An Optical-Design Error Function Using Gaussian Integration

We have used the gaussian-integration techniques described by Forbes to build a default error function for our optical design program. To make the function suitable for practical design, we have added ad-hoc extensions that account for vignetting and allow for a variety of user-defined weights. We have now acquired about a year's experience in using the function to design several different systems. Our results have been generally good, and we have recently extended the function to provide additional control over astigmatic aberrations.