Cinematic dithering for television systems

Claim 2

Means for generating a cinematic dither suitable for dither-quantizing a television signal, comprising: means generating a stream of signals representing a continually repeated series of dither samples, said series comprising p phases, said signals indicating one of Q discrete sizes for each dither sample, p and Q integers, signals of a first phase having sizes arranged in a certain arbitrary order corresponding to an arbitrary frame pattern; means for synchronizing successive phases with successive frames of said television signal; and means, including modulo-Q summing means, for modifying the signals of said first phase to produce for other phases signals corresponding to frame patterns other than said arbitrary pattern.

Claim 3

The means of claim 1 modifying the signals of said first phase and subsequent phases in such manner that sizes of successive dither samples occupying the same relative position in successive phases recur cyclically according to a repeating cycle with a fixed succession of sizes.

Claim 4

The means of claim 1 generating a phase wherein dither samples have sizes arranged in substantially random order, corresponding to a substantially random frame pattern.

Claim 5

The means of claim 1 wherein at least one of the integers p and Q is not an integral power of 2.

Claim 6

The means of claim 2 wherein said repeating cycle includes p/k different sizes, k an integer larger than zero.

Claim 7

The means of claim 5 wherein said repeating cycle corresponds to a constant difference modulo-Q between successive sizes.

Claim 8

Apparatus for generating a p-phase cinematic dither, p not less than three, suitable for dither-quantizing a television signal, said apparatus comprising: means for generating dither samples in terms of signals specifying discrete sample sizes, said means generating a first series of dither samples wherein specified sizes are arranged according to a first frame pattern and continually regenerating said series in synchronism with successive television frames; means for counting television frames modulo p; means for obtaining signals representing cumulative jumps in size as functions of at least the modulo p frame count; means for altering the specified sizes of dither samples of said first series according to signals representing cumulative jumps in size, to obtain another arrangement of sizes correpsonding to a second frame pattern; and means for altering the specified sizes of dither samples of said first series according to signals representing cumulative jumps in size, to obtain another arrangement of sizes corresponding to a third frame pattern.

Claim 9

Apparatus for generating a p-phase cinematic dither, p not less than three, suitable for dither-quantizing a television signal, said apparatus comprising: means for generating dither samples in terms of signals specifying discrete sample sizes, said means generating a first series of dither samples wherein specified sizes are arranged according to a first frame pattern and continually regenerating said series in synchronism with successive television frames; means for counting television frames modulo p; means for obtaining signals representing cumulative jumps in size as functions of at least the modulo p frame count; means for altering the specified sizes of dither samples of said first series according to signals representing cumulative jumps in size, to obtain another arrangement of sizes correpsonding to a second frame pattern; and means for altering the specified sizes of dither samples of said first series according to signals representing cumulative jumps in size, to obtain another arrangement of sizes corresponding to a third frame pattern.

Claim 10

The apparatus of claim 7 including look-up table means for obtaining said signals representing cumulative jumps in size.

Claim 11

The apparatus of claim 7 wherein a cumulative jump in size is also a function of the specified size of the dither sample of said first series associated therewith.

Claim 12

The means of claim 5 including both a repeating cycle with p/j different sizes and a repeating cycle with p/k sizes, where j and k are unequal integers.

Claim 13

For providing an improved dither in a system transmitting a television signal, the means comprising: (a) means for generating signals representing dither samples having Q different sizes in a repeating time series that includes p sub-series, each sub-series synchronous with a frame of said television signal and the entire series repeating after p frames, the sample occupying a specified ordinal position within one sub-series having size z; and (b) means, including aarithmetic adder means, for modifying the signals of said one sub-series by size jumps, to generate a next-following sub-series of dither samples wherein the size of the sample occupying said specified ordinal position has size (z+h) modulo Q, h being the jump in size.

Claim 14

For providing an improved dither in a system transmitting a television signal, the means comprising: (a) means for generating signals representing dither samples having Q different sizes in a repeating time series that includes p sub-series, each sub-series synchronous with a frame of said television signal and the entire series repeating after p frames, the sample occupying a specified ordinal position within one sub-series having size z; and (b) means, including aarithmetic adder means, for modifying the signals of said one sub-series by size jumps, to generate a next-following sub-series of dither samples wherein the size of the sample occupying said specified ordinal position has size (z+h) modulo Q, h being the jump in size.

Claim 15

The means of claim 11 wherein each sub-series of said repeating time series has sample sizes arranged differently from the preceding sub-series.

Claim 16

The means of claim 11 wherein the jump h has constant value for all samples of all sub-series.

Claim 17

The means of claim 11 wherein p is greater than 2, and wherein the absolute value of the simple difference h-Q/2 is not larger than Q/p.

Claim 18

The means of claim 11 wherein Q=rp, r is an integer larger than zero, and h varies cyclically at each sample position such that the same series of h values repeats after p frames.

Claim 19

The means of claim 15 wherein the amount of the jump h depends on the size z that it augments modulo Q.

Claim 20

The means of claim 11 wherein each size z determines only one value of h.

Claim 21

The means of claim 15 wherein samples occupying different positions in a sub-series of samples change sizes in different manner, corresponding to different jump cycles.

Claim 22

The means of claim 11 wherein the sizes of the dither samples of a sub-series occur in random order.

Claim 23

The means of claim 11 wherein the samples of a sub-series have an order of sizes corresponding to an ordered-dither frame pattern.

Claim 24

The means of claim 20 wherein said ordered-dither frame pattern corresponds to horizontal and vertical repetition of the skewed dither matrix ______________________________________ 0 5 8 7 2 4 3 6 1 ______________________________________ the numerals representing dither sizes in relation to the scanning raster, and wherein additional frame patterns are produced by means of size jumps corresponding to repeated modulo 9 addition of 3 to said matrix.

Claim 25

The means of claim 11 further comprising means for dither-quantizing a television signal.

Claim 26

The means of claim 11 wherein Q and p are integers larger than unity, h is an integer larger than zero, and at least one of Q, p and h is not an integral power of 2.

Claim 29

The method of claim 23 wherein all numbers represented by said second signals differ from Q/2 by an absolute difference not larger than Q/p, p an integer larger than unity, and are such that said first arrangement of integers recurs every p frames.

Claim 30

The method of claim 23 wherein second signals represent numbers that vary according to the integer of said first arrangement being added to.

Claim 31

The method of claim 23 wherein said first signals correspond to integers arranged in substantially random order.

Claim 32

The method of claim 23 said first signals correspond to integers in such arrangement that raster scanning results in a regular pattern of dither sizes in relation to the scanning raster.

Claim 35

The method of claim 29 producing additional phase signals representing additional sets of dither samples arranged in such manner that every pair consisting of a set and its immediate successor has the relation of said first and second sets, and such that said first phase signal recurs periodically after a fixed number of television frames.

Claim 38

The method of claim 23 wherein the same number is added modulo Q to all integers of said first arrangement.

Claim 39

An improved method for dither-quantizing a television signal, including steps of: (a) dithering said signal by combining it with an improved dither, said improved dither a cinematic dither including p phases, p not less than three, in a sequency repeated cyclically, each phase comprising signals representing a set of dither samples individually correlated with individual elements of an array of elements that is co extensive with a television picture area and remains fixed for all phases, said signals indicating one of a number of different sizes for each dither sample; said improved dither characterized by a first phase, synchronous with a first frame of the television signal, wherein dither-sample sizes are configured according to a first frame pattern in relation to the aforesaid array, and further characterized by subsequent phases, synchronous with subsequent television frames, wherein dither-sample sizes are configured according to other frame patterns; said first and other frame patterns being such that the size of a dither sample of one phase is a function of only the size of the dither sample correlated with the same array element during the immediately preceding phase; said frame patterns also being such that the (p+1)th frame pattern is the same as the first frame pattern; and (b) quantizing the dithered signal according to discrete quantum levels.

Claim 40

An improved method for dither-quantizing a television signal, including steps of: (a) dithering said signal by combining it with an improved dither, said improved dither a cinematic dither including p phases, p not less than three, in a sequency repeated cyclically, each phase comprising signals representing a set of dither samples individually correlated with individual elements of an array of elements that is co extensive with a television picture area and remains fixed for all phases, said signals indicating one of a number of different sizes for each dither sample; said improved dither characterized by a first phase, synchronous with a first frame of the television signal, wherein dither-sample sizes are configured according to a first frame pattern in relation to the aforesaid array, and further characterized by subsequent phases, synchronous with subsequent television frames, wherein dither-sample sizes are configured according to other frame patterns; said first and other frame patterns being such that the size of a dither sample of one phase is a function of only the size of the dither sample correlated with the same array element during the immediately preceding phase; said frame patterns also being such that the (p+1)th frame pattern is the same as the first frame pattern; and (b) quantizing the dithered signal according to discrete quantum levels.

Claim 41

The method of claim 33 wherein said improved dither is such that, with Q dither-sample sizes denoted by the integers from 0 to Q-1 inclusive, the modulo Q difference between the size of a dither sample of one phase and the size of said correlated dither sample of the next following phase is the same for all sizes and all phases.

Claim 42

The method of claim 33 wherein said improved dither is such that, with Q dither-sample sizes denoted by the integers from 0 to Q-1 inclusive, the modulo Q difference between the size of a dither sample of one phase and the size of said correlated dither sample of the immediately preceding phase is not less than Q/2-Q/p and not more than Q/2+Q/p.

Claim 47

The method of claim 37 wherein Q=aP, a and P being integers with P odd, and wherein sets of second-, third-, and subsequent-phase dither samples are generated by repeated modulo Q addition of a size difference c equal to a selected one of the quantities Q/2+a/2 and Q/2-a/2, thereby obtaining P different frame patterns in a continually repeating sequence.

Claim 48

For generating a dither corresponding to a continually repeating series of at least three different frame patterns and comprising dither samples having amplitudes limited to a fixed number of discrete sizes, a method including steps of: producing signals corresponding to a set of dither samples with sizes arranged in a configuration corresponding to a first frame pattern; anda for subsequent frame patterns, producing signals corresponding to sets of dither samples with sizes so arranged that the size of each sample of any set is unambiguously specified by only the size of a correlated dither sample of the set immediately previous thereto.

Claim 49

For generating a dither corresponding to a continually repeating series of at least three different frame patterns and comprising dither samples having amplitudes limited to a fixed number of discrete sizes, a method including steps of: producing signals corresponding to a set of dither samples with sizes arranged in a configuration corresponding to a first frame pattern; anda for subsequent frame patterns, producing signals corresponding to sets of dither samples with sizes so arranged that the size of each sample of any set is unambiguously specified by only the size of a correlated dither sample of the set immediately previous thereto.

Claim 52

The method of claim 40 also including the step of synchronizing successive signals representing different sets of dither samples with successive television frames, and arranging integer assignments such that every set of samples is represented in any series of p successive frames.

Claim 53

The method of claim 40 assigning integer values in a regular pattern to the elements of said fixed array.

Claim 54

The method of claim 40 assigning integer values in substantially random pattern to the elements of said fixed array.

Claim 55

The method of claim 40 producing digital signals to represent dither samples and their sizes.

Claim 56

The method of claim 40 producing analog signals to represent dither samples and their sizes.

Claim 57

The method of claim 42 arranged to produce first and subsequent sets of dither samples wherein sizes are correlated with said fixed array according to first and subsequent ordered dither frame patterns defined by any of the sets of ordered dither matrices shown in FIG. 10A, FIG. 10D, FIG. 11B and FIG. 11C.

Claim 58

The method of claim 42 assigning values of x 1 to the elements of said array according to a substantially random pattern and assigning values of y to said elements in a regular pattern.

Claim 59

Means for generating a cinematic dither having three or more phases and suitable for television, comprising: (a) means for producing signals representing a first set of dither samples such that each sample is correlated with one element of an array of elements fixed in relation to the picture area of a television display and such that each dither sample is represented to have size rx 1 plus y; r being an integer greater than unity and p an integer greater than 2, x 1 being one of the integers from 0 to p-1 inclusive assigned as x 1 to the array element correlated with said sample, and y being one of the integers from 0 to r-1 inclusive assigned to the same array element; values of x 1 being assigned to the elements of said array according to a selected pattern and values of y being assigned to the same elements according to a selected pattern; (b) means for producing signals representing a second set of dither samples such that each sample is correlated with an element of the aforesaid fixed array and is represented to have size rx 2 plus y, where x 2 is an integer in the range from 0 to p-1 inclusive and its particular value is specified uniquely by the value of x 1 assigned to the correlated element; and (c) means for producing signals representing a third set of dither samples wherein each sample is likewise correlated with an element of the aforesaid fixed array and is represented to have size rx 3 plus y, where values of x 3 are determined by values of x 2 as values of x 2 are determined by values of x 1 .

Claim 60

Means for generating a cinematic dither having three or more phases and suitable for television, comprising: (a) means for producing signals representing a first set of dither samples such that each sample is correlated with one element of an array of elements fixed in relation to the picture area of a television display and such that each dither sample is represented to have size rx 1 plus y; r being an integer greater than unity and p an integer greater than 2, x 1 being one of the integers from 0 to p-1 inclusive assigned as x 1 to the array element correlated with said sample, and y being one of the integers from 0 to r-1 inclusive assigned to the same array element; values of x 1 being assigned to the elements of said array according to a selected pattern and values of y being assigned to the same elements according to a selected pattern; (b) means for producing signals representing a second set of dither samples such that each sample is correlated with an element of the aforesaid fixed array and is represented to have size rx 2 plus y, where x 2 is an integer in the range from 0 to p-1 inclusive and its particular value is specified uniquely by the value of x 1 assigned to the correlated element; and (c) means for producing signals representing a third set of dither samples wherein each sample is likewise correlated with an element of the aforesaid fixed array and is represented to have size rx 3 plus y, where values of x 3 are determined by values of x 2 as values of x 2 are determined by values of x 1 .

Claim 61

The means of claim 48 including means for synchronizing successive signals representing different sets of dither samples with successive television frames, and arranged so that every set of samples is represented in any series of p successive frames.