JPH05292491A - Video telephone system and viewing angle controlling method for the video telephone system - Google Patents

Abstract

PURPOSE:To transmit good sized human figure images to a transmission destination by measuring the distance between a camera and the human figure and controlling the viewing angle of a zoom lens. CONSTITUTION:This method is composed of a camera 2 to which a zoom lens 37 is attached, focal distance measuring circuit 30 to measure the distance from a human figure 36 to the camera 2, and viewing angle control circuit 31 to control the viewing angle of the zoom lens. And, the viewing angle theta0 of the zoom lens 37 is set beforehand when the distance between the human figure 36 and the camera 2 is d0, for the human figure 36 to be a good size inside a display. Further, when a result (d) which the distance between the human figure 36 and the camera 2 is measured at the focal distance measuring circuit 30 is (d)=d0/2, the viewing angle control circuit 31 sets the viewing angle theta to theta=2Xtheta0. Inversely, when the result (d) which the distance between the human figure 36 and the camera 2 is measured at the focal distance measuring circuit 30 is (d)=2Xd0, the viewing angle control circuit 31 sets the viewing angle theta to be theta=theta0/2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a videophone device for transmitting and displaying a caller's image in a good size.

[0002]

2. Description of the Related Art In a portable videophone, a display and a camera are placed very close to each other, and a caller only needs to sit in front of the display to see his / her own image on the camera and be transmitted to the other party. It is common. When using a videophone for business, in addition to this, if not only one's own face but also a still image such as a document can be transmitted, conversation can be efficiently proceeded.

Conventionally, as a method of sending a still image such as a document, a method in which a camera for showing a person (face) is tilted horizontally and a document placed on a desk is shown and transmitted in Japanese Patent Laid-Open No. 3-60294. was there.

However, in a portable TV phone,
Since the display size is small (about 5 inches),
When a still image such as a document is received, it is not possible to see the details of the still image without bringing the face close to the display. Therefore, the side sending the still image receives the image of the other party who is looking at the still image with the face close to the camera (display). The received image is so large that it extends beyond the display because the face is too close to the camera. Those who see such images are unpleasant,
Those who can see it feel ashamed.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to increase or decrease the distance between a person (face) and a camera,
Even if a person appears large or small,
An object of the present invention is to provide a user-friendly TV telephone device having an image zoom function capable of transmitting a person image of a good size to a transmission destination.

[0006]

To achieve the above object, the present invention is provided with a distance measuring means for measuring a distance between a camera and a person, a zoom lens camera, and a view angle control means of the zoom lens, The distance measuring means measures the distance between the camera and the person, and when the distance between the camera and the person is short,
The angle of view is increased so that the zoom lens of the camera has a wide angle, and conversely, when the zoom lens is far away, the angle of view control unit controls the angle of view of the zoom lens so that the zoom lens has a telephoto position.

Further, the distance between the camera and the person is classified into at least three levels, and when the distance is short, the angle of view is increased,
When the distance is standard, the angle of view may be set to a standard value, and when the distance is long, the angle of view may be decreased to control.

Further, when the distance between the camera and the person becomes shorter than a certain value, the moving image to be transmitted may be stopped.

[0009]

When the distance measuring means for measuring the distance between the camera and the person is provided, the zoom lens of the camera has a wide angle when the distance between the camera and the person is short, and when the distance between the camera and the person is long, Since the angle of view of the zoom lens is controlled so that the camera lens is set to the telephoto position, a person image of an appropriate size will always be included in the viewfinder of the camera.

Further, since the distance between the camera and the person is classified into at least three and the angle of view is controlled so that the period of changing the angle of view is lengthened, the background image remains stationary for a longer period of time, and the reception time is longer. The side can receive a stable image, and the transmitting side can transmit the image with high image compression efficiency.

Further, when the distance between the camera and the person becomes shorter than a certain value, the moving image to be transmitted is stopped, thereby eliminating the need for an expensive zoom lens.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the present invention, the structure of a general TV telephone device will be described with reference to FIG. The videophone device includes a camera for displaying a person, a display for displaying the transmitted image, an image CODEC for compressing / expanding the image, a handset having a microphone and a speaker function, and a voice CODEC6 for encoding / decoding voice. , Keyboard 3 for entering phone numbers etc.
(Or a numeric keypad), an ISDN interface 8 for controlling the interface of a communication line such as ISDN, and an image CODEC7, a sound CODEC6, in accordance with an input signal from the keyboard 3.
It is composed of a telephone control circuit 5 for controlling the ISDN interface 8.

This operation will be described below. The caller picks up the handset 4 and enters the telephone number of the called party on the keyboard 3
Enter from. The input telephone number 27 is decrypted by the telephone control circuit 5 and sent to the ISDN interface 8. ISDN
The interface 8 outputs control information such as a telephone number to the ISDN line. When connected to the call destination, the ISDN interface 8 sends the connection information 23 to the telephone control circuit 5. The telephone control circuit 5 confirms the connection with the called party, and then the image CODEC7,
Start voice CODEC6.

The voice CODEC 6 receives the voice of the caller from the handset 4, converts it to digital, compresses and encodes voice information as necessary, and transmits it to the ISDN interface 8. The ISDN interface 8 transfers the encoded voice information to the ISDN line. Also, ISDN interface 8
Selects voice information from the information sent from the call destination and sends it to the voice CODEC6. The voice CODEC 6 decodes these voice information and sends it to the handset 4. The caller can hear the other party's voice from the handset 4.

The image CODEC 7 receives the image of the caller from the camera 2, converts it to digital, compresses and encodes the image, and transmits it to the ISDN interface 8. The ISDN interface 8 transfers the encoded image information to the ISDN line. Further, the ISDN interface 8 selects image information from the information sent from the call destination and sends it to the image CODEC 7.
The image CODEC7 decodes these image information and sends it to the display 1. The caller can see the image of the other party on the display 1.

Conventionally, as shown in FIG. 3, when the distance between the person 36 and the camera 2 is about 50 cm, the person 36 enters a good size (for example, just enough to fit the upper body of the person) in the display. As described above, the angle of view of the camera 2 is predetermined. Therefore, when the distance between the person 36 and the camera 2 is 25 cm, the transmitted person image is as shown in FIG.
The larger the person is, the more they protrude from the display. On the contrary, when the distance between the person 36 and the camera 2 is 100 cm, the transmitted person image becomes small as shown in FIG. 5, and it becomes very difficult to see on a small display.

Next, a block diagram of a TV telephone device which realizes a zoom function of an image capable of transmitting a person image of a good size to a transmission destination, which is a feature of the present invention, will be described with reference to FIG. The invention is the part within the dashed line in the figure.

The image zoom function of the present invention includes a camera 2 having a zoom lens 37, a focal length measuring circuit 30 for measuring the distance from the person 36 to the camera 2, and an angle of view control for controlling the angle of view of the zoom lens. It is composed of a circuit 31.

The operation of the present invention will be described below. As shown in FIG. 6A, the distance between the person 36 and the camera 2 is d.
When the value is 0, the angle of view θ0 of the zoom lens 27 is set in advance so that the person 36 has a good size in the display (for example, just enough to fit the upper half of the person).

As shown in FIG. 6B, the result d obtained by measuring the distance between the person 36 and the camera 2 by the focal length measuring circuit 30 is
When d = d0 / 2, the view angle control circuit 31 determines the view angle θ.
, Θ = 2 × θ0. As a result, person 3
6 approaches camera 2 (or display 1),
The display range displayed in the viewfinder of the camera 2 is the same as that in the case of (a).

On the contrary, as shown in FIG. 6C, the result d of measuring the distance between the person 36 and the camera 2 by the focal length measuring circuit 30.
However, when d = 2 × d0, the view angle control circuit 31 sets the view angle θ to θ = θ0 / 2. As a result, even if the person 36 retreats from the camera 2, the display range displayed in the viewfinder of the camera 2 is the same as in the case of (a).

The focal length measuring circuit used here may be a focal length detecting circuit used in a normal autofocus camera.

Next, the structure of the angle-of-view control circuit 31 is shown in FIG. The view angle control circuit 31 stores registers 50 and 51 that store the distance d0 between the reference person 36 and the camera 2 and the view angle θ0.
And a divider 52, a multiplier 53 and a switch 54.

When the angle of view is fixed, the telephone control circuit 5 controls the switch 54 so as to select the angle of view θ0.

When the angle of view is changed according to the distance d between the person 36 and the camera 2, the switch 54 is controlled so as to select the output 56 of the multiplier 53. Person 36 and camera 2
When the distances d and d0 of are input to the divider 52, d0 / d is output. When this and the angle of view θ0 are input to the multiplier 53, the angle of view θ is output.

In this example, the angle of view θ is obtained using the divider and the multiplier, but ROM may be used for the division and multiplication.

Next, a circuit configuration for controlling the angle of view d which is the second aspect of the angle of view control circuit 31 by switching the angle of view d in three stages (short distance, standard, long distance) will be described with reference to FIG. The angle-of-view control circuit 31 determines the distance d between the reference person 36 and the camera 2.
A register 50 for storing 1 and d2 and a short-distance field angle θ
1, a standard view angle θ2, a long-distance view angle θ3, a register 51, a comparator 60 and a switch 61.

Distances d1, d2 and angles of view θ1, θ2, θ
3 is set by the telephone control circuit 5. Angle of view is person 3
Depending on the distance d between the camera 6 and the camera 2, the comparator 60 and the switch 61 select from the three as follows.

(1) Case of d ≦ d1 This is a case where a person is approaching the camera. The short-distance view angle θ1 that is larger than the normal view angle is selected. As a result, the person image 36 is reduced and enters the viewfinder of the camera 2 in a standard size.

(2) Case of d1 <d <d2 This is the case where the distance d between the person 36 and the camera 2 is standard, and the standard angle of view d2 is selected.

(3) Case of d2≤d This is a case where the person is far from the camera. The long-distance view angle θ3, which is smaller than the normal view angle, is selected.
As a result, the person image 36 is enlarged and enters the viewfinder of the camera 2 in a standard size.

According to the second aspect of the invention, since the angle of view is controlled in three steps, the size of the human figure 36 is not finely controlled, and the image sent to the other party is stable. In addition, since the background image remains stationary for a long time, there is an advantage that the image compression efficiency is improved.

Next, a third invention for transmitting a still image to the other party when the distance between the person 36 and the camera 2 becomes short will be described. The view angle control circuit 31 in this case is shown in FIG. The angle-of-view control circuit 31 includes a register 50 that stores the distance d1 between the person 36 and the camera 2 serving as a reference, and a comparator 60. When the distance d between the person 36 and the camera 2 becomes smaller than d1. , The distance information 38 is provided to the telephone control circuit 5
Output to. On the other hand, the telephone control circuit 5 displays the image code
The image still information 20 is output to C7 and the transmission image is stopped. As a result, the person on the other end of the call 36
Will be transmitted.

The distance d between the person 36 and the camera 2 is d
When it is detected that the time is longer than 1, the telephone control circuit 5
Outputs the moving image start information 20 to the image CODEC 7 and restores the transmitted image to a moving image again.

As a result, the image when the person 36 gets too close to the camera 2 is not sent to the other party, so that the other party does not see the other party's face which fills the display.

[0036]

EFFECTS OF THE INVENTION A distance measuring means for measuring the distance between a camera and a person, a zoom lens camera, and an angle-of-view control means are provided so that the zoom lens of the camera has a wide angle when the distance between the camera and the person is short. When the distance between the person and the person is far, the angle of view of the zoom lens is controlled so that the camera lens is telephoto, and a person image of appropriate size is always put in the viewfinder of the camera. When using a videophone device, it is possible to enjoy a call without being aware of how oneself is reflected.

Since the receiving side can always receive a person image of an appropriate size without receiving an image in which a part of the face is enlarged or a very small image, always receive a good image. Is possible.

Further, since the distance between the camera and the person is classified into at least three stages and the angle of view is controlled so that the switching cycle of the angle of view becomes long, a moving image in which the background image is still is transmitted. Since the time becomes longer, the receiving side can receive a stable image and can efficiently compress the image.

Furthermore, when the distance between the camera and the person becomes shorter than a certain value, the moving image to be transmitted is stopped, thereby eliminating the need for an expensive zoom lens and an inexpensive TV.
A telephone device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional TV phone.

FIG. 2 is a block diagram of a video phone according to the present invention.

FIG. 3 is an explanatory diagram of an image when the distance between the camera and the person is good.

FIG. 4 is an explanatory diagram of an image when the distance between the camera and the person is short.

FIG. 5 is an explanatory diagram of an image when the distance between the camera and the person is long.

FIG. 6 is an explanatory diagram showing a relationship between a distance between a camera and a person and an angle of view.

FIG. 7 is an explanatory diagram of a first configuration example of a view angle control circuit.

FIG. 8 is an explanatory diagram of a second configuration example of the view angle control circuit.

FIG. 9 is an explanatory diagram of a third configuration example of the view angle control circuit.

[Explanation of symbols]

1 ... Display, 2 ... Camera, 3 ... Keyboard, 4 ...
Handset, 5 ... Telephone control circuit, 6 ... Voice CODEC, 7
... image CODEC, 8 ... ISDN interface, 30 ... focal length measuring circuit, 31 ... view angle control circuit, 37 ... zoom lens.

Claims (4)

[Claims] 1. A TV telephone device for transmitting a moving image,
A videophone device comprising: a camera with a zoom lens; a focal length measuring means for measuring a distance between the camera and a person; and an angle of view control means for controlling an angle of view of the zoom lens. 2. A distance between a camera and a person is measured, and when the distance is long, the person is enlarged and displayed, and when the distance is short, the person is reduced and displayed, and the person becomes a certain size in the viewfinder of the camera. An angle-of-view control method for a videophone device, comprising controlling the angle-of-view of a zoom lens of the camera as described above. 3. The storage circuit according to claim 1, wherein when the angle of view of the zoom lens is switched according to the distance between the camera and the person, at least a storage circuit for storing the distance between the camera and the person as a switching reference. Angle of view control means having one. 4. A TV telephone device for transmitting a moving image,
A video telephone device comprising a focal length measuring means for measuring a distance between a camera and a person, and transmitting a still image when the distance between the camera and the person is less than a certain distance.