GB1360705A – Chroma key circuit
– Google Patents
GB1360705A – Chroma key circuit
– Google Patents
Chroma key circuit
Info
Publication number
GB1360705A
GB1360705A
GB1106472A
GB1106472A
GB1360705A
GB 1360705 A
GB1360705 A
GB 1360705A
GB 1106472 A
GB1106472 A
GB 1106472A
GB 1106472 A
GB1106472 A
GB 1106472A
GB 1360705 A
GB1360705 A
GB 1360705A
Authority
GB
United Kingdom
Prior art keywords
camera
gate
voltage
signals
colour
Prior art date
1971-03-12
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.)
Expired
Application number
GB1106472A
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.)
Philips Broadcast Equipment Corp
Original Assignee
Philips Broadcast Equipment 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.)
1971-03-12
Filing date
1972-03-09
Publication date
1974-07-17
1972-03-09
Application filed by Philips Broadcast Equipment Corp
filed
Critical
Philips Broadcast Equipment Corp
1974-07-17
Publication of GB1360705A
publication
Critical
patent/GB1360705A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
H04N9/00—Details of colour television systems
H04N9/64—Circuits for processing colour signals
H04N9/74—Circuits for processing colour signals for obtaining special effects
H04N9/75—Chroma key
Abstract
1360705 Colour television PHILIPS BROADCAST EQUIPMENT CORP 9 March 1972 [12 March 1971] 11064/72 Heading H4F In a television system for superimposing a person viewed by a first camera on a background viewed by a second camera an identification circuit is provided for determining when the first camera is scanning a selected colour, e.g. blue forming the background viewed by the first camera, the identification circuit then producing an output pulse to gate out the signal from the first camera and gate in the signal from the second camera. The R, G, B signals from the first camera are passed to a matrix 22 which develops -(B-M) and -(R-M) colour difference signals which are passed to variable gain amplifiers 23, 24 and 25, 26 each of which also receives an amplification gain control input either from inverter 33 or from one of voltage generators 31, 32 which generate triangular voltages approximating to -sinx and -cosx respectively, where x is an adjustable input voltage. The resulting signals from amplifiers 23, 25 and 24, 26 which are each the inverse of the product of the respective input signals are fed to adder, inverter and clamp circuits 34, 35 to derive (B-M) sinx-(R-M)cosx and (BM)cosx + (R-M)sinx voltages respectively which are fed to AND gate 36 to produce an output pulse when the signals fed to it from 34, 35 indicate a selected colour, input voltage x being adjusted to select this colour, a variable negative bias supply 91 also being connected to gate 36 to provide fine colour adjustment by adjusting the trigger level of gate 36. A delay 37 is provided to compensate for delay caused to the signals from the first camera due to an encoding circuit provided prior to transmission of the signal from the first camera and the output pulses from the identification circuit, the transmitted camera signal also being added to a pedestal voltage, which is removed at the location of the second camera. The pulse from delay 37 is shaped at 38 and clipped at 39. Other embodiments are described for biasing gate 36 with parts of the outputs from 34 and 35 (Fig. 5, not shown), or by passing the output from 34 to two inputs of gate 36, the output from 35 being passed via an AND gate to an inhibit terminal of gate 36 (Fig. 6, not shown). Voltage generators 31, 32 may each comprise an operational amplifier with one input connected to voltage x via a resistor and another input connected to voltage x via a diode arrangement of two oppositely poled diodes for the -cosx generator (Fig. 3, not shown) or a four diode bridge for the -sinx generator (Fig. 4, not shown).
GB1106472A
1971-03-12
1972-03-09
Chroma key circuit
Expired
GB1360705A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
US12369071A
1971-03-12
1971-03-12
Publications (1)
Publication Number
Publication Date
GB1360705A
true
GB1360705A
(en)
1974-07-17
Family
ID=22410266
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB1106472A
Expired
GB1360705A
(en)
1971-03-12
1972-03-09
Chroma key circuit
Country Status (8)
Country
Link
US
(1)
US3678182A
(en)
JP
(1)
JPS5412018B1
(en)
AU
(1)
AU454371B2
(en)
CA
(1)
CA955326A
(en)
DE
(1)
DE2209754C3
(en)
FR
(1)
FR2128875B1
(en)
GB
(1)
GB1360705A
(en)
IT
(1)
IT957549B
(en)
Families Citing this family (20)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR2142820B1
(en)
*
1971-06-25
1975-04-18
Ortf
US3749822A
(en)
*
1971-12-30
1973-07-31
Veer F V D
Animation method and apparatus
US3959813A
(en)
*
1973-12-08
1976-05-25
Robert Bosch G.M.B.H.
Generation of a switching signal for the chroma keying of color video signals
US4109278A
(en)
*
1975-03-21
1978-08-22
Sonex International Corp.
Video traveling matte system
NL7509871A
(en)
*
1975-08-20
1977-02-22
Philips Nv
COLOR TV CHROMA KEY SIGNAL GENERATOR.
JPS6011875B2
(en)
*
1977-08-17
1985-03-28
日本電気株式会社
Chroma key tracking device
NL7807350A
(en)
*
1978-07-07
1980-01-09
Philips Nv
COLOR SELECTION CHANGE FOR COLOR TELEVISION.
US4183045A
(en)
*
1978-08-30
1980-01-08
Rca Corporation
Chroma keying selector system
DE3027053A1
(en)
*
1980-07-17
1982-02-11
Robert Bosch Gmbh, 7000 Stuttgart
METHOD FOR THE CORRECTIVE CORRECTION OF DIGITAL SWITCHING SIGNALS
DE3027054A1
(en)
*
1980-07-17
1982-02-11
Robert Bosch Gmbh, 7000 Stuttgart
METHOD FOR DERIVING A DIGITAL CONTROL SIGNAL
NL8006546A
(en)
*
1980-12-02
1982-07-01
Philips Nv
CAMERA SYSTEM FOR COLOR TELEVISION.
JPS5846783A
(en)
*
1981-09-12
1983-03-18
Sony Corp
Chromakey device
GB2158320A
(en)
*
1984-04-26
1985-11-06
Philips Electronic Associated
Generating a chroma keying signal
US4953008A
(en)
*
1986-09-08
1990-08-28
Encore Video, Inc.
Method and apparatus for uniform saturation, hue and luminance correction
EP0282569B1
(en)
*
1986-09-08
1991-06-26
Mscl, Inc.
Apparatus for correcting video color signals
US5134465A
(en)
*
1989-08-30
1992-07-28
Hitachi Video Engineering, Inc.
Color detecting circuit
US5051828A
(en)
*
1990-04-27
1991-09-24
The Grass Valley Group, Inc.
Keyer with variable shaping
JPH05130502A
(en)
*
1991-11-08
1993-05-25
Pioneer Electron Corp
Image reproducing device
US8264468B1
(en)
2007-06-19
2012-09-11
Imaging Systems Technology, Inc.
Touch system for blue screen
US8330730B1
(en)
2007-09-04
2012-12-11
Imaging Systems Technology, Inc.
Calibrating of interactive touch system for image compositing
Family Cites Families (3)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US2723307A
(en)
*
1953-11-30
1955-11-08
Itt
Montage amplifier
US3595987A
(en)
*
1969-02-20
1971-07-27
Ass Motion Picture Tv Prod
Electronic composite photography
US3619495A
(en)
*
1969-08-21
1971-11-09
Nippon Electric Co
Television picture montage circuit
1971
1971-03-12
US
US123690A
patent/US3678182A/en
not_active
Expired – Lifetime
1972
1972-03-01
DE
DE2209754A
patent/DE2209754C3/en
not_active
Expired
1972-03-09
CA
CA136,640A
patent/CA955326A/en
not_active
Expired
1972-03-09
IT
IT48877/72A
patent/IT957549B/en
active
1972-03-09
GB
GB1106472A
patent/GB1360705A/en
not_active
Expired
1972-03-10
JP
JP2403272A
patent/JPS5412018B1/ja
active
Pending
1972-03-10
AU
AU39852/72A
patent/AU454371B2/en
not_active
Expired
1972-03-13
FR
FR7208628A
patent/FR2128875B1/fr
not_active
Expired
Also Published As
Publication number
Publication date
DE2209754A1
(en)
1972-10-05
FR2128875B1
(en)
1975-04-25
US3678182A
(en)
1972-07-18
AU454371B2
(en)
1974-10-03
JPS5412018B1
(en)
1979-05-19
AU3985272A
(en)
1973-09-13
FR2128875A1
(en)
1972-10-20
IT957549B
(en)
1973-10-20
CA955326A
(en)
1974-09-24
DE2209754C3
(en)
1979-10-04
DE2209754B2
(en)
1979-02-08
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Legal Events
Date
Code
Title
Description
1974-11-27
PS
Patent sealed [section 19, patents act 1949]
1989-11-08
PCNP
Patent ceased through non-payment of renewal fee
