Patent ID: 6529639
Filing Date: 2003-03-04
Classification: G01J,G02B,H04N

Abstract:
A method for determining a modulation transfer function of a radiation detector array comprised of detector elements that are arranged in rows and columns, comprising the steps of:simultaneously illuminating, with a phased slit reticle, at least one plurality of detector elements that are disposed within an area along rows and columns of the radiation detector array, the phased slit reticle comprised of an opaque substrate having a plurality of transparent linear features defining at least a first set and a second set of parallel slits, the first set and the second set of parallel slits forming a grid-like pattern, said phased slit reticle having the first set of parallel slits that are equally spaced apart from another by a distance D1, the phased slit reticle further having the second set of parallel slits that are equally spaced apart from one another by a distance D2, wherein the first set of slits and the second set of slits are orthogonally disposed one to another for defining a two dimensional array of cells, wherein the cells of adjacent columns of the two dimensional array of cells are staggered relative to another by an amount equal to a distance D3, and wherein the cells of adjacent rows of the two dimensional array of cells are overlapped with one another by an amount equal to a distance D4, wherein the value of each of D1, D2, D3 and D4 is a function of the distance between two adjacent detector elements, each of the slits of the first and second set having a width that, when imaged upon the detector array, is substantially less than a width of a single detector element, the phased slit reticle further having a two dimensional phase characteristics between adjacent slits of the first set and the second set that is a function of a distance between adjacent detector elements; determining, from an electrical signal generated by the illuminated detector elements, a line spread function; and determining, from the line spread function, the modulation transfer function of the radiation detector array within the area.