WO2000025291A1 - Procede d'adressage pour ecran a plasma base sur un adressage separe des lignes paires et impaires - Google Patents
Procede d'adressage pour ecran a plasma base sur un adressage separe des lignes paires et impaires Download PDFInfo
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- WO2000025291A1 WO2000025291A1 PCT/FR1999/002474 FR9902474W WO0025291A1 WO 2000025291 A1 WO2000025291 A1 WO 2000025291A1 FR 9902474 W FR9902474 W FR 9902474W WO 0025291 A1 WO0025291 A1 WO 0025291A1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/291—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
- G09G3/2022—Display of intermediate tones by time modulation using two or more time intervals using sub-frames
- G09G3/2033—Display of intermediate tones by time modulation using two or more time intervals using sub-frames with splitting one or more sub-frames corresponding to the most significant bits into two or more sub-frames
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
- G09G3/2022—Display of intermediate tones by time modulation using two or more time intervals using sub-frames
- G09G3/2029—Display of intermediate tones by time modulation using two or more time intervals using sub-frames the sub-frames having non-binary weights
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/296—Driving circuits for producing the waveforms applied to the driving electrodes
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0202—Addressing of scan or signal lines
- G09G2310/0216—Interleaved control phases for different scan lines in the same sub-field, e.g. initialization, addressing and sustaining in plasma displays that are not simultaneous for all scan lines
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0261—Improving the quality of display appearance in the context of movement of objects on the screen or movement of the observer relative to the screen
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0266—Reduction of sub-frame artefacts
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
Definitions
- the invention relates to an addressing method and device for a plasma panel based on separate addressing of the even lines and the odd lines.
- the gray level is not produced in a conventional manner from an amplitude modulation of the signal but from a temporal modulation of this signal, by exciting the corresponding pixel, more or shorter depending on the desired level. It is the phenomenon of integration of the eye which makes it possible to render this level of gray. This integration takes place during the frame scanning time. The eye actually integrates much faster than the frame duration and thus risks detecting, in cases of particular transition of the addressing bits, variations in level which do not reflect reality. Contouring defects or "contouring" according to the English name can thus appear on moving images. These defects can be compared to a poor temporal restitution of the gray level. More generally, false colors appear on the contours of objects, each of the cells of a color component may be subject to this phenomenon.
- the plasma cell has a trigger threshold which is not independent of the state of its immediate neighbors.
- a cell will be all the more easily excitable that its neighbors will be excited, we speak in fact of a phenomenon of priming.
- the barriers separating the different cells are not completely hermetic, a certain a number of free electrons from excited neighboring cells promote excitation of the addressed cell.
- This priming problem is in fact amplified by the non-uniformity of the panel. It is always possible, to encourage the excitation of the cells to vary the control voltages, but this becomes impossible when the glass slabs do not have the same spacing, for example, over the entire panel. In this case, the compromise found at the level of the control voltages does not make it possible to optimize the ignition of all the cells.
- the plasma panel unlike the cathode ray tube has a linear response, that is to say that the level of luminance emitted is strictly proportional to the video level.
- Today's visualization systems are largely based on the use of cathode ray tubes. It is then carried out at the level of the shooting, an operation of a priori compensation for the response of the cathode ray tube. In order to be able to correctly visualize such a signal on a plasma panel, it is therefore necessary to perform the reverse correction (gamma correction) in order to obtain real information in the end.
- Figure 1 shows the shape of the compensation curve 1 of the response of a tube to the emission, the abscissa axis representing the video input level and the ordinate axis representing the video output level after correction.
- Curve 2 corresponds to a linear response obtained after application of the correction as shown in 3.
- the object of the invention is to solve the cited drawbacks.
- the subject of the invention is a method for addressing cells arranged according to a matrix table, each cell being located at the intersection of a row and a column, the table having row and row entries.
- the column inputs each receiving a command word from this column corresponding to the relative video word, for this column, to an addressed line, this word being composed of n bits transmitted sequentially, each sequence corresponding to a sub - scanning, each bit triggering or not, depending on its state, the ignition of the cell of the addressed line and of the column receiving the control word, for a time proportional to the weight of this bit in the word, characterized in that 'the column control words are coded differently depending on whether the word relates to an even or odd line, this difference consisting in that at least m successive bits of determined ranks have different weights from a control word to the other, the sum of the weights of these bits remaining identical from one control word to the other, in order to obtain writing times which are substantially different from one line to the next.
- the writing is simultaneous on two successive lines for at least the first bit of the m successive bits of a control word relating to one of the two lines.
- At least two successive lines are simultaneously selected for at least one of the bits of the column control words whose weight is common from one control word to the other.
- at least one of the bits of identical weight from one control word to the other is used to code a partial luminance value common to two successive lines and the writing is simultaneous on these lines for this bit of the command word relating to one of the two lines,
- the method is implemented for a limited number of rows of the matrix table, these rows corresponding to the areas of the image defined by the video signal having strong vertical transitions, the other areas exploiting sub-scans corresponding to an addressing method for which the column control words have all the identical weights from one line to another.
- the method is implemented for images having strong vertical transitions, the other images using an addressing method for which the column control words have all the identical weights from one line to another.
- the switching from the first addressing method comprising n subscans to a second addressing method comprising a greater number of subscans and for which the column control words have a greater number of bits having weights identical from one line to another is carried out by replacing the selection of a line I when writing a bit of different weight on line I, in the first method, by selecting line I and the immediately preceding or immediately following line for a simultaneous writing on these two lines, in the second method.
- the invention also relates to a device for implementing the above method comprising a video processing circuit for processing the video data received, a correspondence memory for transcoding this data, a video memory for storing the transcoded data, the video memory being connected to column supply circuits for controlling the column addressing of the plasma panel from column control words, a line supply circuit control circuit connected to the video processing circuit for selecting the lines , characterized in that the video processing circuit and the transcoding circuit carry out a different coding of the column control words according to whether the word relates to an even or odd line, this difference consisting in that at least m successive bits of determined ranks among the bits to be transmitted have different weights from one control word to another, l a sum of the weights of these bits remaining identical from one control word to another, in order to obtain writing instants which are substantially different from one line to the next.
- the device is characterized in that the control circuit for the line supply circuits simultaneously selects two consecutive lines during the transmission by the column supply circuits of the first bit of the successive bits of a word of command relating to one of the two lines.
- the device is characterized in that it also comprises a selection circuit receiving the video data for selecting a coding of the column control words corresponding to an addressing according to n sub-scans or to an addressing corresponding to a number higher of sub-scans according to the variations in luminance from one line to another of an image.
- the addressing method according to the invention consists in separating the addressing of the even rows from that of the odd rows using a different coding of the column control words.
- the writing instants from line to line the other, for certain bits of the control words, are significantly different.
- This process allows partial and variable copying of video information from one line to the other. We can thus play on the compromise between the number of underscans / loss of vertical resolution. It is then possible, depending on the content of the video, to modify, for each of the pairs of lines, the number of sub-scans and therefore therefore the maximum difference allowed between two luminance values allowing an error lower than the LSB. Thanks to the invention, the contouring effects are eliminated or at least greatly reduced, the quantification of the low levels is improved.
- FIG. 1 a compensation curve for the response curve of a cathode ray tube
- FIG. 4 a principle for scanning a plasma panel according to the invention
- FIG. 5 a timing diagram for the writing of two consecutive lines according to the invention for bits of column control words having different weights
- FIG. 8 an example of writing on two consecutive lines for bits of column control words having different weights
- a plasma panel consists of two glass slabs separated by a hundred microns. This space is filled with a gas mixture containing neon and xenon. When this gas is electrically excited, the electrons gravitating around the nuclei are extracted and become free.
- the term "plasma" designates this gas in the excited state.
- On each of the two panels of the panel are screen-printed line electrodes for one panel and column for the other panel. The number of row and column electrodes corresponds to the definition of the panel.
- a barrier system is put in place to physically delimit the cells of the panel and limit the phenomena of diffusion from one color to the other. Each crossing of a column electrode and a row electrode will correspond to a video cell containing a volume of gas.
- a cell will be called red, green or blue depending on the phosphor deposit with which it will be covered.
- a video pixel being composed of a triplet of cells (one red, one green and one blue), there are therefore three times more column electrodes than pixels on a line.
- the number of line electrodes is equal to the number of lines on the panel. Given this matrix architecture, it suffices to apply a potential difference to the crossing of a line electrode and a column electrode in order to excite a precise cell and thus occasionally obtain a gas in the plasma state.
- the UV rays generated during the excitation of the gas will bombard the red, green or blue phosphors and thus give a lit red, green or blue cell.
- a line of the plasma panel is addressed as many times as there are defined sub-scans in the gray level information to be transmitted to the pixel, as explained below.
- the selection of the pixel is carried out by the transmission of a voltage called recording pulse, via a supply circuit, along the entire line corresponding to the selected pixel while the information corresponding to the value at the level of gray of the selected pixel is transmitted in parallel on all the electrodes of the column on which the pixel is located. All the columns are fed simultaneously, each of them with a value corresponding to the pixel of this column.
- Each bit of information of a gray level is associated with time information which therefore corresponds to the ignition time of the bit or more generally to the time between two inscriptions: a bit of weight 4 with the value 1 will thus correspond to an ignition of the pixel for a duration 4 times greater than an ignition corresponding to the bit of weight 1.
- This holding time is defined by the time separating the writing top from an erasing top and corresponds to a holding voltage which precisely helps maintain the excitement of the cell after addressing.
- the panel will be scanned n times to transcribe this level, each of these subscans having a duration proportional to the bit that it represents.
- the eye converts this "global" duration corresponding to the n bits into an ignition level value.
- a sequential scan of each of the bits of the binary word is therefore carried out by applying a duration proportional to the weight.
- the addressing time of a pixel, for a bit is the same regardless of the weight of this bit, what changes is the ignition hold time for this bit.
- a cell therefore has only two states: excited or not excited. Therefore, unlike CRT, it is not possible to achieve analog modulation of the level of light emitted. To account for the different gray levels, a time modulation of the cell transmission time in the frame period (called T) must be carried out.
- This frame period is divided into as many sub-periods (sub-scans) as there are video coding bits (number of bits called n). From these n sub-periods, we must be able by combination to reconstruct all the gray levels between 0 and 255. The eye of the observer will integrate these n sub-periods over a frame period and thus recreate the desired gray level .
- a panel is made up of NI rows and Ne columns supplied by NI line supply circuits and Ne column supply circuits. The generation of the gray levels by time modulation requires addressing the panel n times for each pixel of each line. The matrix aspect of the panel will allow us to simultaneously address all the pixels on the same line by sending an electrical pulse of Vccy level to the line supply circuit.
- the signals transmitted on the columns are called column control words and relate to the video signal to be displayed, this relationship being for example a transcoding function of the number of bits used.
- On each of the columns will be present the video information corresponding to the bit of this column control word addressed at this time (corresponding to a sub-scan), it will be materialized by an electrical pulse of "binary" amplitude 0 or Vccx (translating the state of the coded bit).
- Vccx and Vccy at each electrode crossing will cause or not an excitation of the cell. This excitation state will then be maintained over a period proportional to the weight of the underscan performed. This operation will be repeated for all the lines (NI) and for all the addressed bits (n).
- nx NI lines during the duration of the frame, hence the following fundamental relationship: where tad is the time required to address a line.
- a sequencing algorithm makes it possible to address all the lines n times while respecting the respective weight of the sub-scanning carried out between each addressing.
- the abscissa axis represents time and is divided into frame periods of duration T. Each frame period is divided into sub time periods, the duration of which is proportional to the weight of the different sub-scans, thus making it possible to define a level video to be displayed on the plasma screen, (1, 2, 4, 8 ..., 128) for a quantized video on 8 bits and an addressing having 8 sub-scans.
- the ordinate axis represents the level 0 or 1 of the addressing bits during the corresponding frame periods, in other words the off or on state of a cell as a function of time, for a given coding level.
- Curve 5 corresponds to an encoding of the value 128, curve 6 to an encoding of the value 127 and curve 7 to an encoding of the value 128 during the first frame and of the value 127 during the second frame and vice versa for the two subsequent frames.
- the 8 sub-scans being distributed over the 20 ms of the frame, the eye by integrating the video asynchronously, reveals black areas, the part b of the curve 7 corresponding to a level 0 for the duration of two frames successive, and white areas, the part a of the curve 7 corresponding to a level 1 for the duration of two successive frames.
- the contouring phenomenon manifests itself particularly in moving areas where there are strong transitions (contours of objects) or more generally switches at the level of the most significant in the coding of this video. In the case of a color screen, this takes the form of the appearance on the panel, at these contours, of "false colors" due to an incorrect interpretation of the RV B triplet. This phenomenon is therefore linked to the temporal modulation system of the level of the video and to the fact that the eye in its role of integrator reveals incorrect contours.
- One solution to this problem consists in coding the gray level to be transmitted on more bits than is theoretically necessary (8 for coding 256 levels) and thus defining more sub-scanning to better distribute the information in time.
- the respective weights of the sub-scans are reduced, the problems during their switching are limited.
- a transcoding of the gray level will be for example: 1 2 4 8 16 32 32 32 64 64.
- the highest weights can therefore be 64 instead of 128. This solution is however applied to the detriment of the image quality, the resolution being limited accordingly.
- FIG. 3 A sequencing algorithm according to the prior art is shown in FIG. 3 and is exposed below in order to facilitate the understanding of the invention, by exposing the differences compared to this prior art.
- This sequencing algorithm is known by the English name Simultaneous Addressing Scanning or SAS, that is to say scanning with simultaneous addressing. It makes it possible to address all the lines n times (corresponding to the number n of bits) while respecting, between each addressing, the duration corresponding to the weight of the bit relating to this addressing. Each of the lines is addressed for each of the sub-scans in a defined order as shown in FIG. 3 for a system with 4 sub-scans.
- the horizontal axis represents time t and the vertical axis the line number.
- the periods corresponding to the different sub-scans SB0 to SB3 are indicated for the bits 0 to 3 of column control words defining the luminance value to be displayed.
- the display time in fact the holding time after registration, is a function of the weight of the bits of this control word.
- These durations are represented, for each of the bits 0 to 3, by two lines in solid oblique lines respectively framing each of the mentions SBO to SB3, for example the holding duration referenced 8 for the subscanning SB3.
- the shaded areas 9 and 11 correspond to the scanning of the previous frame and the next frame and the intermediate area 10 corresponds to the scanning of the current frame.
- the intersections with the oblique lines successively represent the beginnings of registration relating to the sub-scans SB3, SB2, SB1 and SBO of the same frame ( in this example) which reported on the ordinate axis correspond to line numbers l 3 , l 3 +1, l 3 +2, l 3 +3, for example 100 and the following lines 101, 102 and 103 for SB3 , l 2 , l 2 +1, l 2 +2, l 2 +3 for SB2, etc ...
- These addressing of 4 times 4 lines takes place during a time interval dt.
- the next moment will write lines 104, 105, 106, 107 for SB3 and so on.
- Figure 4 shows how, in time, the 2 addressing algorithms are nested. Everything happens as if we had in this case 8 sub-scans, each applying to a line parity only (even or odd).
- the solid oblique lines correspond to the sub-sweeps SBO to SB3 and the dotted oblique lines to the sub-sweeps SB'O to SB'3. For example at time t, the line addressed for the underscan
- SB3 is an even line l 3 (in fact the group of four successive even lines l 3 , l 3 +2, l 3 +4, l 3 +6)
- the line addressed for the subscanning SB'2 is a line odd the 2 (in fact the group of four odd lines the 2 , the 2 + 2 , the 2 + 4, the 2 , + 6) and so on for the other sub-scans at this time t .
- the even line l 3 is written at time t
- the addressing separation system for lines I and 1 + 1 therefore implies that the addressing times for these lines are different. Consequently, when addressing line I, we are in a maintenance phase on line i + 1. It is in fact possible to erase lines I and 1 + 1 at this instant and to write the same video information on the 2 lines as explained below. Similarly, it is possible to enter the information only on line I, in this case the maintenance phase of line 1 + 1 will not be disturbed.
- the nesting of the sub-scans SB 'in the sub-scans SB can be entirely arbitrary and it is not necessary that any correlation exists between the instants of sub-scanning of these two types (sub-scans of SB type for even lines and SB 'type underscan for odd lines).
- the maintenance times can be completely decorated and depend only on the bit weights of the column control words which will be assigned to each type of underscan.
- the weights of the column control words can be chosen different for the subscanning SB and for the subscanning SB '.
- FIGS. 5 and 6 represent timing diagrams of two successive lines I and 1 + 1 and the writing instants W for these lines.
- Line 1 + 1 is controlled by a nested subscanning SB 'as indicated above.
- T'1 represents the corresponding sub-sweep holding time
- FIG. 5 The diagram of FIG. 5 is to be compared to that of FIG. 4.
- the write orders are specific to a single line, the durations of the subscans are independent from one line to another.
- a line 13 we start the sub-scanning SB3 which is preceded by the sub-scanning SB2.
- the next line 13 + 1 we are, at this instant t, in the course of a sub-scan SB'2 which overlaps the sub-scan SB2 and the sub-scan SB3, as it appears in FIG. 5.
- FIG. 6 no longer refers to FIG. 4 and gives, in general, the principle of the invention using a nested scan.
- the first timing diagram corresponds to line I and represents 4 successive sub-scans Sb1 to Sb4 of holding time t1 to t4.
- the second timing diagram corresponds to the line 1 + 1 and represents 4 successive sub-scans Sb'1 to Sb'4 of holding time t'1 to t'4.
- the holding time T2 is split into two periods t1 and t2 and the holding time T3 in two periods t3 and t4.
- the addition of the write signal makes it possible to split the holding time T'2 into two periods t'2 and t'3.
- variable parameter that can be defined according to the video content.
- the big advantage of this method is that you can easily switch from a 16 sub-scan mode to a 13 sub-scan mode (see example given below) from one frame to another and without transition cycle.
- the adaptation can therefore be made according to the content of the sequence and even according to the content of the image.
- a vertical resolution measurement system can be used to make a decision on the number of subscans to use.
- the method even makes it possible to switch from a couple of lines to another, from a 13 to 16 sub-sweep mode.
- the decision information can be calculated for each pair of lines.
- the coding of a gray level according to this principle is carried out taking into account not only the luminance value of the selected pixel but also the luminance value of the pixel located on the adjacent row for the same column.
- the column control word for a given pixel, is separated into two parts, a first control word corresponding to a value common to the two pixels and a second and third control word corresponding to the specific values of the pixels.
- ni + n2 + n3 2 x (number of sub-scans per line ). If we consider a given number of subscans, the number of subscans relating to the coding bits of the two specific values and of the common value, which is ni + n2 + n3, must correspond to that of the sub-scans carried out in a conventional manner and relating to the coding bits for the line I and to the coding bits for the line 1 + 1.
- ni, n2, n3 are not fixed. It is possible to adjust the relationship between the definition of specific values and that of the common value. The loss of resolution linked to coding will be all the smaller the better the specific values are defined. On the other hand, the total number of sub-scans will be all the higher as the specific values are the least well defined. There is therefore a compromise to be found between the loss of resolution on the one hand and the minimization of the viewing faults on the other.
- the calculation of specific values is carried out as follows:
- VS1 - VS2 must be equal to NG1 - NG2 (always to have a zero coding error).
- D this difference between NG1 and NG2
- ⁇ is a parameter to be defined in the same way as ni, n2, n3.
- This value ⁇ is the result of algorithmic tests and is therefore partially determined empirically.
- the value is chosen according to the induced calculations, for example the value 3/16 facilitating the calculations by the digital signal processor DSP (Digital Signal Processing in English).
- the difference D between the gray values is coded from the nearest multiple of 5 of this value D.
- the specific values VS1 and VS2 are multiples of 5 and the proportion of the specific value compared to the global value (the parameter ⁇ ) is chosen equal to 3/16.
- the value of VS1 is thus the modulo 5 value closest to 60 x 3/16.
- the specific value which contains the difference information between the two coded pixels, is only defined on a restricted number of bits.
- the maximum difference that can be coded will therefore be limited in fact to the maximum value that can be coded as a specific value. This will therefore prevent us from coding large differences.
- the difference that can be coded being limited, one of the specific values will be equal to the maximum value and the other will be equal to 0.
- the common value will be determined so as to minimize the error on the final value. In this case, the final error may be greater than 1.
- n3 12 (code 1, 2,4,6,9,12,15,19,23,27,31, 36)
- FIG. 7 shows such addressing with 16 sub-scans.
- the writes referenced 14 are common to lines I and 1 + 1, for the values 9, 15, 12.
- the entries referenced 15 are specific to lines I and 1 + 1 and relate to the values 10, 20.
- the 16-bit code above corresponds to the weight of the bits of the column control words calculated from the video information: 1 24 56 9 10 12 15 19 20 23 27 31 35 36
- each video information is separated into information specific to the current line I and information common to the 2 adjacent lines I and 1 + 1.
- the specific information is coded on 4 bits whose respective weights are multiples of 5 (5,10,20,35).
- the common information is coded on 12 bits.
- the principle of nesting of the sub-scans makes it possible to increase the value of this maximum difference from which the errors are no longer negligible, which is particularly useful when the vertical resolution (difference in luminance) is large. It makes it possible to pass dynamically from 16 sub-scans (10 sub-scans common to two lines and 4 separate sub-scans) to 13 sub-scans. First of all, the respective order of the different sub-scans is modified as follows:
- This order defines the rank of the bits of the transmitted control words, represented by their weight.
- the first 4 sub-scans (1, 2, 4, 6) are always common to the 2 adjacent lines.
- the sub-scans 5 and 10 and also 20, 35 are themselves always specific to the lines I and 1 + 1 (we therefore always have 2 different pieces of information for these sub-scans).
- 3 sub-scans (9, 15, 12) two cases are possible: either they are common to the 2 lines (and we then return to addressing 16 sub-scans) or they are partially specific (addressing 13, 14 or 15 sub-scans).
- FIG. 8 shows such addressing with 13 sub-scans.
- On line I there are successive sub-scans corresponding to bits of weight 10, 24, 12, 20.
- the entries referenced 16 are common to lines I and 1 + 1, for the values 9 and 24.
- the entries referenced 17 are specific to lines I and 1 + 1 and relate to the values 10, 20, 12 and 27.
- c ' is the entry relating to the sub-scan 9 which is common but the line I is not erased at the end of the maintenance cycle. If there is no erasure, the information entered remains present which implies that the video information which for weight 9 on line 1 + 1 has a different weight (24) on line I.
- line 1 + 1 is deleted at the end of the weight cycle 9.
- the video content of the sub-scan 12 is then written on line I.
- sub-scanning 15 of line 1 + 1 actually lasts 27 (15 + 12).
- An erasure signal common to lines I and 1 + 1 is then made before writing the video information corresponding to the specific values of weight 20.
- sub-scans 19, 23, 27, 31, 36 of an address 16 sub-scans can be transformed into 3 sub-scans 42, 58, 36 for the line I and 19, 50, 67 for line 1 + 1.
- the only constraint is that the video information of the sub-scan 42 of the line I is the same as that of the sub-scan 19 of the line 1 + 1.
- the column control words were coded on 16 bits and, depending on the weight of the bits, the lines were addressed separately or 2 by 2.
- the scanning times for writing the 2 bits, for which the lines were addressed 2 by 2, were therefore divided by 2, reducing the scanning time to that of a column control word of 10 bits (4 + 12/2).
- the column control words are coded on 13 bits, bits being common to two successive lines.
- These column control words have bits of different weight depending on whether the line considered is an even or odd line.
- the weights of the 13-bit column control words (13 subscans) are:
- the weights of the rank bits 7 and 8 have the same sum 36.
- the weights of the rank bits 10, 11, 12 have the same sum 136.
- the lines are addressed 2 by 2, in the example, for the weights: 1, 2, 4, 6, 9 or 24, 19 or 42 (depending on the column command word considered).
- the lines are addressed separately for the weights 5, 10, 20, 35.
- the lines are addressed separately for the weight (15 + 12), (23 + 27), (31 + 36).
- the lines are addressed separately for the weight 12, (27 + 31), 36.
- This switching which corresponds to the transition from an addressing in accordance with FIG. 8 to an addressing in accordance with FIG. 7, is carried out in a simple manner, by replacing the selection of a line I (or of a line 1 + 1) during writing a bit of different weight on line I (or 1 + 1) by selecting line I and the immediately next (or previous) line for simultaneous writing on these two lines.
- This number of sub-scans is related to the number of bits having different weights of a column control word corresponding to one line to the column control word corresponding to the next line and this number, therefore the column control words used for the coding of the image, can be chosen according to the images to be processed, this choice being able to be carried out image by image.
- the weight of the bits concerned can be chosen according to the resolution of the image.
- the line 1 + 1 can benefit from the possible state of excitation of the lines I and I + 2, these not having been extinguished just before. In fact it is possible to benefit from all the sub-scans of all the lines of this system.
- FIG. 9 An exemplary embodiment of the device implementing the scanning method is described below.
- the simplified diagram of the control circuits of a plasma panel 18 is shown in FIG. 9.
- the digital video information arrives at the input E of the device which is also the input of a microprocessor-based video processing circuit 19 and the input of a selection circuit 20.
- the video processing circuit is connected to a correspondence memory 21, at the selection circuit 20, at the input of a video memory 22 and at a scanning generator or control circuit for the line supply circuits 24.
- the video memory transmits the stored information to the input of a circuit 23 grouping the column supply circuits.
- the scan generator 24 transmits synchronization information to the video memory 22 and controls a circuit 25 grouping together the line supply circuits.
- the video information coded on 8 bits and received on the input E is thus transmitted to the selection circuit 20 which stores the video data on a complete image.
- This circuit analyzes the content of the video and calculates the number of times that there is, in the image, a difference in luminance between line I and line 1 + 1 greater than a preset threshold.
- the scanning is carried out by exploiting the principle of nesting of the sub-scans, that is to say from an addressing with 13 sub-scans. Otherwise, 16 sub-scans are performed.
- the information relating to the type of scanning is transmitted to the processing circuit 19 which codes the video information accordingly.
- the processing circuit transmits this information to the scanning circuit 24 so that it scans the screen as a function of this coding.
- the processing circuit 19 exchanges the video data with the memory or correspondence table 21 which, depending on the values of the video words sent as addresses, will supply as data words corresponding to 13 or 16 bit codes whose weights will have previously been defined.
- This transcoding from the correspondence table 21 is defined as a function of the addressing mode used.
- the 13-bit coded words correspond to two types of coding which are differentiated by the bit weight of the coded words:
- a first type of coding providing a first coding word corresponding to the even lines of the plasma panel
- the scanning generator 24 performs, for the duration of a frame and by means of the line supply circuits 25, the line scanning of the screen.
- This circuit 25 supplies the addressing voltage and also the holding voltage for the duration corresponding to the sub-scanning relating to the weight of the bit sent to the columns for this addressing.
- the scan generator 24 performs the sub-scans based on the commands received from the processing circuit.
- Switching from a 13 sub-scan mode to a 16 sub-scan mode is very simple by selecting lines 21 and 21 + 1 instead of the single line 21 or the only line 21 + 1 when writing the bits corresponding to the common value VC.
- the selection circuit 20 can very well be placed upstream of the device and in particular of the processing circuit in order to avoid any delay in the coding of the video words.
- the previous description assumed a line selection of the plasma panel for transmission of video information on the column inputs of the display, but other types of addressing could be envisaged, for example by reversing the function rows and columns without the method departing from the scope of the invention.
- the invention is not limited by the number of bits quantifying the digital video signal to be displayed, nor the number of sub-scans.
- the cells of this device or matrix table with row and column entries can be cells of plasma panels but also micromirrors of circuits with micromirrors. Instead of emitting light directly, these micromirrors reflect, in a punctual manner (a cell corresponding to a micromirror), a light received, when they are selected. Their addressing for selection is then identical to the addressing of the cells of the plasma panels as described in the present application.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Power Engineering (AREA)
- Plasma & Fusion (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Transforming Electric Information Into Light Information (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020017005000A KR20010080280A (ko) | 1998-10-23 | 1999-10-13 | 개별적인 짝수 번호 및 홀수 번호 라인 어드레싱에기초하는 플라즈마 디스플레이 패널을 위한 어드레싱 방법 |
JP2000578801A JP2002528772A (ja) | 1998-10-23 | 1999-10-13 | 偶数番号ラインと奇数番号ラインの別々のアドレスに基づくプラズマスクリーンのアドレス方法 |
DE69902402T DE69902402T2 (de) | 1998-10-23 | 1999-10-13 | Adressierverfahren und plasmaanzeige basierend auf separaten gerade und ungerade numerierten linienadressen |
EP99947562A EP1131810B1 (fr) | 1998-10-23 | 1999-10-13 | Procede d'adressage pour ecran a plasma base sur un adressage separe des lignes paires et impaires |
AU60963/99A AU6096399A (en) | 1998-10-23 | 1999-10-13 | Addressing method for plasma display panel based on separate even-numbered and odd-numbered line addressing |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR98/13314 | 1998-10-23 | ||
FR9813314A FR2785076B1 (fr) | 1998-10-23 | 1998-10-23 | Procede d'adressage pour ecran a plasma base sur un adressage separe des lignes paires et impaires |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000025291A1 true WO2000025291A1 (fr) | 2000-05-04 |
Family
ID=9531918
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1999/002474 WO2000025291A1 (fr) | 1998-10-23 | 1999-10-13 | Procede d'adressage pour ecran a plasma base sur un adressage separe des lignes paires et impaires |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP1131810B1 (fr) |
JP (1) | JP2002528772A (fr) |
KR (1) | KR20010080280A (fr) |
CN (1) | CN1157704C (fr) |
AU (1) | AU6096399A (fr) |
DE (1) | DE69902402T2 (fr) |
FR (1) | FR2785076B1 (fr) |
WO (1) | WO2000025291A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7847771B2 (en) | 2005-05-11 | 2010-12-07 | Hitachi Displays, Ltd. | Display device capable of adjusting divided data in one frame |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2802010B1 (fr) * | 1999-12-06 | 2002-02-15 | Thomson Multimedia Sa | Procede d'adressage de panneau d'affichage au plasma |
FR2826767B1 (fr) * | 2001-06-28 | 2003-12-12 | Thomson Licensing Sa | Procede d'affichage d'une image video sur un dispositif d'affichage numerique |
EP1376521A1 (fr) * | 2002-06-28 | 2004-01-02 | Deutsche Thomson Brandt | Traitement d'images vidéo pour la compensation améliorée de l'effet de faux contours dynamique |
JP4768344B2 (ja) * | 2005-05-11 | 2011-09-07 | 株式会社 日立ディスプレイズ | 表示装置 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0698874A1 (fr) * | 1994-07-25 | 1996-02-28 | Texas Instruments Incorporated | Méthode pour réduire l'artefact temporel dans des systèmes vidéo numériques |
JPH08248916A (ja) * | 1995-03-07 | 1996-09-27 | Oki Electric Ind Co Ltd | 直流型プラズマディスプレイの駆動方法 |
EP0762373A2 (fr) * | 1995-08-03 | 1997-03-12 | Fujitsu Limited | Panneau d'affichage à plasma, méthode de commande de mise en oeuvre d'un balayage entrelacé, et appareil d'affichage à plasma |
-
1998
- 1998-10-23 FR FR9813314A patent/FR2785076B1/fr not_active Expired - Fee Related
-
1999
- 1999-10-13 AU AU60963/99A patent/AU6096399A/en not_active Abandoned
- 1999-10-13 EP EP99947562A patent/EP1131810B1/fr not_active Expired - Lifetime
- 1999-10-13 CN CNB998124699A patent/CN1157704C/zh not_active Expired - Fee Related
- 1999-10-13 WO PCT/FR1999/002474 patent/WO2000025291A1/fr active IP Right Grant
- 1999-10-13 JP JP2000578801A patent/JP2002528772A/ja active Pending
- 1999-10-13 DE DE69902402T patent/DE69902402T2/de not_active Expired - Fee Related
- 1999-10-13 KR KR1020017005000A patent/KR20010080280A/ko active IP Right Grant
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0698874A1 (fr) * | 1994-07-25 | 1996-02-28 | Texas Instruments Incorporated | Méthode pour réduire l'artefact temporel dans des systèmes vidéo numériques |
JPH08248916A (ja) * | 1995-03-07 | 1996-09-27 | Oki Electric Ind Co Ltd | 直流型プラズマディスプレイの駆動方法 |
EP0762373A2 (fr) * | 1995-08-03 | 1997-03-12 | Fujitsu Limited | Panneau d'affichage à plasma, méthode de commande de mise en oeuvre d'un balayage entrelacé, et appareil d'affichage à plasma |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 097, no. 001 31 January 1997 (1997-01-31) * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7847771B2 (en) | 2005-05-11 | 2010-12-07 | Hitachi Displays, Ltd. | Display device capable of adjusting divided data in one frame |
Also Published As
Publication number | Publication date |
---|---|
FR2785076A1 (fr) | 2000-04-28 |
AU6096399A (en) | 2000-05-15 |
EP1131810B1 (fr) | 2002-07-31 |
DE69902402T2 (de) | 2003-01-09 |
DE69902402D1 (de) | 2002-09-05 |
JP2002528772A (ja) | 2002-09-03 |
CN1157704C (zh) | 2004-07-14 |
FR2785076B1 (fr) | 2002-11-15 |
KR20010080280A (ko) | 2001-08-22 |
CN1324477A (zh) | 2001-11-28 |
EP1131810A1 (fr) | 2001-09-12 |
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