Digital image interpolation system for zoom and pan effects

Claim 1

In a video image alteration apparatus wherein pixels relating to an input image derived from a frame of film are sampled at a predetermined rate related to a film scanning speed and a television line standard, and wherein a flow of pixel information is coordinated through a memory section by write control and read control signals, the combination comprising: means for storing image pixel data corresponding to at least one film frame, said frame storing means having a line output and line start and line advance address inputs for selecting a line start position and a line advance increment; means responsive to the line output of said frame storing means for storing at least one line of image pixel data, said line storing means having a pixel output and pixel start and pixel advance address inputs for selecting a pixel start position and a pixel advance increment; a spatial interpolator responsive to the pixel output of said line storing means; and means for generating read control signals for said frame storing means and said line storing means, said generating means providing: (a) a line start position control signal to the line start address input of said frame storing means to select the vertical pan position of the line output signal, (b) a line advance control signal to the line advance address input of said frame storing means to select the vertical repeat pattern of the line output signal, (c) a pixel start position control signal to the pixel start address input of said line storing means to select the horizontal pan position of the pixel output signal, and (d) a pixel advance control signal to the pixel advance address input of said line storing means to select the horizontal repeat pattern of the pixel output signal.