Method and device for generating intermediate picture signals from reference picture signals having a reduced picture frequency

A device for generating a sequence of reference pictures and intermediate pictures derived from said reference pictures, comprising:

• (a) sensor means having an optical axis and movable relative to an object plane so that the optical axis has a directional component parallel to said object plane, said sensor means providing at a standard frequency signals representing at least first and second successive reference pictures and providing signals representing a multiplicative assignment which maps first and second reference pixels of said first reference picture on corresponding first and second reference pixels of said second picture;
• (b) at least one random access picture memory for storing the signals representing the reference pictures in a given address sequence;
• (c) arithmetic means for determining, from the signals representing the multiplicative assignment, signals representing an intermediate multiplicative assignment, N said intermediate multiplicative assignment being equivalent to said multiplicative assignment, n successive intermediate multiplicative assignments mapping the first and second reference pixels of the first reference picture onto corresponding first and second reference pixels of an n-th intermediate picture, where N is an integer greater than or equal to three and n is an integer less than N;
• (d) address calculating means for generating addresses from the signals representing the intermediate multiplicative assignment and from coordinates of pixels of intermediate pictures to be generated, said addresses being provided to address the picture memory;
• and
• (e) output means for providing, as intermediate picture signals, the reference picture signals read at said addresses, the sequence of intermediate picture signals and reference signals being provided at said output means at a frequency which is N times said standard frequency.

A method for generating a sequence of reference pictures and intermediate pictures derived from said reference pictures, comprising the steps of:

• (a) moving an optical sensor means relative to an object plane so that an optical axis of said sensor means has a directional component parallel to said object plane;
• (b) deriving at least first and second successive reference pictures of said object plane at a standard picture frequency using said sensor means;
• (c) in said first and second successive reference pictures, detecting a set of at least first and second reference pixels, each set of reference pixels representing an associated object plane position;
• and
• (d) extrapolating after said second reference picture a sequence of (N-1) intermediate pictures, so that a combined sequence of said second reference picture and intermediate pictures has a frequency that is N times said standard frequency,, where N is an integer greater than or equal to three, the step of extrapolating including:
• (i) generating a multiplicative assignment so that N successive said multiplicative assignments map the reference pixels of the first reference picture on corresponding reference pixels of the second reference picture, and so that n successive multiplicative assignments, of the reference pixels of the first reference picture, map its reference pixels on corresponding reference pixels of an n-th intermediate picture, where n is an integer less than N;
• and
• (ii) determining positions of all pixels other than reference pixels in an intermediate picture from the positions of the reference pixels of the intermediate picture.