profoundEllipseSeg: Create Elliptical Segment

In asgr/ProFound: Photometry Tools

Create Elliptical Segment

Description

Creates a logic matrix for an elliptical segment. This can be useful to allow the extraction of elliptical apertures on a target image (you can just sum the multiplication of the two).

Usage

profoundEllipseSeg(dim = c(101, 101), image = NULL, xcen = dim[1]/2, ycen = dim[2]/2,
  rad = dim[1]/2, ang = 0, axrat = 1, box = 0)

Arguments

dim	Integer vector; the dimension of the logic matrix to return.
image	Numeric matrix; if provided this will be used to compute the dim.
xcen	Numeric scalar; the x centre of the segment aperture ellipse.
ycen	Numeric scalar; the y centre of the segment aperture ellipse.
rad	Numeric scalar; major axis radius for the segment aperture ellipse.
ang	Numeric scalar; major axis angle for the segment aperture ellipse in degrees. When plotted as an R image the angle (theta) has the convention that 0= | (vertical), 45= \, 90= - (horizontal), 135= /, 180= | (vertical). Values outside the range 0 <= ang <= 180 are allowed, but these get recomputed as ang = ang.
axrat	Numeric scalar; axial ratio of the segment aperture ellipse defined as minor-axis/major-axis, i.e. 1 is a circle and 0 is a line.
box	Numeric scalar; the boxiness of the segment aperture ellipse, defined such that r[mod]=(x^(2+box)+y^(2+box))^(1/(2+box)). When box=0 the segment will be a normal ellipse, but modifications between -1<box<1 will produce visually boxy distortions. Negative values have a pin-cushion effect, whereas positive values have a barrel effect (the major and minor axes staying fixed in all cases).

Value

Logical matrix, with the dimensions of dim, or the target image if supplied.

Author(s)

Aaron Robotham

References

Robotham et al, 2017, MNRAS, 466, 1513 (ProFit paper)

See Also

profoundDrawEllipse

Examples

magimage(profoundEllipseSeg())
magimage(profoundEllipseSeg(dim=c(200,200), axrat=0.5, ang=30, rad=30))

asgr/ProFound documentation built on Feb. 10, 2024, 9:04 p.m.