| 摘要 |
A method and apparatus for indicating an in-focus or an out-of-focus condition for an imaging device ( 1, 2 ) in an optical reading and decoding apparatus ( 20 ) for receiving a coded image from a target area ( 29 ) on an article or package. In the method of the invention, two beams of light ( 27, 28 ) are generated to provide two illuminated aiming marks ( 32, 33 ) on the target. An in-focus condition is indicated when the two aiming marks are in a pre-defined spatial relationship relative to each other on the target. The in-focus condition or an out-of-focus condition can be signaled by controlling attributes of aiming marks ( 32, 33 ) or by controlling attributes of status indicator LEDs ( 12 ) on the apparatus ( 20 ) or by controlling an audible sound.
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