The problems involved in lens testing, as opposed to the testing of one lens under one set of conditions, are of sufficient magnitude and complexity that the use of a computer is almost imperative to make the job practical. A machine and method for evaluation of lenses is described which employs a digital computer as a major component, has no restrictions as to the quality of lenses which may be accommodated, and requires no precision targets or auxiliary optics of any type. The results are in a form directly applicable to predictions of performance of complicated systems where the lens is one of several linear dissipators. The reader is introduced to lens testing considerations and a brief discussion of methods, followed by a detailed description of a specific implementation and computerized approach. Next, the basic mathematics involved, including a practical procedure for truncating a Fourier series, are explained in some detail. Finally, examples of measured output and machine accuracy and stability examination are given.
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