| 摘要 |
A positioning system in an optical card reading apparatus, for accurately positioning the optical card (801) relative to the probe array (102) used to read the data stored on the card. The card (801) is provided with a pattern of servo bands (800) and the sensor (103) used to read out data stored on the optical card (801) has a windowing function which is used to narrow its field of view (802) to define a region of interest (900) corresponding to one or the servo bands (800), and the output is fed to an analogue-to-digital converter. Thus, the "windowing" function of the sensor (103) is used to increase the readout speed and, therefore, the speed of detection of servo marks (800) to enable more rapid positioning of the probe array (102) relative to the optical card (801).
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