| 摘要 |
PROBLEM TO BE SOLVED: To form the most suitable eyeball image to securely perform visual axis detection, by composing the calculation processing means to control at least one of a lighting means and a light receiving means based on the outputted value of the eyeball image of an observer when the calculation means failed to calculate the visual line of the observer. SOLUTION: When detection of the visual axis of an observer was not successfully done (#134), CPU, i.e., a calculation processing means, judges whether the minimum output value, i.e., a specific output value of an eyeball image, became higher or remained low (#135). When it remained low and not larger than a prescribed threshold value, CPU resets the quantity of light of IRED (infrared emitting diode), i.e., the lighting means, to be larger (#137). It is also allowed to prolong the accumulation time of the image sensor instead. On the other hand, when the lowest output value is high and larger than the prescribed threshold value, the accumulation mode of the image sensor, i.e., light receiving means, is set to an external light eliminating mod, (#136). |
