An optical scanner captures a plurality of images from a plurality of image-capture devices. In response to the activation signal, an evaluation phase is executed, and in response to the evaluation phase, an acquisition phase is executed. In the evaluation phase, a first set of images is captured and processed to produce a virtual frame comprising a plurality of regions, with each region containing a reduced-data image frame that is based on a corresponding one of the plurality of images. Also in the evaluation phase, attributes of each of the plurality regions of the virtual frame are assessed according to first predefined criteria, and operational parameters for the acquisition phase are set based on a result of the assessment. In the acquisition phase, a second set of at least one image is captured via at least one of the plurality of image-capture devices according to the set of operational parameters.