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cornerPoints

Object for storing corner points

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Description

This object stores information about feature points detected from a 2-D grayscale image.

Creation

Syntax

points = cornerPoints(location)
points = cornerPoints(location,Name,Value)

Description

example

points= cornerPoints(location)constructs acornerPointsobject from anM-by-2 array [xy的位置坐标。

points= cornerPoints(location,Name,Value)sets properties using one or more name-value pairs. Enclose each property name in quotes. For example,points = cornerPoints('Metric',0.0)

Input Arguments

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Location of points, specified as anM-by-2 array of [xy] coordinates.

Properties

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This property is read-only.

Location of keypoints, specified as anM-by-2 matrix. Each row is of the form [xy] and represents the location of a keypoint.Mis the number of keypoints. You cannot set this property, use thelocationinput argument instead.

Number of points held by the corner points object, specified as a numeric value.

Strength of detected feature, specified as a numeric value. The algorithm uses a determinant of an approximated Hessian.

Object Functions

plot Plot points
isempty Determine if points object is empty
length Number of stored points
selectStrongest Select points with strongest metrics
size Return size of points object
selectUniform Select uniformly distributed subset of feature points
gather Retrieve cornerPoints from the GPU

Examples

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Open Live Script

Read an image.

I = imread('cameraman.tif');

Detect feature points.

points = detectHarrisFeatures(I);

Display the ten strongest points.

strongest = selectStrongest(points,10); imshow(I) holdonplot(strongest)

Figure contains an axes object. The axes object contains 2 objects of type image, line.

Display the (x,y) coordinates of the strongest points.

strongest.Location
ans =10x2 single matrix112.4516 208.4412 108.6510 228.1681 136.6969 114.7962 181.4160 205.9876 135.5823 123.4529 100.4951 174.3253 146.7581 94.7393 135.2899 92.6485 129.8439 110.0350 130.5716 91.0424
Open Live Script

Create a checkerboard image.

I = checkerboard(50,2,2);

Load the locations of corner points.

location = [51 51 51 100 100 100 151 151 151;...50 100 150 50 101 150 50 100 150]';

Save the points in acornerPointsobject.

points = cornerPoints(location);

Display the points on the checkerboard.

imshow (I)on情节(分)

Figure contains an axes object. The axes object contains 2 objects of type image, line.

Tips

AlthoughcornerPointsmay hold many points, it is a scalar object. Therefore,numel(cornerPoints) always returns1. This value may differ fromlength(cornerPoints), which returns the true number of points held by the object.

Extended Capabilities

See Also

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Introduced in R2012a

Computer Vision Toolbox Documentation

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Introducing Deep Learning with MATLAB

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