Fractional pixel mapping in a computer-controlled imaging system

Claim 1

System for mapping an image to a viewing plane in a coordinate sys­tem having an observation point on a main axis thereof and a viewing plane extending normal to said axis and spaced from said viewing point, wherein a rectangular digital input image arranged in columns and rows and represented as a matrix of pixel intensity values is used, and wherein said input image is on the side of said viewing plane opposite from said observation point and corner coordinates related to said main axis, char­acterized by the following features: means for making two orthogonal passes with said first pass is over said input image to form an intermediate image and wherein said second pass is over said inter­mediate image to form an output image; means for making line transformations in said first pass wherein said input image columns are converted to intermediate image columns having lengths derived from said input image columns such that there are respective ratios defining the lengths of said input image columns relative to said intermediate image columns; means for making line transformations in said second pass wherein the intermediate image rows are converted to output image rows on said viewing screen having lengths derived from said input image rows such that there are respective ratios defining the lengths of said intermediate image rows relative to said output image rows; means for calculating for each of said line transforma­tions on the basis of said ratios the number of input pixels required respectively from said columns of said input image and said rows of said intermediate image to create output pixels respectively for said intermediate image columns and said final image rows; means for mapping said input pixels sequentially and fractionally to form said output pixels for each of said line transformations; and means for summing and averaging the intensity values of said input pixels applicable to each output pixel and respectively accruing the composite values so obtained to said output pixels.

Claim 7

A method for nonlinear position mapping of input pixels from an input pixel line in an input image to output pixels in an output pixel line in an output image, characterized by the steps of: a) determining (1) the corresponding starting and stopping points for said lines, (2) a size factor function, and (3) the current size factor ratio of the fractional number of consecutively arranged ones of said input pixels required to form one of said output pixel lines, said ratio being at the origin of said lines; b) beginning at the start of said input pixel line and sequentially feeding consecutive available pixels therefrom until a current sum at least equal to said current ratio is reached; c) feeding a pixel to said output pixel line and finding a new current size factor ratio from said size factor function at that point and finding a current difference between said current sum and said current ratio; d) returning to said input pixel line and, starting with the next available pixel, continuing to sequentially feed consecutive available pixels therefrom which are added to said current difference until a new current sum at least equal to said current size factor ratio is reached; and e) returning to step c) to continue the process until there are no more available pixels in the input line.

Claim 8

A method for nonlinear position mapping of input pixels from an input pixel line in an input image to output pixels in an output pixel line in an output image, characterized by the steps of: a) determining (1) the corresponding starting and stopping points for said lines, (2) a size factor function, and (3) the current size factor ratio of the fractional number of consecutively arranged ones of said input pixels required to form one of said output pixel lines, said ratio being at the origin of said lines; b) beginning at the start of said input pixel line and sequentially feeding consecutive available pixels therefrom until a current sum at least equal to said current ratio is reached; c) feeding a pixel to said output pixel line and finding a new current size factor ratio from said size factor function at that point and finding a current difference between said current sum and said current ratio; d) returning to said input pixel line and, starting with the next available pixel, continuing to sequentially feed consecutive available pixels therefrom which are added to said current difference until a new current sum at least equal to said current size factor ratio is reached; and e) returning to step c) to continue the process until there are no more available pixels in the input line.