputting the illumination control signal for maintaining a former illumination of the light source when the calculated shutter-on time is less than the maximum shutter-on time and greater than the minimum shutter-on time, increasing the former illumination of the light source when the calculated shutter-on time is greater than the maximum shutter-on time and decreasing the former illumination of the light source when the calculated shutter-on time is less than the minimum shutter-on time.