The C++ interface for centroids. More...

array	centroids (const array &regions)

Detailed Description

The C++ interface for centroids.

The centroid of each connected component is an (x,y) coordinate that is the average of the (x,y) coordinates of all of the pixels with that label.

The input image should be a 2D, single precision floating point image where the components are numbered sequentially from 1 to N, where N is the overall number of components.

// Get a label matrix for the connected components in an image
const int len = 8;
array r = randn(len, len) * 10.0f;
// Convert to binary
array in = (r > 5.0f);
array labels = regions(in);
print(labels);
// 0   0   0   0   4   0   5   0
// 0   0   0   0   0   0   5   5
// 0   1   0   1   0   0   0   0
// 0   0   1   0   1   1   0   6
// 1   1   0   0   0   1   0   6
// 0   0   0   3   0   0   0   6
// 0   0   0   0   3   0   0   6
// 0   2   0   0   0   3   0   0
array c = centroids(labels);
print(c);
// 1.0000    3.1250    2.6250
// 2.0000    7.0000    1.0000
// 3.0000    6.0000    4.0000
// 4.0000    0.0000    4.0000
// 5.0000    0.6667    6.3333
// 6.0000    4.5000    7.0000

Function Documentation

array af::centroids ( const array & regions )

Parameters

[in] regions numbered connected components (see regions)

Returns: Nx3 matrix of the labels, the x centroid coordinate and the y centroid coordinate

Note: requires a device with compute capability 1.2+