Class WarpedPsf

Inheritance Relationships

Base Type

Class Documentation

class WarpedPsf : public lsst::meas::algorithms::ImagePsf

A Psf class that maps an arbitrary Psf through a coordinate transformation.

If K_0(x,x’) is the unwarped PSF, and f is the coordinate transform, then the warped PSF is defined by

K(f(x),f(x’)) = K_0(x,x’) (*)

We linearize the coordinate transform in the vicinity of the point where the PSF is computed. The definition (*) does not include the Jacobian of the transformation, since the afw convention is that PSF’s are normalized to have integral 1 anyway.

Public Functions

lsst::meas::algorithms::WarpedPsf::WarpedPsf(CONST_PTR( afw::detection::Psf ) undistortedPsf, CONST_PTR( afw::geom::TransformPoint2ToPoint2 ) distortion, CONST_PTR( afw::math::WarpingControl ) control)

Construct WarpedPsf from unwarped psf and distortion.

If p is the nominal pixel position, and p’ is the true position on the sky, then our convention for the transform is that p’ = distortion.applyForward(p)

lsst::meas::algorithms::WarpedPsf::WarpedPsf(CONST_PTR( afw::detection::Psf ) undistortedPsf, CONST_PTR( afw::geom::TransformPoint2ToPoint2 ) distortion, std::string const & kernelName = "lanczos3", unsigned int cache = 10000)
virtual geom::Point2D getAveragePosition() const

Return the average of the positions of the stars that went into this Psf.

For WarpedPsf, this is just the transform of the undistorted Psf’s average position.

virtual PTR(afw::detection::Psf) const

Polymorphic deep copy. Usually unnecessary, as Psfs are immutable.

virtual PTR(afw::detection::Psf)

Return a clone with specified kernel dimensions.

Public Members

virtual int height lsst::meas::algorithms::WarpedPsf::const

Protected Functions

PTR(afw::detection::Psf const)
PTR(afw::geom::TransformPoint2ToPoint2 const)