The invention discloses an indicator function-based fast
decomposition method for a cross
transfer function. The method comprises the steps of (1) obtaining a
light source function J(f, g) of an imaging
system; (2) dividing a region
omega of describing a
light source to obtain a group of orthogonal sub-regions omegaij and describing the
light source function J(f, g) by using an indictor function Iij(f, g) on the orthogonal sub-regions; (3) calculating inverse
Fourier transform of the indictor function Iij(f, g), obtaining a primary function Lij(x, y) in a
spatial domain, projecting a light source mutual
intensity function as shown in the specification in the
spatial domain to a group of primary functions as shown in the specification and obtaining
decomposition of the light source mutual
intensity function as shown in the specification; (4) building a
core function as shown in the specification of the cross
transfer function as shown in the specification in the
spatial domain; and (5)calculating a
convolution of the
core function as shown in the specification and a
mask pattern as shown in the specification and obtaining an
exposure pattern as shown in the specification on an
image plane. The light
source function is expressed by using the indicator function Iij(f, g) on the orthogonal sub-regions, the
decomposition of the light source mutual
intensity function as shown in thespecification is directly obtained by using an orthogonality relationship of the indicator function and a projection coefficient of the light source, the
core function as shown in the specification of the cross
transfer function as shown in the specification is easily obtained, so that
light intensity distribution calculation is fast and efficient.