| 摘要 |
<P>PROBLEM TO BE SOLVED: To simplify a structure for entry detection of an information code and to perform processing of entry detection surely in short time in an optical information reader which detects that the information code relatively enters in an imaging visual field of an image pickup means and automatically performs a reading operation of the information code. <P>SOLUTION: A marker light irradiation part 16 irradiates a reading object with marker light M consisting of four L-shaped patterns M1 corresponding to four corner parts of the imaging visual field of a light receiving sensor and a cross-shaped pattern M2 indicating its center part. Capture of a marker light image irradiated with the marker light M by the light receiving sensor is repeated, a bright and dark pattern for pattern M1 parts of each marker light image is detected, when there is a change over a predetermined amount in the light and dark pattern in comparison with the previous time, it is determined as the entry of a two-dimensional code to the imaging visual field of the two-dimensional code Q and a reading operation of the two-dimensional code Q is automatically performed. Exposure conditions in the case of capturing the marker light image is automatically set so as not to be over exposed. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
