JPS5748869A - Compensation circuit for background density - Google Patents
Compensation circuit for background densityInfo
- Publication number
- JPS5748869A JPS5748869A JP55123218A JP12321880A JPS5748869A JP S5748869 A JPS5748869 A JP S5748869A JP 55123218 A JP55123218 A JP 55123218A JP 12321880 A JP12321880 A JP 12321880A JP S5748869 A JPS5748869 A JP S5748869A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- resistor
- given
- white
- background density
- 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
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
- H04N1/403—Discrimination between the two tones in the picture signal of a two-tone original
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Facsimile Image Signal Circuits (AREA)
- Manipulation Of Pulses (AREA)
Abstract
PURPOSE:To keep the video quality in excellent manner, by following the threshold level to an optimum level quickly, against the change in the background density and contrast in the original, in a background density compensation circuit provided at a facsimile transmitter and the like. CONSTITUTION:An analog video signal is sample-held and given to a white peak value detection circuit 2' and another circuit 17. The time constant consisting of a capacitor 25 and a resistor 26 of the circuit 17 is sufficiently greater than that consisting of a capacitor 8 and a resistor 9. An output voltage V of the circuit 17 is split with registors 18, 19, 20, and a voltage division VH is given to one end of the registor 9 and a voltage division VL is given to one end of a resistor 14 of a circuit 3'. Thus, even if white or black signals are consecutively present (i.e., black or white signals are absent), since the threshold value is existing between the peak value voltage VSH or VSL or consecutive chroma signals and the voltage division VH or VL, accurate binarization can be made.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55123218A JPS5748869A (en) | 1980-09-05 | 1980-09-05 | Compensation circuit for background density |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55123218A JPS5748869A (en) | 1980-09-05 | 1980-09-05 | Compensation circuit for background density |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5748869A true JPS5748869A (en) | 1982-03-20 |
Family
ID=14855116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55123218A Pending JPS5748869A (en) | 1980-09-05 | 1980-09-05 | Compensation circuit for background density |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5748869A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58196766A (en) * | 1982-05-12 | 1983-11-16 | Canon Inc | Binary coding device of picture signal |
| JPS596333U (en) * | 1982-07-05 | 1984-01-17 | 沖電気工業株式会社 | Automatic threshold level control circuit |
| JPS6076956A (en) * | 1983-09-30 | 1985-05-01 | Isuzu Motors Ltd | Deburring robot |
| JPH0360277A (en) * | 1989-07-28 | 1991-03-15 | Canon Inc | Picture binarizing system |
-
1980
- 1980-09-05 JP JP55123218A patent/JPS5748869A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58196766A (en) * | 1982-05-12 | 1983-11-16 | Canon Inc | Binary coding device of picture signal |
| JPS596333U (en) * | 1982-07-05 | 1984-01-17 | 沖電気工業株式会社 | Automatic threshold level control circuit |
| JPS6076956A (en) * | 1983-09-30 | 1985-05-01 | Isuzu Motors Ltd | Deburring robot |
| JPH0360277A (en) * | 1989-07-28 | 1991-03-15 | Canon Inc | Picture binarizing system |
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