System and method for multi-spot beam tracking
AssigneeBWXT Advanced Technologies LLC
InventorRyan Scott Kitchen
Life of this patent
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Abstract
A method is provided for tracking multiple beams in weld pools. The method includes obtaining an input video feed that includes a plurality of frames having a plurality of beams for weld pools. The method also includes, for each frame of the plurality of frames of the input video feed, creating a gradient mask that identifies one or more pixels in the respective frame for a weld pool. The method also includes detecting and filtering contiguous regions based on the gradient mask to obtain a pixel mask for each contour of a weld pool. The method also includes identifying one or more beam locations within the weld pool based on the pixel mask for each contour.
Claims21
A method for tracking multiple beams in weld pools, the method comprising:
- obtaining an input video feed that includes a plurality of frames having a plurality of beams for weld pools;
- for each frame of the plurality of frames of the input video feed, creating a gradient mask that identifies one or more pixels in the respective frame for a weld pool;
- detecting and filtering contiguous regions based on the gradient mask to obtain a pixel mask for each contour of a weld pool;
- and
- identifying one or more beam locations within the weld pool based on the pixel mask for each contour,
- wherein identifying the one or more beam locations within each weld pool comprises:
- identifying a peak intensity by computing a local maximum value within the pixel mask for each contour;
- identifying missing beams for each contour by determining if the peak intensity is below a predetermined range;
- applying a high-pass threshold to surrounding area based on the peak intensity to determine a spot area;
- and
- computing coordinates of the one or more beam location based on a mean value or center of mass of the spot area.
A method for tracking multiple beams in weld pools, the method comprising:
- obtaining an input video feed that includes a plurality of frames having a plurality of beams for weld pools;
- for each frame of the plurality of frames of the input video feed, creating a gradient mask that identifies one or more pixels in the respective frame for a weld pool;
- detecting and filtering contiguous regions based on the gradient mask to obtain a pixel mask for each contour of a weld pool;
- and
- identifying one or more beam locations within the weld pool based on the pixel mask for each contour,
- wherein identifying the one or more pixels comprises:
- for each pixel in the respective frame, calculating a time-based derivative of intensity for the respective pixel based on the respective frame and its predecessor frame in the video feed;
- and
- determining potential locations of weld pools based on the time-based derivative of intensity for each pixel,
- wherein determining potential locations of the weld pools comprises:
- thresholding the time-based derivative for each pixel with a high-low pass filter to create the gradient mask, thereby marking pixels with either a rapid increase or decrease in value as possible weld pool locations, and
- wherein the high-low pass filter is applied to the time-based derivative and includes two threshold values including (i) a low value that is a negative number, for which delta values below the low value represent a phase change from powder to liquid metal, and (ii) a high value that is a positive number, above which either there is increasing heat or a beam is crossing over a pixel.
A method for tracking multiple beams in weld pools, the method comprising:
- obtaining an input video feed that includes a plurality of frames having a plurality of beams for weld pools;
- for each frame of the plurality of frames of the input video feed, creating a gradient mask that identifies one or more pixels in the respective frame for a weld pool;
- detecting and filtering contiguous regions based on the gradient mask to obtain a pixel mask for each contour of a weld pool;
- and
- identifying one or more beam locations within the weld pool based on the pixel mask for each contour,
- wherein identifying the one or more pixels comprises:
- for each pixel in the respective frame, calculating a time-based derivative of intensity for the respective pixel based on the respective frame and its predecessor frame in the video feed;
- and
- determining potential locations of weld pools based on the time-based derivative of intensity for each pixel,
- wherein determining potential locations of the weld pools comprises:
- thresholding the time-based derivative for each pixel with a high-low pass filter to create the gradient mask, thereby marking pixels with either a rapid increase or decrease in value as possible weld pool locations, and
- wherein the method further comprises:
- using a morphological close filter on the gradient mask to close any gaps between isolated pixels surrounding a possible weld pool location.
Dependencies are inferred from the claim text.