| 摘要 |
In the instant reading of bar codes by flash illumination, the disclosed system automatically adapts to bar code configurations of greater extent and/or curvature, for example by measuring distance to one or more points on the bar code and adjusting a lens barrel, and/or by selecting from multiple image paths through a lens system. Plural illumination sources may be used to enhance the uniformity of the reflected bar code image, may be flashed jointly and/or in rapid sequence, and may have flash durations individually adapted to respective segments of a bar code for optimum sensitivity and signal to noise ratio. One or a plurality of reflected light sensors may control integration time of a bar code image sensor, for example during sequential activation of plural illumination sources. Marker light beams may originate in the vicinity of the bar code image sensor and be projected through the optics to produce light spots on the bar code label precisely delineating the image sensor field of view.
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