Patent Document ID: 8408707
Application ID: 12428441
Patent Flag: 1

Claim One:
1. A method of predicting visual acuity of an imaging system, the method comprising: providing a set of K optotypes, numbered k=1,.. . , K (K≧2) of a specified size, to be used to establish a reference set of symbols to estimate visual acuity, and providing a description or image T k (x,y) of each optotype, dependent upon location coordinates (x,y) associated with the optptype image produced by the imaging system; constructing a Wavefront Aberration Image WAI(x,y) that manifests selected image aberrations associated with the imaging system; computing a generalized pupil image GPI(x,y), with non-zero values confined to within a pupil aperture associated with the imaging system, that manifests the selected image aberrations and that is dependent upon at least one wavelength λ of light with which the image is viewed; computing a Point Spread Function PSF(x,y) that is an absolute value squared of a Discrete Fourier Transform (DFT) of the image GPI(x,y); computing a Normalized Point Spread Function NPSF(x,y), proportional to the Point Spread Function PSF (x,y), whose norm is 1: computing an Optical Transfer Function OTF(u,v), expressed as a function of spatial frequency indice (u,v) in a Fourier transform plane, that is a Discrete Fourier Transform of the Normalized Point Spread Function NPSF (x,y), multiplied by a value h of original image size and multiplied by an image magnification index m; generating a Radial Neural Transfer Function RNTF(u,v), where RNTF(u,v) satisfies the following conditions: (i) RNTF(u,v) is a continuous, non-negative function of a spatial frequency variable f=[u 2 +v 2 ] 1/2 ; (ii) RNTF(u,v) has at least one value, f=f(max), for which NRTF(u,v) is a maximum; (iii) for 0<f<f(max), RNTF(u,v) is monotonically increasing in f; (iv) for f>f(max), and RNTF(u,v) is monotonically decreasing toward 0; computing a Neural Transfer Function NTF(u,v) as a product of the Radial Neural Transfer Function RNTF (u,v) and an Oblique Effect Filter function OER(u,v) that compensates for viewing angle of the-original optotype image; generating a Total Transfer Function TTF(u,v), defined as a product of NTF(u,v) and the Optical Transfer Function OTF(u,v); generating a Proportion Correct index PC(j), which presents a probability associated with a correct optotype that would be identififed by a subject having the Wavefront Aberration Image WAI(x,y) for at least one optotype(j).