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EP0335656A1
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EP
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Automatic focus control apparatus
Assignee: Sony Corp
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Filing: 1989-03-28
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Granted: —
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Expires: 2009-03-28
Abstract
Abstract An automatic focus control apparatus (1) makes use of the chromatic aberration of a lens (2), such as a zoom lens (2) of a video camera, to detect focus position information on the basis of amplitude values of respective primary colour signals derived by an image pick-up element (3), and hence control the focus of the lens (2).
Inventors
- 👤 Masanobu C/O Patents Division Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 17:59
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/60; H04N23/67; H04N23/95; H04N23/958; H04N23/959; G; G03; G03B; G03B13/00; G03B13/32; G03B13/34; G03B13/36; G03B3/00; G03B3/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
97 words
Automatic focus control apparatus (1) characterized by: lens means (2) having chromatic aberration; means (3) for converting an optical signal obtained through said lens means (2) to an electrical signal; means (4,5) for processing said electrical signal to obtain a plurality of primary colour signals; means (7,8) for detecting the amplitude level of each of said primary colour signals; means (10) for generating a control signal according to levels of said primary colour signals derived from said level detecting means (7,8); and means (15) for controlling the position of said lens in response to said control signal.
Claim 2
Dependent Claim
97 words
Automatic focus control apparatus (1) characterized by: lens means (2) having chromatic aberration; means (3) for converting an optical signal obtained through said lens means (2) to an electrical signal; means (4,5) for processing said electrical signal to obtain a plurality of primary colour signals; means (7,8) for detecting the amplitude level of each of said primary colour signals; means (10) for generating a control signal according to levels of said primary colour signals derived from said level detecting means (7,8); and means (15) for controlling the position of said lens in response to said control signal.
Claim 3
Dependent Claim
18 words
Apparatus (1) according to a claim 1 wherein said primary colour signals are red, green and blue signals.
Claim 4
Dependent Claim
57 words
Apparatus (1) according to claim 1 or claim 2 wherein said detecting means (7,8) comprises separate series circuits of a filter (7) and a level detector (8) provided for each of said primary colour signals, and first switch means (9) for selectively supplying an output of said level detectors (8) to said control signal generating means (10).
Claim 5
Dependent Claim
42 words
Apparatus (1) according to claim 3 wherein said control signal generating means (10) normalizes the outputs of said level detectors (8) by respectively dividing said outputs by the amplitude levels of the corresponding primary colour signals supplied by said processing means (4,5).
Claim 6
Dependent Claim
26 words
Apparatus (1) according to claim 4 further comprising second switch means (11) for selectively supplying said primary colour signals to said control signal generating means (10).
Claim 7
Dependent Claim
31 words
Apparatus (1) according to claim 5 further comprising analogue-to-digital converter means (12,13) for separately converting the outputs of said level detectors (8) and the output of said second switch means (11).
Claim 8
Dependent Claim
44 words
Apparatus (1) according to claim 6 wherein said control signal generating means (10) includes stored information representing level orders of said primary colour signals versus each focus point of said primary colours, and wherein said control signal is generated according to said stored information.
Claim 9
Dependent Claim
62 words
Apparatus (1) according to any one of the preceding claims wherein said lens means (2) is a zoom lens (2) and said apparatus (1) further comprises means (17) for detecting the zoom amount of said zoom lens (2), the output of said zoom amount detecting means (17) being supplied to said control signal generating means (10) for compensation of said control signal.
Claim 10
Dependent Claim
30 words
Apparatus (1) according to claim 2 further comprising a matrix circuit (6) for converting said red, green and blue primary colour signals to a luminance signal and colour difference signals.
References Cited (Backward Citations)
DE3443558A1
Cited
EP0260990A2
Cited
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