JPH07123383A - Terminal for video conference - Google Patents

Abstract

PURPOSE:To prevent the display luminance of the image received from an opposite party from being dispersed for every opposite party by sampling the luminance of the image that each opposite party receives and adjusting the luminance level of the image of each opposite party so that the luminance of the image sampled for every opposite party may approach a standard value in a video conference system. CONSTITUTION:A luminance detection circuit 30 reads the luminance level of the image from each communication opposite party. When the luminance component of the image of the opposite party which are sampled M times for every opposite party is averaged and the component is the half, for instance, of the standard value of the luminance level of the image to be displayed on an image display device 36, a luminance amplifier circuit 32 is instructed to double the amplification factor of the luminance component of the opposite party. Therefore, the luminance level of the image displayed on the image display device 36 approaches the value of the standard value. In this case, when the luminance level of the opposite image is zero, the sampling of the luminance component of this opposite image is not performed. The reason for this is because the amplification factor for it is prevented from becoming abnormally large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal device in a video conference system for communicating multimedia (image, voice, data, etc.) with a plurality of parties via a communication line.

[0002]

2. Description of the Related Art Conventionally, a video conference system performs multimedia communication by multiplexing images, voice and data with a plurality of parties via a communication line, and mixes voices received from a plurality of parties into one. It is configured to output to a speaker and display images received from a plurality of parties on a multi-window.

[0003]

However, in the conventional example,
Normally, because the sensitivity adjustment of the camera that inputs the image on the other party varies from person to person, and the intensity of the illumination varies from person to person, if the image received from each person is displayed on the monitor with the same brightness, Brightness of each person will vary.

An object of the present invention is to provide a video conference terminal device that solves such problems.

[0005]

A video conference terminal device according to the present invention samples the brightness of an image received by each partner in a video conference system for performing multimedia communication with a plurality of partners via a communication line. It is characterized in that a sampling means and an adjusting means for adjusting the luminance level of the image of each partner are provided so that the luminance of the image sampled for each partner approaches a standard value.

[0006]

With the above means, the luminance level does not vary from one party to another when the image received from each party is output to the monitor.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows a schematic block diagram of an embodiment of the present invention. 10 is a CPU for controlling the entire apparatus, 12
Is an RO that stores programs executed by the CPU 10.
M and 14 are R for storing data used by the CPU 10.
AM, 16 is an operating device including a keyboard and a touch panel for operating the device, and 18 is an ITU-T
(Former CCITT) Recommendation G. A voice coding / decoding circuit for performing coding and decoding of a voice signal according to 722;
Is a microphone for voice input, 22 is a voice mixing circuit for mixing received voices of a plurality of partners, and 24 is a speaker for outputting voice.

Numeral 26 is ITU-T Recommendation H.264. An image encoding / decoding circuit that executes encoding and decoding of an image signal according to 261; 28, a camera that inputs an image; 30; a luminance detection circuit that detects the luminance level of the received image;
A brightness amplifier circuit for amplifying the brightness signal of the received image, 34
Is a display control circuit for displaying images of a plurality of partners on a multi-window, and 36 is a display device including an LCD or CRT for displaying images.

38 is ITU-T Recommendation H.264. Reference numeral 221 is a demultiplexing circuit that multiplexes and separates images, voices, and data according to 221, and 40 is a line control circuit that controls connection and communication with a communication line.

FIG. 2 shows an image encoding / decoding circuit 26 circuit 3
The structure of the image frame supplied to the display control circuit 34 via 0 and 32 is shown. Image signals from a plurality of partners are time-division multiplexed, and the image signals of each partner are stored in one time slot for each component.

In FIG. 2, reference numeral 50 designates a time slot for storing the luminance component Y (1) of the image signal from the partner # 1, 5
2 is a time slot for storing the color difference component Cb (1) of the image signal from the partner # 1, and 54 is a time slot for storing the color difference component Cr (1) of the image signal from the partner # 1.

Reference numeral 56 is a time slot for storing the luminance component Y (2) of the image signal from the partner # 2, 58 is a time slot for storing the color difference component Cb (2) of the image signal from the partner # 2, and 60 is the partner. Color difference component Cr of the image signal from # 2
This is a time slot for storing (2).

Reference numeral 62 is a time slot for storing the luminance component Y (3) of the image signal from the partner # 3, 64 is a time slot for storing the color difference component Cb (3) of the image signal from the partner # 3, and 66 is the partner. Color difference component Cr of the image signal from # 3
This is a time slot for storing (3).

Reference numeral 68 is a time slot for storing the luminance component Y (4) of the image signal from the partner # 4, 70 is a time slot for storing the color difference component Cb (4) of the image signal from the partner # 4, and 72 is a partner. Color difference component Cr of image signal from # 4
This is a time slot for storing (4).

FIG. 2 shows the case where there are four opponents, and the time slot 72 is followed by a time slot with the same repetition.

FIG. 3 shows a window display example of the display device 36. In FIG. 3, 74 is a screen of the display device 36 in the video conference system, 76 is a window for displaying an image received from the other party # 1 on the screen 74, and 78 is an image received from the other party # 2 on the screen 74. , A window for displaying the image received from the other party # 3 on the screen 74, and 82 for the other party # on the screen 74.
4 is a window for displaying the image received from No. 4. Figure 3
Shows the case where there are four opponents. Each window 76-
82 overlap each other.

FIG. 4 shows the memory configuration of the RAM 14.
100 is a variable N for storing the number of opponents, 102 is a variable M for storing the maximum number of samplings of the luminance component of the image received from each opponent, 104 is a standard value of the luminance level of the image displayed on the display device 36. Variable Ys, 106 is a variable I for storing the number of the partner, and 108 is a variable Y for storing the luminance component of the image of the partner I.

110 is a variable Yi (1) for storing the sum of the sampling values of the brightness components of the image of the partner # 1, and 112 is a variable Yi (2) for storing the sum of the sampling values of the brightness components of the image of the partner # 2. , 114 are variables Yi for storing the sum of the sampling values of the luminance components of the image of the partner #N.
(N).

Reference numeral 116 is a variable Mi (1) for storing the number of samplings of the brightness component of the image of the partner # 1, 118 is a variable Mi (2) for storing the number of samplings of the brightness component of the image of the partner # 2, and 120 is a partner. It is a variable Mi (N) that stores the number of times the luminance component of the image of #N is sampled.

120 is a variable Ai (1) for storing the amplification factor of the luminance component of the image of the partner # 1, 122 is a variable Ai (2), 124 for storing the amplification factor of the luminance component of the image of the partner # 2.
Is a variable A that stores the amplification factor of the luminance component of the image of the partner #N
i (N).

FIG. 5 shows a flow chart of the program stored in the ROM 12. At the start of communication, the variable N is the number of the other parties, the variable M is the maximum number of times the luminance component of the image received from each party is sampled, and the variable Ys is the image display device 3.
6, the standard value of the brightness of the image to be output from the variable Yi
It is assumed that 0 is set in (I), 0 is set in the variable Mi (I), and the initial value of the amplification factor of the luminance component of the image of the partner I is set in the variable Ai (I). Further, this program is activated each time the image frame shown in FIG. 2 is received.

First, the variable I is set to 1 (S1). If the variable I is less than or equal to the variable N, the process proceeds to S3, and if not, the process ends (S2).

The brightness level of the image of the partner I detected by the brightness detection circuit 30 is read into the variable Y (S3). If the variable Y is 0, the process proceeds to S7, and if not, the process proceeds to S5 (S5).
4). The variable Y is added to the variable Yi (I) (S5), and 1 is added to the variable Mi (I) (S6).

If the variable Mi (I) is smaller than the variable M, then S
12. If not, proceed to S8 (S7). The variable Ai (I) is multiplied by Ys / (Yi (I) / M) (S8),
The brightness amplification circuit 32 is instructed to set the amplification factor of the brightness component of the image of the partner I to the value of the variable Ai (I) (S9). The variable Yi (I) is set to 0 (S10), and the variable Mi (I) is set.
Is set to 0 (S11). 1 is added to the variable I and S2
Return to (S12).

For example, in S8, the average value Yi (I) / M of the brightness components of the sampled image of the partner I is the standard value of the brightness level of the image to be displayed on the image display device 36 (that is, the value of the variable Ys). 2), the amplification factor Ai (I) of the luminance component of the image of the partner I is doubled, and the luminance level of the image displayed on the image display device 36 approaches the value of the variable Vs.

When the variable V indicating the brightness level of the image of the partner I is 0 in S4, the luminance component of the image of the partner I is not sampled in S5 and S6. This is to prevent the average value Yi (I) / M of the luminance component from approaching 0 and the amplification factor Ai (I) of the luminance component of the image of the other party I from abnormally increasing. This is for example to prevent the amplification factor Ai (I) of the luminance component of the image of the partner I from continuing to increase when the partner I stops transmitting an image.

In the above embodiment, the ROM 12 and the RAM 14 are used as a storage device for storing programs and data, but a floppy disk, a hard disk or a memory card may be used.

In the above embodiment, ITU-T Recommendation H.264 is used as the image encoding / decoding method. 261 is adopted, MP
EG (Moving Picture Coding)
Other image encoding / decoding methods such as Experts Group) may be used.

Although a moving image is used as an image in the above embodiment, it may be a still image or a continuous still image.

In the above embodiment, ITU-T Recommendation H.264 is used as the multimedia multiplexing method. 221 is used,
A method of allocating a plurality of calls to images, voices and data may be used.

In the above embodiment, a plurality of voices of the other party are multiplexed by the time division multiplexing method, but frequency multiplexing, phase difference multiplexing and packet multiplexing may be used.

In the above embodiment, sampling is not performed when the variable Y indicating the brightness level of the image of the partner I is 0 in S4, but sampling is performed when the variable Y indicating the brightness level of the image of the partner I is smaller than a certain value. You may not.

In the above embodiment, the variable Ys is set at the start of communication, but the user may change it by operating the operating device 16 during communication. Further, the variable Ys may be set for each partner so that only the brightness of the image of the partner to be noticed can be increased.

In the above embodiment, all the luminance components sampled by the variable M times are averaged, but the larger luminance component among the sampled luminance components may be averaged by a certain number. Also, for a certain period of time, the luminance component of the image of the partner I is sampled into a variable Yi (I),
You may average by Mi (I) which is the number of times of sampling.

[0036]

As can be easily understood from the above description, according to the present invention, when displaying an image received from each partner, the brightness level does not vary from partner to partner.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention.

FIG. 2 is a frame structure diagram of an image frame according to the present embodiment.

FIG. 3 is an example of a display screen.

FIG. 4 is a memory configuration of a RAM 14.

FIG. 5 is a flowchart of a program stored in the ROM 12.

[Explanation of symbols]

10: CPU 12: ROM 14: RAM 16: Operating device 18: Voice encoding / decoding circuit 20: Microphone
22: audio mixing circuit 24: speaker 26: image encoding / decoding circuit 28: camera 30: luminance detection circuit 3
2: Luminance amplifier circuit 34: Display control circuit 36: Display device 38: Demultiplexing circuit 40: Line control circuit 50 to 72: Time slot 74: Display device screen 76: Window of partner # 1 78: Window of partner # 2 80: Window of opponent # 3 82: Window of opponent # 4 100: Variable N for storing the number of opponents N 102: Variable for storing the maximum number of times of sampling of the luminance component of the image received from each opponent M 104: On the display device 36 Variable Ys 106 that stores the standard value of the brightness level of the displayed image: Variable I that stores the number of the other party 108: Other party I
Y 110 for storing the luminance component of the image of the other party: partner # 1
Yi (1) 112 for storing the sum of the sampling values of the luminance components of the image of the other image 112: A variable Yi (2) 11 for storing the sum of the sampling values of the luminance components of the image of partner # 2 11
4: Variable Yi (N) storing the total of the sampling values of the luminance components of the image of the partner #N 116: Variable Mi (1) storing the number of samplings of the luminance component of the image of the partner # 1
118: Variable Mi (2) for storing the number of samplings of the luminance component of the image of the partner # 2 120: Variable Mi for storing the number of samplings of the luminance component of the image of the partner #N
(N) 120: Variable Ai (1) storing the amplification factor of the luminance component of the image of the partner # 1 122: Variable Ai (2) 124 storing the amplification factor of the luminance component of the image of the partner # 2 124: Partner #N Variable Ai for storing the amplification factor of the luminance component of the image
(N)

Claims (1)

[Claims] 1. In a video conference system for performing multimedia communication with a plurality of partners via a communication line, a sampling means for sampling the brightness of an image received by each partner and the brightness of the image sampled for each partner are standard values. And a adjusting means for adjusting the brightness level of the image of each of the other parties so as to approach each other.