Image Processing Toolbox

bweuler

Compute the Euler number of a binary image

Syntax

eul = bweuler(BW,n)

Description

eul = bweuler(BW,n) returns the Euler number for the binary image BW. eul is a scalar whose value is the total number of objects in the image minus the total number of holes in those objects. n can have a value of either 4 or 8, where 4 specifies 4-connected objects and 8 specifies 8-connected objects; if the argument is omitted, it defaults to 8.

Class Support

BW can be of class uint8 or double. eul is of class double.

Example

BW = imread('circles.tif');
imshow(BW);


bweuler(BW)

ans =

    -2

Algorithm

bweuler computes the Euler number by considering patterns of convexity and concavity in local 2-by-2 neighborhoods. See [2] for a discussion of the algorithm used.

See Also

bwmorph, bwperim

References

Horn, Berthold P. K., Robot Vision. New York: McGraw-Hill, 1986. pp. 73-77.

Pratt, William K. Digital Image Processing. New York: John Wiley & Sons, Inc., 1991. p. 633.

bwarea

bwfill