Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/40—Picture signal circuits
  • H04N1/405—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
  • H04N1/4055—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a clustered dots or a size modulated halftone pattern
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/387—Composing, repositioning or otherwise geometrically modifying originals
  • H04N1/3871—Composing, repositioning or otherwise geometrically modifying originals the composed originals being of different kinds, e.g. low- and high-resolution originals

Definitions

• the invention relates to a method for improved image reproduction in reproduction technology, in particular in the production of printing forms.
• ⁇ * a stair-shaped distortion of the smooth contours of the original is created, which has an intolerably disruptive effect in the print reproduction.
• the color separations are usually obtained in such a way that only the halftone images are scanned in electronic devices or cameras. These halftone excerpts are then assembled with a film bearing the non-rasterized line drawing. An intermediate negative is produced from this montage on a third film. This is copied again and provides a color separation, which now bears the combination of rasterized halftone images and non-rasterized line drawings and is used for printing form production.
• One is therefore forced to take this material and time-consuming path, which, due to the many copying processes, also brings considerable uncertainty into the overall process if one wants to maintain the smooth contours of the line drawing in the halftone images up to the printing form.
• O ⁇ f urged is not portable. In addition, there is an increased need for storage when storing entire images.
• the present invention is based on the object of avoiding the disadvantages indicated and of specifying a method which works with improved image reproduction in the production of printing forms, in particular in printing technology or textile printing technology.
• the line drawing information is scanned simultaneously with the scanning of the halftone image from a special template or when outputting from an electronic image memory, with the same line fineness as the halftone image.
• the sample values of the line information are supplied according to the invention in a special circuit which " stores the contents of several adjacent scan lines and obtains intermediate values refined in each sample point by comparison with the surroundings of the point.
• a combination of 2 3 recording beams may still be advantageous, which corresponds to a doubling of the fineness of the halftone screen in the line recording.
• FIG. 1 shows a schematic representation of the insertion of the arrangement according to the invention into the basic structure of an electronic device for producing color separations
• FIG. 6 shows a circuit example for a gate circuit. Best way to carry out the invention
• FIG. 1 shows the principle of an electronic device for producing color separations, in which a circuit 14 for refining the line recording according to the invention is included.
• a circuit 14 for refining the line recording according to the invention is included.
• Such a device consists of a scanning cylinder 1, which carries the halftone information 2.
• a further scanning cylinder 3 carries the line information 4.
• the combined, color-corrected and rastered starting product 6 is recorded on a further cylinder 5 in the form of a color separation for further processing for printing form production. That can e.g. B. happen by light rays on photosensitive film. All three cylinders 1, 3, 5 are driven by a motor 7 at the same speed.
• a scanning element 9 for scanning the halftone information 2 is arranged in front of the cylinder 1, and a scanning element 10 for scanning the line information 4 is arranged in front of the cylinder 3.
• a recording element 12 is arranged in front of the recording cylinder 5.
• the scanning members 9 and 10 as well as the recording member 12 perform an axial feed movement to the cylinders by means of the spindle 13, which is driven by the motor 11.
• the interplay between rotary motion, feed and a clock 8 arranged on the same shaft with the cylinders 1, 3, 5 results in the scanning as well as the halftone recording raster.
• the clock generator 8 also generates a pulse which indicates the start of each circumferential line. Both measures are over Lines 20 and 21 are fed to a multiplier 19 which processes the clock for a raster computer 17 in which the shape and size of the raster points to be recorded are generated in accordance with the samples of the halftone scanner 9.
• Sampled values from the scanning element 9 first run through an analog color computer 15 which carries out the color correction.
• the raster computer 17 works digitally. Therefore, the values corrected in the color calculator 15 are previously digitized in an analog-digital converter 16.
• the raster clock of line 20 and the clock for the beginning of line 21 are also fed to circuit 14, of which a circuit example is explained in more detail with reference to FIG. 4.
• the size and shape of the halftone halftone dots are generated in the halftone computer 17 and recorded by means of a plurality of separately controllable write beams, such as, for. B. in DE-PS 2107738 and DE-PS 1901101 described. Because of the complicated and diverse structure of the halftone halftone dots, the number of writing beams in a scanning line width is generally higher than would be necessary for the refinement of the line reproduction according to the invention.
• contours 51 how the refinement of the line record is achieved.
• B. arranged within a writing line width B three recording beams which can be controlled separately.
• the individual beams can advantageously consist of groups of recording beams combined, of a single-beam recording device for displaying halftone halftone dots, such as. B. described in DE-PS 2107738.
• these recording beams z. B. controlled by the circuit 14 three times, so that nine fields can be addressed separately in a grid mesh B x L.
• the contour shapes 51 chosen arbitrarily as an example in FIGS. 2 and 3 are reproduced in a refined manner by certain dot patterns within each grid field B x L in the sense of the invention.
• three light modulators 50 and the light source 49 are also shown in FIG. 2.
• FIG. 1 An example of the circuit 14 (FIG. 1) for obtaining the dot pattern is shown in FIG.
• the line information from the line scanner 10 passes via line 22 and a demultiplexer 25 into a four-way removable memory 23 ad, which stores the values of four successive scan lines so that there is a scan line in each memory section. Three parts of the memory hold the environmental information of the point to be evaluated, while the fourth part writes the next scan line.
• a certain pattern of the point to be written by the recording element 12 is assigned to the point surrounding information, which is available in the three memories each loaded with adjacent image lines, via a read-only memory 39.
• the read-only memory 39 is programmed in such a way that this dot pattern optimally matches the contour detected by the scanning and refines its reproduction in the form according to the invention.
• a line counter 24 controls the cyclic switching of the removable memory 23 ad (e.g. 4 x SEMI 4200 from Electronic Memories and Magnetics) via a 2-bit line 41, by determining via a de-multiplexer 25 (eg SN 74139 from Texas Instruments) into which part of the removable memory the line information is read. It also controls the read pulse that comes from the control unit via line 42, which it applies via a further demultiplexer 26 (eg SN 74130 from Texas Instruments) in accordance with the removable memory.
• a de-multiplexer 25 eg SN 74139 from Texas Instruments
• the line counter 24 puts over 3 subtractors (eg SN 7482 from Texas Instruments), which subtract constantly by 1, 2 or 3, and over a multiplexer 34 (eg SN 74153 from Texas Instruments) the addresses are available for those lines from which reading can take place.
• the address counter 28 (for example 3 x SN 74293 from Texas Instruments), clocked via line 20 from the clock generator 8 (FIG. 1) with the sampling clock, sets together with an adder 29 (for example 3 x SN 74283 from Texas Instruments), which constantly adds by 1, and a subtractor 30 (eg 3 x SN 74283 from Texas Instruments), which constantly subtracts by 1, the three point addresses from which can be read out .
• the controller is designed for linear program execution and consists of a program counter 31 (eg SN 7492 from Texas Instruments) and a programmable memory 32 (eg 2 x SN 74188 from Texas Instruments). This contains the microprogram for control, the pulse diagram of which is shown in FIG. 5.
• the control unit is clocked at a multiple of the sampling frequency (here, for example, 12 times), which is via a frequency multiplier 33 in a PLL circuit (for example described in the RCA application report ICAN 6101) is generated.
• the factor 12 provides the control unit with twelve program steps for the duration of a sampling cycle. This switches in the course of these program steps
• Control unit via line 43 (2-bit), via the multiplexer 34, in succession the three removable memory parts, which currently contain the full adjacent line information, via a further multiplexer 35 (for example SN 74153 from Texas Instruments) ) to a shift register 36 (e.g. 3 x SN 7495A) and selects three points within each line via line 44 (2 bits) via a multiplexer 37 (e.g. 6 x 74153 from Texas Instruments) so that at the input of the shift register 36 nine point information appear in succession.
• the control unit delivers a pulse via line 45 to each point information, which causes the shift register to shift, so that after the nine
• control 46 the control unit issues a register 38 (e.g. 2 x SN 74174 from Texas Instruments) with a load pulse, so that the 9-bit
• Information is transferred to the register 38 in order to be available there for the next sampling period to generate the dot pattern, while the shift register 36 is free to collect the next information.
• the information stored in register 38 together with 2-bit information coming from the controller via line 48, forms the address for the programmable baren 39.
• the address part, which comes from the register 38 remains constant for the duration of the write cycle for a whole point (W x L), while the address part, which comes from the control unit via line 48, is switched three times within a point.
• the point to be written is thus also resolved in three lines in the circumferential direction, whereby the refinement also takes effect in the circumferential direction.
• a control signal for the circuit 18 is available at its outputs 40 ac (Fig. 1) ready.
• FIG. 5 shows the time course of the output pulses from the programmable memory 32.
• Fig. 6 shows an example of the circuit 18 (Fig. 1) which appropriately combines raster signals and refined bar signals before recording.
• This can e.g. B. be light beams which are modulated by light modulators 50 (FIG. 2) on photosensitive film.
• the light modulators are controlled via the six lines 58 af.
• These lines are outputs of six OR gates 57 af, at the inputs of which the raster information from the output Lines of the AND gates 53 af and the line information refined according to the invention from the lines 40 ac (FIG. 4) converge.
• the raster information is in each case at an input of the AND gates 53 af; the other inputs are in parallel on line 54.
• the raster information is suppressed when writing a refined line pattern or not.
• Two electronic changeover switches 52 can group the six recording signals 57 af by activating the switches 52 via line 55, optionally in three groups of two adjacent recording beams or in Switch two groups of three adjacent recording beams each.

Landscapes

• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Facsimile Image Signal Circuits (AREA)
• Facsimile Scanning Arrangements (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Image Processing (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6092993

Family Applications (1)

Country Status (9)

Cited By (4)

Families Citing this family (16)

Citations (5)

Family Cites Families (6)

• 1980
  • 1980-01-26 DE DE19803002781 patent/DE3002781A1/de not_active Withdrawn
• 1981
  • 1981-01-12 CS CS836123A patent/CS238392B2/cs unknown
  • 1981-01-12 CS CS81231A patent/CS233717B2/cs unknown
  • 1981-01-17 WO PCT/DE1981/000016 patent/WO1981002206A1/de not_active Ceased
  • 1981-01-17 BR BR8106436A patent/BR8106436A/pt unknown
  • 1981-01-17 JP JP56500487A patent/JPS57500172A/ja active Pending
  • 1981-01-17 US US06/302,421 patent/US4419691A/en not_active Expired - Lifetime
  • 1981-01-17 EP EP81100332A patent/EP0033106B1/de not_active Expired
  • 1981-01-21 CA CA000369028A patent/CA1171963A/en not_active Expired
  • 1981-01-23 DD DD81227171A patent/DD160128A5/de unknown

Patent Citations (5)

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