US5579049A
Expired / Lapsed
US
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Apparatus and method for controlling exposure by shutter speed control and/or gain control
Assignee: Fujifilm Corp
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Filing: 1993-12-22
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Granted: 1996-11-26
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Expires: 2013-12-22
Abstract
Abstract An object of the present invention is to bring a video signal obtained by imaging into a proper level without use of a controllable diaphragm. An imaging apparatus is provided with no controllable diaphragm. Peak detection is performed by a peak detecting circuit for each vertical scanning interval. A peak value is applied to a control device. Necessary shutter speed control in a shutter control circuit, gain control in a pre-amplifier circuit and gain control in a GCA are carried out. Consequently, the level of the video signal obtained by the imaging is adjusted to a proper level without controlling a diaphragm, to obtain an image of proper brightness.
Inventors
- 👤 Hiroshi Shimaya
- 👤 Yutaka Maeda
- 👤 Chiaki Ichikawa
- 👤 Toshio Nakajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:11
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/70; H04N23/72; H04N23/73
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
270 words
An imaging apparatus comprising: shutter means in which a shutter speed is variable; imaging means for imaging a subject under exposure conditions realized by said shutter means to output a video signal representing an image of the subject; amplifying means for amplifying the video signal outputted from said imaging means; a peak detecting circuit for performing peak detection of the video signal outputted from said imaging means; an average level detecting circuit for detecting an average level of the video signal outputted from said imaging means; first level difference detecting means for detecting a first peak level difference between a peak level obtained by said peak detecting circuit and a proper peak level; shutter controlling means for controlling said shutter means so that said first peak level difference becomes small; second level difference detecting means for detecting a second level difference between the peak level obtained by said peak detecting circuit and the average level obtained by said average level detecting circuit; and controlling means for carrying out at least one of shutter speed control in said shutter means and gain control in said amplifying means so that said detected average level approaches a proper average level when the second level difference detected by said second level difference detecting means exceeds a reference value, while carrying out at least one of the shutter speed control in said shutter means and the gain control in said amplifying means so that at least said detected peak level approaches said proper peak level when the second level difference detected by said second level difference detecting means is not more than said reference value.
Claim 2
Dependent Claim
270 words
An imaging apparatus comprising: shutter means in which a shutter speed is variable; imaging means for imaging a subject under exposure conditions realized by said shutter means to output a video signal representing an image of the subject; amplifying means for amplifying the video signal outputted from said imaging means; a peak detecting circuit for performing peak detection of the video signal outputted from said imaging means; an average level detecting circuit for detecting an average level of the video signal outputted from said imaging means; first level difference detecting means for detecting a first peak level difference between a peak level obtained by said peak detecting circuit and a proper peak level; shutter controlling means for controlling said shutter means so that said first peak level difference becomes small; second level difference detecting means for detecting a second level difference between the peak level obtained by said peak detecting circuit and the average level obtained by said average level detecting circuit; and controlling means for carrying out at least one of shutter speed control in said shutter means and gain control in said amplifying means so that said detected average level approaches a proper average level when the second level difference detected by said second level difference detecting means exceeds a reference value, while carrying out at least one of the shutter speed control in said shutter means and the gain control in said amplifying means so that at least said detected peak level approaches said proper peak level when the second level difference detected by said second level difference detecting means is not more than said reference value.
Claim 3
Dependent Claim
104 words
The imaging apparatus according to claim 1, wherein said amplifying means comprises a first amplifier circuit for amplifying the video signal outputted from said imaging means and a second amplifier circuit for finely adjusting the level of the video signal outputted from said first amplifier circuit, said controlling means carrying out gain control in said first amplifier circuit when at least one of a difference between said detected average level and the proper average level, and the difference between said peak level and the proper peak level is large, while carrying out gain control in said second amplifier circuit when the difference is small.
Claim 4
Dependent Claim
162 words
An image apparatus comprising: shutter means in which a shutter speed is variable; imaging means for imaging a subject under exposure conditions realized by said shutter means to output a video signal representing an image of the subject; amplifying means for amplifying the video signal outputted from said imaging means; a peak detecting circuit for performing peak detection of the video signal outputted from said imaging means; an average level detecting circuit for detecting an average level of the video signal outputted from said imaging means; level difference detecting means for detecting a level difference between a peak level obtained by said peak detecting circuit and the average level obtained by said average level detecting circuit; and controlling means for carrying out shutter speed control in said shutter means and gain control in said amplifying means so that said detected average level approaches a proper average level, when the level difference detected by said level difference detecting means exceeds a reference value.
Claim 5
Dependent Claim
162 words
An image apparatus comprising: shutter means in which a shutter speed is variable; imaging means for imaging a subject under exposure conditions realized by said shutter means to output a video signal representing an image of the subject; amplifying means for amplifying the video signal outputted from said imaging means; a peak detecting circuit for performing peak detection of the video signal outputted from said imaging means; an average level detecting circuit for detecting an average level of the video signal outputted from said imaging means; level difference detecting means for detecting a level difference between a peak level obtained by said peak detecting circuit and the average level obtained by said average level detecting circuit; and controlling means for carrying out shutter speed control in said shutter means and gain control in said amplifying means so that said detected average level approaches a proper average level, when the level difference detected by said level difference detecting means exceeds a reference value.
Claim 6
Dependent Claim
92 words
The imaging apparatus according to claim 3, wherein said amplifying means comprises a first amplifier circuit for amplifying the video signal outputted from said imaging means and a second amplifier circuit for finely adjusting the level of the video signal outputted from said first amplifier circuit, said controlling means carrying out gain control in said first amplifier circuit when a difference between said detected average level and the proper average level is large, while carrying out gain control in said second amplifier circuit when said difference between the average levels is small.
Claim 7
Dependent Claim
108 words
The imaging apparatus according to claim 3, further comprising weighted average level calculating means for calculating a weighted average level of the peak level obtained by said peak detecting circuit and the average level obtained by said average level detecting circuit at a predetermined ratio, said controlling means carrying out at least one of the shutter speed control in said shutter means and the gain control in said amplifying means so that the weighted average level obtained by said weighted average level calculating means approaches a proper weighted average level when the level difference detected by said level difference detecting means is not more than said reference value.
Claim 8
Dependent Claim
67 words
The imaging apparatus according to claim 3, wherein said controlling means carries out at least one of the shutter speed control in said shutter means and the gain control in said amplifying means so that the peak level obtained by said peak detecting circuit becomes a proper peak level, when the level difference detected by said level difference detecting means is not more than said reference value.
Claim 9
Dependent Claim
122 words
The imaging apparatus according to claim 3, further comprising weighted average level calculating means for calculating a weighted average level of the peak level obtained by said peak detecting circuit and the average level obtained by said average level detecting circuit at a predetermined ratio, said controlling means carrying out at least one of the shutter speed control in said shutter means and the gain control in said amplifying means so that at least one of the weighted average level and the peak level obtained by said peak detecting circuit approaches corresponding one of a proper weighted average level and a proper peak level, when said level difference detected by said level difference detecting means is not more than said reference value.
Claim 10
Dependent Claim
52 words
The imaging apparatus according to claim 3, further comprising: peak level difference detecting means for detecting a peak level difference between the peak level obtained by said peak detecting circuit and a proper peak level; and shutter controlling means for controlling said shutter means so that said peak level difference becomes smaller.
Claim 11
Dependent Claim
36 words
The imaging apparatus according to claim 3, wherein said controlling means carries out both the shutter speed control and the gain control, when the level difference detected by said difference detecting means exceed the reference value.
Claim 12
Dependent Claim
216 words
An imaging apparatus comprising: shutter means in which a shutter speed is variable; imaging means for imaging a subject under exposure conditions realized by said shutter means to output a video signal representing an image of the subject; amplifying means for amplifying the video signal outputted from said imaging means; a peak detecting circuit for detecting a peak level of the video signal outputted from said imaging means; an average level detecting circuit for detecting an average level of the video signal outputted from said imaging means; weight ratio determining means for determining a weight ratio so that the larger a level difference between the peak level detected by said peak detecting circuit and the average level detected by said average level detecting circuit is, the larger the weight ratio is, whereas the smaller the level difference is, the smaller the weight ratio is; weighted average level calculating means for calculating a weighted average level of the detected peak level and the detected average level using the weight ratio determined by said weight ratio determining means; and controlling means for carrying out shutter speed control in said shutter means and gain control in said amplifying means so that the weighted average level calculated by said weighted average level calculating means approaches a proper weighted average level.
Claim 13
Dependent Claim
216 words
An imaging apparatus comprising: shutter means in which a shutter speed is variable; imaging means for imaging a subject under exposure conditions realized by said shutter means to output a video signal representing an image of the subject; amplifying means for amplifying the video signal outputted from said imaging means; a peak detecting circuit for detecting a peak level of the video signal outputted from said imaging means; an average level detecting circuit for detecting an average level of the video signal outputted from said imaging means; weight ratio determining means for determining a weight ratio so that the larger a level difference between the peak level detected by said peak detecting circuit and the average level detected by said average level detecting circuit is, the larger the weight ratio is, whereas the smaller the level difference is, the smaller the weight ratio is; weighted average level calculating means for calculating a weighted average level of the detected peak level and the detected average level using the weight ratio determined by said weight ratio determining means; and controlling means for carrying out shutter speed control in said shutter means and gain control in said amplifying means so that the weighted average level calculated by said weighted average level calculating means approaches a proper weighted average level.
Claim 14
Dependent Claim
94 words
The imaging apparatus according to claim 10, wherein said amplifying means comprises a first amplifier circuit for amplifying the video signal outputted from said imaging means and a second amplifier circuit for finely adjusting the level of the video signal outputted from said first amplifier circuit, said controlling means carrying out the gain control in said first amplifier circuit when a level difference between said calculated weighted average level and the proper weighted average level is large, while carrying out the gain control in said second amplifier circuit when said level difference is small.
Claim 15
Dependent Claim
26 words
The imaging apparatus according to claim 10, further comprising illuminating means for illuminating the subject, said imaging means imaging the subject illuminated by said illuminating means.
Claim 16
Dependent Claim
35 words
The imaging apparatus according to claim 10, wherein said controlling means carries out both the shutter speed control and the gain control so that the calculated weighted average level approaches the proper weighted average level.
Claim 17
Dependent Claim
213 words
In an imaging apparatus comprising an electronic shutter in which a shutter speed is controlled, an imaging device for imaging a subject under exposure conditions realized by said electronic shutter to output a video signal representing an image of the subject, and an amplifier circuit for amplifying the video signal outputted from said imaging device, a method of controlling the imaging apparatus comprising the steps of: detecting a peak level and an average level of the video signal outputted from said imaging device; detecting a first peak level difference between the detected peak level and a proper peak level, and a second level difference between the detected peak level and the detected average level; controlling the shutter speed in said electronic shutter so that the first peak level difference becomes small; and carrying out at least one of the shutter speed control in said electronic shutter and gain control in said amplifier circuit so that said detected average level approaches a proper average level when said second level difference exceeds a reference value, while carrying out at least one of the shutter speed control and the gain control so that at least said detected peak level approaches the proper peak level, when the second level difference is not more than said reference value.
Claim 18
Dependent Claim
213 words
In an imaging apparatus comprising an electronic shutter in which a shutter speed is controlled, an imaging device for imaging a subject under exposure conditions realized by said electronic shutter to output a video signal representing an image of the subject, and an amplifier circuit for amplifying the video signal outputted from said imaging device, a method of controlling the imaging apparatus comprising the steps of: detecting a peak level and an average level of the video signal outputted from said imaging device; detecting a first peak level difference between the detected peak level and a proper peak level, and a second level difference between the detected peak level and the detected average level; controlling the shutter speed in said electronic shutter so that the first peak level difference becomes small; and carrying out at least one of the shutter speed control in said electronic shutter and gain control in said amplifier circuit so that said detected average level approaches a proper average level when said second level difference exceeds a reference value, while carrying out at least one of the shutter speed control and the gain control so that at least said detected peak level approaches the proper peak level, when the second level difference is not more than said reference value.
Claim 19
Dependent Claim
103 words
The method according to claim 14, wherein said amplifier circuit comprises a first amplifier circuit for amplifying the video signal outputted from said imaging device and a second amplifier circuit for finely adjusting the level of the video signal outputted from said first amplifier circuit, said method further comprising: carrying out gain control in said first amplifier circuit when at least one of a difference between said average level and the proper average level and the difference between said peak level and the proper peak level is large, while carrying out gain control in said second amplifier circuit when said difference is small.
Claim 20
Dependent Claim
133 words
In an imaging apparatus comprising an electronic shutter in which a shutter speed is controlled, an imaging device for imaging a subject under exposure conditions realized by said electronic shutter to output a video signal representing an image of the subject, and an amplifier circuit for amplifying the video signal outputted from said imaging device, a method of controlling the imaging apparatus comprising the steps of: detecting a peak level and an average level of the video signal outputted from the imaging device; detecting a level difference between the detected peak level and the detected average level; and carrying out shutter speed control in said electronic shutter and gain control in said amplifier circuit so that said detected average level approaches a proper average level when said level difference exceeds a reference value.
Claim 21
Dependent Claim
133 words
In an imaging apparatus comprising an electronic shutter in which a shutter speed is controlled, an imaging device for imaging a subject under exposure conditions realized by said electronic shutter to output a video signal representing an image of the subject, and an amplifier circuit for amplifying the video signal outputted from said imaging device, a method of controlling the imaging apparatus comprising the steps of: detecting a peak level and an average level of the video signal outputted from the imaging device; detecting a level difference between the detected peak level and the detected average level; and carrying out shutter speed control in said electronic shutter and gain control in said amplifier circuit so that said detected average level approaches a proper average level when said level difference exceeds a reference value.
Claim 22
Dependent Claim
93 words
The method according to claim 16, wherein said amplifier circuit comprises a first amplifier circuit for amplifying the video signal outputted from said imaging device and a second amplifier circuit for finely adjusting the level of the video signal outputted from said first amplifier circuit, said method further comprising: carrying out gain control in said first amplifier circuit when a difference between the detected average level and the proper average level is large, while carrying out the gain control in said second amplifier circuit when said difference between the average levels is small.
Claim 23
Dependent Claim
73 words
The method according to claim 16, further comprising: calculating a weighted average level of the detected peak level and the detected average level at a predetermined ratio; and carrying out at least one of the shutter speed control in said electronic shutter and the gain control in said amplifier circuit so that said weighted average level approaches a proper weighted average level when said level difference is not more than said reference value.
Claim 24
Dependent Claim
52 words
The method according to claim 16, further comprising: carrying out at least one of the shutter speed control in said electronic shutter and the gain control in said amplifier circuit so that the detected peak level becomes a proper peak level when said level difference is not more than said reference value.
Claim 25
Dependent Claim
89 words
The method according to claim 16, further comprising: calculating a weighted average level of the detected peak level and the detected average level at a predetermined ratio; and carrying out at least one of the shutter speed control in said electronic shutter and the gain control in said amplifier circuit so that selected one of said weighted average level and the detected peak level approaches corresponding one of a proper weighted average level and a proper peak level when said level difference is not more than said reference value.
Claim 26
Dependent Claim
41 words
The method according to claim 16, further comprising: detecting a peak level difference between the detected peak level and a proper peak level; and controlling the shutter speed in said electronic shutter so that the detected peak level difference becomes small.
Claim 27
Dependent Claim
27 words
The method according to claim 16, wherein both the shutter speed control and the gain control are carried out, when said level difference exceeds the reference value.
Claim 28
Dependent Claim
174 words
In an imaging apparatus comprising an electronic shutter in which a shutter speed is controlled, an imaging device for imaging a subject under exposure conditions realized by said electronic shutter to output a video signal representing an image of the subject, and an amplifier circuit for amplifying a video signal outputted from said imaging device, a method of controlling the imaging apparatus comprising the steps of: detecting a peak level and an average level of the video signal outputted from said imaging device; determining a weight ratio so that the larger a level difference between said detected peak level and said detected average level is, the larger the weight ratio is, whereas the smaller said level difference is, the smaller the weight ratio is; calculating a weighted average level of said peak level and said average level in accordance with the determined weight ratio; and carrying out shutter speed control in said electronic shutter and gain control in said amplifier circuit so that the calculated weighted average level approaches a proper weighted average level.
Claim 29
Dependent Claim
174 words
In an imaging apparatus comprising an electronic shutter in which a shutter speed is controlled, an imaging device for imaging a subject under exposure conditions realized by said electronic shutter to output a video signal representing an image of the subject, and an amplifier circuit for amplifying a video signal outputted from said imaging device, a method of controlling the imaging apparatus comprising the steps of: detecting a peak level and an average level of the video signal outputted from said imaging device; determining a weight ratio so that the larger a level difference between said detected peak level and said detected average level is, the larger the weight ratio is, whereas the smaller said level difference is, the smaller the weight ratio is; calculating a weighted average level of said peak level and said average level in accordance with the determined weight ratio; and carrying out shutter speed control in said electronic shutter and gain control in said amplifier circuit so that the calculated weighted average level approaches a proper weighted average level.
Claim 30
Dependent Claim
96 words
The method according to claim 23, wherein said amplifier circuit comprises a first amplifier circuit for amplifying the video signal outputted from said imaging device and a second amplifier circuit for finely adjusting the level of the video signal outputted from said first amplifier circuit; said method further comprising: carrying out the gain control in said first amplifier circuit when a difference between said calculated weighted average level and the proper weighted average level is large, while carrying out the gain control in said second amplifier circuit when said difference between the average levels is small.
Claim 31
Dependent Claim
29 words
The method according to claim 23, further comprising: illuminating the subject; and imaging the subject under the illumination to obtain the video signal representing the image of the subject.
Claim 32
Dependent Claim
32 words
The method according to claim 23, wherein both the shutter speed control and the gain control are carried out so that the calculated weighted average level approaches the proper weighted average level.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1999-11-26 | 2000-05-27 | 2000-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-26 | 2004-05-27 | 2004-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-26 | 2008-05-27 | 2008-11-26 | $7700.00 | Window Closed / Lapsed |