Determining condition of conveyor belt by calculating apparent velocities from captured images of conveyor belt

{
  "publication_number": "US12008746B2",
  "country": "US",
  "kind": "B2",
  "title": "Determining condition of conveyor belt by calculating apparent velocities from captured images of conveyor belt",
  "abstract": "An inspection device includes an acquisition unit that acquires a plurality of images, captured from a given height, of an inspection object controlled to move at a constant velocity, a comparison unit that compares movements of the inspection object in the images on the basis of the plurality of images, and a determination unit that determines the condition of the inspection object on the basis of a comparison result.",
  "claims": [
    "1. A system comprising: a conveyor belt that is configured to move at a constant velocity; a camera installed at a constant installation height above the conveyor belt and in a downwards-oriented direction towards the conveyor belt, the camera configured to capture a plurality of first images of the conveyor belt as the conveyor belt moves; at least one memory configured to store instructions; and at least one processor configured to execute instructions to: acquire, from the plurality of first images, a plurality of second images at successive acquisition clock times; on a basis of the plurality of second images, compare movement of the conveyor belt in the second images; and determine a condition of the conveyor belt on a basis of a comparison result, by: for each of a plurality of pairs of the second images, determining a number of pixels that a region has moved from one image of the pair to the other image of the pair; for each pair, determining an apparent moving amount according to the number of pixels that the region has moved; for each pair, calculating an apparent velocity by dividing the determined apparent moving amount by a difference between the acquisition clock times of the pair; and comparing the plurality of calculated apparent velocities for the plurality of pairs.",
    "2. The system according to claim 1, wherein the at least one processor determines the condition of the conveyor belt on a basis of the plurality of calculated apparent velocities and a predetermined threshold.",
    "3. The system according to claim 2, wherein the at least one processor determines the condition of the conveyor belt on a basis of a difference between a highest apparent velocity and a lowest apparent velocity among the plurality of apparent velocities, and the predetermined threshold.",
    "4. The system according to claim 1, wherein the at least one processor determines the condition of the conveyor belt on a basis of a degree of separation of the plurality of the apparent velocities from a logical value corresponding to when the conveyor belt is not deteriorated.",
    "5. The system according to claim 1, wherein the at least one processor calculates the apparent velocity in each of a plurality of divided regions obtained by dividing a capturing region of each second image.",
    "6. An inspection method comprising: installing a camera at a constant installation height above a conveyor belt and in a downwards-oriented direction towards the conveyor belt, the camera configured to capture a plurality of first images of the conveyor belt as the conveyor belt moves; acquiring, by a processor, from the plurality of first images, a plurality of second images at successive acquisition clock times; on a basis of the plurality of second images, comparing, by the processor, movement of the conveyor belt in the second images; and determining, by the processor, a condition of the conveyor belt on a basis of a comparison result, by: for each of a plurality of pairs of the second images, determining a number of pixels that a region has moved from one image of the pair to the other image of the pair; for each pair, determining an apparent moving amount according to the number of pixels that the region has moved; for each pair, calculating an apparent velocity by dividing the determined apparent moving amount by a difference between the acquisition clock times of the pair; and comparing the plurality of calculated apparent velocities for the plurality of pairs.",
    "7. A non-transitory computer-readable medium storing a program comprising instructions executable by a processor to: acquire, from a plurality of first images of a conveyor belt captured as the conveyor belt moves and by a camera installed at a constant installation height above the conveyor belt and in a downwards-oriented direction towards the conveyor belt, a plurality of second images at successive acquisition clock times; on a basis of the plurality of second images, compare movement of the conveyor belt in the second images; and determine a condition of the conveyor belt on a basis of a comparison result, by: for each of a plurality of pairs of the second images, determining a number of pixels that a region has moved from one image of the pair to the other image of the pair; for each pair, determining an apparent moving amount according to the number of pixels that the region has moved; for each pair, calculating an apparent velocity by dividing the determined apparent moving amount by a difference between the acquisition clock times of the pair; and comparing the plurality of calculated apparent velocities for the plurality of pairs."
  ],
  "description_excerpt": "This application is a National Stage Entry of PCT/JP2018/045000 filed on Dec. 6, 2018, the contents of all of which are incorporated herein by reference, in their entirety.\n\nThe present invention relates to an inspection device, an inspection method, and a storage medium.\n\nA device for inspecting the condition of an inspection object that is a device controlled to operate at a constant velocity has been known.\n\nFor example, Patent Literature 1 describes a belt flaw detection device that inspects the condition of a conveyor belt that is an example of an inspection object, such as a flaw or the like on the conveyor belt. According to Patent Literature 1, the belt flaw detection device uses a plurality of distance sensors placed side by side in the belt width direction to measure the distance from each sensor to the belt. Then, the belt flaw detection device performs flaw detection and longitudinal tear generation time prediction in accordance with the measured result.\n\nPatent Literature 1: JP 9-12128 A\n\nAs described in Patent Literature 1, the condition of an inspection object may be inspected with use of a distance sensor by measuring the distance to the inspection object. However, a distance sensor that can be used for precise measurement is very expensive. Therefore, a method using a distance sensor as described in Patent Literature 1 causes a problem of high cost.\n\nIn view of the above, an object of the present invention is to provide an inspection device, an inspection method, and a storage medium that can solve the problem of high cost in inspecting an inspection object.",
  "cpc": [
    "G06T 7/0004",
    "B65G 2203/0275",
    "B65G 2203/0291",
    "B65G 2203/041",
    "B65G 2203/042",
    "B65G 43/02",
    "B65G 43/08",
    "G01N 2021/8411",
    "G01N 21/84",
    "G01N 21/8914",
    "G06T 2207/30108"
  ],
  "ipc": [
    "B65G 43/02",
    "B65G 43/08",
    "G06T 7/00"
  ],
  "assignees": [
    "NEC Corp"
  ],
  "inventors": [
    "Jun Takada"
  ],
  "filing_date": "2018-12-06",
  "publication_date": "2024-06-11",
  "grant_date": "2024-06-11",
  "priority_date": "2018-12-06",
  "application_number": "US-201817296792-A",
  "family_id": "70973752",
  "cited_by_count": 0,
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}