Quadrature formula for computed tomography (Q606680)

The authors present a Gaussian quadrature formula for integrals of the form \[ \int_B f(x,y) U_n(x\cos\theta+y\sin\theta)\,dx\,dy \] over the unit disk \(B\) for the Chebyshev polynomials \(U_n\) of second kind. The formula involves \(n\) Radon projections on \(B\), has the maximal degree \(3n+1\) of precision, and is unique by this property. It may be seen as a two-dimensional extension of a formula of Micchelli-Rivlin on \([-1, 1]\) for the \(U_n\).