Imaging module and reader for,and method of,expeditiously setting imaging parameters of imagers for imaging targets to be read over a range of working dista

摘要

Method of setting an imaging parameter for imaging targets to be electro-optically read over a range of working distances, comprising: providing near and far imagers with respectively wide and narrow fields of view; capturing a portion of an image of the target; determining distance to target and light intensity of captured image portion; capturing an image of the target; wherein, based on at least one of determined distance and light intensity: near or far imager is selected; illumination level for the target is controlled; value of the parameter is set. Targets may be barcode symbols. Parameter may be exposure or gain. Parameter values may be stored in a look-up table (LUT). Imaging sensors may operate at a predetermined frame rate. Light intensity may be determined at a faster rate than the frame rate. Image may comprise pixels arranged in rows and columns. Illumination level may be less for close targets and greater for remote targets and may be varied as a continuous analogue function or stepwise multi-level function. Each imager may have its own optical axis. Distance may be determined by a range finder that emits an aiming beam (eg. laser) along an axis offset from the imagers optical axes.