EP0281502A1 - Méthode d'affichage de couleurs individuelles en les remplaçant par des niveaux de gris - Google Patents

Méthode d'affichage de couleurs individuelles en les remplaçant par des niveaux de gris Download PDF

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Publication number
EP0281502A1
EP0281502A1 EP88730022A EP88730022A EP0281502A1 EP 0281502 A1 EP0281502 A1 EP 0281502A1 EP 88730022 A EP88730022 A EP 88730022A EP 88730022 A EP88730022 A EP 88730022A EP 0281502 A1 EP0281502 A1 EP 0281502A1
Authority
EP
European Patent Office
Prior art keywords
color
memory
colors
brightnesses
brightness
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP88730022A
Other languages
German (de)
English (en)
Inventor
Gerald Dipl.-Ing. Schmidt
Manfred-Rüdiger Sellke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of EP0281502A1 publication Critical patent/EP0281502A1/fr
Ceased legal-status Critical Current

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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
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • G09G5/02—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the way in which colour is displayed
    • G09G5/028—Circuits for converting colour display signals into monochrome display signals

Definitions

  • the invention relates to a method for the replacement of individual colors by gray values on an output device that processes exclusively gray values by means of a device in which the colors are stored in a predetermined number in the form of data words containing their respective red, green and blue components in a color memory and for Representation each called by an address word designating them from the color memory and output for display on a color output device.
  • Devices of the type specified above are known as components of communication terminals that are able to process telecommunication services such as screen text and videotex (cf. "Nachzintechnische Zeitschrift-ntz", volume 37, 1984, number 4, pages 214 ff).
  • the communication terminals are each connected to a data transmission network (public telephone network) via a modem for information exchange.
  • the exchange of information data takes place in a data syntax defined according to uniform standards (eg CEPT standard), in which the transmitted and displayed information data are contained in coded form.
  • uniform standards eg CEPT standard
  • code tables which contain the representable elements, such as characters, patterns and colors, which are defined in the context of the respective standard.
  • the code tables can be permanently implemented in code memories of the individual communication terminals, as a result of which a supply of constantly available ones representable elements is provided, or on the other hand, to supplement this supply from a central office via the data transmission network into the code memory of the individual communication terminals.
  • a special code memory is e.g. B. the color memory in which the permanently implemented and / or downloaded colors are stored in a predetermined number (according to CEPT standard 32 of a total of 4096 displayable colors) in the form of data words containing their respective red, green and blue components.
  • the characters and patterns decoded with the aid of the code tables are output together with a color called up by a data word representing them from the color memory for display on a color-capable output device (usually a color monitor).
  • Figure 2 shows a block diagram for a screen text decoder in which the characters and patterns decoded in a character ROM serving as a code memory are stored in a shift register with so-called attributes, such as Flashing, underlining, inverting and so on a. be provided; subsequently, the associated colors are assigned to the characters and patterns by means of a color table contained in a color memory before the colored characters and patterns are output as color signals for a color monitor via a digital / analog converter.
  • attributes such as Flashing, underlining, inverting and so on a.
  • the scene to be recorded can be illuminated in such a way that, in addition to a good colored one, a good achromatic black / white reproduction is ensured on the television set, when editing images with synthetically generated colors for the above-mentioned telecommunication services or for programs for home and personal computers mostly no consideration of a possible black and white representation of the colored images; one reason for this is, for example, the associated limitation of the available stock of colors. Accordingly, the reproduction quality of such synthetically generated images on black and white monitors is often poor.
  • the invention has for its object to provide a method which enables an improved black / white reproduction of synthetically generated color images without influencing the color image generation.
  • the associated color brightness is determined for each stored color in an evaluation device assigned to the color memory, in that the determined color brightnesses are assigned gray values in accordance with their brightness gradations, different colors having the same color brightness Gray values are assigned so that the gray values are stored in a gray value memory in the order in which the colors on which they are based and are called up from the gray value memory by the same address word that calls them and are output for display on the gray value processing output device.
  • the main advantage of the method according to the invention is that, without influencing the color selection and without interfering with existing devices which process and display the colors, a high-contrast, alternative representation of the colors by gray values is made possible, the black / white image thus produced having the impression of brightness is equivalent to the corresponding color image.
  • An intervention in the processing and representation of the colors is avoided in that a corresponding supply of the gray values assigned to the colors is created in parallel to the existing supply of colors in the color memory, and parallel to the call of a color the call of the associated one Gray values are done.
  • the high-contrast representation of the colors by gray values is made possible by the assignment of different gray values to different colors in which the respective color brightnesses match.
  • the gray values are called up from the gray value memory in parallel with the colors being called up from the color memory and in the same way, as a further advantage of the method according to the invention, only a small amount of additional circuitry is required to the existing device with the color memory.
  • the determination of the color brightnesses is advantageously carried out in a summing device in which the respective red, green and blue components are weighted in adaptation to the eye sensitivity curve and subsequently summed up to the respective color brightness.
  • the summing device consists of a resistance network known per se, the weighting being carried out by means of resistance voltage dividers whose voltage divider taps are combined to form a summation point via further resistors.
  • Another design and control technology special According to a further embodiment of the method according to the invention, simple determination of the color brightness is carried out in such a way that the color brightness is called up from a color brightness memory in which color brightness determined once for all colors of the CEPT standard is stored.
  • This method variant offers a further advantage that the color brightnesses stored in the color brightness memory can be modified in terms of their values for each individual color, so that the assignment of gray values to the colors according to the method according to the invention is not rigidly predetermined, but to different external conditions, such as B. different types of black / white monitors used to represent the gray values or the individual brightness perception of different users can be adapted.
  • the color brightness memory with the color brightnesses arranged in a color brightness table is loaded from a memory device in which a plurality of color brightness tables are stored which differ in the different assignments of color brightnesses to colors. It is therefore possible for the user to select from the several color brightness tables available the one that guarantees the best possible conversion of the colors into gray values.
  • the assignment of the gray values to the determined color brightnesses is advantageously carried out in such a way that the determined color brightnesses are first sorted in ascending order, that the sorted color brightnesses are assigned increasingly higher gray values according to their order, in the case that a first color brightness is assigned to a color an identical second color brightness follows another color, the second color brightness and a gray value increased by a predetermined amount is assigned to the color brightnesses that follow in the order. Since the gray values assigned to the subsequent color brightnesses are increased each time in several cases of matching color brightnesses of different colors, it is achieved that a different gray value is assigned to each of these colors if the color brightnesses of different colors match.
  • An increase in the readability of alphanumeric characters is advantageously achieved in that the predetermined amount is chosen larger for colors that are assigned to alphanumeric characters than for foreground and background colors.
  • FIG. 1 shows a block diagram of a screen text subscriber station in an embodiment designed to carry out the method according to the invention.
  • the part of the block diagram shown on the left of the dashed dividing line X represents a conventional subscriber station, while on the right of the dividing line X is shown a circuit extension 1 provided for carrying out the method according to the invention.
  • the screen text subscriber station shown has a screen text decoder 2 which is connected on the input side via a modem (modulator / demodulator) 3 to a public telephone network 4 and a dialing device 5 belonging to the subscriber station.
  • the screen text decoder 2 is connected to a color monitor 6 in the area to the left of the dashed dividing line via three video outputs R, G and B for the colors red, green and blue, and in the area of the circuit extension 1 to the right of the dividing line X via another video output S / W for black / white signals is connected to a black / white monitor 7 that processes only gray values.
  • the screen text decoder 2 contains a microprocessor 8 which is connected to an address and data bus 9.
  • the address and data bus 9 is connected here to the modem 3 via an interface 10, which is only indicated.
  • the monitor module 14 is connected on the output side to a character memory 15, in which a supply of continuously available representable characters implemented in the screen text decoder 2 shown is stored.
  • Both the page memory 12, the attribute memory 13 and the character memory 15 are connected via a data bus 16 to a color memory 17, in which the downloaded characters from the page memory 12 and the existing ones Characters from the character memory 15 after assignment of attributes (eg flashing) from the attribute memory 13 the associated colors are assigned; these colors, the maximum number of which per BTX page is 32, are stored in a color table in the color memory 17.
  • the now colored characters and patterns are output via a 3-channel digital / analog converter 18 as color component signals via the outputs R, G and B for the color monitor 6.
  • the address and data bus 9 is connected to a further program memory 19 which contains a program for converting colors into associated gray values in accordance with the method according to the invention;
  • the following are also connected to the address and data bus 9: a color brightness memory 20 which contains the red, green and blue components of all 4096 colors which can be represented in the CEPT standard together with color brightnesses determined once for the individual colors, and a gray value memory 21.
  • a color brightness memory 20 which contains the red, green and blue components of all 4096 colors which can be represented in the CEPT standard together with color brightnesses determined once for the individual colors
  • a gray value memory 21 For the color brightness memory 20 several boxes are shown staggered to clarify that several different assignments of color brightnesses to colors can be stored in the color brightness memory 20, from which the respective user can select the assignment that seems most suitable to them.
  • the gray value memory 21 contains 32 memory locations of 5 bits each, each of which enables 32 different gray value levels to be stored.
  • the corresponding color brightnesses are determined from the color brightness memory 20 for the colors stored in the color memory 17; gray values in gray value levels from 1 to 32 are assigned to the color brightnesses and in stored in the gray value memory 21 in the same order as the colors are contained in the color brightness memory 17.
  • the gray values associated with the colors are output on the black / white monitor 7 via a digital / analog converter 22.
  • the method according to the invention is explained as a program sequence in the screen text decoder 2 according to FIG. 1 on the basis of the structogram shown in FIG.
  • the program itself is stored in the program memory 19.
  • the screens of monitors 6 and 7 are deleted.
  • the colors of a BTX page are then loaded into the color memory 17 in the form of their red, green and blue components. A maximum of 32 colors can be stored in the color memory 17 per BTX page.
  • the associated color brightness is determined for each color in the color memory 17 by accessing the color brightness memory 20, in which all 4096 colors defined in the CEPT standard are stored with color brightnesses that are assigned to them once; the colors contained in the color brightness memory 20 are individually compared with the colors stored in the color memory 17, and if they match, the associated color brightness from the color memory 17 is assigned the associated color brightness from the color brightness memory 20. Since the red, green and blue components of the individual colors contained in the color memory 17 are available as digital values, the assigned color brightnesses can alternatively also be determined arithmetically, taking into account the eye sensitivity curve, by directing the red, green and blue components in adaptation to the eye sensitivity curve and in a summing device the respective color brightnesses are added up.
  • the color brightnesses of identical colors are marked and then all color brightnesses, starting from the lowest color brightness value, are sorted in ascending order. If the number of colors contained in the color memory 17 corresponds to the maximum possible number of 32, then each color brightness is assigned one of 32 gray values in accordance with its storage in the ascending order, identical color brightnesses also being assigned the same gray values.
  • the gray values are subsequently stored in the gray value memory 21 in accordance with the order of the colors in the color memory 17 and output via the digital / analog converter 22 to the black / white monitor 7 in the same way as the colors from the color memory 17 via the Digital / analog converter 18 are output on the color monitor 6.
  • a gray value is assigned to each of the determined color brightnesses in such a way that the maximum color brightness receives the gray value 32 and all other color brightnesses have further gray values in the gray value gradations of 1 received to 32.
  • the same gray values second gray value follows and the associated colors are unequal, the second and all gray values following in ascending order are incremented by one gray value level.
  • the gray values assigned to the alphanumeric characters are incremented so that their gray value differs from the next lower gray value by more than one gray value level.
  • incrementing the gray value a match between gray values of different colors can again be brought about.
  • the individual gray values are again compared with one another in the ascending order, with the second and all subsequent gray values being incremented by one gray value level in the event that a gray value is followed by an identical second gray value in the ascending order and the associated colors are not the same will. Due to the previous program steps, the highest gray value can rise to a value above the 32nd gray value level.
  • gray values are decremented in the ascending order until the lowest gray value corresponds to the first gray value level. If the highest gray value is then still greater than the 32nd gray value level, the distances of successive gray values are reduced in a subsequent method step insofar as these distances are greater than a gray value level.
  • the gray values are subsequently stored in the gray value memory 21 in the order of the colors in the color memory 17 and parallel to them via the digital / analog converter 22 on the black / white monitor 7 as a black / white image equivalent in terms of brightness to the color image spent.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Controls And Circuits For Display Device (AREA)
EP88730022A 1987-02-03 1988-01-29 Méthode d'affichage de couleurs individuelles en les remplaçant par des niveaux de gris Ceased EP0281502A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3703527 1987-02-03
DE19873703527 DE3703527A1 (de) 1987-02-03 1987-02-03 Verfahren zur ersatzweisen darstellung einzelner farben durch grauwerte

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EP0281502A1 true EP0281502A1 (fr) 1988-09-07

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EP88730022A Ceased EP0281502A1 (fr) 1987-02-03 1988-01-29 Méthode d'affichage de couleurs individuelles en les remplaçant par des niveaux de gris

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DE (1) DE3703527A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0347720A3 (en) * 1988-06-18 1990-06-13 Hitachi, Ltd. Apparatus and method for gray scale display
EP0359236A3 (fr) * 1988-09-13 1991-08-07 Kabushiki Kaisha Toshiba Appareil de commande d'affichage pour la conversion d'une gradation en couleurs/monochrome pour un T.R.C. en une gradation pour un panneau à plasma
US5293485A (en) * 1988-09-13 1994-03-08 Kabushiki Kaisha Toshiba Display control apparatus for converting color/monochromatic CRT gradation into flat panel display gradation
EP0525780A3 (en) * 1991-07-31 1995-06-21 Tokyo Shibaura Electric Co Display control device for use with flat-panel display and color crt display
EP1887782A3 (fr) * 2006-08-07 2009-06-10 Samsung Electronics Co., Ltd. Procédé et appareil de conversion des images en couleur en images monochromes, et appareil de formation d'image l'incorporant

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4236175A (en) * 1978-02-15 1980-11-25 U.S. Philips Corporation Converter circuit and monochrome picture display device comprising such a converter circuit
EP0185328A2 (fr) * 1984-12-13 1986-06-25 Ascii Corporation Système de commande d'affichage

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4236175A (en) * 1978-02-15 1980-11-25 U.S. Philips Corporation Converter circuit and monochrome picture display device comprising such a converter circuit
EP0185328A2 (fr) * 1984-12-13 1986-06-25 Ascii Corporation Système de commande d'affichage

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0347720A3 (en) * 1988-06-18 1990-06-13 Hitachi, Ltd. Apparatus and method for gray scale display
US5119086A (en) * 1988-06-18 1992-06-02 Hitachi Ltd. Apparatus and method for gray scale display
EP0359236A3 (fr) * 1988-09-13 1991-08-07 Kabushiki Kaisha Toshiba Appareil de commande d'affichage pour la conversion d'une gradation en couleurs/monochrome pour un T.R.C. en une gradation pour un panneau à plasma
US5293485A (en) * 1988-09-13 1994-03-08 Kabushiki Kaisha Toshiba Display control apparatus for converting color/monochromatic CRT gradation into flat panel display gradation
US5438652A (en) * 1988-09-13 1995-08-01 Kabushiki Kaisha Toshiba Display control apparatus for converting color/monochromatic CRT gradation into flat panel gradation
EP0525780A3 (en) * 1991-07-31 1995-06-21 Tokyo Shibaura Electric Co Display control device for use with flat-panel display and color crt display
US5491496A (en) * 1991-07-31 1996-02-13 Kabushiki Kaisha Toshiba Display control device for use with flat-panel display and color CRT display
EP1887782A3 (fr) * 2006-08-07 2009-06-10 Samsung Electronics Co., Ltd. Procédé et appareil de conversion des images en couleur en images monochromes, et appareil de formation d'image l'incorporant
US7830550B2 (en) 2006-08-07 2010-11-09 Samsung Electronics Co., Ltd. Image converting method and apparatus, and image forming apparatus having the same

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