ScalePointFeature

ScalePointCorner feature object

A subclass of PointFeature for features with scale.

Methods

plot	Plot feature position
plot_scale	Plot feature scale
distance	Descriptor distance
ncc	Descriptor similarity
uv	Return feature coordinate
display	Display value
char	Convert value to string

Properties

u	horizontal coordinate
v	vertical coordinate
strength	feature strength
scale	feature scale
descriptor	feature descriptor (vector)

Properties of a vector of ScalePointFeature objects are returned as a vector. If F is a vector (Nx1) of ScalePointFeature objects then F.u is a 2xN matrix with each column the corresponding point coordinate.

ScalePointFeature.ScalePointFeature

Create a scale point feature object

f = ScalePointFeature() is a point feature object with null parameters.

f = ScalePointFeature(u, v) is a point feature object with specified coordinates.

f = ScalePointFeature(u, v, strength) as above but with specified strength.

f = ScalePointFeature(u, v, strength, scale) as above but with specified feature scale.

ScalePointFeature.plot

Plot feature

F.plot(options) overlay a marker at the feature position. The default is a point marker.

F.plot(options, ls) as above but the optional line style arguments ls are passed to plot.

If F is a vector then each element is plotted.

Options

'circle'	Indicate scale by a circle
'disk'	Indicate scale by a translucent disk
'color', C	Color of circle or disk (default green)
'alpha', A	Transparency of disk, 1=opaque, 0=transparent (default 0.2)
'scale', S	Scale factor for drawing circles and arrows.

Examples

Mark the feature coordinates with a white asterisk

f.plot('w*')

Mark each feature with a blue translucent disk

f.plot('disk', 'color', 'b', 'alpha', 0.3);

Mark each feature with a green circle and with exagerated scale

f.plot('circle', 'color', 'g', 'scale', 2)