EP0263295A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electronic still camera for compensating color temperature dependency of color video signals
Assignee: Fujifilm Holdings Corp
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Filing: 1987-08-28
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Granted: —
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Expires: 2007-08-28
Abstract
Abstract The output level of the color video signals, especially the G-signal or the luminance signal from a solid-state imaging device (22, 24) of an electronic still camera, is maintained constant regardless of the color temperature for optimum adjustment of the white balance. This is made possible in such a manner that the gain of a variable-gain amplifier (50, 124R, 124G, 124B) for white balance adjustment is separately controlled for each of the three primary colors as a function of a measured color temperature, or that the light exposure realized by the diaphragm (14) and the shutter (18) is adjusted as a function of the color temperature. A control circuit (58, 130) for effecting the adjustment includes lookup table data (130) for compensating for color-temperature-dependent sensitivity characteristics of the solid-state imaging device (22, 24). The color temperature is measured by a color temperature sensor (80, 78) or a sensor (32, 180) sensing the color component of incident light. In such a manner, changes in sensitivity characteristics of the solid-state imaging device (22, 24) or the difference in sensitivity characteristics between the solid-state imaging device (22, 24) and the light measurement device (36) as a function of the color temperature may be compensated.
Inventors
- 👤 Masahiro Fuji Photo Film Co. Ltd. Konishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 17:37
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/80; H04N23/84; H04N23/88; H04N23/70
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
196 words
An apparatus for adjusting white balance of an electronic still camera for photographing a scene by a solid-state imaging device (22, 24) to produce color video signals indicating an image of the scene, said apparatus comprising: photosensor means (32, 36, 42, 66) for receiving incident light from the scene to produce a first signal in association with a quantity of the incident light; and color temperature sensing means (80, 78) for measuring color temperature of the scene to produce a second signal in association with the color temperature; CHARACTERIZED IN THAT said apparatus further comprises: amplification means (50, 124R, 124G, 124B) for amplifying separated-color components of the color video signals and having amplification gains independently adjustable for the separated-color components; and control means (58, 130) for controlling the gains of said amplification means in response to the first and second signals; said control means (58, 130) adjusting the gains of said amplification means (50, 124R, 124G, 124B) so that average levels of the separated-color signals produced from said amplification means (50, 124R, 124G, 124B) are approximately equal to one another and maintained substantially at a predetermined value without dependency on the color temperature of the scene.
Claim 2
Independent Claim
196 words
An apparatus for adjusting white balance of an electronic still camera for photographing a scene by a solid-state imaging device (22, 24) to produce color video signals indicating an image of the scene, said apparatus comprising: photosensor means (32, 36, 42, 66) for receiving incident light from the scene to produce a first signal in association with a quantity of the incident light; and color temperature sensing means (80, 78) for measuring color temperature of the scene to produce a second signal in association with the color temperature; CHARACTERIZED IN THAT said apparatus further comprises: amplification means (50, 124R, 124G, 124B) for amplifying separated-color components of the color video signals and having amplification gains independently adjustable for the separated-color components; and control means (58, 130) for controlling the gains of said amplification means in response to the first and second signals; said control means (58, 130) adjusting the gains of said amplification means (50, 124R, 124G, 124B) so that average levels of the separated-color signals produced from said amplification means (50, 124R, 124G, 124B) are approximately equal to one another and maintained substantially at a predetermined value without dependency on the color temperature of the scene.
Claim 3
Dependent Claim
98 words
An apparatus according to claim 1, wherein, said solid-state imaging device (22, 24) includes a charge-coupled device (22, 24); CHARACTERIZED IN THAT said control means (58, 130) includes memory means (130) for storing table data (132) for deriving the gains of said amplification means (50, 124R, 124G, 124B) for the respective separated-color signals to be obtained from said charge-coupled device (22, 24) by using the first and second signals as parameters; the gains of said amplification means (50, 124R, 124G, 124B) being adjusted by referring to the table data (132) in accordance with the first and second signals.
Claim 4
Dependent Claim
68 words
An apparatus according to claim 2, CHARACTERIZED BY color separation means (50, 120) for separating output color video signals from said solid-state imaging device (22, 24) into three primary color signals of red, green and blue; said amplification means (50, 124R, 124G, 124B) including three variable-gain amplifiers having adjustable gains for amplifying respective ones of the three primary color signals produced from said color separation means (50, 120).
Claim 5
Independent Claim
176 words
An apparatus for controlling light exposure of an electronic still camera for shooting a scene by a solid-state imaging device (22, 24) for forming video signals indicating an image of the scene, said apparatus comprising: photosensitive means (32, 36, 42, 66) for receiving incident light from the scene to produce a first signal in association with a quantity of the incident light; and color temperature sensing means (80, 78) for sensing color temperature of the scene to produce a second signal in association with the color temperature; CHARACTERIZED IN THAT said apparatus further comprises: light exposure control means (14, 28, 18, 40, 66, 58) for controlling light exposure to said solid-state imaging device (22, 24) in response to the first and second signals; said light exposure control means (14, 28, 18, 40, 66, 58) controlling the light exposure to said solid-state imaging device (22, 24) in accordance with the first signal for compensating difference in sensitivity characteristics with the color temperature between said solid-state imaging device (22, 24) and said photosensitive means (32, 36, 42, 66).
Claim 6
Independent Claim
176 words
An apparatus for controlling light exposure of an electronic still camera for shooting a scene by a solid-state imaging device (22, 24) for forming video signals indicating an image of the scene, said apparatus comprising: photosensitive means (32, 36, 42, 66) for receiving incident light from the scene to produce a first signal in association with a quantity of the incident light; and color temperature sensing means (80, 78) for sensing color temperature of the scene to produce a second signal in association with the color temperature; CHARACTERIZED IN THAT said apparatus further comprises: light exposure control means (14, 28, 18, 40, 66, 58) for controlling light exposure to said solid-state imaging device (22, 24) in response to the first and second signals; said light exposure control means (14, 28, 18, 40, 66, 58) controlling the light exposure to said solid-state imaging device (22, 24) in accordance with the first signal for compensating difference in sensitivity characteristics with the color temperature between said solid-state imaging device (22, 24) and said photosensitive means (32, 36, 42, 66).
Claim 7
Dependent Claim
87 words
An apparatus according to claim 4, wherein, said solid-state imaging device (22, 24) forms color video signals; said electronic still camera including matrix circuit means for forming a luminance signal from the color video signals in accordance with a predetermined rule for signal mixing; CHARACTERIZED IN THAT said light exposure control means (14, 28, 18, 40, 66, 58) performs such a control that the luminance signal formed by said matrix circuit means is maintained substantially at a predetermined level in association with the first and second signals.
Claim 8
Dependent Claim
83 words
An apparatus according to claim 4, wherein said solid-state imaging device forms color video signals; said electronic still camera includes matrix circuit means (60) for forming a luminance signal from the color video signals in accordance with a predetermined rule of signal mixing; CHARACTERIZED IN THAT said exposure control means (14, 28, 18, 40, 60, 58) performs such a control that a G-component of the color video signals is maintained substantially at a predetermined level in association with the first and second signals.
Claim 9
Dependent Claim
71 words
An apparatus according to claim 4, wherein, said solid-state imaging device (22, 24) includes a charge-coupled device (22, 24); said photosensitive means (32, 36, 42, 66) including a silicon photodiode; CHARACTERIZED IN THAT said exposure control means (14, 28, 18, 40, 66, 58) corrects the first signal in accordance with the second signal to control light exposure to said solid-state imaging device (22, 24) in response to the thus corrected signal.
Claim 10
Dependent Claim
58 words
An apparatus according to claim 7 CHARACTERIZED IN THAT said exposure control means (14, 28, 18, 40, 66, 58) corrects a quantity of the incident light indicated by the first signal to a lower value when the color temperature indicated by the second signal is low for thereby increasing light exposure to said solid-state imaging device (22, 24).
Claim 11
Dependent Claim
26 words
An apparatus according to claim 4 CHARACTERIZED IN THAT said exposure control means controls a diaphragm (14) and a shutter (18) of said electronic still camera.
Claim 12
Independent Claim
240 words
An apparatus for controlling white balance and output signal level of an electronic still camera for shooting a scene by a solid-state imaging device (22, 24) to form color video signals indicating an image of the scene, comprising: exposure control means (14, 28, 18, 40, 66) for controlling light exposure to said solid-state imaging device (22, 24); photosensitive means (32, 36, 42, 66) for receiving incident light from the scene to produce a first signal in association with an intensity of the incident light; and color temperature sensing means (80, 78) for measuring color temperature of the scene to produce a second signal in association with the color temperature; CHARACTERIZED IN THAT said apparatus further comprises: variable amplification means (50, 124R, 124G, 124B) for amplifying separated-color signals of the video signals and having adjustable amplification gains for respective ones of the separated-color signals; and control means (58, 130) responsive to the first and second signals for controlling said exposure control means (14, 28, 18, 40, 66) and said variable amplification means (50, 124R, 124G, 124B); said control means (58, 130) maintaining output of the color video signals substantially at a predetermined level in such a manner as to compensate for change in white balance and difference in sensitivity characteristics of said solid-state imaging device (22, 24) from said photosensitive means (32, 36, 42, 66) with the quantity of the incident light and the color temperature, while adjusting the white balance.
Claim 13
Independent Claim
240 words
An apparatus for controlling white balance and output signal level of an electronic still camera for shooting a scene by a solid-state imaging device (22, 24) to form color video signals indicating an image of the scene, comprising: exposure control means (14, 28, 18, 40, 66) for controlling light exposure to said solid-state imaging device (22, 24); photosensitive means (32, 36, 42, 66) for receiving incident light from the scene to produce a first signal in association with an intensity of the incident light; and color temperature sensing means (80, 78) for measuring color temperature of the scene to produce a second signal in association with the color temperature; CHARACTERIZED IN THAT said apparatus further comprises: variable amplification means (50, 124R, 124G, 124B) for amplifying separated-color signals of the video signals and having adjustable amplification gains for respective ones of the separated-color signals; and control means (58, 130) responsive to the first and second signals for controlling said exposure control means (14, 28, 18, 40, 66) and said variable amplification means (50, 124R, 124G, 124B); said control means (58, 130) maintaining output of the color video signals substantially at a predetermined level in such a manner as to compensate for change in white balance and difference in sensitivity characteristics of said solid-state imaging device (22, 24) from said photosensitive means (32, 36, 42, 66) with the quantity of the incident light and the color temperature, while adjusting the white balance.
Claim 14
Dependent Claim
44 words
An apparatus according to claim 10 CHARACTERIZED IN THAT said control means (58, 130) performs such a control that an output level of a G-component of the separated-color signals is maintained substantially at a predetermined level in association with the first and second signals.
Claim 15
Dependent Claim
73 words
An apparatus according to claim 10, wherein said electronic still camera includes matrix circuit means (60) for forming a luminance signal from the color video signal according to a predetermined rule of signal mixing; CHARACTERIZED IN THAT said control means (58, 130) performs such a control that the luminance signal formed by said matrix circuit means (60) will be maintained substantially at a predetermined level in association with the first and second signals.
Claim 16
Dependent Claim
69 words
An apparatus according to claim 10, 11 or 12 CHARACTERIZED IN THAT said control means (58, 130) corrects the first signal in accordance with the second signal, controls said exposure means (14, 28, 18, 40, 66) and said variable amplification means (50, 124R, 124G, 124B) in accordance with the corrected signal, and controls said variable amplification means (50, 124R, 124G, 124B) by the corrected signal and the second signal.
Claim 17
Independent Claim
36 words
An apparatus according to any one of claims 10 through 13 CHARACTERIZED IN THAT said exposure control means (14, 28, 18, 40, 66) controls a diaphragm (14) and a shutter (18) of said electronic still camera.
Claim 18
Dependent Claim
106 words
An apparatus according to claim 14 CHARACTERIZED IN THAT said control means (58, 130) includes memory means for storing table data (132) for deriving the gains to be adjusted of said variable amplification means (50, 124R, 124G, 124B) for the respective separated-color components of the video signals, an opening extent of the diaphragm (14) and an exposure time of the shutter (18), with the first and second signals used as parameters; said control means (58, 130) consulting a portion of the table data (132) related with the first and second signals to control said diaphragm (14), shutter (18) and variable amplification means (50, 124R, 124G, 124B).
Claim 19
Dependent Claim
225 words
A camera control apparatus for an electronic still camera for controlling white balance and output signal level of an electronic still camera for shooting a scene by a solid-state imaging device (22, 24) to form color video signals indicating the scene, comprising: exposure control means (14, 28, 18, 40, 182) for controlling light exposure to said solid-state imaging device (22, 24); CHARACTERIZED IN THAT said apparatus further comprises variable amplification means (50, 124R, 124G, 124B) for amplifying separated-color components of the color video signals and having adjustable amplification gains for respective ones of the separated-color components; incident color component sensing means for receiving light incident from the scene to produce signals in association with respective color components of the incident light; and control means (58, 130) for controlling said variable amplification means (50, 124R, 124G, 124B) and said exposure control means (14, 28, 18, 40, 182) in response to signals from said incident color component sensing means (32, 180); said control means (58, 130) maintaining output of the color video signals substantially at a predetermined level and adjusting white balance in such a manner as to compensate for changes in the white balance and difference in sensitivity characteristics between said solid-state imaging device (22, 24) and said photosensitive means (32, 180) caused by the variable incident light quantity and the color temperature of the scene.
Claim 20
Dependent Claim
225 words
A camera control apparatus for an electronic still camera for controlling white balance and output signal level of an electronic still camera for shooting a scene by a solid-state imaging device (22, 24) to form color video signals indicating the scene, comprising: exposure control means (14, 28, 18, 40, 182) for controlling light exposure to said solid-state imaging device (22, 24); CHARACTERIZED IN THAT said apparatus further comprises variable amplification means (50, 124R, 124G, 124B) for amplifying separated-color components of the color video signals and having adjustable amplification gains for respective ones of the separated-color components; incident color component sensing means for receiving light incident from the scene to produce signals in association with respective color components of the incident light; and control means (58, 130) for controlling said variable amplification means (50, 124R, 124G, 124B) and said exposure control means (14, 28, 18, 40, 182) in response to signals from said incident color component sensing means (32, 180); said control means (58, 130) maintaining output of the color video signals substantially at a predetermined level and adjusting white balance in such a manner as to compensate for changes in the white balance and difference in sensitivity characteristics between said solid-state imaging device (22, 24) and said photosensitive means (32, 180) caused by the variable incident light quantity and the color temperature of the scene.
Claim 21
Dependent Claim
32 words
An apparatus according to claim 16 CHARACTERIZED IN THAT said light exposure control means (14, 28, 18, 40, 182) controls a diaphragm (14) and a shutter (18) of said electronic still camera.
Claim 22
Dependent Claim
115 words
An apparatus according to claim 17, CHARACTERIZED IN THAT said control means (58, 130) includes memory means for storing table data (132) for deriving the gains to be adjusted of said variable amplification means (50, 124R, 124G, 124B) for the respective separated-color components of the video signals, an opening extent of the diaphragm (14) and an exposure time of the shutter (18) using signal values from said incident color component sensing means as parameters; said control means (58, 132) consulting a portion of said table data (132) related with the signal from said incident color component sensing means (32, 180) to control said diaphragm (14), shutter (18) and variable amplification means (50, 124R, 124G, 124B).
Claim 23
Dependent Claim
126 words
An apparatus according to claim 16, 17 or 18, CHARACTERIZED IN THAT said control means (58, 130) determines color temperature of the scene from the signals of respective color components from said incident color component sensing means (32, 180), corrects the signal of the incident light quantity determined in association with signals from said incident color component sensing means (32, 180) by the thus determined color temperature, controls said exposure control means (14, 28, 18, 40, 182) and said variable amplification means (50, 124R, 124G, 124B) in response to the thus corrected signal of the incident light quantity to cause said variable amplification means (50, 124R, 124G, 124B) to be controlled in accordance with the corrected signal of the incident light quantity and the color temperature.
Claim 24
Independent Claim
55 words
An apparatus according to any one of claims 16 through 19, CHARACTERIZED IN THAT said control means (58, 130) performs such a control in accordance with the signal from said incident color component sensing means (32, 180) that an output level of a G-component of the separated-color signals is maintained substantially at a predetermined level.
Claim 25
Independent Claim
80 words
An apparatus according to any one of claims 16 through 19, wherein, said electronic still camera includes matrix circuit means (60) for forming a luminance signal from the color video signals in accordance with a predetermined rule of signal mixing; said control means (58, 130) performing such a control in accordance with signals from said incident color component sensing means (32, 180) that the luminance signal produced from said matrix circuit means (60) is maintained substantially at a predetermined level.
References Cited (Backward Citations)
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