Method and apparatus for object surveillance along a transport path

An object surveillance system for an object travelling along a transport mechanism of a transport path comprising:

• a plurality of object tracking modules with each tracking module comprising:
• first means, operably coupled to a tracking means, for sensing the object;
• second means, operably coupled to a tracking means, for sensing the object;
• means, operably coupled to the tracking means, for representing a position of the transport mechanism with respect to a given reference point;
• means, operably coupled to the tracking means, for assigning a unique object identifier to the object in response to detection of the object by at least the first means for sensing, and for associating said identifier with a representation from said means for representing said position of said transport mechanism;
• tracking means for tracking a given location of the object in response to input from the first means for sensing, the second means for sensing, the means for assigning the unique identifier, and the means for representing a position of the transport mechanism with respect to a given reference point, said tracking means comprising:
• means for determining a first reference indication corresponding to the arrival detected by the first means for sensing;
• means for determining a second reference indication corresponding to the arrival detected by the second means for sensing;
• and,
• means for comparing an expected arrival reference indication with an actual arrival reference indication;
• system tracking means for communicating with each tracking means for tracking the given location of the object.

A document surveillance system for tracking a document traveling along a transport path in a document sorting system comprising:

• a plurality of sensors, positioned in sequence along the transport path, for detecting an edge of the document;
• optical character reading mechanism, positioned along the transport path, for reading characters located on the document;
• means, operably coupled to the plurality of sensors, for determining document status of the document as it travels along the transport path wherein the means for determining document status further comprises means for passing edge detection information between the plurality of sensors, said edge detection information comprising a unique document identifier and a representation of a position of a transport mechanism associated with said transport path;
• and
• a document labeling mechanism for labeling the document in response to output from the optical character reader.

A method of surveillance for an object travelling along a transport mechanism of a transport path comprising the steps of:

• detecting an arrival of an object using a first means for sensing;
• determining a first reference indication corresponding to the arrival detected by the first means for sensing, said first reference indication being representative of a first position of said transport mechanism;
• assigning a unique object identifier to the object in response to detecting the arrival of the object;
• communicating the object identifier and the first reference indication to a message queue associated with a second means for sensing;
• detecting the arrival of the object using the second means for sensing;
• determining a second reference indication corresponding to the arrival detected by the second means for sensing, said second reference indication being representative of a second position of said transport mechanism;
• retrieving from the message queue the unique object identifier and the first reference indication;
• computing a net difference between the first reference indication and the second reference indication;
• comparing the net difference to a predetermined expected arrival time;
• and
• determining an object status in response to the value of the net difference.

A method of surveillance for an object traveling along a transport path comprising the steps of:

• detecting a leading edge of an object using a first means for sensing;
• determining a first reference indication corresponding to the time in which the leading edge was detected;
• assigning a unique object identifier to the object in response to detecting the leading edge of the object;
• communicating an arrival message, whose content includes the unique object identifier and the first reference indication to a message queue associated with a next subsequent means for sensing;
• detecting a trailing edge of the object by the first means for sensing;
• determining a second reference indication corresponding to the time at which the trailing edge was detected by the first means for sensing;
• determining a net object blockage time in response to the first reference indication and the second reference indication;
• generating an object jam signal when the net object blockage time is substantially different than a designated blockage tolerance;
• communicating a trail message, whose context includes the object identifier and the second reference indication to the message queue;
• detecting the leading edge of the object using the next subsequent means for sensing;
• recording a third reference indication corresponding to the time in which the next subsequent means for sensing detected the leading edge of the object;
• retrieving from the message queue the arrival message;
• comparing the first reference indication to the third reference indication resulting in a net arrival indicator;
• generating a new document identifier when the net arrival indicator is less than a predetermined range;
• generating a new arrival message whose contents include the new object identifier and the third reference indication;
• and
• adjusting the message queue in response to the net arrival indicator.