JPH05328338A - Moving image coding device - Google Patents

Abstract

PURPOSE:To make it unnecessary to manually turn off a transmitting image and to prevent the display of the transmitting image from interrupting the observation of a receiving image. CONSTITUTION:A moving variable judging circuit 4 calculates the mean value of the amplitude of one frame in an inter-frame difference signal (c), and when the mean value is more than a previously determined threshold, outputs an image synthesis request signal (e) and a timer circuit 5 continuously outputs an image synthesis control signal (f) for a prescribed time based upon the signal (e). A digital image synthesis control circuit 6 controls an image transmission signal (d) based upon the signal (f) and changes the size of the transmission image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an image synthesizing control circuit of a moving picture coder. In particular, the present invention relates to an image synthesis control circuit that synthesizes a transmission image signal and a reception image signal. In particular, the present invention relates to an image composition control circuit for automatically switching the picture-in-picture size of a video conference system.

[0002]

2. Description of the Related Art Conventionally, a moving picture coding apparatus synthesizes a transmission image signal and a reception image signal, and if the transmission image has a picture-in-picture function so that the transmission image can be viewed on a reception image monitor apparatus, it is synthesized. The size of the image is unchanged,
Human beings decided whether to "turn on" or "off" by external control.

[0003]

However, in such a conventional moving picture coding apparatus, when the movement of the transmitted image is small, it is not necessary to see the image by the monitor device, so that it is difficult to see the received image. There was an annoying problem because human beings were "off" one by one so that it would not become.

The present invention solves the above problems.
It is an object of the present invention to provide a moving picture coding apparatus that does not require the transmission image to be turned off manually and that does not disturb the reception image.

[0005]

According to the present invention, an analog-digital converter for inputting an analog image transmission signal, converting it into a digital signal and outputting the image transmission signal, and an analog-digital converter for inputting this image transmission signal, one frame before A noise reducer that generates an inter-frame difference signal from the difference signal with the image transmission signal and outputs the image transmission signal of the current frame, and a digital image reception signal are input and combined with this image transmission signal of the current frame to generate an image synthesis signal. In a moving image coding apparatus including a digital image synthesizing control circuit for outputting and a digital-analog converter for converting the image synthesizing signal into an analog signal, an amount of motion of an image is measured based on the generated inter-frame difference signal. A motion amount determination circuit that outputs an image synthesis request signal based on the measured amount of movement, and a motion amount determination circuit that outputs the image synthesis request signal A timer circuit for continuously outputting an image synthesis control signal to the digital image synthesis control circuit for a predetermined time, and the digital image synthesis control circuit outputs the image transmission signal of the current frame to be synthesized based on the image synthesis control signal. It is characterized by including means for controlling and changing the size of the transmitted image.

Further, according to the present invention, the motion amount determining means calculates an average value of the amplitudes of one frame of the inter-frame difference signal, and the calculated average value is equal to or more than a predetermined threshold value. Means for outputting an image synthesis request signal may be included.

Further, according to the present invention, the noise reducer reduces a noise level of an output signal of this subtractor by performing a non-linear conversion on a subtracter for subtracting the image transmission signal from an input image transmission signal one frame before. A non-linear level converter that outputs an inter-frame difference signal, an adder that adds the inter-frame difference signal and the image transmission signal of the preceding frame to output the image transmission signal of the current frame, and the present frame And a frame memory for temporarily storing the image transmission signal of 1) and outputting it as the image transmission signal of the preceding frame.

[0008]

The motion amount determination circuit measures the image motion amount based on the inter-frame difference signal generated by the noise reducer,
An image synthesis request signal is output based on the measured amount of movement. The timer circuit outputs an image synthesis control signal to the digital image synthesis control circuit continuously for a predetermined time based on the image synthesis request signal. The digital image synthesis control circuit controls the image transmission signal of the current frame to be synthesized based on the image synthesis control signal to change the size of the transmission image.

As described above, it is not necessary to manually "turn off" the transmitted image, and it is possible to prevent the received image from being disturbed.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a moving picture coding apparatus according to an embodiment of the present invention.

In FIG. 1, a moving picture coding apparatus includes an analog-digital converter 2 which receives an analog image transmission signal a from a camera 1, converts it into a digital signal, and outputs a digital image transmission signal b as an image transmission signal, The noise reducer 3 which inputs the digital image transmission signal b, generates the inter-frame difference signal c from the difference signal from the image transmission signal of the preceding frame, and outputs the image transmission signal d of the current frame, and the digital image reception signal g. A digital image synthesizing control circuit 6 for inputting and synthesizing with the image transmitting signal d of the current frame and outputting, and a digital-analog converter for converting the image synthesizing signal into an analog signal and outputting the analog image receiving signal h to the monitor device 8. 7 and 7.

A feature of the present invention is that the motion amount determining circuit 4 measures the motion amount of the image based on the inter-frame difference signal c and outputs the image synthesis request signal e based on the measured motion amount. , A timer circuit 5 for continuously outputting an image composition control signal f to the digital image composition control circuit 6 based on the image composition request signal e, and the digital image composition control circuit 6 outputs the image composition control signal f based on the image composition control signal f. It is characterized by including means for controlling the image transmission signal d of the frame to change the size of the transmission image.

Further, the motion amount judging means 4 calculates an average value of the amplitudes of one frame of the inter-frame difference signal c, and when the calculated average value is equal to or more than a predetermined threshold value, image synthesis is performed. It includes means for outputting the request signal e.

Further, the noise reducer 3 nonlinearly converts the noise level of the subtractor 32 for subtracting the image transmission signal b from the input image transmission signal of one frame before and the noise level of the output signal of the subtractor 32 to reduce the noise level. The non-linear level converter 30 that outputs the differential signal c and the inter-frame differential signal c
An adder 33 that outputs the image transmission signal d by adding the above and the image transmission signal one frame before, and a frame memory 31 that temporarily stores the image transmission signal d and outputs it as the image transmission signal one frame before. Including.

The operation of the moving picture coding apparatus having such a configuration will be described. FIG. 2 is a timing chart of input / output 1 signal waveforms of the timer circuit of the moving picture coding apparatus of the present invention. FIG. 3 is a diagram showing a composite screen when the motion picture of the moving picture coding apparatus of the present invention has little motion. FIG. 4 is a diagram showing a composite screen when the motion of the transmission image of the moving image encoding apparatus of the present invention is large.

In FIG. 1, an analog-digital converter 2 is an analog image transmission signal a input from the camera 1.
Is converted into a digital image transmission signal b and output to the noise reducer 3. The noise reducer 3 including the non-linear level converter 30, the frame memory 31, the subtractor 32, and the adder 33 includes an image transmission signal one frame before read from the digital image transmission signal b by the subtractor 32 from the frame memory 31. And outputs the inter-frame difference signal to the non-linear level converter 30.
At 0, the noise level of the inter-frame difference signal is reduced by the non-linear conversion to output the inter-frame difference signal c. Further, the adder 33 adds the inter-frame difference signal c and the image transmission signal of the previous frame read from the frame memory 31 again to reproduce the image transmission signal d of the current frame, and writes it in the frame memory 31 and digitally Output to the image composition control circuit 6.

The motion amount determination circuit 4 receives the inter-frame difference signal c, and calculates the average value of the amplitude of the inter-frame difference signal c as 1.
The frame data is measured, and if the average value is greater than or equal to a predetermined threshold value, it is determined that the image has large movement, and the image synthesis request signal e is output to the timer circuit 5. As shown in FIG. 2, the timer circuit 5 outputs to the image synthesis control circuit 6 an image synthesis control signal f which continues to be “on” for a predetermined time even if the image synthesis request signal e is frequently “on” or “off”. .

The image synthesis control circuit 6 is constantly input with the digital image reception signal g transmitted from the other party,
When the image composition control signal f is "OFF", the image transmission signal d input from the own camera is composed in a small size and output to the digital-analog converter 7. The digital-analog converter 7 converts the output signal of the image composition control circuit 6 into an analog image reception signal h and then displays it on the monitor device 8 as a composition screen shown in FIG.

When the movement of the transmission image input from the own camera is large, the image composite signal f is turned "on", and the image transmission signal input from the own camera is added to the digital image reception signal g transmitted from the other party. d is combined in a large size, and the monitor device 8 is displayed as a combined screen shown in FIG.
Project to.

Further, in this embodiment, as in the prior art, the composition of the received image and the transmitted image can be "off" by the image composition on / off control signal i from the outside. Further, it is possible to determine whether the combined size can be changed or fixed by an external variable size selection signal j.

[0021]

As described above, the present invention has an excellent effect that it is not necessary to manually "turn off" the transmitted image, and it is possible to prevent the received image from being disturbed.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a moving image encoding apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart of input / output signal waveforms of a timer circuit of the moving picture coding apparatus according to the present invention.

FIG. 3 is a diagram showing a composite screen when the motion picture of the moving picture coding apparatus of the present invention has little motion.

FIG. 4 is a diagram showing a composite screen when the motion of the transmission image of the moving image encoding apparatus of the present invention is large.

[Explanation of symbols]

 1 camera 2 analog-digital converter 3 noise reducer 4 motion amount determination circuit 5 timer circuit 6 image synthesis control circuit 7 digital-analog converter 8 monitoring device 30 nonlinear level converter 31 frame memory 32 subtractor 33 adder a analog image transmission signal b digital image transmission signal c interframe difference signal d image transmission signal e image synthesis request signal f image synthesis control signal g digital image reception signal h analog image reception signal i image synthesis on / off control signal j variable size selection signal

Claims (3)

[Claims] 1. An analog-digital converter for inputting an analog image transmission signal, converting it into a digital signal and outputting the image transmission signal, and a differential signal between the image transmission signal and the image transmission signal one frame before. A noise reducer that generates an interframe difference signal and outputs an image transmission signal of the current frame; and a digital image synthesis control circuit that inputs a digital image reception signal and synthesizes the image transmission signal of the current frame to output an image synthesis signal. In the moving picture coding apparatus including the digital-analog converter that converts the image composite signal into an analog signal, the motion amount of the image is measured based on the generated inter-frame difference signal, and the measured motion amount is calculated. A motion amount determination circuit that outputs an image synthesis request signal based on the image synthesis request signal and an image that continues for a predetermined time based on the image synthesis request signal. And a timer circuit for outputting a composition control signal to the digital image composition control circuit, and the digital image composition control circuit controls the image transmission signal of the current frame to be composed based on the image composition control signal to control the transmission image of the transmitted image. A moving picture coding apparatus comprising means for changing the size. 2. The motion amount determining means calculates an average value of the amplitudes of one frame of the inter-frame difference signal, and when the calculated average value is equal to or more than a predetermined threshold value, image synthesis is performed. The moving picture coding apparatus according to claim 1, further comprising means for outputting a request signal. 3. The noise reducer includes a subtracter for subtracting the image transmission signal from an input image transmission signal of one frame before, and a noise level of an output signal of the subtractor which is non-linearly converted to reduce the noise level. A non-linear level converter that outputs a signal, an adder that adds the inter-frame difference signal and the image transmission signal of the preceding frame to output the image transmission signal of the current frame, and the image transmission signal of the current frame 2. The moving picture coding apparatus according to claim 1, further comprising: a frame memory for temporarily storing and outputting as a picture transmission signal of the preceding frame.