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Determination of train presence and motion state in railway environments

  • US 9,070,020 B2
  • Filed: 08/21/2012
  • Issued: 06/30/2015
  • Est. Priority Date: 08/21/2012
  • Status: Expired due to Fees
First Claim
Patent Images

1. A method for applying computer vision techniques to automatically detect and classify the presence or absence of a train within a railway track area, the method comprising:

  • determining foreground feature data for each of a plurality of frames of video input data via applying a background subtraction mask to each of the frames, wherein the video input data is acquired from a region of interest defined around a train track area within an image scene of a stream of the video image data that comprises a portion of a railway track area;

    determining for each of the plurality of frames a frame differencing ratio of a value of motion feature data determined for the each frame to a value of motion feature data determined for an immediately previous frame of the plurality of frames;

    labeling each of the frames as “

    train present”

    if the determined foreground feature data value is equal to or is greater than a background subtraction threshold value that is selected as indicative of the presence of a foreground object having the size of a train car, or as “

    train absent”

    if the determined foreground feature data value is less than the background subtraction threshold value;

    labeling each of the frames as “

    motion present”

    if the determined frame differencing data value is equal to or greater than a motion threshold value that is selected as indicative of a change in the visual features consistent with the movement of a train car within the frame data, or as “

    static”

    if the determined frame differencing data value is less than the motion threshold value;

    classifying a segment of the input video data comprising a group of consecutive video frames that each comprise the “

    train absent”

    label and the “

    static”

    label as a “

    no train present”

    segment;

    classifying a segment of the input video data comprising a group of consecutive video frames that each comprise the “

    train present”

    label and the “

    motion present”

    label as a “

    train present and in transition”

    segment;

    classifying a segment of the input video data comprising a group of consecutive video frames that each comprise the “

    train present”

    label and the “

    static”

    label as a “

    train present and stopped”

    segment;

    determining a presence or a motion state of a train within the region of interest of the video scene at a time of inquiry as the “

    no train present”

    , the “

    train present and in transition”

    or the “

    train present and stopped”

    classification of the segment comprising the video frame of the time of inquiry;

    determining a distribution of the “

    train present” and



    train absent”

    labels of the plurality of the video segments within an auto-correction time period;

    in response to the determined distribution of the “

    train present” and



    train absent”

    labels not meeting an expected distribution for the auto-correction time period, exchanging the “

    train present” and

    the “

    train absent”

    labels that are determined for each of the video frames; and

    repeating the steps of classifying the segments of the input video data of consecutive video frames that each comprise the “

    train absent”

    label and the “

    static”

    label into the “

    no train present”

    segment groups, the segments of the input video data of consecutive video frames that each comprise the “

    train present”

    label and the “

    motion present”

    label as the “

    train present and in transiton”

    segments, and the segments of the input video data of consecutive video frames that each comprise the “

    train present”

    label and the “

    static”

    label as the “

    train present and stopped”

    segment groups, as a function of the exchanged “

    train present” and



    train absent”

    labels.

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