Optical bar code scanner having object detection
AssigneeMicroscan Systems, Inc.
InventorJames E. Thomas
Life of this patent
Estimating the term…
Abstract
In a bar code scanner of the fixed amount type, laser beam reflections from the target location are collected by an object detector that senses predetermined specular reflections and determines whether an object is present or absent, and whether the object has a bar code label or lacks a bar code label.
Claims18
A bar code scanner for reading bar code labels on objects comprising:
- means for producing a beam of coherent light;
- means for causing said beam to scan target locations which are adapted to receive objects having bar code labels thereon;
- bar code detection means responsive to light reflected from said beam of coherent light scanned across bar code labels on objects present at said target locations;
- object presence detector means responsive to specular reflections caused by the scanning of said beam on objects present at said target locations.
A bar code scanner apparatus comprising:
- means for producing a beam of laser light;
- means for causing said beam of laser light to scan coded alternately reflective and non-reflective inked indicia on a reflective surface of an object;
- and
- object detection means for detecting the presence of such object in the absence of said indicia by sensing specular reflections from said reflective surface of the object when present and detecting the absence of said object by sensing the absence of said specular reflections when an object is not present.
A method of detecting the presence of an object in a bar code scanning process in which a plurality of objects that may have bar code labels are transported past a bar code scanner, comprising the steps of:
- illuminating with coherent light a field of view in which said objects when present are transported;
- detecting specular reflections from a surface of each of said objects when present by photodetecting specular reflections and processing an electrical signal resulting therefrom, said step of processing said electrical signal including substeps of sampling and holding said electrical signal for integrating said electrical signal over successive sweeps of said laser beam across a reflective surface of the object;
- and
- determining whether an object is present or absent by comparing the level of detected specular reflections with a predetermined threshold.
A method of detecting the presence of an object in a bar code scanning process in which a plurality of objects that may have bar code labels are transported past a bar code scanner, comprising the steps of:
- illuminating with coherent light a field of view in which said objects when present are transported:
- detecting specular reflections from a surface of each of said objects when present;
- determining whether an object is present or absent by comparing the level of detected specular reflections with a predetermined threshold, and
- processing reflections from the field of view of said scanning beam of coherent light so as to determine the presence of an object with label and bar code, the presence of an object with label but without bar code, the presence of an object without label, and the absence of an object.
A bar code scanner apparatus comprising:
- means for producing a beam of laser light;
- means for causing said beam of laser light to scan coded indicia on an object;
- and
- object detection means for detecting specular reflections from an object when present and detecting the absence of specular reflections when an object is not present, wherein said object detection means comprises a photodetector and a signal processor for processing electrical signals resulting from the detection of said specular reflections by said photodetector, wherein said signal processor comprises sample-and-hold circuit means for integrating a detected signal resulting from reflections due to successive sweeps of said laser beam across a reflective surface of the object.
Dependencies are inferred from the claim text.