The optical transfer function (MTF) has been widely used in the design and manufacture of optical system. The area under the MTF curve can show image quality of the optical system directly. However, for a long time, as the evaluation remained at the qualitative level, it has little value in practice. When the author started the research of MTF curve integral calculation method, no related literatures were available.
With the aid of the OSLO optical design software, optimized optical system structure and corresponding MTF curve discrete data are obtained by means of iterative optimization with the software. Then, the original MTF curve data are fit by MATLAB software and the integral result of the curve is calculated through the relevant numerical method. With the software programmed by the authors, the subjects planned to be evaluated can be ranked in order of image quality automatically. This method can be used as a criterion for evaluating image quality. Application cases show that the evaluation methodology proposed by author is reliable and can be easily operated. This method is supposed to bring about a new way to evaluate the image quality of optical system with the MTF curve.