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Connected components, labeling, centroids, ...

Image and Signal Processing

enum  af_rprops_t { AF_RP_Area = 0, AF_RP_Centroid = 1, AF_RP_Orientation = 2, AF_RP_AxisLengths = 4 }
array regions (const array &image, unsigned connectivity)
 Connected component labeling of a binary image.
array areas (const array &regions)
 Calculate area of each numbered component in regions.
array centroids (const array &regions)
 Calculate centroid of each numbered component in regions.
array moments (const array &regions, af_rprops_t property)
 Calculate property for each numbered component in regions.
void moments (array &areas, array &centroids, const array &regions)
 Calculate both area and centroid for each numbered component in regions.
void moments (array &areas, array &centroids, array &axes, array &orientations, const array &regions)
 Calculate various properties for each numbered component in regions.

Enumeration Type Documentation

enum af_rprops_t

Properties to calculate for every connected component

Enumerator:
AF_RP_Area 

[1 x nregions] vector

AF_RP_Centroid 

[2 x nregions] vector

AF_RP_Orientation 

[1 x nregions] vector

AF_RP_AxisLengths 

[2 x nregions] vector


Function Documentation

array af::regions ( const array &  image,
unsigned  connectivity 
)

Connected component labeling of a binary image.

Parameters:
[in]imageBinary image
[in]connectivityeither 4 or 8
Returns:
Labeled image (0 is background, regions are 1,2,3,..)
Examples:
examples/image/image_demo.cpp.
array af::areas ( const array &  regions)

Calculate area of each numbered component in regions.

Parameters:
[in]regionsnumbered connected components (see regions)
Returns:
row vector of areas (one per region)
Examples:
examples/image/image_demo.cpp.
array af::centroids ( const array &  regions)

Calculate centroid of each numbered component in regions.

Parameters:
[in]regionsnumbered connected components (see regions)
Returns:
2xN matrix of centroids (one column per region)
array af::moments ( const array &  regions,
af_rprops_t  property 
)

Calculate property for each numbered component in regions.

Parameters:
[in]regionsnumbered connected components (see regions)
[in]property(see af_rprops_t), determines output size
Returns:
matrix of properties (one column per region, size depends on property)
Examples:
examples/image/image_demo.cpp.
void af::moments ( array &  areas,
array &  centroids,
const array &  regions 
)

Calculate both area and centroid for each numbered component in regions.

Parameters:
[out]areas(1xN vector)
[out]centroids(2xN matrix)
[in]regionsnumbered connected components (see regions)
void af::moments ( array &  areas,
array &  centroids,
array &  axes,
array &  orientations,
const array &  regions 
)

Calculate various properties for each numbered component in regions.

Parameters:
[out]areas(1xN vector)
[out]centroids(2xN matrix)
[out]axes(2xN matrix)
[out]orientations(1xN matrix)
[in]regionsnumbered connected components (see regions)
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