JPS5694874A - Video signal processor - Google Patents

Video signal processor

Info

Publication number
JPS5694874A
JPS5694874A JP17189179A JP17189179A JPS5694874A JP S5694874 A JPS5694874 A JP S5694874A JP 17189179 A JP17189179 A JP 17189179A JP 17189179 A JP17189179 A JP 17189179A JP S5694874 A JPS5694874 A JP S5694874A
Authority
JP
Japan
Prior art keywords
contrast
reference level
gradation
amplitude
signal
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.)
Pending
Application number
JP17189179A
Other languages
Japanese (ja)
Inventor
Yoshihiro Miyamoto
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.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP17189179A priority Critical patent/JPS5694874A/en
Publication of JPS5694874A publication Critical patent/JPS5694874A/en
Pending legal-status Critical Current

Links

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
    • H04N1/4056—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 the pattern varying in one dimension only, e.g. dash length, pulse width modulation [PWM]

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Image Signal Circuits (AREA)

Abstract

PURPOSE:To realize not only a binary coding of the intermediate gradation but a uniform picture quality even to the variable density of the original, by forming a pair of the adjacent picture element signals of the time-series picture element signals to compare them with the different reference level signals with every picture element and then extracting the multi-gradation binary coded signal. CONSTITUTION:In case the difference between the highest and lowest luminances of the video signal is small like the width F, the amplitude M of the reference level signal is decreased by the gain variable amplifier 15 and in accordance with the width F. Thus the binary coded signal output having an increased contrast is obtained. The contrast is increased by controlling the amplitude of the reference level signal, thus reproducing a high-contrast picture. On the other hand, the amplitude of the reference level signal is decreased in case the DC level is lowered with a small difference of luminance and a dark original surface. At the same time, the DC level sent from the variable power source 16 and to be added by the voltage adder 17 is controlled to a low level to cope with a low contrast and low luminance. Accordingly, a faithful multi-gradation binary coded signal is obtained also in this case, thus realizing a reproduction of a high-contrast gradation pattern.
JP17189179A 1979-12-28 1979-12-28 Video signal processor Pending JPS5694874A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17189179A JPS5694874A (en) 1979-12-28 1979-12-28 Video signal processor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17189179A JPS5694874A (en) 1979-12-28 1979-12-28 Video signal processor

Publications (1)

Publication Number Publication Date
JPS5694874A true JPS5694874A (en) 1981-07-31

Family

ID=15931713

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17189179A Pending JPS5694874A (en) 1979-12-28 1979-12-28 Video signal processor

Country Status (1)

Country Link
JP (1) JPS5694874A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4847695A (en) * 1986-02-06 1989-07-11 Canon Kabushiki Kaisha Image processing apparatus in which the minimum and maximum widths of a pulse-width modulated signal can be independently adjusted in accordance with predetermined data signals

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4883724A (en) * 1972-02-08 1973-11-08
JPS4933414A (en) * 1972-07-27 1974-03-27
JPS5046425A (en) * 1973-08-30 1975-04-25
JPS5345537U (en) * 1976-09-22 1978-04-18
JPS54129919A (en) * 1978-03-31 1979-10-08 Ricoh Co Ltd Facsimile transmission system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4883724A (en) * 1972-02-08 1973-11-08
JPS4933414A (en) * 1972-07-27 1974-03-27
JPS5046425A (en) * 1973-08-30 1975-04-25
JPS5345537U (en) * 1976-09-22 1978-04-18
JPS54129919A (en) * 1978-03-31 1979-10-08 Ricoh Co Ltd Facsimile transmission system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4847695A (en) * 1986-02-06 1989-07-11 Canon Kabushiki Kaisha Image processing apparatus in which the minimum and maximum widths of a pulse-width modulated signal can be independently adjusted in accordance with predetermined data signals
US4987495A (en) * 1986-02-06 1991-01-22 Canon Kabushiki Kaisha Image processing apparatus with image formation condition detection for control of processing

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