corner_harris(image, method='k', k=0.05, eps=1e-06, sigma=1)

This corner detector uses information from the auto-correlation matrix A:

A = [(imx**2)   (imx*imy)] = [Axx Axy]
    [(imx*imy)   (imy**2)]   [Axy Ayy]

Where imx and imy are first derivatives, averaged with a gaussian filter. The corner measure is then defined as:

det(A) - k * trace(A)**2

or:

2 * det(A) / (trace(A) + eps)

Parameters

image : ndarray

Input image.

method : {'k', 'eps'}, optional

Method to compute the response image from the auto-correlation matrix.

k : float, optional

Sensitivity factor to separate corners from edges, typically in range :None:None:`[0, 0.2]`. Small values of k result in detection of sharp corners.

eps : float, optional

Normalisation factor (Noble's corner measure).

sigma : float, optional

Standard deviation used for the Gaussian kernel, which is used as weighting function for the auto-correlation matrix.

Returns

response : ndarray

Harris response image.

Compute Harris corner measure response image.

Examples

This example is valid syntax, but we were not able to check execution

>>> from skimage.feature import corner_harris, corner_peaks
... square = np.zeros([10, 10])
... square[2:8, 2:8] = 1
... square.astype(int)
array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
       [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
       [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
       [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
       [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
       [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
       [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
       [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]])

This example is valid syntax, but we were not able to check execution

>>> corner_peaks(corner_harris(square), min_distance=1, threshold_rel=0)
array([[2, 2],
       [2, 7],
       [7, 2],
       [7, 7]])

See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

skimage.feature.brief.BRIEF skimage.feature.corner.corner_subpix skimage.feature.orb.ORB skimage.feature.corner.corner_harris

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