Abstract: Each of a detection sample object and a non-detection sample object is illuminated with S-polarization light, for instance. S-polarization light and P-polarization light reflected from each sample object are detected by different photodetecting elements. Glossiness values and light quantities of the detection and non-detection sample objects are judged based on detection outputs of the photodetecting elements, and a glossiness difference and a light quantity difference are calculated. An evaluation function having at least one of the glossiness and the light quantity as a variable is determined by using the glossiness difference and the light quantity difference. Thresholds for object discrimination are calculated based on evaluation function values of the detection and non-detection sample objects.

Abstract: An optical scanner and an optical scanning device, an optical sensor unit, a coded data reader, and a POS system employing an optical scanner. The optical comprises an elastically deformable element, a vibrational input segment disposed at a first end of the elastically deformable element, a driven segment disposed at a second end of the elastically deformable element, a vibration source for inducing vibration in the vibrational input segment, whereby the vibration induced in the vibrational input segment produces elastic deformation of the elastically deformable element and consequent movement of the driven segment, and a stop for limiting a range of the movement of the driven segment.