JPH01286592A - Visual line coincidence video telephone system - Google Patents

Abstract

PURPOSE:To avoid steady attenuation of lightness of display and to make it compatible with the coincidence of visual line by switching the display and the picture input to a television camera in time division. CONSTITUTION:A time division split mirror 5 or a mirror type high speed shutter whose reflectance is varied timewise at a high speed by the electric or mechanical principles is placed in front of the display device 3. Then the display and the picture input to the television camera 2 are switched in time division. Then the steady attenuation of the lightness of display is avoided and the result is made compatible with the coincidence of visual line.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical field to which the invention pertains) The present invention relates to a video telephone device that can match the line of sight of a person reflected on an image display with the line of sight of a person looking at the image display. It is.

(Prior Art) As an example of the conventional videophone device is shown in FIG. The remote human eyes 1 take images of each other's faces, send them to the other party, and display them on the display 3 of the other party, as if they were face-to-face. This is a device that allows you to have a conversation as if you were actually there.

However, when the human eye 1 is looking at the display 3, the line of sight is directed towards the display.
It is out of direction from the TV camera 2. Therefore, both parties look at the display 3 directly in front of each other,
Even when they look at each other, their line of sight is shifted, giving the impression that they are looking away from each other, or looking down or up.

In order to make eye contact with the other party, both parties must look in the direction of the television camera 2, but this makes it difficult to see the display. Since it is difficult to align each other's gaze in this way, there is a problem in that it is difficult to obtain a sense of presence similar to an actual face-to-face conversation.

On the other hand, as shown in another example in FIG. 4, by using a half mirror 4 to view the reflected display image, the direction of the television camera 2 and the direction of the display on the display 3 can be made to match. proposed a method of aligning the lines of sight with each other, but the brightness of the display depends on the characteristic values (fixed values) of the reflectance and transmittance of the half mirror 4.

There was a problem in that the input signal level to the television camera was constantly attenuated. In addition, there are problems such as the discomfort caused by viewing the reflected display image, the need to install the display above or below a half mirror, and the fact that the display image does not look like a half mirror.
There was a problem in that the design of the terminal was limited because it needed to be arranged so that it would not be visible to television cameras.

(Object of the Invention) An object of the present invention is to realize a video telephone device that prevents constant attenuation of the brightness of the display and also achieves line-of-sight alignment.

(Structure of the Invention) (Characteristics of the Invention and Differences from the Prior Art) In order to achieve the above object, the present invention provides a mirror or a mirror-type high-speed shutter whose reflectance changes rapidly over time based on an electrical or mechanical principle. The main feature is that by installing the camera in front of the display, the display and image input to the television camera can be switched in a time-divided manner.

Thereby, it is possible to prevent steady attenuation of the brightness of the display and to achieve line-of-sight alignment.

A conventional line-of-sight type videophone device using a half mirror uses a mirror whose reflectance does not change over time, and is different from the present invention in this point.

(Example) FIG. 1 is a configuration diagram showing a first example of the present invention,
1 is a human eye, 2 is a television camera, 3 is a display, and 5 is a time division mirror whose reflectance changes rapidly over time. The position of the human eye is assumed to be the position where the display device 3 is viewed from directly in front, and the time division mirror 5 is placed perpendicular to the display surface on the optical central axis (X-Y) connecting the human eye and the display. Install. Further, a television camera is installed at a position where the optical axis (Z-W) reflected by the time division mirror and the image input center axis of the television camera 2 coincide.

The reflectance of the time-division mirror 5 changes rapidly, and periods in which it acts as a reflecting mirror and periods in which it acts as a mere transparent optical medium are alternately repeated. When acting as a mere transparent optical medium 1 The human eye can see the face image of the communication partner displayed on the display 0 When acting as a reflective mirror
The face of the person looking at the display is photographed by a television camera.

With this configuration, when a person's eyes look directly at the display, an image of the person's face captured from directly in front can be input to the camera and sent to the other party. As a result, if both parties communicating look directly at the display, the line of sight of the other party's video will match the line of sight of the person watching.

As the above-mentioned time division mirror 5, an element whose optical transmittance and reflectance change depending on voltage, such as a transmissive liquid crystal element or an electrochromic element, is used.
A voltage signal is changed in a high-speed alternating current manner and applied to the element, and the state in which it acts as a transparent optical medium and the state in which it acts as a single reflecting mirror are alternately repeated at high speed.

In addition, a mechanical shutter can also be used as the time division mirror 5. If a mechanical shutter is used, the surface of the shutter can be treated to become a reflective mirror, so that the reflection state and the transmission can be adjusted. The states can be alternately repeated, and the same functions as those using the liquid crystal element or electrochromic element described above can be achieved.

The reflectance and transmittance values of a time division mirror are not intermediate values between reflection and transmission like a half mirror, but are completely reflected when acting as a reflecting mirror and completely when acting as a transmission medium. By selecting the mirror to be transparent, the brightness of the display and the level of the input signal to the TV camera will not constantly attenuate, and when the mirror is in the transparent state, the brightness of the display can be seen as it is. can. Furthermore, when the mirror is in a reflective state, a single person's facial image can be photographed with the same brightness.

In this embodiment, the video signal input to the television camera is an image reflected on a one-time division mirror (a person's face image) and an image transmitted through the time division mirror (background transmitted through the mirror), which are alternately repeated. is input. The image that is desired to be transmitted to the other party during a videophone call is only the human face image reflected on the time-division mirror, and it is desirable to delete the input signal when the mirror is in the transparent state and transmit it selectively.

FIG. 2 shows a second embodiment of the present invention for such selective image input, in which 6 is a clock signal generator, and a time division mirror 5 as shown in FIG. 2(A) is used. is switched between a reflective state A1 and a transparent state A2. Reference numeral 7 denotes a high-speed input camera which, in synchronization with the clock signal shown in Fig. 2 (A) above, captures an image at high speed (camera shooting time Bi) as shown in Fig. 2 (B) within the time period when the mirror is in the reflection state A1. can be taken in.

As the high-speed input camera 7, by using a camera using a CCD image sensor or an MO8 image sensor,
One image frame can be captured in a minute time of 0 seconds or less. Further, these image sensors can be brought into an imaging state only during a necessary period of time by means of an externally applied electric signal, and images can be selectively input without imaging during unnecessary periods of time.

Therefore, the time division mirror can be set to 1/1 by the clock signal.
By keeping the mirror in the reflective state for only a minute period of about 1,000 seconds and simultaneously capturing images at high speed in synchronization with the clock signal, it is possible to selectively input only the image reflected by the mirror to the camera.

In a video signal such as a normal videophone, 10
Since ~30 image frames are transmitted and received, assuming that the imaging time for one image frame is 1/1000 seconds, the actual time that the time division mirror is in the reflecting state (that is, the camera is in the imaging state) is , 0.01 seconds to 0.0 seconds per second.
Since the mirror is in a transparent state for the rest of the time, the brightness and visibility of the display are hardly affected.

(Effect of the invention) As explained above, the present invention is a time division mirror.

Alternatively, by installing a mirror-type high-speed shutter in front of the display, it is possible to switch between the display display and the image input to the TV camera in a time-divided manner, which prevents constant attenuation of the brightness of the display display. At the same time, it is possible to realize a videophone device that is compatible with line-of-sight alignment.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the first embodiment of the present invention, Fig. 2 is a block diagram of the second embodiment in which images can be selectively input only when the mirror is in a reflective state, and Fig. 3 is a block diagram of the second embodiment. FIG. 4 is a block diagram of a conventional videophone device using a half mirror. 1...Human eye, 2...TV camera, 3.
・・Display unit, 4・half mirror 15・
・・Time division mirror, 6 ・・Clock signal generator,
7...High-speed input camera. Patent Applicant: Nippon Telegraph and Telephone Corporation Figure 1 2 Television camera Figure 2 Figure 3 Figure 4 Figure 4 Half mirror

Claims (1)

[Claims] A mirror or mirror-shaped high-speed shutter whose reflectance changes rapidly over time is installed in front of the display on the optical central axis connecting the display surface and the position of the eyes of a person looking directly at the display. A television camera is installed at a position where the optical axis reflected by the mirror or mirror-type high-speed shutter coincides with the image input center axis of the television camera, and the display display and image input to the television camera are switched in a time-divided manner. Eye-line matching videophone device.