Image capture simulation using an accurate and realistic lens model

This paper describes a digital image capture simulator that incorporates a lens model based on point-spread function (PSF) data from a commercial lens design package. This lens model has significant advantages over a simple MTF based model, because it accounts for all image degrading aberrations commonly encountered in image capture systems. Lens design data in the form. of a set of highly resolved PSFs are generated off-line using the lens design package. The data are computed for a range of wavelengths, image plane locations and field positions. To simulate a specific imaging system, these PSFs are resampled according to the sensor pixel pitch, system spectral sensitivities, sensor location, etc. The input to the simulator can be either a digital test target or a digital image of a real scene, which is highly over-sampled with respect to the final simulated image and whose spatial and spectral characteristics are well known; The simulator output, in the form of the raw data generated by an actual digital capture device, will be highly useful in the parametric study of the design parameters of image capture-systems. The performance and limitations of the lens component of the simulator are described.