JPH05137126A - Multi-media transmission system - Google Patents

Abstract

PURPOSE:To execute the simultaneous transmission of a dynamic image and a still image and to improve the transmission efficiency of a transmission line. CONSTITUTION:In a transmission part 2, the dynamic image from a dynamic image source 1 is divided into pixel units in which four picture elements (a), (b), (c) and (d) are units and inputted to A/D converters 1-4. Respective picture elements are encoded based on a prescribed converting expression by encoders 1-4 and modulators 1-4 modulate the outputs of the encoders 1-3 by different modulation frequencies, synthesize them by a synthesizer 18 and output them to a coaxial cable 19. Also, a still image signal obtained from the still image source is transmitted from a different transmission part. On the other hand, in a reception part, a demodulator demodulates a transmission image signal and a decoder decodes the image signal encoded by the transmission part 2. Reception of dynamic/still image in the reception part is controlled by a controller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multimedia transmission system for transmitting still images and moving images.

[0002]

2. Description of the Related Art Conventionally, moving image data has been transmitted in, for example, a video conference system. In addition, when transmitting such moving image data, for example, a method of transmitting by using a plurality of ISDN channels is known.

[0003]

However, in the above-mentioned conventional system, since moving image information and still image information are transmitted using the same transmission channel, moving image information and still image information are transmitted at the same time. However, there is a problem that the moving image information and the still image information cannot be combined.

[0004]

The present invention has been made for the purpose of solving the above-mentioned problems, and has the following structure as one means for solving the above-mentioned problems. That is, in a multimedia transmission system for transmitting moving image information using a plurality of channels, when transmitting still image information in addition to the moving image information, at least a part of the plurality of channels is used for still image transmission. Transmits image information.

[0005]

With the above structure, the moving image and the still image can be simultaneously transmitted, and the transmission efficiency of the transmission path is improved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of a multimedia transmission system (hereinafter referred to as a system) according to an embodiment of the present invention. In the figure,
The moving image transmitting unit 2 transmits the moving image signal output from the moving image source 1, and the still image transmitting unit 37 transmits the still image signal output from the still image source 41. Also, the receiver 2
At 0, the moving image and the still image are received via the coaxial cable 19, and they are combined and output.

The moving image source 1 is an image source of a moving image obtained from, for example, a VTR, a video camera or the like, and the transmitting unit 2 is
As shown in FIG. 2, the moving image to be transmitted is divided into four pixel units each including four pixels a, b, c and d adjacent to each other in the scanning line direction and then transmitted. The system clock generation unit 3 extracts a synchronization signal from the moving image signal from the moving image source 1 and generates various timing signals used in the system. Further, the A / D converters 1 to 4 (4 to 7) perform A / D conversion on the input moving image signal based on the sampling signal from the system clock generating unit. These A / D converters 1 to 4
Of the encoders 1 to 4 (9 to
12) is entered. The encoders 1 to 4 encode the outputs of the A / D converters 1 to 4 based on a predetermined conversion formula described later.

The modulators 1 to 4 (13 to 16) are encoders.
1 to 4 outputs different modulation frequencies f ₁ , F₂ , F₃ , F
_Four Modulate with, resulting in four transmission channels
There is. In addition, the transmission control unit 1 (17)
Receive the transmission control signal by the baseband transmitted,
It controls the operation of the four modulators. And the multiplexer 1
8, the modulated image signals output from the modulators 1 to 4 are combined.
And output it on the coaxial cable 19 which is the transmission line of the system.
Force

In the receiving section 20, the system clock extracting section 21 extracts a clock required in the receiving section from the transmitted moving image signal. Demodulators 1-3 (22-25)
Selectively receive the modulated video signal, and f ₁ , respectively
The transmission image signal modulated at the frequencies of f ₂ , f ₃ and f ₄ is demodulated. In addition, the decoders 1 to 4 (27 to 30) decode the image signal encoded by the transmission unit 2. The internal bus II 26 is a bus that connects the outputs of the demodulators 1 to 4 and the inputs of the decoders 1 to 4.

The controller 31 sends a control signal to the moving image transmitting unit 2 and the still image transmitting unit 37 in accordance with an instruction from the MMI unit 32 which controls the user interface, and at the same time, displays the moving / still image of the receiving unit 20. Control reception. In the decoder 5 (33), the encoder 5 (3
The still image signal encoded in 9) is decoded. And
The combiner 34 combines the moving image signals decoded by the decoders 1 to 4 and the still image signal decoded by the decoder 5. The combined image signal is D / A converted by the D / A converter 35 and output to the monitor 36.

In the transmitting section 37 for transmitting the still image, the still image signal obtained from the still image source 41 is encoded by the encoder 5 (3
9), the modulator 5 (38) modulates it at the frequency f4, and sends it to the coaxial cable 19. Transmission control unit 2 (4
0) controls the operation of the modulator 5 and the encoder 5 by the transmission control signal sent from the receiving unit 20. The encoding conversion formula used in the system of this embodiment will be described in detail.

Now, when the pixel unit has N ₀ pixels as a unit, a pixel set consisting of these N ₀ pixels is P
₀ , the average value of the image signal of each pixel belonging to the pixel set P ₀ is m _01, and then the pixel set P ₀ is two pixel sets P ₁ and Q
Divided into _1, the average value of the image signal of each pixel belonging to P _1, Q ₁ and m _11, n ₁₁ respectively. Furthermore, the pixel set P
₁ into two pixel sets P ₂₁ and Q ₂₁ , and pixel set Q ₁
Is divided into two pixel sets P ₂₂ , Q _22, and the average value of the image signal of each pixel belonging to P ₂₁ , Q ₂₁ is m ₂₁ , n ₂₁ , respectively.
P _22, Q ₂₂ belonging to the average value of the image signal of each pixel, respectively, and m _22, n _22.

Similarly, the division of the pixel set is continued until the number of pixels belonging to the pixel sets P and Q becomes one pixel, and the average value of the image signals of the pixels belonging to each pixel set is obtained. , N ₀ average values m and N ₀ −1 average values n yield N ₀ k values. _{That, k 01 = m 01 k 11} = m 11 -m 01 k 21 = m 21 -m 11 k 22 = m 22 -n 11 k 31 = m 31 -m 21 k 32 = m 32 -n 21 k 33 = _{m 33 -m 22 k 34 = m} 34 -n 22:: the finding.

Therefore, four pixels a, as shown in FIG.
For the pixel unit in units of b, c, and d, the coding conversion formula is as follows: Encoder 1: k ₀₁ = 1/4 {a + b + c + d} (1) Encoder 2 : K ₁₁ = 1/2 {a + b} -1/4 {a + b + c + d} (2) Encoder 3: k ₂₁ = a-1 / 2 {a + b} (3) Encoder 4: k ₂₂ = c −1/2 {c + d} (4) can be applied, and the decoding conversion formula is as follows: Decoder 1: a = k ₀₁ + k ₁₁ + k ₂₁ (5) Decoder 2: b = k ₀₁ + k ₁₁ -K ₂₁ (6) Decoder 3: c = k ₀₁ -k ₁₁ + k ₂₂ (7) Decoder 4: d = k ₀₁ -k ₁₁ -k ₂₂ (8) can be applied.

The operation of the system according to the embodiment of the present invention will be described below. In FIG. 1, when a display request for a moving image signal of the moving image source 1 is input from the MMI unit 32 via a user interface such as a keyboard and a mouse, the controller 31 uses the baseband to send a moving image transmitting unit. 2 sends a control signal so that a moving image may be transmitted using four channels, and the demodulator 4 (25) sends an internal bus II.
It is set so that the decoder 4 outputs the signal and the decoder 4 does not output the signal to the combiner 34.

Transmission control unit 1 (17) of the moving image transmission unit 2
Receives the control signal, modulators 1 to 4 (22 to 2
5) is activated to start transmitting the moving image signal input from the moving image source 1. That is, when the moving image signal is input from the moving image source 1, the system clock generating unit 3 separates the horizontal and vertical synchronizing signals from the moving image signal, and the A / D converter 1 as shown in FIG. .About.4 to generate a quadruple interleaved sampling signal with a period 4T which is four times the pixel period of the input moving image signal. A / D converter 1
To 4 are sampling signals φ interleaved in quadruple
A moving image from the moving image source 1 is sampled by the pixel series a, b, c, and d using ₁ , φ ₂ , φ ₃ , and φ ₄ , and A / D
Convert. The signals from the A / D converters 1 to 4 are latched so that they are simultaneously output at the clock φ ₀ , and then output to the encoders 1 to 4 via the internal bus I 8.

In the encoder 1 (9), the A / D which is the image signal of the pixel series a, b, c, d based on the above equation (1).
The outputs from the converters 1 to 4 are averaged in a cycle of 4T, converted into a serial signal, and then output to the modulator 1 (13). In the encoder 2 (10), the difference between the average value of the A / D converters 1 and 2 and the average value of the A / D converters 1 to 4 is calculated in the cycle 4T based on the equation (2), and the serial signal is obtained. Convert to modulator 2 (1
Output to 4). Further, the encoder 3 (11) obtains the difference between the output of the A / D converter 1 and the average of the outputs of the A / D converters 1 and 2 in the cycle 4T based on the equation (3) to obtain the serial signal. And output to the modulator 3 (15). Similarly,
The encoder 4 (12) obtains the difference between the output of the A / D converter 3 and the average value of the outputs of the A / D converters 3 and 4 in the cycle 4T based on the equation (4) and serializes the difference. It is converted into a signal and output to the modulator 4 (16).

The modulators 1 to 4 are encoders 1 to 4 respectively.
The serial signal output from the frequency f ₁ , f ₂ , f
It is modulated by ₃ , f and output to the multiplexer 18. Also,
The multiplexer 18 multiplexes the modulated signals from the modulators 1 to 4 and outputs the multiplexed signals to the coaxial cable 19. Here, the modulation frequencies are f ₁ = 25 MHz, f ₂ = 50 MHz, and f ₃ = 75 MHz.
Hz, f ₄ = 100 MHz or the like is used.

In the receiving section 20, the coaxial cable 19
Frequencies f ₁ , f ₂ and f respectively inputted via
The modulated signals of ₃ and f ₄ are demodulated by the demodulators 1 to 4 and output to the decoders 1 to 4 via the internal bus II26. At the same time, the output from the demodulator 1 (22) has a synchronization signal extracted by the system clock extraction unit 21, and the system signals Φ ₁ , Φ ₂ , Φ ₃ , and Φ _{4 are} quadruple interleaved in a cycle 4T.
Is created.

The outputs from the demodulators 1 to 4 are the internal bus II2.
It is output to the decoders 1 to 4 via 6. Decoder 1
In (27), the demodulators 1 to
The image signals corresponding to the pixel series a are decoded in the cycle 4T by adding the output signals of 3 to obtain the system signal φ ₁
Is output to the combiner 34 at the timing. Decoder 2 (2
8) is the pixel sequence b by subtracting the signal of the demodulator 3 from the sum of the demodulator 1 and the demodulator 2 based on the equation (6).
The image signal corresponding to is decoded in a cycle of 4T and output to the synthesizer 34 at the timing of the system signal φ ₂ .

Similarly, in the decoder 3 (29), the signal of the demodulator 2 is subtracted from the sum of the output signals of the demodulator 1 and the demodulator 4 based on the equation (7) to obtain the pixel series. The image signal corresponding to C is decoded in a cycle of 4T and output to the synthesizer 34 at the timing of the system signal φ ₃ . further,
In the decoder 4 (30), the demodulator 1 based on the equation (8) is used.
By subtracting the outputs of the demodulator 2 and the demodulator 4 from the output of, the image signal corresponding to the pixel series d is decoded by the synchronous 4T and output to the combiner 34 at the timing of the system signal φ ₄ . Then, the image signals corresponding to the pixel sequences a, b, c, d output from the decoders 1 to ₄ are sequentially combined with the system signals φ ₁ , φ ₂ , φ ₃ , and φ ₄ , and the D / A conversion is performed. After being converted into an analog signal by the device 34, it is output to the monitor 36.

While the moving image of the moving image source 1 is displayed on the monitor 36, the still image source 4 is transmitted through the MMI section 32.
When the request to synthesize and display the still image of No. 1 is input, the controller 31 uses the baseband to transmit the moving image transmitting unit 2
Then, the use of the transmission channel corresponding to the modulation frequency f ₄ is stopped, and the band limiting signal is sent so that the moving image is transmitted using only the three channels. Then, the demodulator 4 (25) outputs a signal to the decoder 5 (33), and the internal bus II2
6 is controlled so that the pseudo data is output so that the value of k ₂₂ shown in the above equation is 0, and the decoder 5 causes the synthesizer 3
4 is set to output. Further, the controller 31 transmits a still image transmission request signal to the still image transmitting unit 37 using the baseband.

Transmission control unit 1 (17) of the moving image transmission unit 2
Stops the operation of the modulator 4 (16) corresponding to the modulation frequency f ₄ when receiving the band limited signal. Further, the transmission control unit 2 (40) of the still image transmission unit 37 operates the modulator 5 (38) and the encoder 5 (39) when receiving the still image transmission request signal, and the still image source 41 The output still image is encoded by the encoder 5, modulated by the modulator 5 at the frequency f ₄ , and then output to the coaxial cable 19. The still image signal modulated at the frequency f ₄ is demodulated by the demodulator 4 (25) of the receiving unit 20 and is decoded by the decoder 5 (33).
After being decoded by, it is output to the combiner 34.

On the other hand, in the moving image transmitting section 2, the moving image signals encoded by the encoders 1 to 3 are modulated by the modulators 1 to 3 at the frequencies f ₁ , f ₂ and f ₃ , respectively, and combined. Bowl 18
Is output to the coaxial cable 19. Frequencies f ₁ and f
_The moving image signals modulated by ₂ and f ₃ are demodulated by the demodulators 1 to 3 of the receiver 20 and output to the decoders 1 to 3 via the internal bus II 26. Then, in the decoders 1 and 2, decoding is performed in the same manner as in the case where the above-described moving image is transmitted by using four channels, and the pixel series a and b are respectively decoded.
The image signal corresponding to is output to the synthesizer 34. Also,
In the decoders 3 and 4, (7) necessary for decoding,
Since a value of 0 which is pseudo data output from the demodulator 4 is used as the value of k _{22 in} the equation (8), the output value is k ₀₁ −k ₁₁ = ½ (c + d) ( 9) and the average value of the values of both the c and d pixel series is output to the combiner 34.

As a result, in the combiner 34, the moving image signals output from the decoders 1 to 4 and the still image signal output from the decoder 5 are combined, and the combined signal is output to the monitor 36. To be done. As described above, according to the present embodiment, one of a plurality of channels on the transmission path is assigned to the transmission of a still image, and at the same time, the pseudo data for the moving image is received in the decoding process in the receiving unit. By providing the above, there is an effect that the moving image and the still image can be simultaneously transmitted without providing a dedicated channel for the still image on the transmission path, and the transmission efficiency is improved.

<Description of Modification> Next, a modification of the above embodiment will be described. FIG. 4 is a block diagram showing the configuration of a multimedia transmission system according to a modified example of the above embodiment. This system uses optical transmission having a plurality of channels as a signal transmission means. In the figure, only the transmission part is shown, and the same components as those in the above embodiment are not shown. Figure 4
, The semiconductor laser (LD1 to LD1
4) 101 to 104 each receive an electric signal from an encoder (not shown) and receive 0.78 μm, 0.83 μm,
It oscillates 0.88 μm and 1.3 μm optical signals and acts as a modulator. Further, the semiconductor laser (LD5) 115 oscillates an optical signal of 1.55 μm by the electric signal for transmission control which is the baseband signal in the above embodiment.

The multiplexer / demultiplexers 70, 80, 90 have a function of multiplexing or demultiplexing an optical signal into or from the optical fiber 100, and the optical filters 1 to 4 (111 to 11).
4), 0.78 μm, 0.83 μm, 0.
It selectively transmits wavelengths in the 88 μm and 1.3 μm bands. And PIN Photo Diode (PD1-4)
Reference numerals 116 to 119 convert an incident optical signal into an electric signal and serve as a demodulator together with the optical filter.

The optical filters 5 and 120 selectively transmit wavelengths in the 1.55 μm band, and use the PIN Photo Diode.
e105 and 121 convert an incident optical signal into an electric signal.
These LD5 (115) and filter 5 (106, 12
0) and PD5 (105, 121) are used for transmitting and receiving the baseband signal of the transmission channel number control signal.

In this modification, LDs 1 to 4 (101 to 10)
An electric signal from an encoder (not shown) is used as an input signal of 4), an output electric signal from a controller is used as an input signal of LD5 (115), and PD1 to 4 (1
By connecting the output signals of 16 to 119) to the internal bus II and the decoder, and connecting the outputs of the PD5 (105, 121) to the transmission control units 1 and 2 (not shown),
The operation of the above embodiment is carried out using the optical transmission line.

By using the optical transmission path as described above, the band of moving / still images to be transmitted can be further widened and the transmission distance can be lengthened. The present invention may be applied to a system including a plurality of devices or an apparatus including one device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

In the present embodiment, the ISDN transmission line may be used as the transmission line, or another transmission line may be used. Further, other coding methods than the coding methods in the above embodiments, for example, ADCT method, vector quantization,
Alternatively, a moving image coding method including motion compensation may be used. Further, in this case, the compression rate may be controlled by controlling the quantization parameter for compression.

[0032]

As described above, according to the present invention,
Compared to the case where a transmission channel dedicated to a still image is provided on the transmission path, the transmission efficiency is improved, and the moving image and the still image can be simultaneously transmitted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a multimedia transmission system according to an embodiment of the present invention,

FIG. 2 is a diagram showing a configuration of a pixel unit according to an embodiment,

FIG. 3 shows a quadruple interleaved system clock,

FIG. 4 is a block diagram showing a configuration of a system according to a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moving image source 2 Moving image transmitting part 4-7 A / D converting part 9-12 Encoder 13-16, 38 Modulator 19 Coaxial cable 20 Receiving part 22-25 Demodulating part 27-30 Decoder 33 Still image Decoder 37 Still image transmitter 39 Still image encoder 41 Still image source 17,40 Transmission controller 31 Controller

Claims (1)

[Claims] 1. A multimedia transmission system for transmitting moving image information using a plurality of channels, wherein at least a part of the plurality of channels is transmitted when transmitting still image information in addition to the moving image information. A multimedia transmission system characterized by transmitting still image information using the same.