corner_subpix(image, corners, window_size=11, alpha=0.99)

A statistical test decides whether the corner is defined as the intersection of two edges or a single peak. Depending on the classification result, the subpixel corner location is determined based on the local covariance of the grey-values. If the significance level for either statistical test is not sufficient, the corner cannot be classified, and the output subpixel position is set to NaN.

Parameters

image : ndarray

Input image.

corners : (N, 2) ndarray

Corner coordinates :None:None:`(row, col)`.

window_size : int, optional

Search window size for subpixel estimation.

alpha : float, optional

Significance level for corner classification.

Returns

positions : (N, 2) ndarray

Subpixel corner positions. NaN for "not classified" corners.

Determine subpixel position of corners.

Examples

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

>>> from skimage.feature import corner_harris, corner_peaks, corner_subpix
... img = np.zeros((10, 10))
... img[:5, :5] = 1
... img[5:, 5:] = 1
... img.astype(int)
array([[1, 1, 1, 1, 1, 0, 0, 0, 0, 0],
       [1, 1, 1, 1, 1, 0, 0, 0, 0, 0],
       [1, 1, 1, 1, 1, 0, 0, 0, 0, 0],
       [1, 1, 1, 1, 1, 0, 0, 0, 0, 0],
       [1, 1, 1, 1, 1, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 1, 1, 1, 1, 1],
       [0, 0, 0, 0, 0, 1, 1, 1, 1, 1],
       [0, 0, 0, 0, 0, 1, 1, 1, 1, 1],
       [0, 0, 0, 0, 0, 1, 1, 1, 1, 1],
       [0, 0, 0, 0, 0, 1, 1, 1, 1, 1]])

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

>>> coords = corner_peaks(corner_harris(img), min_distance=2,
...                       threshold_rel=0)
... coords_subpix = corner_subpix(img, coords, window_size=7)
... coords_subpix
array([[4.5, 4.5]])

See :

Back References

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

skimage.feature.corner.corner_subpix

Local connectivity graph

Hover to see nodes names; edges to Self not shown, Caped at 50 nodes.

Using a canvas is more power efficient and can get hundred of nodes ; but does not allow hyperlinks; , arrows or text (beyond on hover)

SVG is more flexible but power hungry; and does not scale well to 50 + nodes.

All aboves nodes referred to, (or are referred from) current nodes; Edges from Self to other have been omitted (or all nodes would be connected to the central node "self" which is not useful). Nodes are colored by the library they belong to, and scaled with the number of references pointing them

---

File: /skimage/feature/corner.py#740
type: <class 'function'>
Commit: