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Banner PresencePLUS P4 Series User Manual

Page 118

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These three results combine to give information about the elongation and orientation of a blob . The equations
used to compute these statistics are fairly complicated, but the results usually have an intuitively useful meaning,
described below. The first step in computing these results is to compute the M

2,0

, M

0,2

and M

1,1

statistical

moments:

where A is the area, (x

c

, y

c

) are the coordinates of the centroid and (x

i

, y

i

) are the coordinates of pixel i. These

values represent the variance with respect to x, the variance with respect to y, and the covariance, respectively.
The final results can be calculated as follows.

P/N 000000

Banner Engineering Corp. - Minneapolis, MN USA - www.bannerengineering.com

Tel: 763.544.3164

118

7/2009

PresencePLUS Software Tools