Particle Filter Measurements

NI Vision Assistant

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Particle Filter Measurements

Use any of the following measurements or a combination of the following measurements to keep or remove particles from the image.

  • Center of Mass X and Center of Mass Y—X- and Y-coordinates of the particle center of mass
  • First Pixel X and First Pixel Y—X- and Y-coordinates of the first pixel of the particle
  • Bounding Rect (Left, Right, Top, and Bottom)
    • X-coordinate of the leftmost point in the particle
    • Y-coordinate of highest point in the particle
    • X-coordinate of the rightmost point in the particle
    • Y-coordinate of the lowest point in the particle
  • Max Feret Diameter Start X and Max Feret Diameter Start Y—X- and Y-coordinates of the particle center the Max Feret Diameter Start
  • Max Feret Diameter End X and Max Feret Diameter End Y—X- and Y-coordinates of the particle center the Max Feret Diameter End
  • Max Horiz. Segment Length (Left, Right, and Row)
    • X-coordinate of the leftmost pixel in the Max Horiz. Segment. Always given as a pixel measurement.
    • X-coordinate of the rightmost pixel in the Max Horiz. Segment. Always given as a pixel measurement.
    • Y-coordinate for all of the pixels in the Max Horiz. Segment. Always given as a pixel measurement.
  • Bounding Rect (Width, Height, and Diagonal)
    • Distance between Bounding Rect Left and Bounding Rect Right
    • Distance between Bounding Rect Top and Bounding Rect Bottom
    • Distance between opposite corners of the Bounding Rect
  • Perimeter—Length of the outer boundary of the particle. Because the boundary is comprised of discrete pixels, Vision Assistant subsamples the boundary points to approximate a smoother, more accurate perimeter.
  • Convex Hull Perimeter—Perimeter of the Convex Hull
  • Hole's Perimeter—Sum of the perimeters of each hole in the particle
  • Max Feret Diameter—Distance between the Max Feret Diameter Start and the Max Feret Diameter End
  • Equivalent Ellipse (Major Axis, Minor Axis, and Minor Axis (Feret))
    • Length of the major axis of the Equivalent Ellipse
    • Length of the minor axis of the Equivalent Ellipse
    • Length of the minor axis of the ellipse with the same area as the particle, and Major Axis equal in length to the Max Feret Diameter
  • Equivalent Rect (Long Side, Short Side, Diagonal, and Short Side (Feret))
    • Longest side of the Equivalent Rect
    • Shortest side of the Equivalent Rect
    • Distance between opposite corners of the Equivalent Rect
    • Shortest side of the rectangle with the same area as the particle, and longest side equal in length to the Max Feret Diameter
  • Average Horiz. Segment Length—Average length of a horizontal segment in the particle. Sum of the horizontal segments that do not superimpose any other horizontal segment. Always given as a pixel measurement
  • Average Vert. Segment Length—Average length of a vertical segment in the particle. Sum of the vertical segments that do not superimpose any other vertical segment. Always given as a pixel measurement
  • Hydraulic Radius—Particle area divided by its perimeter
  • Waddel Disk Diameter—Diameter of a disk with the same area as the particle
  • Area—Area of the particle
  • Holes' Area—Sum of the areas of each hole in the particle
  • Particle & Holes' Area—Area of a particle that completely covers the image
  • Convex Hull Area—Area of the Convex Hull of the particle
  • Image Area—Area of the image
  • Number of Holes—Number of holes in the particle. Vision Assistant can detect holes inside a particle as small as one pixel
  • Number of Horiz. Segments—Number of horizontal segments in the particle. always given as pixel measurements.
  • Number of Vert. Segments—Number of horizontal segments in the particle. Always given as pixel measurements.
  • Orientation—Angle of the line passing through the particle center of mass with the lowest moment of inertia
  • Max Feret Diameter Orientation—Angle of the Max Feret Diameter
  • %Area/Image Area—Percentage of the particle's Area covering the Image Area
  • %Area/(Particle & Holes' Area)—Percentage of the particle's Area in relation to its Particle & Holes' Area
  • Ratio of Equivalent Ellipse Axes—Equivalent Ellipse Major Axis divided by Equivalent Ellipse Minor Axis
  • Ratio of Equivalent Rect Sides—Equivalent Rect Long Side divided by Equivalent Rect Short Side
  • Elongation Factor—Max Feret Diameter divided by Equivalent Rect Short Side (Feret). The more elongated the shape of a particle, the higher its elongation factor
  • Compactness Factor—Area divided by the product of Bounding Rect Width and Bounding Rect Height. The compactness factor belongs to the interval [0, 1]. The closer the shape of a particle is to a rectangle, the closer to 1 the compactness factor
  • Heywood Circularity Factor—Perimeter divided by the circumference of a circle with the same area. The closer the shape of a particle is to a disk, the closer the Heywood circularity factor to 1
  • Type Factor—Factor relating area to moment of inertia
  • Angle—Degrees of rotation counterclockwise from the x-axis. Range: [0 °, 180 °)
  • Sum...—Moments of various orders relative to the x- and y-axes
  • Moment of Inertia...—Moments about the particle Center of Mass. Gives a representation of the distribution of the pixels in a particle with respect to its center of gravity. Shift invariant.
  • Norm. Moment of Inertia...—Moment of Inertia normalized with regard to the particle Area. Shift and scale invariant.
  • Hu Moment...—Moments derived from the Norm. Moment of Inertia measurements. Shift, scale, and rotation invariant.
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