pysteps.feature.shitomasi.detection¶

pysteps.feature.shitomasi.detection(input_image, max_corners=1000, max_num_features=None, quality_level=0.01, min_distance=10, block_size=5, buffer_mask=5, use_harris=False, k=0.04, verbose=False, **kwargs)¶

Interface to the OpenCV Shi-Tomasi features detection method to detect corners in an image.

Corners are used for local tracking methods.

Parameters

input_image: ndarray_ or MaskedArray_

Array of shape (m, n) containing the input image.

In case of ndarray, invalid values (Nans or infs) are masked, otherwise the mask of the MaskedArray is used. Such mask defines a region where features are not detected.

The fill value for the masked pixels is taken as the minimum of all valid pixels.

max_corners: int, optional

The maxCorners parameter in the Shi-Tomasi corner detection method. It represents the maximum number of points to be tracked (corners). If set to zero, all detected corners are used.

max_num_features: int, optional

If specified, this argument is substituted for max_corners. Set to None for no restriction. Added for compatibility with the feature detector interface.

quality_level: float, optional

The qualityLevel parameter in the Shi-Tomasi corner detection method. It represents the minimal accepted quality for the image corners.

min_distance: int, optional

The minDistance parameter in the Shi-Tomasi corner detection method. It represents minimum possible Euclidean distance in pixels between corners.

block_size: int, optional

The blockSize parameter in the Shi-Tomasi corner detection method. It represents the window size in pixels used for computing a derivative covariation matrix over each pixel neighbourhood.

use_harris: bool, optional

Whether to use a Harris detector or cornerMinEigenVal.

k: float, optional

Free parameter of the Harris detector.

buffer_mask: int, optional

A mask buffer width in pixels. This extends the input mask (if any) to limit edge effects.

verbose: bool, optional

Print the number of features detected.

Returns

points: ndarray: Array of shape (p, 2) indicating the pixel coordinates of p detected corners.

References

Jianbo Shi and Carlo Tomasi. Good features to track. In Computer Vision and Pattern Recognition, 1994. Proceedings CVPR’94., 1994 IEEE Computer Society Conference on, pages 593–600. IEEE, 1994.