| 摘要 |
PROBLEM TO BE SOLVED: To enhance the reliability by determining the difference between the image information obtained without lighting the eyeball of an observer and the image information obtained with lighting, and slightly weakening the effect of external light removal when an external light removal is performed. SOLUTION: A frame memory 202 stores the eyeball image of an observer in the lighting state of a light source, and a frame memory 203 stores the eyeball image of the observer in the non-lighting state of the light source. Read buffers 206, 207 output picture elements one by one in order, when the picture element data of the frame memories 202, 203 are read one line at a time and transferred to the buffers. A differential amplifier 208 determines the difference between the picture element outputs from the read buffers 206, 207, and multiplies it by a gain followed by outputting. A signal output terminal 209 outputs the output of the differential amplifier 208 to a MPU. In an external light removal, the effect of external light removal is slightly weakened. |
