Television – Camera – system and detail – With electronic viewfinder or display monitor
Reexamination Certificate
1997-04-24
2001-02-20
Garber, Wendy (Department: 2712)
Television
Camera, system and detail
With electronic viewfinder or display monitor
C348S333020
Reexamination Certificate
active
06191819
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a picture-taking apparatus having the capability of detecting a point viewed by an eye of a user.
It is known in the art that the point viewed by a user is detected so that the object corresponding to the viewed-point is brought in focus (refer to, for example, Japanese Patent Laid-Open Nos. 1-241511 and 2-32312). The inventor of this invention has also proposed a selection-by-viewing technique in which marks representing various functions such as zooming, fading, etc., are displayed on a viewfinder screen of a video camera so that a user can select one of these by viewing a desired mark (Japanese Patent Application No. 4-202).
However, there are some problems in a technique in which the focus area moves to follow the viewed-point. That is, a user must always view an object to be focused. If the user makes a quick scan over the entire area of a viewing screen with his/her eye to know the features of a scene, the focus area moves quickly to follow the movement of the viewed-point, which results in an unsightly image. Even if the user tries to view an object as fixedly as he/she can, the viewed-point always moves slightly because human eyes have small movements called flicks that cannot be controlled. Therefore, the AF (autofocus) area in the viewfinder flickers following the movement of the viewed-point, which may be offensive to the eye of the user.
Furthermore, another problem occurs if the mechanism for automatically focusing an image at a moving point viewed by a user is combined with the selection-by-viewing mechanism proposed by the inventor of the present invention in Japanese Patent Application No. 4-202. That is, when the AF area is in the middle of movement to follow the point viewed by a user, if the user views a selection-by-viewing mark displayed in a peripheral area of the viewfinder to use the selection-by-viewing capability, then the AF area also moves following the movement of the viewed-point and thus an object different from the desired one is unintentionally brought in focus.
Furthermore, in tracking AF techniques used in conventional video cameras in which the focus area moves to follow a moving subject, if the subject to be focused is in an end area of the viewing screen, a user has to move the subject to the middle of the viewing screen because the focus area initially is located at the middle of the viewing screen. Moreover, if an object that is tracked by the AF mechanism crosses another object located at a distance similar to that of the tracked object, there is a possibility that the correct tracking is lost.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the present invention to provide a video camera having capabilities of easy focusing and stable function selection by means of viewing.
The above object is achieved by the present invention having various aspects described below. That is, according to one aspect of the present invention, there is provided a video camera having autofocus capability or the capability of automatically focusing an object image formed in a focus area on the screen of a viewfinder, wherein the video camera comprises viewed-point detecting means that detects a plurality of points on the viewfinder screen viewed by a user and determines a representative viewed-point from the plurality of detected viewed-points using a statistical technique; and setting means for setting a focus area on the viewfinder screen or an AF frame representing the outline of the focus area such that the representative viewed-point detected by the viewed-point detecting means is positioned at the center of the focus area or the AF frame wherein the focus area or the AF frame follows the movement of the viewed-point.
In this video camera, since a representative viewed-point is given from a plurality of viewed-points, various kinds of control can be accomplished stably regardless of a certain degree of flicker in the viewed-point.
According to another aspect of the present invention, there is provided a video camera which further comprises fixing means for fixing the position of the above-described focus area or the AF frame.
With this arrangement, a user can aim his/her eye at an object on the viewfinder screen, and then can fix the focus area or the AF frame there using the fixing means. Thus, the user does not need to always view an object to be focused.
According to still another aspect of the present invention, there is provided a video camera further comprising control means for controlling the movement of the focus area or the AF frame such that when the focus area or the AF frame is fixed at a viewed-point if an object in the focus area or the AF frame moves then the control means moves the focus area or the AF frame to follow the movement of the object.
With this arrangement, when the focus area or the AF frame is fixed at a viewed-point even if an object in the focus area or the AF frame moves, the focus area or the AF frame moves following the movement of the object, thereby keeping the object within the focus area.
According to another aspect of the present invention, there is provided a video camera comprising a selection-switch-by-viewing for selecting a function in such a manner that if the viewed position stays at one of a plurality of marks indicating different functions displayed on the viewfinder screen then the function designated by the mark is activated; selection means for selecting whether the marks associated with the selection-switch-by-viewing are displayed on the viewfinder screen or not; and control means for suppressing the movement of the focus area or the AF frame even if the point viewed by a user stays at a mark as long as the marks are displayed according to the selection decision of the above selection mean.
With the above arrangement, when the marks are displayed on the viewfinder screen according to the decision of the selection means, even if the point viewed by a user stays at a mark, the above control means suppresses the movement of the AF frame of the focus area so that the focus area does not move unnecessarily.
According to a further aspect of the present invention, there is provided a video camera comprising a selection-switch-by-viewing for selecting a function in such a manner that if the viewed position stays at one of a plurality of marks indicating different functions displayed on the viewfinder screen then the function designated by the mark is activated; and control means for controlling the display of the marks associated with the selection-switch-by-viewing in such a manner that the marks are not displayed when the focus area or the AF frame is moving to follow the movement of the viewed-point, and the marks are displayed and thus the selection-switch-by-viewing becomes available when the focus area or the AF frame is fixed at a viewed-point.
With this arrangement, the marks associated with the selection-switch-by-viewing are displayed on the viewfinder screen only when the focus area or the AF frame is fixed, so that the focus area does not move unnecessarily.
REFERENCES:
patent: 4595990 (1986-06-01), Garwin et al.
patent: 5253008 (1993-10-01), Konishi et al.
patent: 5541655 (1996-07-01), Kaneda
patent: 5606390 (1997-02-01), Arai et al.
patent: 1-241511 (1989-09-01), None
patent: 2-32312 (1990-02-01), None
patent: 5304631 (1992-12-01), None
patent: 5110925 (1993-04-01), None
patent: 5-183798 (1993-07-01), None
patent: 5183798 (1993-07-01), None
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Garber Wendy
Harrington Alicia M.
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