Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T11/00—2D [Two Dimensional] image generation
  • G06T11/20—Drawing from basic elements, e.g. lines or circles
  • G06T11/206—Drawing of charts or graphs
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K15/00—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers
  • G06K15/02—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers
  • G06K15/12—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers by photographic printing, e.g. by laser printers
  • G06K15/128—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers by photographic printing, e.g. by laser printers generating or processing printable items, e.g. characters
• • 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
  • G09G5/42—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the display of patterns using a display memory without fixed position correspondence between the display memory contents and the display position on the screen

Definitions

• This invention pertains generally to the generation of raster images, and more particularly to a processor and method for generating binary raster scans from symbolic input commands.
• OI. ⁇ FI It is in general an object of the invention to provide a new and improved processor and method for generating serial output data from symbolic input commands.
• Another object of the invention is to provide a processor and method of the above character which are particularly suitable for use in a laser engraving system such as a laser platemaker, an artwork generator for direct exposure of printed circuit boards or the formation of an image on an intermediate film, or an intelligent copier, i.e. , a copier driven by a computer.
• a laser engraving system such as a laser platemaker, an artwork generator for direct exposure of printed circuit boards or the formation of an image on an intermediate film, or an intelligent copier, i.e. , a copier driven by a computer.
• the input commands define the x and y positions of each -charac ⁇ ter in the output image as well as the address of the descripti data for the character in the character memory.
• the input command data for a given scan line has been completely assem- bled in the character store, it is transferred to a character buffer, and the character store is free to assemble the input command data for another line.
• the descriptive data pointed to by the data in the character buffer is retrieved from the character memory and converted to a serial format for modulation of the beam.
• the descriptive data is stored in a compressed run length encoded format and decompressed to provide a serial output bit stream.
• OMFI -3- Figure 1 is a block diagram of one embodiment of a raster image processor according to the invention.
• Figure 2 is a diagrammatic illustration of the descriptive data for the characters encoded in a run length coded for- mat for storage in the character memory in the embodiment of Figure 1.
• Figure 3 is a diagrammatic illustration of the symbolic input commands employed in the embodiment of Figure 1.
• Figures 4 and 5 are flow diagrams illustrating the operation of the image processor of Figure 1.
• the raster image processor is illustrated in connection with a computer 11 and a laser engraving system 12,
• the computer can be any suitable digital computer such as one of the PDP-11 family of minicomputers manufactured by Digital Equipment Corporation, and it is provided with conventional peripheral devices such as an input terminal and a magnetic memory disk system.
• the laser engraving system can, for example, be a laser plate aker of the type described in detail in U.S. Patent 4,240,119 and the other patent(s)/application(s) referenced therein.
• This system includes means for generating a reading laser beam which scans input copy in raster fashion to pro ⁇ vide signals representative of the copy, means for generating a writing laser beam which scans an output medium in raster fashion, and means for modulating the writing beam in accord ⁇ ance with the input copy signals to form an image of the copy on the output medium.
• the invention is disclosed with specific reference to a laser platemaking system in which the symbolic input commands are typesetting commands and the output image is • composed largely of alpha-numeric characters, the invention is equally applicable to other systems and characters such as printed circuit artwork, lineart and logotypes.
• character as used herein is not limited to alpha-numeric characters or con ⁇ ventional printing symbols, but includes any type of artwork or information to be included in the output image. Descrip ⁇ tive data for such artwork or information can be generated, for example, by scanning the same with the reading beam of the platemaker and converting the resulting signals to the desired digital format.
• the input commands are plotting commands
• the output medium can be either a layer of photoresist or other photosensitive material on the printed circuit boards themselves or a photosensitive film which is used as a master in exposing the boards.
• the image processor includes a data input bus 16 and a data output bus 17. Data is transferred to the input bus from the bus system of computer 11 by a transceiver 18 and an input latch 19, and data is transferred from output bus 17 to the computer bus system by an output latch 21 and trans- ceiver 18. Address signals from the computer bus system are delivered to input bus 16 by a receiver 22, a decoder 23 and a buffer 24. A controller 26 transfers control signals between the bus system of the computer and the image processor.
• a character memory 28 is provided for storing descriptive data for the characters which make up the image to be formed, and an address counter 29 is associated with this memory.
• the descriptive data is generated by the computer and loaded into the character memory.
• the descriptive data for the characters is compressed and stored in a run length encoded format in the character memory.
• the data is organized 'in 16-bit words consisting of two run length bytes (bits 0-5 and 6-11) , a color bit (bit 12) , a mode bit (bit 13) and two op code bits (bits 14-15) .
• Bits 0-.11 define the length of runs to be imaged in the color (black/white) specified by color bit 12.
• Load bit 13 indicates whether the image bits defined by bits 0-11 are to be treated as a single run or two separate runs. If the mode bit is 0, the entire run of bits described by bits 0-11 is imaged with the color specified by the color bit. If the mode bit is 1, bits 0-11 are treated as two separate words, with the word defined by bits 0-5 being imaged with the color specified by the color bit and the word defined by bits 6-11 being imaged with the opposite color.
• Op code bits 14, 15 tell the decompressor how to interpret the run length code code that follows in accordance with the following table: Bit 15 Bit 14 Interpretation
• a character store 31 is provided for storing symbolic input commands for the characters to be imaged in a given scan line, and an address counter 32 is associated with this stor
• the symbolic input commands are generated by the computer and loaded into the character store. As illustrated in
• the symbolic code for each character consists of four 16-bit words. Bits 0-14 of the first word define the x position of the character in the output image, and bit 15 indicates whether the character is valid, i.e., wheth it has already been imaged.
• the second word points to the starting address of the character description in character memory 28, the third word is not used, and the fourth word contains a repeat code for vertical redundancy compression.
• a decompressor 41 is provided for converting the run length encoded data from character memory 28 to a serial bit stream format, and this serial output data is stored in a dual line buffer 42 for application to the modulator for the writing beam of platemaker.
• An address counter 43 is associated wit decompressor 41 and line buffer 42.
• a central processing unit (CPU) 46 controls the operation of the processor.
• the CPU comprises an arithmetic and logic unit (ALU) 47 and a writeable control store (WCS) 48 in whic microinstructions for the ALU are stored. The sequence in "
• O -7- which the microinstructions are executed is controlled by a microprogram sequencer 49 which receives inputs through a multiplexer 51.
• the instructions output from the WCS are • stored in a pipeline register 52 so that one instruction
• the CPU is composed of LSI bipolar bit slice components from the Advanced Micro Devices 2900 microcomputer family, which is advantageous from the 0 standpoints of speed and availability of components.
• the image processor is interfaced directly to the bus system of host computer 11, -and when the processor is in the LOAD mode the WCS can be loaded by transferring microinstructions from the host computer.
• the processor executes the microinstructions and has the capability of reading directly from the memory of the host computer through non-processor requests.
• WCS output registers 56-58 permit the contents of WCS 48 to be read into the host comput in the LOAD mode for checking.
• the processor is synchronized with the scan of the output beam, and when the y scan line counter matches the character code y address, the data from the character store is trans ⁇ ferred to character buffer 36. At this time, the computer can begin assembling the input commands or character codes for the next scan line in the character store.
• CPU 46 scans the character buffer for valid character codes. When one is found r the CPU stops scanning and fetches the first word of the character description which is being pointed to by the character code. Decompressor 41 decompresses this data and places it in scan line buffer 42. The address of the data in the scan line buffer corresponds to the x posi- tion address of the character being decompressed. When all of the data for the portion of a character to be imaged in a given scan line has been decompressed, the CPU begins scanning the character buffer for the next valid character code. When the portion of a character in a given scan ' line has been completely imaged, the valid data bit for that character is cleared, and the portion of the character buffer where that character is stored is available for a new character code.
• the number of bits defined by the run length code of the descriptive data is transferred to the repeat code in character buffer 36, and this number is decremented for each successive scan line.
• the image processor and method of the invention have a number of important features and advantages. They permit binary raster scans to be generated from symbolic input commands and they generate serial output data in a more efficient manner than computers heretofore provided. While the processor and method have been described with specific reference to a laser engraving system, they are equally applicable to other applications in which a serial bit stream is required.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Optics & Photonics (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Image Processing (AREA)
• Controls And Circuits For Display Device (AREA)
• Dot-Matrix Printers And Others (AREA)
• Record Information Processing For Printing (AREA)

Applications Claiming Priority (1)

Publications (2)

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Family Applications (1)

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• 1981
  • 1981-11-06 BR BR8109047A patent/BR8109047A/pt unknown
  • 1981-11-06 AU AU78916/81A patent/AU546263B2/en not_active Expired - Fee Related
  • 1981-11-06 AU AU7891682A patent/AU7891682A/xx active Pending
  • 1981-11-06 EP EP19810903171 patent/EP0093110A4/en not_active Withdrawn
  • 1981-11-06 JP JP81503698A patent/JPS58501891A/ja active Pending
  • 1981-11-06 WO PCT/US1981/001491 patent/WO1983001696A1/en not_active Application Discontinuation
• 1982
  • 1982-11-08 IT IT49438/82A patent/IT1189413B/it active
  • 1982-11-08 CA CA000415126A patent/CA1180768A/en not_active Expired
• 1983
  • 1983-05-30 FI FI831929A patent/FI831929L/fi not_active Application Discontinuation
  • 1983-06-24 NO NO832311A patent/NO832311L/no unknown
  • 1983-07-05 DK DK309983A patent/DK309983A/da not_active Application Discontinuation

Non-Patent Citations (1)

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