A Simple Accurate Fresnel Integral Algorithm and Application to Wedge Diffraction

Fresnel integrals are fundamental to the solution of many diffraction problems, but to estimate wedge diffraction with good accuracy, the algorithm used to approximate the Fresnel integral often requires high accuracy in amplitude and phase.The algorithm described here was developed many years ago to allow rapid wedge diffraction calculation on early computers, but has not been previously published.Included here is the application of this algorithm to wedge diffraction, by image theory, which avoids the singularities at shadow boundaries that occur when using the Geometrical Theory of Diffraction methods.