Television – Camera – system and detail – With electronic viewfinder or display monitor
Reexamination Certificate
1995-07-26
2001-01-30
Ho, Tuan (Department: 2712)
Television
Camera, system and detail
With electronic viewfinder or display monitor
C348S352000, C396S051000
Reexamination Certificate
active
06181377
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to viewpoint detecting device.
2. Related Background Art
Imaging equipment such as video cameras have shown remarkable progress in recent years, toward a smaller size and more diversified functions.
Along with such progress, for the purpose of reducing the cumbersome operations associated with such diversified functions and of achieving the operation intended by the operator, there is being introduced the viewpoint detecting device enabling the execution of various functions and the control of various operations by viewpoint of the operator.
Such viewpoint detecting device, for example in case of a camera such as a video camera, enables focusing to a position watched by the operator or functions as a switch for executing any of the functions when a corresponding index mark is watched by the operator.
In the following there will be explained an example of the video camera in which the viewpoint detecting device is utilized for lens focusing and zooming.
The viewpoint detecting device, conventionally equipped in the video camera or the like, has the viewpoint input functions for effecting the zooming operation by selecting zooming marks “TELE” and “WIDE” displayed on the image area of the view finder with the viewpoint and the focusing operation at the watched position of said image area.
FIG. 1
is a schematic block diagram of a video camera with viewpoint switching function.
The video camera shown in
FIG. 1
is provided with a phototaking lens system
1
including a zoom lens for taking the image of an object; a view finder
3
containing a finder image area
2
for observing the object to be taken by the phototaking lens system
1
; an eyepiece lens
4
provided in front of the view finder
3
; viewpoint detection means
6
for detecting the viewpoint of an eye
5
of the photographer; a display circuit
7
for displaying, on the image area
2
, an AF frame approximately showing the focusing area, viewpoint switch marks to be explained later and other information such as tape counter and phototaking mode, required for the photographer; a system control circuit
8
for controlling various parts of the camera; a memory
9
for memorizing the coordinate values of the viewpoint switch marks on the finder image area; and an adder
10
for the outputs of the phototaking lens system
1
and the display circuit
7
.
The above-mentioned viewpoint detecting means
6
is provided with an infrared light emitting diode
60
for irradiating the eye
5
of the photographer with infrared light; a dichroic mirror
61
transmitting the visible light but reflecting the infrared light; a condenser lens
62
for condensing the infrared light reflected by said dichroic mirror
61
; a photoelectric converting element
63
for converting the infrared light, condensed by said condenser lens
62
, into an electrical signal; and a viewpoint detecting circuit
64
for determining the point watched by the photographer on the finder image area, based on the image of the eye
5
of the photographer on said photoelectric converting element
63
.
As the dichroic mirror
61
transmits the visible light, the photographer can observe the finder image area
2
through the eyepiece lens
4
. Also as the dichroic mirror
61
reflects the infrared light, the reflected image of the eye
5
, irradiated by the infrared light emitting diode
60
, is condensed by the condenser lens
62
and focused on the photoelectric converting element
63
.
The viewpoint detecting circuit
64
determines the viewpoint of the photographer on the finder image area
2
, based on the image of the eye
5
on the photoelectric converting element
63
, according to the above-mentioned principle or an algorithm disclosed in the Japanese Patent Laid-open Application Nos. 1-241511 and 2-32312.
In the following there will be explained the functions of the viewpoint switch provided in the view finder of the present conventional video camera.
An example of the display on the finder image area is schematically shown in FIG.
2
.
On the finder image area
100
, there is displayed a menu consisting of index marks
1
a
,
1
b
represented by letters “W” and “T” and indicating mutually different operations. For example “W” indicates the zooming operation toward the wide angle side, while “T” indicates that toward the telephoto side. A numeral “
902
” at the lower right corner indicates, for example, a date.
Now reference is made to a flow chart shown in
FIG. 3
, for explaining the zooming operation utilizing the viewpoint detection. Groups of coordinates of predetermined ranges including the visual switch index marks are memorized in a memory, and each group includes all the coordinates within the range of each index mark shown in FIG.
2
. These groups are represented for example by &agr; and &bgr; respectively for the wide angle side and the telephoto side. At first, when the power supply to the video camera is turned on (step S
1
), variables l and m are reset to zero (step S
2
), whereby the viewpoint switches are made ready. The variables l, m respectively indicate the numbers of coincidences of the watching point of the photographer with any of the coordinates of the groups &agr; and &bgr;. While the photographer looks into the view finder and the viewpoint detection is executed properly (step S
3
), the system control circuit
8
continuously receives the coordinate of the watching point of the photographer on the finder image area from the viewpoint detecting means
6
.
In the following there will be explained, as an example, the functions when the photographer watches the wide angle index mark “W” in the finder image area. When the coordinate of the viewpoint coincides with any of the coordinates in the group &agr; (step S
4
), the system control circuit
8
terminates any function other than the zooming operation toward the wide angle side (S
6
), then resets the variable m to 0 (S
5
), discriminates whether the variable l is equal to or larger than a predetermined number (5 in the present example) (S
6
), and, if less, adds 1 to l (S
8
). Then there is again discriminated whether l is equal to or larger than 5 (S
9
), and, if less, the sequence returns to the step S
3
to receive the coordinate of the viewpoint from the viewpoint detecting circuit
64
.
On the other hand, if the step S
9
identifies that l is equal to or larger than 5, the zoom lens is shifted toward the wide angle side, and the sequence then returns to the step S
3
to receive the coordinate of the viewpoint again. If the step S
6
identifies that l is equal to or larger than 5, the sequence jumps to a step S
11
. Even when the coordinate of the viewpoint coincides with any of the coordinates in the group &agr;, if the coordinate of the viewpoint moves outside the group &agr; before the number of coincidences reaches 5, the variable l is reset to zero (steps S
13
, S
28
). When the index mark “T” is looked at, a similar procedure is also executed.
In the above-explained configuration, however, the photographer is required to continue to look at the mark “W” for zooming toward the wide angle side or the mark “T” for zooming toward the telephoto side until the image angle reaches a value desired by the photographer by the zooming, so that the photographer becomes tired.
The above-mentioned drawback is not limited to the zooming operation but is associated with any analog adjustment of the function, and is commonly encountered in a control system utilizing the viewpoint detecting device.
SUMMARY OF THE INVENTION
In consideration of the foregoing, a first object of the present invention is to provide a viewpoint detecting device capable of alleviating the fatigue of the photographer, resulting from continued watch of the index mark.
The above-mentioned object can be attained, according to a preferred embodiment of the present invention, by a viewpoint detecting device comprising display means for displaying index marks, showing settable ranges of a predetermined function, on a monitor image
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Ho Tuan
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