Patent EP0318278A2 successfully refreshed from Google Patents.
EP0318278A2
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Automatic focusing apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1988-11-24
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Granted: —
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Expires: 2008-11-24
Abstract
Abstract An automatic focusing apparatus uses an image signal provided by a taking lens system of a camera for focusing the taking lens system. The apparatus comprises: a taking lens system; a pickup element for converting the optical image of an object formed by the taking lens system into a corresponding electric signal; a signal processing circuit which processes the output signal of the pickup element to provide two focus signals corresponding to the respective quantities of horizontal and vertical high-frequency components of the object in an image plane; a lens driving mechanism for driving the taking lens system; and a control unit for controlling the lens driving mechanism according to the two focus signals to focus the taking lens system. Preferably, the apparatus further comprises: a detector for detecting the condition of the object or taking conditions; and a changeover circuit for changing over the characteristics of the signal processing circuit on the basis of the output of the detector. The additional use of information about the vertical direction enable focusing the taking lens system for any object including such as a horizontal line. Since the characteristics of the signal processing circuit are changed selectively according to the condition of the object or taking conditions, stable and accurate focusing operation can be achieved regardless of the variation of the condition of the object.
Inventors
- 👤 Ryuichiro Kuga
- 👤 Masayuki Yoneyama
- 👤 Teruyoshi Miura
- 👤 Yoshiaki Hirao
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 18:25
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36; G02B7/365; H; H04; H04N; H04N23/00; H04N23/60; H04N23/67; H04N23/673
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
102 words
An automatic focusing apparatus comprising: a taking lens system including a focusing lens unit; photoelectric conversion means for converting an optical image formed by the taking lens system into a corresponding electric signal; signal processing means for generating first and second focus signals respectively corresponding to the quantities of horizontal and vertical high-frequency components of an image plane on the basis of the output signal of the photoelectric conversion means; lens driving means for driving the focusing lens unit; and control means for controlling the lens driving means according to the first and second focus signals to focus the taking lens system.
Claim 2
Dependent Claim
102 words
An automatic focusing apparatus comprising: a taking lens system including a focusing lens unit; photoelectric conversion means for converting an optical image formed by the taking lens system into a corresponding electric signal; signal processing means for generating first and second focus signals respectively corresponding to the quantities of horizontal and vertical high-frequency components of an image plane on the basis of the output signal of the photoelectric conversion means; lens driving means for driving the focusing lens unit; and control means for controlling the lens driving means according to the first and second focus signals to focus the taking lens system.
Claim 3
Dependent Claim
208 words
An automatic focusing apparatus according to Claim 1, wherein said signal processing means comprises: horizontal differentiation means for removing dc component of a horizontal signal included in the output signal of the photoelectric conversion means; gate signal generating means for generating a signal for extracting a central portion of the image plane; first gate means for sampling signals on a time axis from an output of the horizontal differentiation means in response to the signal from the gate signal generating means; horizontal band-pass filter means for extracting the horizontal high-frequency signal component from an output signal of the first gate means; first rectifying means for generating a first focus signal by rectifying an output of the horizontal band-pass filter means; vertical differentiation means for removing dc component of a vertical signal from the output signal of the photoelectric conversion means; second gate means for sampling signals on a time axis from an output of the vertical differentiation means in response to the signal from the gate signal generating means; vertical band-pass filter means for extracting the vertical high-frequency signal component from anoutput signal of the second gate means; and second rectifying means for generating a second focus signal by rectifying an output of the vertical band-pass filter means.
Claim 4
Dependent Claim
25 words
An automatic focusing apparatus according to Claim 2, wherein each of said first and second rectifying means comprise series connected rectifying circuit and adding circuit.
Claim 5
Dependent Claim
88 words
An automatic focusing apparatus according to Claim 3, wherein said rectifying circuit comprises: an absolute value circuit for providing an absolute value of an input signal inputted to the rectifying circuit; a low-pass filter; a comparator for comparing an output signal of the low-pass filter and an output signal of the absolute value circuit; and switching means controlled by an output of the comparator for selectively applying either the output signal of the low-pass filter or the output signal of the absolute value circuit to the low-pass filter.
Claim 6
Dependent Claim
65 words
An automatic focusing apparatus according to Claim 3, wherein said adding circuit comprises: a comparator for comparing the level of an input signal inputted to the adding circuit with a predetermined level; switching means for selectively providing either the input signal or a signal of zero level according to an output of the comparator; and an integrator for integrating output signals of the switching means.
Claim 7
Dependent Claim
134 words
An automatic focusing apparatus comprising: a taking lens system including a focusing lens unit; photoelectric conversion means for converting an optical image of an object formed by the taking lens system into a corresponding electric signal; signal processing means for generating first and second focus signals respectively corresponding to the quantities of horizontal and vertical high-frequency components of an image plane on the basis of an output signal of the photoelectric conversion means; detecting means for detecting a condition of the object or a taking condition; changeover means for selectively changing over characteristics of the signal processing means according to an output of the detecting means; lens driving means for driving the focusing lens unit; and control means for controlling the lens driving means for focusing according to the first and second focus signals.
Claim 8
Dependent Claim
134 words
An automatic focusing apparatus comprising: a taking lens system including a focusing lens unit; photoelectric conversion means for converting an optical image of an object formed by the taking lens system into a corresponding electric signal; signal processing means for generating first and second focus signals respectively corresponding to the quantities of horizontal and vertical high-frequency components of an image plane on the basis of an output signal of the photoelectric conversion means; detecting means for detecting a condition of the object or a taking condition; changeover means for selectively changing over characteristics of the signal processing means according to an output of the detecting means; lens driving means for driving the focusing lens unit; and control means for controlling the lens driving means for focusing according to the first and second focus signals.
Claim 9
Dependent Claim
27 words
An automatic focusing apparatus according to Claim 6, wherein said detecting means includes focal length detecting means for detecting a focal length of said taking lens system.
Claim 10
Dependent Claim
25 words
An automatic focusing apparatus according to claim 6, wherein said detecting means includes aperture detecting means for detecting f number of the taking lens system.
Claim 11
Dependent Claim
23 words
An automatic focusing apparatus according to Claim 6, wherein said detecting means includes peak detecting means for detecting a luminance of the object.
Claim 12
Dependent Claim
237 words
An automatic focusing apparatus according to Claim 6, wherein said signal processing means comprises: horizontal differentiation means for removing dc component of a horizontal signal included in the output signal of said photoelectric conversion means; gate signal generating means for generating a signal for extracting a central portion of the image plane; first gate mane for sampling signals on a time axis from an output of the horizontal differentiation means in response to the output signal of the gate signal generating means; horizontal band-pass filter means for extracting a horizontal high-frequency signal component from an output signal of the first gate means; first rectifying means for rectifying an output of the horizontal band-pass filter means to generate a first focus signal; vertical differentiation means for removing dc component of a vertical signal included in the output signal of the photoelectric conversion means; second gate means for sampling signals on a time axis from an output of the vertical differentiation means in response to the output signal of the gate signal generating means; vertical band-pass filter means for extracting a vertical high-frequency signal component from an output signal of the second gate means; and second rectifying means for rectifying an output of the vertical band-pass filter means to generate a second focus signal, wherein characteristics of at least either the horizontal band-pass filter means or the vertical band-pass filter means are changed over selectively by said changeover means.
Claim 13
Dependent Claim
25 words
An automatic focusing apparatus according to Claim 10, wherein each of said first and second rectifying means comprise series connected rectifying circuit and adding circuit.
Claim 14
Dependent Claim
88 words
An automatic focusing apparatus according to Claim 11, wherein said rectifying circuit comprises: an absolute value circuit for providing the absolute value of an input signal inputted to the rectifying circuit; a low-pass filter; a comparator for comparing an output signal of the low-pass filter and an output signal of the absolute value circuit; and switching means controlled by an output of the comparator for selectively applying either the output signal of the low-pass filter or the output signal of the absolute value circuit to the low-pass filter.
Claim 15
Dependent Claim
66 words
An automatic focusing apparatus according to Claim 11, wherein said adding circuit comprises: a comparator for comparing a level of an input signal inputted to the adding circuit with a predetermined level; switching means for selectively providing either the input signal of the adding circuit or a zero input according to an output of the comparator; and an integrator for integrating outputs of the switching means.
Claim 16
Dependent Claim
33 words
An automatic focusing apparatus according to Claim 10, wherein the characteristics of said horizontal band-pass filter means or the vertical band-pass filter means are changed by changing coefficients of the respective filter means.
References Cited (Backward Citations)
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