Method for determining aperture shape

Claim 1

A method for selecting the shape of an occluding aperture which is to be positioned at a predetermined aperture location in a light path extending between an illuminated line object and a linear photosensor array whereby, through use of the aperture, a light intensity measurement is obtained across the linear photosensor array which is uniformly proportional to the light intensity across the illuminated line object, comprising the steps of: (a) providing a constant light intensity across the illuminated line object during a testing period; (b) measuring the light intensity across the linear photosensor array during the testing period without an occluding aperture in the light path; (c) selecting a target, constant value light intensity which is to be achieved through use of occluding aperture; (d) selecting an initial aperture shape and representing the selected shape mathematically; (e) constructing a mathematical model for the light intensity at any point across the linear photosensor array, with an aperture of the selected shape in place at the predetermined aperture location; (f) using the light intensity measured across the photosensor array during the testing period and the mathematical model to compute the light intensity across the photosensor array with an aperture of the selected shape in place; (g) during a selected number of iterations, adjusting the mathematical expression representative of aperture shape in an orderly fashion adapted to minimize the total deviation of the computed light intensity across the linear photosensor array from the target constant value light intensity; (h) selecting a final design aperture shape in accordance with the one of the adjusted mathematical expressions for aperture shape which produces the least total deviation in computed light intensity from the target constant value light intensity.

Claim 2

A method for selecting the shape of an occluding aperture which is to be positioned at a predetermined aperture location in a light path extending between an illuminated line object and a linear photosensor array whereby, through use of the aperture, a light intensity measurement is obtained across the linear photosensor array which is uniformly proportional to the light intensity across the illuminated line object, comprising the steps of: (a) providing a constant light intensity across the illuminated line object during a testing period; (b) measuring the light intensity across the linear photosensor array during the testing period without an occluding aperture in the light path; (c) selecting a target, constant value light intensity which is to be achieved through use of occluding aperture; (d) selecting an initial aperture shape and representing the selected shape mathematically; (e) constructing a mathematical model for the light intensity at any point across the linear photosensor array, with an aperture of the selected shape in place at the predetermined aperture location; (f) using the light intensity measured across the photosensor array during the testing period and the mathematical model to compute the light intensity across the photosensor array with an aperture of the selected shape in place; (g) during a selected number of iterations, adjusting the mathematical expression representative of aperture shape in an orderly fashion adapted to minimize the total deviation of the computed light intensity across the linear photosensor array from the target constant value light intensity; (h) selecting a final design aperture shape in accordance with the one of the adjusted mathematical expressions for aperture shape which produces the least total deviation in computed light intensity from the target constant value light intensity.

Claim 11

A method for selecting the shape of an occluding aperture which is to be positioned at a predetermined aperture location in a light path extending between an illuminated line object and a linear photosensor array whereby, through use of the aperture, a light intensity measurement is obtained across the linear photosensor array which is uniformly proportional to the light intensity across the illuminated line object, comprising the steps of: (a) providing a constant light intensity across the illuminated line object during a testing period; (b) measuring the light intensity across the linear photosensor array during the testing period without an occluding aperture in the light path; (c) selecting a target, constant value light intensity which is to be achieved through use of occluding aperture which value is no greater than approximately the lowest light intensity value associated with the illuminated line object which was measured across the linear photosensor array during the testing period; (d) selecting an initial aperture shape and representing the selected shape mathematically as a polynomial equation; (e) constructing a mathematical model for the light intensity at any point across the linear photosensor array, with an aperture of the selected shape in place at the predetermined aperture location; (f) using the light intensity measured across the photosensor array during the testing period and the mathematical model to compute the light intensity across the photosensor array with an aperture of the selected shape in place; (g) during a selected number of iterations, adjusting the coefficients of the polynomial equation representative of aperture shape in an orderly fashion adapted to minimize the total deviation of the computed light intensity across the linear photosensor array from the target constant value light intensity; (h) selecting a final design aperture shape in accordance with the one of the coefficient-adjusted, polynomial expressions for aperture shape which produces the least total deviation in computed light intensity from the target constant value light intensity.

Claim 12

A method for selecting the shape of an occluding aperture which is to be positioned at a predetermined aperture location in a light path extending between an illuminated line object and a linear photosensor array whereby, through use of the aperture, a light intensity measurement is obtained across the linear photosensor array which is uniformly proportional to the light intensity across the illuminated line object, comprising the steps of: (a) providing a constant light intensity across the illuminated line object during a testing period; (b) measuring the light intensity across the linear photosensor array during the testing period without an occluding aperture in the light path; (c) selecting a target, constant value light intensity which is to be achieved through use of occluding aperture which value is no greater than approximately the lowest light intensity value associated with the illuminated line object which was measured across the linear photosensor array during the testing period; (d) selecting an initial aperture shape and representing the selected shape mathematically as a polynomial equation; (e) constructing a mathematical model for the light intensity at any point across the linear photosensor array, with an aperture of the selected shape in place at the predetermined aperture location; (f) using the light intensity measured across the photosensor array during the testing period and the mathematical model to compute the light intensity across the photosensor array with an aperture of the selected shape in place; (g) during a selected number of iterations, adjusting the coefficients of the polynomial equation representative of aperture shape in an orderly fashion adapted to minimize the total deviation of the computed light intensity across the linear photosensor array from the target constant value light intensity; (h) selecting a final design aperture shape in accordance with the one of the coefficient-adjusted, polynomial expressions for aperture shape which produces the least total deviation in computed light intensity from the target constant value light intensity.