EP0263510A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Automatic focusing device
Assignee: Canon Inc
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Filing: 1987-10-07
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Granted: —
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Expires: 2007-10-07
Abstract
Abstract An automatic focusing device which is arranged to perform a focusing action by detecting the peak value of a high frequency component of a video signal obtained from within a focus detecting area set on the image sensing plane of an image sensor and by driving a photo taking optical system in such a way as to increase the detected peak value comprises: a peak position detecting circuit which locates a position on the image sensing plane at which the peak value of the high frequency component of the video signal is detected; and a gate control circuit which changes the position of the focus detecting area in accordance with the detected peak position which is located by the peak position detecting circuit.
Inventors
- 👤 Takeshi Baba
- 👤 Yukichi Niwa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 11:09
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/60; H04N23/67; H04N23/673
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
116 words
A focus detecting device for detecting a focal point by obtaining a focus signal corresponding to a focused degree from a video signal obtained from within a focus detecting area which is set on the image sensing plane of image sensing means, comprising: a) peak detecting means for detecting the peak value of said focus signal corresponding to a focused degree obtained from within said focus detecting area; b) position detecting means for detecting a position at which said peak value is detected within said focus detecting area on said image sensing plane; and c) position control means for controlling the position of said focus detecting area according to the output of said position detecting means.
Claim 2
Dependent Claim
116 words
A focus detecting device for detecting a focal point by obtaining a focus signal corresponding to a focused degree from a video signal obtained from within a focus detecting area which is set on the image sensing plane of image sensing means, comprising: a) peak detecting means for detecting the peak value of said focus signal corresponding to a focused degree obtained from within said focus detecting area; b) position detecting means for detecting a position at which said peak value is detected within said focus detecting area on said image sensing plane; and c) position control means for controlling the position of said focus detecting area according to the output of said position detecting means.
Claim 3
Dependent Claim
41 words
A device according to claim 1, further comprising focal point adjusting means which is arranged to perform a focusing action by driving a photo taking optical system in the direction of increasing the peak value detected by said peak detecting means.
Claim 4
Dependent Claim
34 words
A device according to claim 1, wherein said peak detecting means is arranged to detect the peak value of the high frequency component of a video signal obtained from within said focus detecting area.
Claim 5
Dependent Claim
51 words
A device according to claim 3, wherein said peak detecting means and said position detecting means are arranged to detect the peak value of said high frequency component and the detected position thereof within said focus detecting area every time a vertical scanning action is performed on said image sensing plane.
Claim 6
Dependent Claim
47 words
A device according to claim 1, wherein said position control means is arranged to shift the focus detecting area to such a position as to have the peak position which is detected by said position detecting means located in the middle part of said focus detecting area.
Claim 7
Dependent Claim
39 words
A device according to claim 1, wherein said position control means is arranged to vary the size of said focus detecting area as well as to control the position of said focus detecting area on said image sensing plane.
Claim 8
Dependent Claim
41 words
A device according to claim 5, wherein said position control means is arranged to reduce the size of said focus detecting area after said focus detecting area which is detected by said position detecting means is shifted to a new position.
Claim 9
Dependent Claim
46 words
A device according to claim 1, wherein said position control means is arranged to set said focus detecting area in the middle part of the image sensing plane in a predetermined size as a standard focus detecting area at the beginning of a focus detecting action.
Claim 10
Dependent Claim
27 words
A device according to claim 1, wherein a restricting area is set on said image sensing plane to limit the shiftable range of said focus detecting area.
Claim 11
Dependent Claim
61 words
A device according to claim 6, wherein said position control means is arranged to bring said focus detecting area back to said standard focus detecting area when the detected position on said image sensing plane of said peak value obtained from within said focus detecting area has remained outside of said restricting area for more than a predetermined period of time.
Claim 12
Dependent Claim
36 words
A device according to claim 3, wherein said position control means is arranged not to shift said focus detecting area when said peak value obtained from within said focus detecting area is below a predetermined level.
Claim 13
Dependent Claim
73 words
A device according to claim 2, wherein said focal point adjusting means is arranged to drive and shift said photo taking optical system to the end of an optical system shifting range when the peak value detected by said peak detecting means is below a predetermined level; and to bring the focal point adjusting action thereof to a stop when said peak value remains below said predetermined level throughout the whole shifting range.
Claim 14
Dependent Claim
162 words
A device according to claim 1, wherein said peak detecting means includes a peak detecting circuit which is arranged to produce a peak detection signal every time the peak value of the high frequency component of the video signal obtained by scanning said image sensing plane is detected; said position detecting means includes a counter which is arranged to be reset for every vertical scanning action on said image sensing plane and a peak position detecting circuit which is arranged to produce the count value of said counter as position information in response to said peak detection signal; and said position control means includes a gate control circuit which is arranged to control the focus detecting area on said image sensing plane by varying the passing range of said video signal and a micro-processor which is arranged to control said gate control circuit on the basis of the output of said peak detecting circuit and that of said peak position detecting circuit.
Claim 15
Independent Claim
84 words
A device for following an object imaged on an image sensing plane, comprising: a) peak detecting means for detecting the peak value of a high frequency component obtained within a follow-up area set on said image sensing plane; b) position detecting means for detecting a position at which said peak value is detected on said image sensing plane within said follow-up area; and c) position control means for controlling the position of said follow-up area according to the output of said position detecting means.
Claim 16
Independent Claim
84 words
A device for following an object imaged on an image sensing plane, comprising: a) peak detecting means for detecting the peak value of a high frequency component obtained within a follow-up area set on said image sensing plane; b) position detecting means for detecting a position at which said peak value is detected on said image sensing plane within said follow-up area; and c) position control means for controlling the position of said follow-up area according to the output of said position detecting means.
Claim 17
Dependent Claim
32 words
A device according to claim 14, wherein said follow-up area is used also as a focus detecting area within which the degree of focus on an object to be photographed is detected.
Claim 18
Dependent Claim
62 words
A device according to claim 14, wherein said peak detecting means is arranged to detect the peak value of said high frequency component obtained by every vertical scanning action on said image sensing plane; and said position detecting means is arranged to detect the position on said image sensing plane of said peak value every time said vertical scanning action is performed.
Claim 19
Dependent Claim
34 words
A device according to claim 14 or 16, wherein said position control means is arranged to change the position of said follow-up area to a peak detecting position detected by said position detecting means.
Claim 20
Dependent Claim
21 words
A device according to claim 17, wherein said position control means is arranged to vary the size of said follow-up area.
Claim 21
Dependent Claim
28 words
A device according to claim 17, wherein, on said image sensing plane, there is set a follow-up limit area for limiting the shiftable limit of said follow-up area.
Claim 22
Dependent Claim
47 words
A device according to claim 19, wherein said position control means is arranged to set, at the beginning of the follow-up action of the device, said follow-up area in the middle part of said image sensing plane as an initial area which is of a predetermined size.
Claim 23
Dependent Claim
52 words
A device according to claim 20, wherein said position control means is arranged to set said follow-up area in said initial area in case that the detected position of said peak value on said image sensing plane remains outside of said follow-up limit area for more than a predetermined period of time.
Claim 24
Independent Claim
84 words
A device for detecting a movement of an object to be photographed, comprising: a) peak detecting means for detecting the peak value of a high frequency component obtained from within a detecting area set on an image sensing plane; b) location detecting means for detecting a location at which said peak value is detected on said image sensing plane; and c) movement detecting means for detecting a movement of said object on the basis of changes in the output of said location detecting means.
Claim 25
Independent Claim
84 words
A device for detecting a movement of an object to be photographed, comprising: a) peak detecting means for detecting the peak value of a high frequency component obtained from within a detecting area set on an image sensing plane; b) location detecting means for detecting a location at which said peak value is detected on said image sensing plane; and c) movement detecting means for detecting a movement of said object on the basis of changes in the output of said location detecting means.
Claim 26
Dependent Claim
28 words
A device according to claim 22, further comprising shifting means for shifting said detecting area to the location of said peak value detected by said location detecting means.
Claim 27
Dependent Claim
35 words
A device according to claim 22 or 23, wherein said peak detecting means and said location detecting means are arranged to operate every time a vertical scanning action is performed on said image sensing plane.
References Cited (Backward Citations)
No citation records indexed.
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