US5185602A
Expired / Lapsed
US
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Method and apparatus for producing perception of high quality grayscale shading on digitally commanded displays
Assignee: Nvidia Corp
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Filing: 1989-04-10
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Granted: 1993-02-09
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Expires: 2009-04-10
Abstract
Abstract The perception of grayscale shading on a digitally commanded display is produced by commanding pixels of the display with brightness-setting signals of differing average duty cycles. Brightness-setting signals having one brightness level associated with them are phase shifted in relation to time and distributed to spaced apart pixel locations at which the one brightness level is to be produced. The energization of spatially adjacent pixels is scattered in time and pixels which are energized at the same time are selected to be spatially scattered so as to avoid the perception of visual disturbances such as flickering and surface streaming.
Inventors
- 👤 Chester F. Bassetti, Jr.
- 👤 Dayakar C. Reddy
- 👤 Ekaputra Laiman
- 👤 Bryan M. Richter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:50
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/12; H04N3/127; G; G09; G09G; G09G3/00; G09G3/20; G09G3/2003; G09G3/2007; G09G3/2044; G09G3/2051; G09G3/2092; G09G3/34; G09G3/36; G09G3/3611; G09G2320/00; G09G2320/02; G09G2320/0247; G09G2320/0261; G09G2320/0266; G09G2320/0271; G09G2320/0276; G09G2360/00; G09G2360/18; G09G3/2018; G09G3/2022; G09G3/2025
Claims Analysis
Total Claims: 51
Claim 1
Independent Claim
207 words
A method for producing the perception of images having four or more levels of distinguishable brightness on a digitally controlled display, comprising: defining a set of brightness-setting waveforms each consisting of a number, D, of ON/OFF command bits, the number D satisfying the relationship D=na-1 D=mb-1 a≠b where a, b, n, m and D are integers greater than zero, the integration of each of said D brightness-setting waveforms producing a different average brightness level over an integration period equal to D bit times; defining a first square phase-placement matrix of dimensions D cells by D cells; filling the cells of the phase-placement matrix with at least four different non-consecutive phase shifting values wherein for each brightness-setting waveform there are D possible phases, each phase corresponding to a different bit of the brightness setting waveform; and each cell of the phase-placement matrix corresponding to a pixel in a matrix of D pixels by D pixels in the digitally controlled display; and producing two or more brightness-setting signals having waveforms corresponding to two or more of the brightness-setting waveforms, the produced signals being applied to pixels of the matrix of pixels and shifted in accordance with different non-consecutive phase shifting values in the corresponding cells of the phase-placement matrix.
Claim 2
Independent Claim
207 words
A method for producing the perception of images having four or more levels of distinguishable brightness on a digitally controlled display, comprising: defining a set of brightness-setting waveforms each consisting of a number, D, of ON/OFF command bits, the number D satisfying the relationship D=na-1 D=mb-1 a≠b where a, b, n, m and D are integers greater than zero, the integration of each of said D brightness-setting waveforms producing a different average brightness level over an integration period equal to D bit times; defining a first square phase-placement matrix of dimensions D cells by D cells; filling the cells of the phase-placement matrix with at least four different non-consecutive phase shifting values wherein for each brightness-setting waveform there are D possible phases, each phase corresponding to a different bit of the brightness setting waveform; and each cell of the phase-placement matrix corresponding to a pixel in a matrix of D pixels by D pixels in the digitally controlled display; and producing two or more brightness-setting signals having waveforms corresponding to two or more of the brightness-setting waveforms, the produced signals being applied to pixels of the matrix of pixels and shifted in accordance with different non-consecutive phase shifting values in the corresponding cells of the phase-placement matrix.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein the value D further satisfies the relationship D=i.sup.2 +1 where i is a value greater than one.
Claim 4
Dependent Claim
40 words
The method of claim 2, further including the step of selecting the numbers "a" and "b" to satisfy the relationship D=a.sup.2 +b.sup.2, where "a" is not evenly divisible into D, and "b" is not evenly divisible into D, when a>1.
Claim 5
Dependent Claim
44 words
The method of claim 1 wherein at least two matrix cells of the phase-placement matrix contain identical phase shifting values, and wherein matrix cells containing identical values are spaced apart from one another by at least one matrix cell not containing an identical value.
Claim 6
Dependent Claim
125 words
The method of claim 4, wherein the images being produced are formed of a series of pixels, each having a designated brightness level, further including the steps of defining a second square phase-placement matrix of dimensions D cells by D cells; filling the cells of the alternative phase-placement matrix with an alternative pattern of phase shifting values; and comparing a level of brightness to be produced at a next-to-be-displayed pixel to a level of brightness produced at a previously-displayed pixel; using the first phase-placement matrix with the next-to-be-displayed pixel when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are equal; and using the second phase-placement matrix when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are unequal.
Claim 7
Dependent Claim
113 words
The method of claim 1, wherein the images being produced are formed of a series of pixels, each having a designated brightness level, and further wherein the number, D, of ON/OFF command bits of the brightness-setting waveform is defined by the relationship D=A 2 +B 2 , A and B are integers, A≠B, and A 2 +B 2 +1 possible brightness-setting waveforms are defined, and further including the steps of discarding a brightness-setting waveform corresponding to a brightness level substantially equal to but not identical to the minimum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms; and selecting from the remaining brightness-setting waveforms for controlling the series of pixels.
Claim 8
Dependent Claim
53 words
The method of claim 6, further including the steps of discarding a brightness-setting waveform corresponding to a brightness level substantially equal to but not identical to the maximum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms; and selecting from the remaining brightness-setting waveforms for controlling the series of pixels.
Claim 9
Dependent Claim
109 words
A stippling method comprising the steps of: defining a plurality of different brightness levels, each being relatively uniformly spaced in brightness level from the other; defining a square display area of at lest four pixels; commanding diagonally adjacent pairs of the pixels to a first brightness level; and commanding horizontally adjacent pixels to different brightness levels, wherein the different brightness level selected is the next brightness level of the plurality of brightness levels which is above or below the first brightness level; and further wherein the pixels are commanded to the first or different brightness levels by way of brightness setting waveforms, each having the same number of bits.
Claim 10
Dependent Claim
109 words
A stippling method comprising the steps of: defining a plurality of different brightness levels, each being relatively uniformly spaced in brightness level from the other; defining a square display area of at lest four pixels; commanding diagonally adjacent pairs of the pixels to a first brightness level; and commanding horizontally adjacent pixels to different brightness levels, wherein the different brightness level selected is the next brightness level of the plurality of brightness levels which is above or below the first brightness level; and further wherein the pixels are commanded to the first or different brightness levels by way of brightness setting waveforms, each having the same number of bits.
Claim 11
Dependent Claim
18 words
The method of claim 8, wherein the pixels are commanded to be at least six different brightness levels.
Claim 12
Dependent Claim
18 words
The method of claim 8, wherein the pixels are commanded to be at least sixteen different brightness levels.
Claim 13
Independent Claim
368 words
A system for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce, over a number of consecutive frames, the perception of an image having one or more levels of brightness which are selectable from a plurality of levels of brightness, comprising: row addressing means for designating the row number of a desired pixel; column addressing means for designating the column number of the desired pixel; image memory means responsive to the row and column numbers for the desired pixel for producing brightness data indicating a desired level of brightness to be produced at the desired pixel; waveform memory means for storing a predetermined set of brightness-setting waveforms, wherein each of the waveforms has a predetermined number of bits and produces a different brightness level when applied to a pixel, one bit per frame, over a number of consecutive frames, and for selecting one of the stored brightness-setting waveforms in response to the brightness data, the waveform memory means including bit position selecting means for selecting a designated bit from the selected brightness-setting waveform and outputting said selected bit as a display command bit for use by the display unit to control the state of the desired pixel during a particular frame being displayed by the display unit; and phase-placement patterning means, responsive to the row and column numbers for the desired pixel, to the brightness data, and to the particular frame being displayed, for storing a set of predetermined phase-placement patterns and for designating to the waveform memory means, in accordance with a phase-placement pattern which is selected in response to the brightness data, the bit of the selected brightness-setting waveform to be output by the waveform memory means for the desired pixel and the particular frame being displayed, wherein each of the phase-placement patterns is associated with a different brightness level and a corresponding brightness-setting waveform, and each pattern designates different non-consecutive phase from pixel to pixel with which its corresponding brightness-setting waveform is to be applied to the pixels of the display unit, so that for a particular frame and a particular pixel, the phase-placement pattern means designates a bit of the selected brightness-setting waveform which is to be output.
Claim 14
Independent Claim
368 words
A system for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce, over a number of consecutive frames, the perception of an image having one or more levels of brightness which are selectable from a plurality of levels of brightness, comprising: row addressing means for designating the row number of a desired pixel; column addressing means for designating the column number of the desired pixel; image memory means responsive to the row and column numbers for the desired pixel for producing brightness data indicating a desired level of brightness to be produced at the desired pixel; waveform memory means for storing a predetermined set of brightness-setting waveforms, wherein each of the waveforms has a predetermined number of bits and produces a different brightness level when applied to a pixel, one bit per frame, over a number of consecutive frames, and for selecting one of the stored brightness-setting waveforms in response to the brightness data, the waveform memory means including bit position selecting means for selecting a designated bit from the selected brightness-setting waveform and outputting said selected bit as a display command bit for use by the display unit to control the state of the desired pixel during a particular frame being displayed by the display unit; and phase-placement patterning means, responsive to the row and column numbers for the desired pixel, to the brightness data, and to the particular frame being displayed, for storing a set of predetermined phase-placement patterns and for designating to the waveform memory means, in accordance with a phase-placement pattern which is selected in response to the brightness data, the bit of the selected brightness-setting waveform to be output by the waveform memory means for the desired pixel and the particular frame being displayed, wherein each of the phase-placement patterns is associated with a different brightness level and a corresponding brightness-setting waveform, and each pattern designates different non-consecutive phase from pixel to pixel with which its corresponding brightness-setting waveform is to be applied to the pixels of the display unit, so that for a particular frame and a particular pixel, the phase-placement pattern means designates a bit of the selected brightness-setting waveform which is to be output.
Claim 15
Dependent Claim
44 words
The system according to claim 11 wherein the phase-placement patterns are squares of dimensions D pixels by D pixels; the dimension D being selected in accordance with the relations D=na-1 D=mb-1 a≠b where a, b, n, m and D are integers greater than zero.
Claim 16
Dependent Claim
22 words
The system of claim 12 wherein the dimensions D satisfies the relationship D=i.sup.2 +1 where i is an integer greater than one.
Claim 17
Dependent Claim
12 words
The system of claim 12 wherein dimension D is a prime member.
Claim 18
Dependent Claim
127 words
The system of claim 11 wherein the phase-placement patterning means has a first set of predetermined phase-placement patterns and a second set of predetermined phase-placement patterns different from the first set, and further including means responsive to brightness data from the image memory means for comparing a desired level of brightness to be produced at a next-to-be-displayed pixel to a desired level of brightness produced at a previously-displayed pixel, and for controlling the phase-placement patterning means to use the first set of phase-placement patterns with the next-to-be-displayed pixel when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are equal, and to use the second set of phase-placement patterns when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are unequal.
Claim 19
Dependent Claim
9 words
The system of claim 12 wherein D equals 17.
Claim 20
Dependent Claim
104 words
The system of claim 11 wherein the phase-placement patterns comprise a matrix of P rows and Q columns, wherein each row of the matrix includes a wrap-around sequence which designates a different non-consecutive phase from pixel to pixel with which a corresponding brightness waveform is to be applied to the pixels of the display unit; and further wherein the wrap-around sequence in each row is shifted in position by a predetermined number of pixels from one row to the next, with any portion of the wrap-around sequence which extends beyond the end of a row being wrapped around to the beginning of the row.
Claim 21
Dependent Claim
36 words
The system of claim 17, wherein P equals Q and the predetermined number of pixels by which the wrap-around sequence is offset within each row, from one row to the next, is three (3) or greater.
Claim 22
Dependent Claim
46 words
The system of claim 18 wherein P equals Q, and Q equals 17, the wrap-around sequence is 17 pixels long, each brightness-setting waveform is 17 bits long, and the war-around sequence is offset by four pixels from one row to the next in each phase-placement pattern.
Claim 23
Dependent Claim
83 words
The system of claim 11 wherein the bits of the brightness-setting waveform command a pixel to be OFF or to be ON, and further wherein, in each waveform, the bits which command a pixel to be ON are positioned, and the phases of the brightness-setting waveforms designated by the phase-placement patterns to be applied from pixel to pixel are selected, so that the pixels which are ON in the frame are substantially uniformly distributed in the rows and columns of the display unit.
Claim 24
Dependent Claim
83 words
The system of claim 19 wherein the bits of the brightness-setting waveform command a pixel to be OFF or to be ON, and further wherein, in each waveform, the bits which command a pixel to be ON are positioned, and the phase from pixel to pixel designated by the phase-placement patterns to be applied from pixel to pixel are selected, so that the pixels which are ON in the frame are substantially uniformly distributed in the rows and columns of the display unit.
Claim 25
Dependent Claim
91 words
The system of claim 11, wherein each brightness-setting waveform in the set of brightness-setting waveforms has N bits, where N=A 2 +B 2 , A and B are integers, A≠B, and A 2 +B 2 +1 possible brightness-setting waveforms are defined, and further wherein a brightness-setting waveform is discarded which corresponds to a brightness level substantially equal to but not identical to the minimum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and the remaining brightness-setting waveforms are used for controlling the pixels of the display unit.
Claim 26
Dependent Claim
54 words
The system of claim 22, further wherein a brightness-setting waveform is discarded which corresponds to a brightness level substantially equal to but not identical to the maximum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and the remaining brightness-setting waveforms are used for controlling the pixels of the display unit.
Claim 27
Independent Claim
267 words
A method for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce over a number of consecutive frames the perception of an image having a number of levels of brightness greater than six, comprising the steps of: a. defining an irregular rectangle of A pixels in height and B pixels in length, where A and B are integers, and A≠B, A 2 +B 2 >6; b. defining a set of brightness-setting waveforms having a number of bits equal in number to the sum N=A 2 B 2 , wherein each brightness-setting waveform produces a different level of brightness when applied to a pixel over a period of N frames; c. defining a set of wrap-around sequences of N pixels in length, wherein each wrap-around sequence corresponds to a different brightness-setting waveform, and each wrap-around sequence designates a different non-consecutive phase from pixel to pixel with which a corresponding brightness waveform is to be applied to the pixels of the display unit; defining a first set of phase-placement patterns each pattern of which is associated with a different brightness level and a corresponding brightness-setting waveform, and each such pattern being constructed of a wrap-around sequence corresponding to the different brightness level, wherein in each phase-placement pattern the corresponding wrap-around sequence is used in each row, but offset every A-rows by B-pixels; and e. applying the brightness-setting waveforms to the pixels of the display unit by utilizing the phase-placement patterns to define the non-consecutive phase from pixel to pixel with which the brightness-setting waveforms are applied to the pixels of the display unit.
Claim 28
Independent Claim
267 words
A method for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce over a number of consecutive frames the perception of an image having a number of levels of brightness greater than six, comprising the steps of: a. defining an irregular rectangle of A pixels in height and B pixels in length, where A and B are integers, and A≠B, A 2 +B 2 >6; b. defining a set of brightness-setting waveforms having a number of bits equal in number to the sum N=A 2 B 2 , wherein each brightness-setting waveform produces a different level of brightness when applied to a pixel over a period of N frames; c. defining a set of wrap-around sequences of N pixels in length, wherein each wrap-around sequence corresponds to a different brightness-setting waveform, and each wrap-around sequence designates a different non-consecutive phase from pixel to pixel with which a corresponding brightness waveform is to be applied to the pixels of the display unit; defining a first set of phase-placement patterns each pattern of which is associated with a different brightness level and a corresponding brightness-setting waveform, and each such pattern being constructed of a wrap-around sequence corresponding to the different brightness level, wherein in each phase-placement pattern the corresponding wrap-around sequence is used in each row, but offset every A-rows by B-pixels; and e. applying the brightness-setting waveforms to the pixels of the display unit by utilizing the phase-placement patterns to define the non-consecutive phase from pixel to pixel with which the brightness-setting waveforms are applied to the pixels of the display unit.
Claim 29
Dependent Claim
66 words
The method of claim 24 wherein the brightness-setting waveforms have bit states of one or zero, and the distribution of the bit states within each brightness-setting waveform and the non-consecutive phases of the brightness-setting waveforms designated in the phase-placement patterns, are selected to substantially uniformly distribute the bits having a state of one over the rows and columns of each frame displayed by the display unit.
Claim 30
Dependent Claim
70 words
The method of claim 25, wherein A 2 +B 2 +1 possible brightness-setting waveforms are defined, the method further including the step of f. discarding a brightness-setting waveform corresponding to a brightness level substantially equal to but not identical to the minimum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and g. selecting from the remaining brightness-setting waveforms for controlling the pixels of the display unit.
Claim 31
Dependent Claim
57 words
The method of claim 26, further including the steps of g. discarding a brightness-setting waveform corresponding to a brightness level substantially equal to but not identical to the maximum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and i. selecting from the remaining brightness-setting waveforms for controlling the pixels of the display unit.
Claim 32
Dependent Claim
32 words
The method of claim 25, including the steps of selecting A equal to 1 and B equal to 4, to provide brightness-setting waveforms 17 bits in length, and 18 possible brightness-setting waveforms.
Claim 33
Dependent Claim
106 words
The method of claim 24 wherein the step "e." further includes the steps of defining a second set of phase-placement patterns different from the first set; k. comparing a level of brightness to be produced at a next-to-be-displayed pixel to a level of brightness produced at a previously-displayed pixel; l. using the first set of phase-placement patterns with the next-to-be-displayed pixel when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are equal; and m. using the second set of phase-placement placement patterns with the next-to-be displayed pixel when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are unequal.
Claim 34
Dependent Claim
66 words
The apparatus of claim 25, wherein A 2 +B 2 +1 possible brightness-setting waveforms are defined, and further wherein a brightness-setting waveform is discarded which corresponds to a brightness level substantially equal to but not identical to the minimum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and the remaining brightness-setting waveforms are used for controlling the pixels of the display unit.
Claim 35
Dependent Claim
54 words
The apparatus of claim 30, further wherein a brightness-setting waveform is discarded which corresponds to a brightness level substantially equal to but not identical to the maximum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and the remaining brightness-setting waveforms are used for controlling the pixels of the display unit.
Claim 36
Independent Claim
214 words
A method for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce over a number of consecutive frames the perception of an image having more than six levels of brightness, comprising the steps of: a. defining a set of brightness-setting waveforms each having N bits, where N=A 2 B 2 , A and B are integers, A≠B, and wherein each brightness-setting waveform produces a different level of brightness when applied to a pixel of the display unit over a period of N frames, and each bit of brightness-setting waveform represents a different phase of the waveform; b. applying the brightness-setting waveforms to pixels of the display unit in accordance with a set of warp-around sequences, wherein each wrap-around sequence controls the application of a corresponding brightness-setting waveform to pixels of the display unit in groups of N consecutive pixels located in a predetermined block of pixels, so that in each group of N consecutive pixels a different non-consecutive phases of the brightness-setting waveform is applied to each pixel from one pixel to the next, and the location of a group of N consecutive pixels in a particular row is controlled to be offset by B-pixels from the relative location of a group of N consecutive pixels A-rows away.
Claim 37
Independent Claim
214 words
A method for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce over a number of consecutive frames the perception of an image having more than six levels of brightness, comprising the steps of: a. defining a set of brightness-setting waveforms each having N bits, where N=A 2 B 2 , A and B are integers, A≠B, and wherein each brightness-setting waveform produces a different level of brightness when applied to a pixel of the display unit over a period of N frames, and each bit of brightness-setting waveform represents a different phase of the waveform; b. applying the brightness-setting waveforms to pixels of the display unit in accordance with a set of warp-around sequences, wherein each wrap-around sequence controls the application of a corresponding brightness-setting waveform to pixels of the display unit in groups of N consecutive pixels located in a predetermined block of pixels, so that in each group of N consecutive pixels a different non-consecutive phases of the brightness-setting waveform is applied to each pixel from one pixel to the next, and the location of a group of N consecutive pixels in a particular row is controlled to be offset by B-pixels from the relative location of a group of N consecutive pixels A-rows away.
Claim 38
Dependent Claim
34 words
The method of claim 32 wherein step "a." further includes the step of selecting A and B so that an irregular rectangle is defined of A pixels in height and B pixels in length.
Claim 39
Dependent Claim
31 words
The method of claim 33 wherein step "b." further includes the step of d. sizing the predetermined block of pixels to be N pixels in length and N rows in height.
Claim 40
Dependent Claim
67 words
The method of claim 33 wherein step "b." further includes the step of d. defining a set of phase-placement patterns, each pattern of which is associated with a different brightness level and a corresponding brightness-setting waveform, wherein each phase-placement pattern is constructed of a wrap-around sequence; and e. applying the brightness-setting waveforms to the pixels of the display unit in accordance with the set of phase-placement patterns.
Claim 41
Dependent Claim
110 words
The method of claim 35 wherein step "e." further includes the step of g. defining a first set of predetermined phase-placement patterns and a second set of predetermined phase-placement patterns different from the first set, and h. comparing a level of brightness to be produced at a next-to-be-displayed pixel to a level of brightness produced at a previously-displayed pixel; i. using the first set of phase-placement patterns with the next-to-be-displayed pixel when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are equal; and j. using the second set of phase-placement patterns when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are unequal.
Claim 42
Dependent Claim
29 words
The method of claim 32, wherein 18 levels of brightness are provided and step "a." includes the step of setting A equal to one and B equal to 4.
Claim 43
Dependent Claim
75 words
The method of claim 32, wherein the brightness-setting waveform of N bits defines A 2 +B 2 +1 possible brightness-setting waveforms, the method further including the steps of g. discarding a brightness-setting waveform corresponding to a brightness level substantially equal to but not identical to the minimum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and h. selecting from the remaining brightness-setting waveforms for controlling the pixels of the display unit.
Claim 44
Dependent Claim
57 words
The method of claim 38, further including the steps of i. discarding a brightness-setting waveform corresponding to a brightness level substantially equal to but not identical to the maximum brightness level available from the A 2 +B 2 +1 brightness-setting waveforms, and j. selecting from the remaining brightness-setting waveforms for controlling the pixels of the display unit.
Claim 45
Independent Claim
213 words
An apparatus for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce over a number of consecutive frames the perception of an image having more than six levels of brightness, comprising: means for defining a set of brightness-setting waveforms each having N bits, where N=A 2 B 2 , A and B are integers, A≠B, and wherein each brightness-setting waveform produces a different level of brightness when applied to a pixel of the display unit over a period of N frames, and each bit of brightness-setting waveform represents a different phase of the waveform; means for applying the brightness-setting waveforms to pixels of the display unit in accordance with a set of warp-around sequences, wherein each wrap-around sequence controls the application of a corresponding brightness-setting waveform to pixels of the display unit in groups of N consecutive pixels located in a predetermined block of pixels, so that in each group of N consecutive pixels a different non-consecutive phases of the brightness-setting waveform is applied to each pixel from one pixel to the next, and the location of a group of N consecutive pixels in a particular row is controlled to be offset by B-pixels from the relative location of a group of N consecutive pixels A-rows away.
Claim 46
Independent Claim
213 words
An apparatus for controlling a digitally commanded display unit having pixels arranged in rows and columns to produce over a number of consecutive frames the perception of an image having more than six levels of brightness, comprising: means for defining a set of brightness-setting waveforms each having N bits, where N=A 2 B 2 , A and B are integers, A≠B, and wherein each brightness-setting waveform produces a different level of brightness when applied to a pixel of the display unit over a period of N frames, and each bit of brightness-setting waveform represents a different phase of the waveform; means for applying the brightness-setting waveforms to pixels of the display unit in accordance with a set of warp-around sequences, wherein each wrap-around sequence controls the application of a corresponding brightness-setting waveform to pixels of the display unit in groups of N consecutive pixels located in a predetermined block of pixels, so that in each group of N consecutive pixels a different non-consecutive phases of the brightness-setting waveform is applied to each pixel from one pixel to the next, and the location of a group of N consecutive pixels in a particular row is controlled to be offset by B-pixels from the relative location of a group of N consecutive pixels A-rows away.
Claim 47
Dependent Claim
31 words
The apparatus of claim 40 wherein the defining means A and B are selected so that an irregular rectangle is defined of A pixels in height and B pixels in length.
Claim 48
Dependent Claim
28 words
The apparatus of claim 41 wherein the predetermined block of pixels in the applying means is sized to be N pixels in length and N rows in height.
Claim 49
Dependent Claim
67 words
The apparatus of claim 42 wherein the applying means further includes means for defining a set of phase-placement patterns, each pattern of which is associated with a different brightness level and a corresponding brightness-setting waveform, wherein each phase-placement pattern is constructed of a wrap-around sequence; and means for applying the brightness-setting waveforms to the pixels of the display unit in accordance with the set of phase-placement patterns.
Claim 50
Dependent Claim
20 words
The apparatus of claim 40 wherein 18 levels of brightness are provided and A equals one and B equals 4.
Claim 51
Dependent Claim
115 words
The apparatus of claim 43 wherein the phase-placement patterning means has a first set of predetermined phase-placement patterns and a second set of predetermined phase-placement patterns different from the firsts set, and further including means for comparing a level of brightness to be produced at a next-to-be-displayed pixel to a level of brightness produced at a previously-displayed pixel, and for controlling the defining means to use the first set of phase-placement patterns with the next-to-be-displayed pixel when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are equal, and to use the second set of phase-placement patterns when the desired levels of brightness of the next-to-be-displayed and the previously-displayed pixels are unequal.
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