EP0445562A1 - Method of adapting a videotex display to a telematic terminal - Google Patents

Abstract

Method of adapting intended to permit information processed according to the CEPT 1 standard to be displayed on a telematic terminal of the type provided for application of the CEPT 2 standard. This method provides translation of the colours of one palette according to the CEPT1 standard into one of the colours of another palette according to the CEPT2 standard, as a function of the luminance of the colours of the first palette, an approximation of the CEPT 1 alphanumeric character matrices until a matrix according to the CEPT 2 standard is obtained and transcription of the change in coloration of an animated image by flicking from one colour to another for each of the individually coloured alphanumeric or graphic elements involved in the image in question.

Description

The invention relates to a videotex display adaptation method for a telematic terminal.

It is more particularly intended to allow the display of information processed according to the CEPT 1 standard of the European Conference of Postal and Telecommunications Administrations on a videotex terminal extrapolated from a terminal capable of processing information arranged according to the CEPT 2 standard, called Teletel.

In the absence of universally adopted standards in the field of videotex, manufacturers have had to build terminals of which a part of the constituent elements are specifically adapted to one or other of the possible standards, such as for example the controllers of these terminals, the software and possibly the memories containing this software.

However, the coexistence of different standards has drawbacks, in particular in terms of costs, when the material in question is intended to have a large commercial distribution and therefore consequently possibilities of low cost price are desired.

This led the promoters of the CEPT 2 standard to offer relatively reduced operating possibilities visually, if we compare them to those provided by the CEPT 1 standard and in particular with the variant that constitutes the FTZ 157D2E standard, called also BTX, from the German organization Fernmeldetechnisches Zentralamt, with the counterpart of a lower cost of the necessary terminals.

However, the wealth of operational possibilities that the CEPT 1 standard can offer, if it is necessary or desirable for certain applications, is not essential.

It can therefore be interesting in terms of production, marketing and operation to have a videotex terminal, capable of processing information according to the CEPT 1 standard, which is extrapolated from a conventional terminal, less rich in potential, but also less expensive.

The present invention therefore proposes an adaptation method intended to allow the display of information processed according to the CEPT 1 standard on a telematics terminal extrapolated from a videotex terminal capable of processing information arranged according to the CEPT 2 standard.

• une traduction des couleurs d'une première palette prévue selon la norme CEPT 1 en une des couleurs d'une seconde palette prévue selon la norme CEPT 2, en fonction de la luminance de ces couleurs de première palette, ces dernières étant réparties en fonction de leurs luminances dans l'une ou l'autre des parties qui divisent la première palette en autant de parties équivalentes qu'il y a de couleurs dans une seconde palette, de manière à traduire par une même couleur de seconde palette les différentes couleurs relevant d'une même partie;
• une approximation des matrices de caractère alphanumérique par élimination périodique d'une ligne et/ou une colonne de pixels d'une matrice, dite de base, jusqu'à obtention d'une matrice selon la norme CEPT 2, après adjonction ou retrait de pixels à la matrice initiale selon la norme CEPT 1, si nécessaire, pour obtenir cette matrice, dite de base, qui a même hauteur en pixels que la matrice selon la norme CEPT 2 et même largeur que la plus large des matrices selon la norme CEPT 1;
• une transcription de l'évolution de la coloration d'une image animée par basculement d'une couleur à une autre pour chacun des éléments alphanumériques et graphiques, individuellement colorés, concernés de l'image considérée.

According to a characteristic of the invention, this adaptation method comprises:

• a translation of the colors of a first palette provided according to the CEPT 1 standard into one of the colors of a second palette provided according to the CEPT 2 standard, as a function of the luminance of these colors of the first palette, the latter being distributed as a function of their luminances in one or other of the parts which divide the first palette into as many equivalent parts as there are colors in a second palette, so as to translate by the same color of the second palette the different colors belonging to 'the same game;
• an approximation of the matrices of alphanumeric character by periodic elimination of a row and / or a column of pixels from a so-called basic matrix, until a matrix according to the CEPT 2 standard is obtained, after adding or removing pixels to the initial matrix according to the CEPT 1 standard, if necessary, to obtain this so-called basic matrix which has the same height in pixels as the matrix according to the CEPT 2 standard and the same width as the widest of the matrices according to the CEPT 1 standard ;
• a transcription of the evolution of the coloring of an animated image by switching from one color to another for each of the alphanumeric and graphic elements, individually colored, concerned of the image considered.

The invention, its characteristics and its advantages are explained in the following description, in conjunction with the figures listed below.

Figure 1 shows a CEPT 2 conversion table of the colors to be displayed provided according to the CEPT 1 standard.

FIGS. 2A, 2B, 3A, 3B, 3C, 4A, 4B and 4C show three examples of adaptation of character matrices in accordance with the method according to the invention.

As indicated above, the method according to the invention is intended to make it possible to use the information provided by screen images in CEPT 1 standard by means of a videotex terminal capable of interpreting the display indications provided for these images. in order to make them readable on a compatible terminal, extrapolated from a CEPT 2 videotex terminal, less rich in construction in display possibilities, without loss of significant information for the images coming from at least a certain number of servers.

The exploitation of the possibilities of videotex terminals, as well as that of personal computers or not, depends on the real needs of the users who in a certain number of cases do not have the use of some of the functionalities offered by the devices whose have. For example, it is not essential to have a display on a color screen for consulting an alphanumeric database, such as a telephone directory, even if such a screen is likely to add some approval to its users.

Screen images intended for CEPT 1 videotex terminals are thus likely to include colors chosen from a first palette providing sixteen basic colors to which are added sixteen downloadable colors chosen from four thousand eighty sixteen, while only a palette of eight colors is available in CEPT 2 standard.

où L est la luminance de la couleur à reproduire, R étant la valeur fournie de sa composante rouge, V celle de sa composante verte et B celle de sa composante bleue.An adaptation is therefore necessary and it is carried out by taking into account the luminance of the color provided for in standard CEPT 1, this luminance being obtained by the application of a conventional formula, for example:

$\text{L = 0.3 * R + 0.59 * V + 0.11 * B}$

where L is the luminance of the color to be reproduced, R being the supplied value of its red component, V that of its green component and B that of its blue component.

The palette likely to be obtained in CEPT 1 standard is divided into eight parts equivalent to each of which is assigned one of the eight corresponding colors of the palette offered in CEPT 2 standard. Each color of the CEPT 1 standard is therefore translated by the color in CEPT 2 standard corresponding to the part in the range of luminance values from which there is its own luminance value.

This distribution is given in FIG. 1 and it is seen there that, for example the colors such as black, blue under normal or reduced intensity and red under normal intensity which are likely to be provided in standard CEPT 1 and which have a luminance between 0 and 27 are represented by black on a compatible videotex terminal, extrapolated from a CEPT 2 videotex terminal. Likewise magenta and yellow under reduced intensity which have a luminance between 28 and 59 and which are provided in CEPT 1 standard will be translated by red.

The possible flashing of the screen image which is provided in a plurality of different forms in CEPT 1 standard is simply translated in a unique manner.

The characters to be displayed from an image on the videotex terminal screen which can possibly be produced graphically like any other form are most often produced by means of character matrices of predetermined dimensions, in particular for reasons of reduction in the number of data to be transmitted and processed. Character matrices form rectangular cells, the dimensions of which are measured in pixels. According to the CEPT 1 standard, matrices of 12 * 10, 6 * 10, 5 * 10 and 12 * 12 are especially provided, the first digit corresponding to the width of the matrix in pixels and the second to its height, while CEPT 2 standard provides 8 * 10 matrices.

Consequently, an adaptation is made to obtain alphanumeric characters recognizable on a compatible videotex terminal, extrapolated from a videotex terminal from characters supplied in CEPT 1 standard, even if the differences in dimensions in pixels of the matrices prevent reproduction by 'identical.

To this end, as the examples shown in FIGS. 2A, 2B, 3A, 3B, 3C, 4A, 4B and 4C show, an approximation is made so as to subtract and / or possibly add pixels to restore the information. alphanumeric to display despite the change in matrix size, sometimes at the cost of a slight distortion of certain characters.

A first approximation is made by periodically eliminating a row and / or a column of pixels of determined rank in order to reduce the size of the matrix
supplied in CEPT 1 standard at the level provided for in CEPT 2 standard.

In the example presented in FIGS. 2A and 2B, the matrix on the left is assumed to be a matrix 12 * 10 type CEPT 1, called here basic, and by means of which the letter H is represented by two vertical lines, having a height of 10 pixels and a width of 2 pixels each, and by a horizontal bar, having a length of 6 pixels and a thickness of 2 pixels. The adaptation necessary for the representation of this H on an 8 * 10 CEPT 2 matrix is obtained by elimination of a column, or height, of pixels every "n" columns, with "n" here equal to 3, so that columns 1, 4, 7, 10 are eliminated and allow to simply obtain the representation of H shown in figure 2B .

A similar process is implemented for the transformation of an alphanumeric character produced in matrix 12 * 12 type CEPT 1 into a character displayed in matrix 8 * 10 CEPT 2, an elimination of a line, or length, of pixels every "m" columns then being carried out, "m" being for example equal to 5, so that the rows 6 and 12 are eliminated.

When the CEPT 1 character matrix is a 6 * 5 matrix, as shown in FIG. 3A, and the target representation matrix is an 8 * 10 CEPT 2 matrix, the necessary adaptation is obtained by a conversion corresponding to a first phase of extension of the initial matrix 6 * 5 into a basic matrix 12 * 10 which undergoes, in the second phase, the elimination of columns provided for the passage of a matrix 12 * 10 into a matrix 8 * 10 mentioned more high.

The extension planned in the first phase corresponds to the duplication of the number of pixels both in line and in column, as can be seen in FIG. 3B where the horizontal and vertical lines of the character "E" have doubled in size both in length as in thickness compared to those of the initial character "E", provided for a 6 * 5 matrix as presented in FIG. 3A.

Similarly if the CEPT 1 character matrix is a 6 * 10 matrix, as presented in FIG. 4A, the necessary adaptation will be obtained by a conversion corresponding to a first phase of extension of this 6 * 10 matrix into a 12 matrix. * 10 basic and in the second phase of elimination of columns already mentioned twice above.

The extension is carried out by duplicating the number of line pixels which leads to a widening of the character shown, as shown in Figure 4B in the case of a character "X". This enlargement is thereafter reduced during the phase corresponding to the passage from a matrix 12 * 10 to the matrix 8 * 10 by elimination of four columns chosen from twelve, for example as mentioned above, as well as the shows Figure 4C.

The CEPT 1 standard also provides for possible animation of the images which are likely to be displayed on the screen.
from a videotex terminal, this animation resulting in a progressive variation of the colors of an initial image, this applies in particular to the characters to be displayed for which an individual evolution of the coloring is possible.

To this end, the CEPT 1 standard provides for coding colors on 1, 2 or 4 bits corresponding to a display of 2, 4 or 16 colors and possible animation with these same possibilities, it being understood that these colors are likely to be chosen both from the basic colors and from the downloadable colors mentioned above. The CEPT 2 standard, on the other hand, only provides for coding on two bits, thus allowing an evolution from one color to another, these colors being chosen from the eight colors available.

Consequently, an approximation is necessary to display an image provided in CEPT 1 standard on a compatible terminal, extrapolated from a Videotex terminal.

To this end, the transcription of the initial coloring of an image is translated using the eight possible colors, according to the adaptation process mentioned above, both for the alphanumeric characters and for the other graphics.

However, the CEPT 1 standard also provides for redefinable characters in dynamics, DRCS in English abbreviation, which each form a matrix whose coloring pixels are individually downloaded in for further processing character by character. Each pixel of a character is capable of being defined by several bits depending on the choices made, for example a least significant bit and one most significant bit, these character definition bits possibly make it possible to define up to sixteen chosen colors. among four thousand and ninety six, according to predetermined color tables and preselected according to a known method, for the various displays.

In the proposed embodiment, when four or sixteen colors are provided with such dynamically redefinable characters, these colors are considered to belong to one or the other of two different groups, which each correspond to a given color.

The evolution of the coloring during animation is obtained by individual switching from one color to another for the various alphanumeric elements and / or graphics so that the transcription of the final coloring of the image corresponds to that planned for this image in the final animation phase.

This is obtained by converting the first four or eight colors, taken respectively from the eight or sixteen simultaneously possible in CEPT 1 standard, for example by luminance order, into one of eight colors in CEPT 2 standard and the following four or eight according to the CEPT 1 standard in another color from the CEPT 2 palette.

A degraded animation effect is therefore likely to be obtained with assurance of compliance with the color conversions for the initial state and for the final state of each of the images.

Claims (4)

Adaptation method intended to allow the display of information processed according to the CEPT 1 standard on a telematics terminal of the CEPT 2 type, characterized in that it comprises: a translation of the colors of a first palette provided according to the CEPT 1 standard into one of the colors of a second palette provided according to the CEPT 2 standard, as a function of the luminance of these colors of the first palette, the latter being distributed according to of their luminances in one or other of the parts which divide the first palette into as many equivalent parts as there are colors in a second palette, so as to translate by the same color of the second palette the different colors of the same party; - an approximation of the alphanumeric matrices by periodic elimination of a row and / or a column of pixels from a so-called basic matrix, until a matrix according to the CEPT 2 standard is obtained, after adding or removing pixels to the initial matrix according to the CEPT 1 standard, if necessary, to obtain this matrix, called basic, which has the same height in pixels as the matrix according to the CEPT standard 2 and same width as the widest of the matrices according to the CEPT standard 1; - a transcription of the evolution of the coloring of an animated image by switching from one color to another for each of the alphanumeric or graphic elements, individually colored, concerned with the image considered. Adaptation method according to claim 1, characterized in that the approximation of the initial matrices of size smaller than that of the matrix of the basic matrix is carried out by duplication of the number of pixels. Method of adaptation, according to at least one of claims 1 and 2, characterized in that the periodic elimination of the columns of pixels from a base matrix is carried out from the first at one of the ends of the basic matrix. Adaptation method according to claim 1, characterized in that the transcription of the final coloring of an image after possible animation switching is fixed by the final coloring indications provided for this image.

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