Imaging system with multilevel dithering using two memories

Claim 3

The apparatus as in claim 1, wherein the input levels are quantized with the smallest input level mapped directly to the smallest output level, and the largest input level mapped directly to the largest output level.

Claim 4

The apparatus as in claim 1, wherein the quantized values (Q<S>) of the input levels, stored in said first memory means, are related to the number of output levels (NOL) and the number of input levels (NIL) of the imaging system by: Δ.sub.Q =(NIL-1)/(NOL-1); and for each output level (OL)={0 through (NOL-1)}, Q<S>=OL, for those values of S that satisfy: int {(OL)(Δ.sub.Q)+0.5}≦S<int {(OL+1)(Δ.sub.Q)+0.5}.

Claim 5

The apparatus as in claim 3, wherein said adding means produces a finite number of unique sum values (S) which map to a single, given output level, and wherein the dither template values are normalized by symmetrically distributing the dither template values between 0 and an average value, where the average value is determined by averaging the numbers of unique sum values which map to each of the given output levels.

Claim 6

The apparatus as in claim 4, wherein the normalized dither template values (D<x',y'>) are related to the number of output levels (NOL) and the number of input levels (NIL) of the imaging system; a Δ d ; a dither template (T<x',y'>); and a number of template levels of the imaging system (NTL) by: Δ.sub.Q =(NIL-1)/(NOL-1); Δ.sub.d =Δ.sub.Q /(NTL); and D<x',y'>=int {Δ.sub.d (T<x',y'>)+0.5) }.

Claim 7

The apparatus as in claim 4, wherein the dither template values are phase adjusted by spatially shifting the values within the dither template.

Claim 8

The apparatus as in claim 6, wherein the phase adjusted dither template values (d<x',y'>) are related to the number of output levels (NOL) and the number of input levels (NIL) of the imaging system; a Δ d ; a dither template (T<x',y'>); a number of template levels of the imaging system (NTL); a phase value of the x,y address of an input cell (phase -- x, phase -- y); and the dimensions of said second memory means (M mm , N mm ) by: Δ.sub.Q =(NIL-1)/(NOL-1); Δ.sub.d =Δ.sub.Q /(NTL); D<x',y'>=int {Δ.sub.d (T<x',y'>)+0.5}; and d<x',y'>=D<(x'+phase.sub.13 x)modulo(M.sub.mm), (y'+phase.sub.-- y)modulo(N.sub.mm)>.

Claim 11

The apparatus as in claim 8, wherein the input levels are quantized with the smallest input level mapped directly to the smallest output level, and the largest input level mapped directly to the largest output level.

Claim 12

The apparatus as in claim 8, wherein said adding means produces a finite number of unique sum values (S) which map to a single, given output level, and wherein the dither template values are normalized by symmetrically distributing the dither template values between 0 and an average value, where the average value is determined by averaging the numbers of unique sum values which map to each of the given output levels.

Claim 13

The apparatus as in claim 10, wherein the dither template values are phase adjusted by spatially shifting the values within the dither template.

Claim 14

An apparatus as in claim 11, further comprising an image adjustment system, said image adjustment system being responsive to raw input levels produced by the input device to provide an input level.

Claim 15

An imaging system comprising: an output device which produces any number of output levels; an input device which also produces any number of input levels provided the number of input levels is greater than or equal to the number of output levels, said input device having an input cell identified by a given address; an image processor, coupled between said input and output devices, for translating the input levels to corresponding output levels, said image processor including: Look Up Table (LUT) generator means for generating quantized values for the input levels and for generating dither template values; first memory means for storing the quantized values; second memory means for storing dither template values, said second memory means being responsive to the address of the input cell to provide a dither template value which corresponds to the address of the input cell; and means for adding an input level of the input cell to the dither template value provided by said second memory means to provide an address to said first memory means such that said first memory means provides a quantized value which corresponds to the given input level.

Claim 16

An imaging system comprising: an output device which produces any number of output levels; an input device which also produces any number of input levels provided the number of input levels is greater than or equal to the number of output levels, said input device having an input cell identified by a given address; an image processor, coupled between said input and output devices, for translating the input levels to corresponding output levels, said image processor including: Look Up Table (LUT) generator means for generating quantized values for the input levels and for generating dither template values; first memory means for storing the quantized values; second memory means for storing dither template values, said second memory means being responsive to the address of the input cell to provide a dither template value which corresponds to the address of the input cell; and means for adding an input level of the input cell to the dither template value provided by said second memory means to provide an address to said first memory means such that said first memory means provides a quantized value which corresponds to the given input level.

Claim 17

The imaging system as in claim 13, wherein the input levels are quantized with the smallest input level mapped directly to the smallest output level, and the largest input level mapped directly to the largest output level.

Claim 18

The imaging system as in claim 13, wherein said adding means produces a finite number of unique sum values (S) which map to a single, given output level, and wherein the dither template values are normalized by symmetrically distributing the dither template values between 0 and an average value, where the average value is determined by averaging the numbers of unique sum values which map to each of the given output levels.

Claim 19

The imaging system as in claim 15, wherein the dither template values have been phase adjusted by spatially shifting the values within the dither template.

Claim 20

The imaging system as in claim 13, further comprising a second image processor, and wherein the input levels of the input device are components of a color system.

Claim 23

The method as in claim 18, wherein said generating step includes: quantizing the input levels with the smallest input level mapped directly to the smallest output level, and the largest input level mapped directly to the largest output level.

Claim 24

The method as in claim 18, wherein said generating step includes: relating the quantized values of the input levels (Q<S>) to the number of output levels (NOL) and the number of input levels (NIL) of the imaging system by: Δ.sub.Q =(NIL-1)/(NOL-1); and for each output level (OL)={0 through (NOL-1)}, Q<S>=OL, for those values of s that satisfy: int {(OL)(Δ.sub.Q)+0.5}≦S<int{(OL+1)(Δ.sub.Q)+0.5 }.

Claim 25

The method as in claim 20, wherein said adding step is accomplished using an adding means which produces a finite number of unique sum values (S) which map to a single, given output level, and wherein said generating step includes: normalizing the dither template values by distributing the dither template values between 0 and an average value, where the average value is determined by averaging the numbers of unique sum values which map to each of the given output levels.

Claim 26

The method as in claim 21, wherein said generating step includes: phase adjusting the dither template values by spatially shifting the values within the dither template.