Systems and methods for reducing weighing errors associated with partially off-scale items

• US 8,552,313 B2
• Filed: 12/09/2009
• Issued: 10/08/2013
• Est. Priority Date: 12/09/2008
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Atwater, Charles Forrister, McQueen, Alexander M., O'Donnell, Patrick M.
• Primary Examiner(s): Gibson, Randy W
• Application Number:
  US12/634,252
• Publication Number:
  US 20100139989A1
• Time in Patent Office: 1,399 Days
• Field of Search: 235/462.13, 235/383, 177/45, 177/50, 177/245, 177/25.15, 177/262
• US Class Current: 177/25.15
• CPC Class Codes: G01G 19/4144 for controlling weight of goods in commercial establishments, e.g. supermarket, P.O.S. systems
• CPC Class Codes: G01G 23/00 Auxiliary devices for weighing apparatus
• CPC Class Codes: G01G 23/3735 using a digital network
• CPC Class Codes: G06V 10/245 by locating a pattern; Special marks for positioning

Abstract

Systems and methods are provided for reducing erroneous weighing of items by detecting items extending beyond a peripheral edge of a weigh platter associated with a data reader. For example, in response to a weigh request a scale guard module acquires data indicative of whether an item extends between the weigh platter and another surface, compares the acquired data to reference data, and based on the comparison, determines whether an item extends off the weigh platter and thus on to another surface. The scale guard module may utilize non-electromagnetic compression waves, radio waves, a portion of a data reader'"'"'s scan field to scan a set of patterns extending along at least one edge of the weigh platter, an imaging based scanner to capture an image of at least one edge of the weigh platter, light beams extending along at least one edge of the weigh platter, or any combination thereof.

Claims

1. A system for reducing weighing errors of an item being weighed on a weigh platter of a scale associated with a data reader installed in a checkout counter surface or other fixed object, the system comprising:

a weigh platter including a top surface adjacent the checkout counter surface or other fixed object, the top surface of the weigh platter including a lateral edge that is adjacent an edge of the checkout counter surface or other fixed object;

a data reader configured to detect a change in light reflected off a region of the top surface of the weigh platter proximate the lateral edge of the top surface of the weigh platter; and

a controller coupled to the data reader, the controller configured to determine whether an item rests partially on the checkout counter or other fixed object and partially on the weigh platter based on whether the item blocks a portion of the light that would otherwise reflect off of said region proximate the lateral edge;

a reference pattern positioned on the top surface of the weigh platter proximate and along the lateral edge,

wherein the data reader is configured to detect the pattern when the pattern is unobstructed by an item and the controller is configured to determine whether an item blocks a portion of the light that would otherwise reflect off of the region proximate the lateral edge of the top surface of the weigh platter based on whether the item interrupts the reference pattern.

2. The system of claim 1, wherein the data reader comprises an imaging based scanning system including an image sensor that detects an image of a target within a field of view of the image sensor, and the imaging based scanning system is configured such that a full extent of the reference pattern is within the field of view of the image sensor when the reference pattern is unobstructed.

3. The system of claim 1, wherein the data reader comprises a laser based scanning system configured to generate a scan pattern along a scan arc, project the scan pattern onto an optical code, and detect light reflected by the optical code for decoding the optical code, and the laser based scanning system is further configured to project at least a portion of the scan arc along a full extent of the reference pattern when the reference pattern is unobstructed and to detect light reflected by the pattern.

4. A system for reducing weighing errors of an item being weighed on a weigh platter of a scale associated with a data reader installed in a checkout counter surface or other fixed object, the system comprising:

a weigh platter including a top surface adjacent the checkout counter surface or other fixed object, the top surface of the weigh platter including a lateral edge that is adjacent an edge of the checkout counter surface or other fixed object;

a data reader configured to detect a change in light reflected off a region of the top surface of the weigh platter proximate the lateral edge of the top surface of the weigh platter; and

a controller coupled to the data reader, the controller configured to determine whether an item rests partially on the checkout counter or other fixed object and partially on the weigh platter based on whether the item blocks a portion of the light that would otherwise reflect off of said region proximate the lateral edge;

an imager configured to capture an image of the region proximate the lateral edge of the top surface of the weigh platter; and

a memory for storing a reference image, the reference image comprising an image of the region proximate the lateral edge of the top surface of the weigh platter when an item does not rest partially on the weigh platter and partially on the checkout counter or other fixed object,

wherein the controller is configured to cause the imager to capture an image of the region proximate the lateral edge of the top surface of the weigh platter and determine whether an item blocks a portion of the light that would otherwise reflect off of the region of the top surface of the weigh platter based on a comparison of the captured image and the reference image.

5. A system for reducing weighing errors of an item being weighed on a weigh platter of a scanner-scale associated with a data reader installed in a checkout counter surface or other fixed object, the system comprising:

a weigh platter including a top surface adjacent the checkout counter surface or other fixed object, the top surface of the weigh platter including first and second lateral edges that are adjacent respective first and second edges of the checkout counter surface or other fixed object;

a first reference pattern positioned on the top surface proximate and along the first lateral edge of the weigh platter;

a data reader configured to detect the first reference pattern when the first reference pattern is unobstructed; and

a controller coupled to the data reader, the controller configured to determine whether an item rests partially off the weigh platter based on whether the item interrupts the first reference pattern.

6. The system of claim 5, further comprising:

a second reference pattern positioned on the top surface proximate and along the second lateral edge of the weigh platter,

wherein the data reader is configured to detect the second reference pattern when the second pattern is unobstructed and the controller is configured to determine whether an item rests partially off the weigh platter based on whether the item interrupts at least one of the first reference pattern and the second reference pattern.

7. The system of claim 5, wherein the data reader comprises an imaging based scanning system including an image sensor that detects an image of a target within a field of view of the image sensor, and the imaging based scanning system is configured such that a full extent of the first reference pattern is within the field of view of the image sensor when the first reference pattern is unobstructed.

8. The system of claim 5, wherein the data reader comprises a laser based scanning system configured to generate a scan pattern along a scan arc, project the scan pattern onto an optical code, and detect light reflected by the optical code for decoding the optical code, and the laser based scanning system is further configured to project at least a portion of the scan arc along a full extent of the first reference pattern when the first reference pattern is unobstructed and to detect light reflected by the first reference pattern.

9. The system of claim 5, further comprising:

a set of mirrors configured to redirect a line-of-sight of the data reader to read along a lengthwise region of the surface proximate and along the first lateral edge of the weigh platter corresponding to the first reference pattern.

10. The system of claim 5, further comprising:

a filter coupled to the data reader, wherein the filter is tuned to a frequency of the first reference pattern, an output of the filter indicating whether the item at least partially interrupts the first reference pattern, and wherein the controller is configured to monitor the output of the filter to determine whether the item rests partially off the weigh platter.

11. The system of claim 5, further comprising:

an edge detector coupled to the data reader, wherein the edge detector is configured to detect edge transitions in the first reference pattern and the controller is configured to monitor the number of edge transitions detected by the edge detector to determine whether the item rests partially off the weigh platter.

12. The system of claim 5, further comprising:

an interlock component coupled to the controller and configured to disable a weigh function associated with the weigh platter when the controller determines that an item rests partially off the weigh platter.

13. The system of claim 5, further comprising:

external indicia configured to notify an operator of whether an item rests partially off the weigh platter.

14. The system of claim 5 wherein the first reference pattern comprises regularly spaced apart features.

15. The system of claim 5 wherein the first reference pattern comprises non-uniformly spaced apart features and the spacing between the features is selected to compensate for a scan angle of the data reader so that a frequency of the first reference pattern is approximately constant when the data reader detects the first reference pattern when the first reference pattern is unobstructed.

16. The system of claim 5 wherein the first reference pattern comprises a series of holes extending through the top surface of the weigh platter to thereby create an alternating pattern of high and low reflectance sections on the top surface of the weigh platter.

17. The system of claim 5 wherein the first reference pattern comprises a series of stamped depressions, whereby the stamped depressions create an alternating pattern of high and low reflectance sections on the top surface of the weigh platter.

18. The system of claim 5 wherein the first reference pattern comprises a plurality of spaced apart retroreflective sections to thereby create an alternating pattern of high and low reflectance sections on the top surface of the weigh platter.

19. The system of claim 5 wherein the top surface of the weigh platter is brushed in a direction substantially parallel to a scan direction of the item to thereby create a high reflectance surface that is resistant to wear.

20. A method for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, said weigh platter including a top surface having first and second lateral edges that are adjacent a checkout counter or other fixed object, the method comprising the steps of:

scanning, via the data reader, a first reference pattern positioned on the top surface proximate and along a first lateral edge of the top surface of the weigh platter;

determining whether a full extent of the first reference pattern is detected by the data reader; and

determining whether an item rests partially off the weigh platter based on whether the data reader detected the full extent of the first reference pattern.

21. The method of claim 20, wherein the data reader comprises an imaging based scanning system and wherein the step of scanning the first reference pattern comprises capturing an image corresponding to a location of the first reference pattern and analyzing the captured image to determine whether a number of edge transitions in the captured image corresponds to a number of edge transitions in the full extent of the first reference pattern.

22. The method of claim 20, wherein the data reader comprises a laser based scanning system and wherein the step of scanning the first reference pattern comprises

projecting a scan line along the full extent of the first reference pattern and monitoring light reflected by the first reference pattern for a frequency of the first reference pattern over the scan line.

23. The method of claim 20, further comprising:

upon determining that an item rests partially off the weigh platter, notifying an operator that an item rests partially off the weigh platter.

24. A system for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader disposed in a checkout counter of other station, the system comprising:

a weigh platter including a top surface with first and second lateral edges;

an imager configured to capture an image of a portion of the top surface of the weigh platter, including regions proximate and along the first and second lateral edges of the top surface of the weigh platter;

a memory for storing a reference image, the reference image comprising an image of the portion of the top surface of the weigh platter when an item does not rest partially off the weigh platter; and

a processor coupled to the imager and the memory, the processor configured to cause the imager to capture an image of the portion of the top surface of the weigh platter and determine whether an item rests partially off the weigh platter based on a comparison of the captured image and the reference image.

25. The system of claim 24, wherein the data reader comprises an imaging based scanning system including an image sensor and the imager comprises the image sensor of the imaging based scanning system.

26. The system of claim 24, wherein the processor is configured to calculate a sum-of-absolute-differences between corresponding pairs of captured image pixels and reference image pixels to determine whether an item rests partially off the weigh platter.

27. The system of claim 24, further comprising:

external indicia configured to notify an operator of whether an item rests partially off the weigh platter.

28. A method for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, said weigh platter including a top surface having first and second lateral edges that are adjacent a checkout counter or other fixed object, the method comprising the steps of:

capturing an image of a portion of the top surface of the weigh platter including regions proximate and along the first edge of the top surface of the weigh platter;

comparing the captured image with a reference image, the reference image comprising an image of a portion of the top surface of the weigh platter including regions proximate and along the adjacent first and second lateral edges of the top surfaces of the weigh platter when an item does not rest partially off the weigh platter; and

based on the comparing of the captured image and the reference image, determining whether an item rests partially off the weigh platter.

29. The method of claim 28, wherein the image is captured in response to a request received from a host.

30. The method of claim 28, wherein the step of comparing the captured image with a reference image comprises calculating a sum-of-absolute-differences between corresponding pairs of captured image pixels and reference image pixels.

31. The method of claim 28, further comprising:

isolating a set of captured image pixels corresponding to the first edge of the top surface of the weigh platter, wherein the isolated set of captured image pixels are compared to corresponding reference image pixels.

32. The method of claim 28, further comprising:

periodically capturing an updated reference image, the updated reference image comprising an image of a portion of the top surface of the weigh platter including regions proximate and along the first edge of the top surface of the weigh platter when an item does not rest partially off the weigh platter; and

updating the reference image with the updated reference image.

33. A system for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, the system comprising:

a weigh platter including a top surface with a peripheral edge that is adjacent a checkout counter or other fixed object;

a radiating antenna disposed proximate and to one side of the peripheral edge of the weigh platter, the radiating antenna configured to transmit electromagnetic waves across the peripheral edge of the weigh platter;

a receiving antenna disposed on a side of the peripheral edge of the weigh platter opposite the radiating antenna. the receiving antenna configured to receive the electromagnetic waves from the radiating antenna;

a transmitter coupled to the radiating antenna, the transmitter configured to drive the radiating antenna with a signal so that the radiating antenna transmits the electromagnetic waves across the peripheral edge of the weigh platter;

a receiver coupled to the receiving antenna, the receiver configured to monitor the receiving antenna for an alteration in a coupling of the electromagnetic waves from the radiating antenna to the receiving antenna to determine whether an item rests partially off the weigh platter,

wherein the radiating antenna is configured to transmit electromagnetic waves within the range of approximately three megahertz to approximately thirty megahertz and the receiving antenna is configured to receive electromagnetic waves within the range of approximately three megahertz to approximately thirty megahertz.

34. The system of claim 33, wherein the radiating antenna comprises the weigh platter.

35. The system of claim 33, wherein the receiving antenna comprises a loop of wire at least partially surrounding the weigh platter.

36. The system of claim 33, further comprising:

a controller coupled to the receiver, the controller configured to monitor an output of the receiver to determine whether an item rests partially off the weigh platter.

37. The system of claim 33, further comprising:

external indicia configured to notify an operator of whether an item rests partially off the weigh platter.

38. A method for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, the method comprising:

transmitting electromagnetic waves across a peripheral edge of the weigh platter from a radiating antenna to a receiving antenna;

monitoring the receiving antenna to detect an alteration in a coupling of the electromagnetic waves from the radiating antenna to the receiving antenna;

determining whether an item rests partially off the weigh platter based whether an alteration in the coupling of the electromagnetic waves from the radiating antenna to the receiving antenna is detected, wherein the step of monitoring the receiving antenna to detect an alteration in a coupling of the electromagnetic waves from the radiating antenna to the receiving antenna comprises comparing an amplitude of the electromagnetic waves received at the receiving antenna to a predetermined threshold;

periodically measuring an amplitude of the electromagnetic waves received at the receiving antenna when an item does not rest partially off the weigh platter; and

updating the predetermined threshold with the measured amplitude.

39. A method for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, the method comprising:

transmitting electromagnetic waves across a peripheral edge of the weigh platter from a radiating antenna to a receiving antenna;

monitoring the receiving antenna to detect an alteration in a coupling of the electromagnetic waves from the radiating antenna to the receiving antenna;

determining whether an item rests partially off the weigh platter based whether an alteration in the coupling of the electromagnetic waves from the radiating antenna to the receiving antenna is detected;

configuring the weigh platter to form a radiating antenna.

40. A system for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, the system comprising:

a weigh platter including a top surface with first and second opposing edges;

a housing section including a lower housing section supporting the weigh platter and an upper housing section rising above a top surface of the weigh platter on a side of the weigh platter that extends between the first and second opposing edges;

a first set of transducers disposed along the adjacent first and second edges of the top surface, the first set of transducers configured to transmit or receive non-electromagnetic compression waves;

a second set of transducers disposed on the upper housing section, the second set of transducers configured to transmit or receive non-electromagnetic compression waves;

a transmitter coupled to one of the first set of transducers or the second set of transducers, the transmitter configured to drive the set of transducers with a signal so that the set of transducers transmit non-electromagnetic compression waves; and

a receiver coupled to the other one of the first set of transducers or the second set of transducers, the receiver configured to monitor the set of transducers coupled to the receiver for an alteration in amplitude of incident compression waves transmitted by the set of transducers driven by the transmitter to determine whether an item rests partially off the weigh platter.

41. The system of claim 40, wherein

the first set of transducers comprise a plurality of individual linearly-aligned transducers configured to transmit non-electromagnetic compression waves,

the transmitter is coupled to the first set of transducers,

the second set of transducers comprise a single transducer configured to receive the compression waves transmitted by the first set of transducers, and

the receiver is coupled to the second set of transducers.

42. The system of claim 40, wherein

the second set of transducers comprise a single transducer configured to transmit non-electromagnetic compression waves,

the transmitter is coupled to the second set of transducers,

the first set of transducers comprise a plurality of individual linearly-aligned transducers configured to receive the compression waves transmitted by the first set of transducers, and

the receiver is coupled to the first set of transducers.

43. The system of claim 40, wherein the first and second sets of transducers comprise a piezoelectric film.

44. The system of claim 40, wherein the first and second sets of transducers are configured to transmit or receive non-electromagnetic compression waves within the range of approximately 200 kilohertz to approximately 400 kilohertz.

45. The system of claim 40, further comprising:

a controller coupled to the receiver, the controller configured to monitor an output of the receiver to determine whether an item rests partially off the weigh platter.

46. The system of claim 40, further comprising:

external indicia configured to notify an operator whether an item rests partially on the weigh platter and partially on the checkout counter or other fixed object.

47. A method for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader, said data reader including an upper housing section rising above a top surface of the weigh platter, a first set of transducers positioned along at least a portion of a peripheral edge of the weigh platter, and a second set of transducers disposed on the upper housing section, said first and second sets of transducers configured to transmit or receive non-electromagnetic compression waves, the method comprising:

transmitting from a set of emitters to a set of sensors non-electromagnetic compression waves, the set of emitters comprising one of the first set of transducers or the second set of transducers and the set of sensors comprising the other one of the first set of transducers or the second set of transducers;

monitoring the set of sensors to detect an alteration in amplitude of incident compression waves transmitted by the set of emitters; and

determining whether an item rests partially off the weigh platter based whether an alteration in the amplitude of incident compression waves transmitted by the set of emitters is detected at the set of sensors.

48. The method of claim 47, wherein the set of emitters comprise the second set of transducers and the set of sensors comprise the first set of transducers.

49. The method of claim 47, wherein the first set of transducers comprise a plurality of individual linearly-aligned transducers and the second set of transducers comprise a single transducer.

50. The method of claim 47, wherein the step of monitoring the set of sensors to detect an alteration in amplitude of incident compression waves transmitted by the set of emitters comprises comparing an amplitude of the incident compression waves received by the set of sensors to a predetermined threshold.

51. The method of claim 50, further comprising:

periodically measuring an amplitude of the compression waves received by the set of sensors when an item does not rest partially off the weigh platter; and

updating the predetermined threshold with the measured amplitude.

52. A system for reducing weighing errors of an item being weighed on a weigh platter associated with a data reader installed in a checkout counter of other fixed object, the system comprising:

a weigh platter including a top surface with first and second opposing edges that are adjacent the checkout counter or other fixed object;

a first set of transducers disposed along the adjacent first edges of the top surface, the first set of transducers configured to transmit and receive non-electromagnetic compression waves;

a second set of transducers disposed along the adjacent second edges of the top surface, the second set of transducers configured to transmit and receive non-electromagnetic compression waves;

a transmitter coupled to the first and second sets of transducers, the transmitter configured to drive the transducers with a signal so that the transducers transmit non-electromagnetic compression waves away from the top surface of the weigh platter; and

a receiver coupled to the first and second sets of transducers, the receiver configured to monitor the transducers to detect compression waves reflected by an item toward the top surface of the weigh platter to determine whether an item rests partially off the weigh platter.