JP3074653B2 - Image communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image communication apparatus for transmitting an image, such as a videophone or a video conference system.

[0002]

2. Description of the Related Art In a video conference system, a camera is provided with a swing function so as to be able to capture the facial expressions of each of the conference attendees, in response to an operation on the transmission side or a request from the reception side. Thus, the camera can be pointed in a desired direction.

[0003]

SUMMARY OF THE INVENTION By the way, CCITT
Recommendation H. (International Telegraph and Telephone Advisory Committee) In the coding method of H.261, the difference from the previous frame is transmitted as an image signal, and the larger the difference from the previous frame, the larger the data amount. If the amount of data increases in this way, the amount of free space in the transmission buffer decreases, and if the amount of free space decreases, the quantization step size of the image data increases, and as a result, those with poor image quality are transmitted. Will be.

[0004] Therefore, when the camera is swung, an image different from the previous frame is naturally transmitted. Therefore, during the swing, the image quality is significantly deteriorated, and the communication partner (reception side) is not transmitted. Gives discomfort. In addition, even when the camera stops swinging, it takes a long time until the image captured by the stopped camera becomes vivid because the amount of free space in the transmission buffer is small at that time. There is a disadvantage.

The present invention has been made in view of the above circumstances, and prevents a communication partner from being uncomfortable by sending a low-quality image while the camera is swung.
It is an object of the present invention to provide an image communication device capable of hastening the refinement of an image when the camera has stopped swinging.

[0006]

An image communication apparatus according to the present invention is an image communication apparatus for inputting an image obtained by one camera to a transmission buffer and transmitting the image to a partner, and moving the camera. And control means for stopping input of an image to the transmission buffer and transmitting a difference signal while the camera is moving, and for starting input of an image to the transmission buffer when the movement of the camera is stopped. It is characterized by that.

[0007]

According to the above arrangement, the input of an image is stopped while the camera is moving, and for example, it is only necessary to transmit a "no difference" signal indicating that there is no difference from the data in the frame memory. By this "no difference" signal, the communicating party will continue to see the image of the previous frame even while the camera is moving, thereby relieving the discomfort of seeing an image of poor quality. Also, the "no difference" signal, which is quantitatively less than the difference signal, reduces the amount of data in the transmission buffer and increases the free space in the buffer. Therefore, when the movement of the camera is stopped and the input of a new image is started, image data with a reduced quantization step size is transmitted due to the increase in the space of the buffer, and the received image is refined. It will be done soon. When a new image input is started, the input image is output as it is instead of the difference signal.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a schematic configuration of a video conference system as an image communication device. The video conference system includes an imaging camera 1 for converting a captured video into an electric signal, a display 2 for displaying the video, and a video connected to the imaging camera 1 and the display 2 for encoding / decoding a video signal. A codec 3, a multi-demultiplexer 4 connected to the video codec 3 for switching signals, and a network interface 5 connected to the multi-demultiplexer 4 for connecting a network to the video conference system. , Said multi-
A delay 6 connected to the demultiplexer 4, an audio codec 7 connected to the delay 6, an audio input / output unit 8 connected to the audio codec 7, and an end connected to the multi-demultiplexer 4. An end signal controller 9 and an end / network signal controller 10 connected to the network interface 5
And these end-to-end signal control section 9 and end-to-end signal
The system includes a system control unit 11 connected to the network signal control unit 10 and a swing mechanism unit 12 for changing the direction of the imaging camera 1.

The system control section 11 drives the swing mechanism section 12 in response to an operation on the transmission side or a request from the reception side, and changes the direction of the imaging camera 1. Further, when the system control unit 11 starts swinging the imaging camera 1,
While the input of the image by the imaging camera 1 is stopped,
When the movement of the imaging camera 1 is stopped, control is performed so that image input by the imaging camera 1 is started.

FIG. 2 is a flowchart showing the control of the image input stop during the camera swing by the system control unit 11. First, it is determined whether or not there is a request to change the direction of the camera 1 from the receiving side (S1). If there is a direction changing request, the process proceeds to step 3; It is determined whether the direction change operation has been performed (S2). If there is no change operation, the process ends. If there is a change operation, the camera swing operation to the designated change position is started (S3), and the imaging camera 1
Is stopped (S4). When the image input is stopped, a "no difference" signal indicating that there is no difference from the data in the frame memory is transmitted.

Next, it is determined whether or not the imaging camera 1 has moved to a position facing a designated direction (S5). If it has not moved to the position, the determination in step 5 is continued,
When the camera has moved to the position, the camera swing operation is terminated (S6), the data in the frame memory is deleted, and the image input by the imaging camera 1 is restarted (S7), and the process returns.

According to the above arrangement, when the camera 1 starts swinging, the input of the image is stopped and "no difference" indicating that there is no difference from the data in the frame memory.
By transmitting the signal, the communication partner is set to the imaging camera 1
The user will continue to see the image of the previous frame even during the swing of the camera, so that he / she is free from the discomfort of seeing a video with poor image quality. Also, the "no difference" signal reduces the amount of data in the transmission buffer and increases the free space in the buffer. For this reason, when the image pickup camera 1 stops swinging and a new image input is started, image data with a reduced quantization step size is transmitted due to an increase in the space in the buffer, and the received image is refined. Will be done earlier. When a new image input is started, the input image is output as it is instead of the difference signal.

As described above, since the "no difference" signal is output during the swing of the imaging camera 1 as described above, the image is captured on the receiving screen immediately before the start of the camera swing. The moving image is continuously displayed, and it is not possible to know where the camera is facing while the camera is moving, but it is possible to point the imaging camera 1 in a desired direction. For example, when requesting a camera orientation change from the receiving side, several camera positions are determined in correspondence with several directions in which the imaging camera 1 will be turned, and the receiving side is set to a desired direction. What is necessary is just to automatically change the direction of the camera in the direction to obtain the desired image by designating the corresponding position number.
Also, when changing the direction of the camera by operation on the sending side,
In order to confirm the camera direction separately from the video to be transmitted, the image signal of the imaging camera 1 can be directly guided to a display dedicated to camera direction confirmation. Of course, even in this case, the image input to the video codec 3 is stopped.

[0014]

[0015]

As described above, according to the present invention, in an image communication apparatus for transmitting an image obtained by one camera, a low-quality image is displayed on a receiving side while the camera is moving. In addition to this, it is possible to achieve an effect that the received image after the movement of the camera is stopped can be quickly refined.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a video conference system as one embodiment of the present invention.

FIG. 2 is a flowchart showing image input stop control during camera swing in a system control unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Imaging camera 2 Display 3 Video codec 11 System control part 12 Swing mechanism part

Claims (1)

(57) [Claims] 1. An image obtained by one camera is transmitted.
An image communication device that inputs data to a buffer and sends it to the other party.
Means for moving the camera, and inputting an image to the transmission buffer while the camera is moving.
An image communication apparatus, comprising: a control unit that stops and transmits a no difference signal and starts inputting an image to a transmission buffer when the movement of the camera is stopped.