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Circle Fit: Deviation of the particle edge from a best-fit circle, normalized to the range [0,1] where a
perfect fit has a value of 1. (real [0, 1]; 1 is the value for a perfect circle; values near zero are for
particles that are not at all circular)
Compactness: A shape parameter derived from the perimeter and the area. The more convoluted the
shape, the greater the value. A filled circle should have a value of 1.0.
Formula: perimeter
2
/ (4 x PI x Area). (real ≥ 1)
Convex Perimeter: An approximation of the perimeter of the convex hull of a particle. Derived from
feret measurements. (real > 0)
Date: The date the image was captured. (text string of the form mm/dd/year)
Diameter (ABD): The diameter based on a circle with an area that is equal to the ABD Area (real > 0)
Diameter (ESD): The Mean value of 36 feret measurements. (real > 0)
Edge Gradient: Average intensity of the pixels making up the outside border of a particle after a Sobel
Edge Detect convolution filter has been applied to the raw camera image. (real [0, 255])
Elongation: A length / breadth ratio based on Perimeter and Area with the assumption that Area =
length x breadth and Perimeter = 2(length + breadth). (real ≥ 1; 1 is the value for a filled circle or
square; larger values are for elongated particles)
Feret Measurement: The perpendicular distance between parallel tangents touching opposite sides of
the particle. VisualSpreadsheet makes 36 feret measurements for each particle, one each 5 degrees
between -90 degrees and +90 degrees.
Feret Angle Max: Angle of the largest feret measurement. (real [-90, +90])
Feret Angle Min: Angle of the smallest feret measurement (real [-90, +90])
Filter Score: The statistical filter score. (real ≥0)
Image File: The collage image filename that contains this particle. (text string of the form
filename_nnnnnn.tif)
Image Height: The image height in pixels of the particle in the saved collage image. (integer > 0)
Image Width: The image width in pixels of the particle in the saved collage image. (integer > 0)
Image X: The left most X coordinate in pixels of the particle image in the saved collage image.
(integer ≥ 0)
Image Y: The top Y coordinate in pixels of the particle in the saved collage image. (integer ≥ 0)
Intensity: The average grayscale value of the pixels making up a particle (grayscale sum / number of
pixels making up the particle). (real [0, 255]; 255 is most intense)
Length: The maximum value of 36 feret measurements. (real > 0)
Particle ID: The particle identification number.
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