Computer Based General Shape Description with Polygonal Harmonics and a Roughness Index

Abstract

Description of particle shape is of wide importance in the engineering industries. Although the theory of polygonal harmonic shape analysis has been presented previously as a method for characterizing rugged particles, detailed computer implementation has not yet been described. Particle and object images have been digitized using a video camera and personal computer, and their harmonic persistences determined. The harmonic persistences are shown to relate to computer generated Fourier shapes with zero phase angle, but not to relate to Fourier coefficients describing rugged silhouettes. A relationship between the second harmonic persistence and aspect ratio is demonstrated, and it is verified that polygonal harmonics, combined with a surface roughness index, provide a general scheme for particle shape description as has been previously suggested.

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References

Nakagawa

Furuuchi

Yamahata

Gotoh

Shape classification of granular materials by rotating cylinder with blades. Thirteenth Annual Meeting of Fine Particle Society, Hawaii, 1983.

Viswanathan

Aravamudhan

Mani

B. P.

Separation based on shape: recovery efficiency of spherical particles. Powder Technology, 1984, 39, 83–91.

Murali

Pitchumani

Clark

N. N.

A settler for continuous particle shape separation. Int. J. Min. Processing, 1986, 18, 237–249.

Bocoum

B. M. K.

Batch sieving of cylindrical particles by cascadography. MS thesis, West Virginia University, 1988.

Clark

N. N.

Meloy

T. P.

Particle sample shape description with an automated cascadograph particle analyzer. Powder Technology, 1988, 54, 271–277.

Beddow

J. K.

Particulate science and technology, 1981 (Chemical Publishing, New York).

Flook

Fourier analysis of particle shape. Proceedings Fourth Particle Size Analysis Conference, Loughborough, 1981. Published as Particle size analysis, (Eds Stanley Wood

N. G.

Allen

) 1982, (Wiley Heyden, London).

Mandelbrot

B. B.

Fractals: form, chance and dimension, 1977 (W. H. Freeman, San Francisco).

Flook

A. G.

The use of dilation logic on the quantimet to achieve fractal dimension characterization. Powder Technology, 1978, 21, 295–298.

10.

Beddow

J. K.

Leurkins

D. W.

Modern image analysis. Proceedings Fourteenth Powder and Bulk Solids Conference, Rosemont, Il, 1989, pp. 381–391.

11.

Clark

N. N.

Three techniques for implementing digital fractal analysis. Powder Technology, 1986, 46, 45–52.

12.

Hurter

P. N.

Clark

N. N.

Persistence of polygonal harmonics as shape descriptors. Particle Characterization, 1987, 4, 101–105.

13.

Schwartz

Exner

The implementation of the concept of fractal dimension on a semiautomatic image analyzer. Powder Technology, 1980, 27, 207.

14.

Clark

N. N.

A new scheme for particle shape characterization based on fractal dimension and fractal harmonics. Powder Technology, 1987, 51, 243–249.

15.

Van Egmond

J. W.

Clark

N. N.

Development and testing of a computer program for polygonal harmonic shape analysis. J. Powder Bulk Solids Technol., (in press).

16.

Kaye

B. H.

Multifractal description of a rugged fine particle profile. Particle Characterization, 1984, 1, 14.

17.

Clark

N. N.

Gabriele

Shuker

Drag coefficient of irregular particles in Newton's settling regime. Powder Technology, 1989, 59, 69–72.