| 摘要 |
A reader for electro-optically reading two-dimensional symbols of different heights, includes a scanner for scanning the symbols with light in a raster scan pattern of an adjustable height, and for detecting light scattered from the symbols to generate electrical signals indicative of the detected light. A controller not only decodes the electrical signals to read the symbols, but also controls the scanner to adjust the height of the raster scan pattern, and optionally the rate of height adjustment, upon a determination that a symbol being scanned is a two-dimensional symbol, and that the two-dimensional symbol has not been read after a predetermined time period has elapsed. The controller can also be programmed to read symbols only of a certain height.
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