Photography – Eye tracking
Reexamination Certificate
2001-08-17
2002-09-24
Perkey, W. B. (Department: 2851)
Photography
Eye tracking
C396S123000
Reexamination Certificate
active
06456788
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improvements of an optical apparatus and a camera having line-of-sight detecting means for detecting a line of sight, i.e. gazing point of a user.
2. Description of the Related Art
An apparatus is known, which detects a gazing point of a photographer, that is, his line-of-sight direction from an output from a sensor for detecting an image of the photographer's eyeball. A camera having a line-of-sight detecting function has been provided, which uses the photographer's line of sight to select a focus detecting area (hereinafter referred to as “the AF point”) reflecting the photographer's intention.
Apparatuses of this kind are based on the fact that a point on an observing screen that the observer (photographer) intends to observe coincides with his line of sight (the point on the screen which he is actually viewing). However, the observer's line of sight actually deviates from his intention, and for example, even if he intends to view a predetermined point, his line of sight may temporally delay in reaching the point. Further, after the observer's line of sight has coincided with the point the observer intends to view, it may be affected by a human physiological factor; the line of sight may move due to fine movement of the observer's eyeball. Moreover, the observing apparatus may tremble while being held by the photographer, to change the relative positional relationship between the observer's eyeball and the observing apparatus, thereby moving the gazing point obtained through the line-of-sight detection. These factors cause the detected line of sight to deviate from the point on the observing screen that the observer intends to observe.
Thus, the observer's line of sight does not always coincide with the point on the observing screen that he intends to observe, and the gazing point obtained through the line-of-sight detection is distributed to a certain extent with respect to the point that the observer intends to observe. That is, the detected gazing point reflects the point that the observer intends to observe, but is not always accurate.
Thus, to compensate for this, proposals have been made, which take into consideration defocus information on the AF point near the gazing point as well as the reliability of the line-of-sight detection, that is, how reliable results of the line-of-sight detection are.
According to U.S. Pat. No. 6,229,959, focusing is carried out by selecting one of a plurality of AF points near the gazing point based on defocus information on these AF points. According to U.S. Pat. No. 5,614,985, focusing is carried out by selecting one of AF points adjacent the gazing point. Further, according to Japanese Laid-Open Patent Publication (Kokai) No. 11-014897, when the camera is in a vertical position, the line-of-sight detection is not so reliable, so that focusing is carried out by selecting one of AF points vertically adjacent one selected by the line-of-sight detection.
These prior art techniques make it prerequisite that AF point is selected based on the line of sight and that the gazing point obtained from the observer's line of sight is present near the AF point, and determine the AF point near or adjacent the gazing point.
Further, a plurality of areas constituting a range of AF points which can be selected for focusing concentrate in the vicinity of the location of the gazing point or consist of areas adjacent the AF point selected based on the gazing point. Therefore, the selection range of AF points is not set to be wide.
Moreover, if a small number of AF points are arranged in one dimension, the selection range can be extended only in the one dimension. Further, there already exists a camera in which AF points are arranged in two dimensions, but the extension of the selection range and its direction must be indicated. Further, the observer's gazing point does not always lead to a high probability that a main subject is present at one of the plurality of AF points arranged on the observing screen.
According to Japanese Laid-Open Patent Publication (Kokai) No. 8-152552, each AF point is weighted based on gazing point information, the reliability thereof and also weighted based on defocus information. Then, an AF point having the highest score based on the sum of the resulting two weighted values is selected, and focusing is carried out based on defocus information obtained from the selected AF point.
The defocus information, however, must be calculated for each of the AF points, so that a long time is required after the weighting calculation based on the gazing point information and the reliability thereof has been started and before one AF point is selected. Thus, the prior art leaves room for improvement; it is desirable that a proper AF point can be selected even if the actually detected line of sight deviates significantly from the observer's intention and that the time required for selecting the AF point is reduced.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an optical apparatus and a camera having line-of-sight detecting means, which are capable of selecting a proper AF point selected even if the actually detected line of sight deviates significantly from the observer's intention and capable of reducing the time required for selecting the AF point.
To attain the above object, a first aspect of the present invention provides an optical apparatus comprising a plurality of focus detecting areas provided on an observing screen and from which focus information on a subject is detected, a line-of-sight detecting device that picks up an image of an eyeball of a user to detect a location of a gazing point of the user, a grouping circuit that groups the focus detecting areas into a plurality of groups with priorities based on the detected location of the gazing point, and a selecting circuit that selects one of the groups according to the priorities and selects at least one focus detecting area from the selected group.
Preferably, the optical apparatus according to the first aspect further comprises a position detecting device that detects position information on a position of the optical apparatus, and the grouping circuit groups the focus detecting areas into the plurality of groups with priorities based on the detected location of the gazing point and the detected position information.
Preferably, the optical apparatus according to the first aspect further comprises a reliability determining circuit that determines reliability of the detected location of the gazing point, and the grouping circuit groups the focus detecting areas into the plurality of groups with priorities based on the detected location of the gazing point and-a result of the determination of the reliability.
Also preferably, the grouping circuit executes the grouping according to preset tables.
In a preferred embodiment, the selecting circuit executes a process of selecting a focus detecting area from a group with a higher priority of the plurality of groups, and if the selection from this group fails, executes a process of selecting a focus detecting area from each of the remaining groups by sequentially lowering the priority of the group until the selection succeeds.
Preferably, the plurality of groups includes a group with a highest priority that contains a focus detecting area near the location of the gazing point.
Also preferably, the selecting circuit uses different selecting methods between a group with a highest priority and the other groups of the plurality of groups.
More preferably, the optical apparatus according to the first aspect further comprises a correcting circuit that corrects individual differences in eyeball characteristics of the user, and the reliability determining circuit determines the reliability of the detected location of the gazing point using a size of the user's pupil detected by the correcting circuit and a number of corrections executed by the correctin
Perkey W. B.
Robin Blecker & Daley
LandOfFree
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