JP4212972B2 - Image transmission automatic bandwidth control system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image transmission automatic band control system for transmitting a continuous stream such as a moving image through a CSMA / CD network such as Ethernet (registered trademark).
[0002]
[Prior art]
In a conventional call collision control method in a local area network, a master repeater monitors a carrier on a communication path for a specific period at a fixed period, specifies a use situation of the communication path according to a carrier detection degree, and uses a LAN. The slave repeater that must change whether or not the communication path can be used is extracted from the LAN use table indicating the level of the slave and the slave repeater management table including the name of the slave repeater to be called and the call level value, and the slave repeater is extracted. The master repeater performs collective management by sending a call control signal to the corresponding slave repeater, receiving it, updating its own call availability flag, and controlling the call request from the terminal. (For example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-6948
[Problems to be solved by the invention]
Since the call collision control method in the conventional local area network is a collective management by the master repeater, a call request procedure is necessary, and the bandwidth of the communication path during the procedure period may be wasted. There was a point.
[0005]
Further, since the call collision control method in the conventional local area network is batch management by the master repeater, there is a problem that all transmissions are stopped when the master repeater fails.
[0006]
In addition, the conventional call collision control method in the local area network has a problem in that the master repeater has a slave repeater management table in advance, so that communication devices can be freely increased or decreased on the communication path for connection.
[0007]
Furthermore, the call collision control method in the conventional local area network has no concept of the bandwidth of the communication path, and the master repeater determines whether or not the slave repeater can make a call based on the carrier detection level. There was a problem that the bandwidth could not be used effectively.
[0008]
The present invention has been made to solve the above-described problems, and the video transmission apparatus that is freely connected to the LAN eliminates the need for an apparatus for managing the entire network by detecting the collision of the LAN. The video transmission device connected to the LAN can increase or decrease the transmission band transmitted by detecting the collision of the LAN, can efficiently use the LAN transmission band, and does not have a device for managing the entire LAN. It is an object of the present invention to obtain an image transmission automatic band control system that eliminates a permission procedure and increases an opportunity to transmit an image generated in the meantime.
[0009]
[Means for Solving the Problems]
Image transmission automatic bandwidth control system according to the present invention, an image of the moving image and an analog / digital converter, receives the images transmitted device you sent to the network, the image which the image transmission apparatus sends out, reproduced, or accumulate It comprises a receiving device, a CSMA / CD local area network having a predetermined transmission band connecting the image transmission device and the image receiving device, and the image transmission device detects a LAN collision and controls image transmission. der to perform is, sent by packetizing moving image, the image transmission device of a constant rate for transmitting the packet at regular time intervals, when the image transmission apparatus was increased to LAN, changing the image transmission band Without delaying the fixed time interval, and sending the packet at the beginning of the temporarily extended time to transmit another image. It is intended to reduce the transmission band by collision detection to location.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described.
Embodiment 1 FIG.
An image transmission automatic band control system according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a diagram showing a configuration of an image transmission automatic band control system according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing a configuration of an image transmission apparatus constituting the image transmission automatic band control system. is there. 3 and 4 are diagrams for explaining the band control of the image transmission apparatus constituting the image transmission automatic band control system.
[0011]
As shown in FIG. 1, an image transmission automatic band control system is an image transmission apparatus 11 that converts a moving image from analog to digital and sends it to a network, and an image reception apparatus that receives, reproduces, or stores a transmission image from the image transmission apparatus 11. 12, an image transmission device 14 configured to include a LAN 13 for connecting the image transmission device 11 and the image reception device 12, and having the same configuration as the image transmission device 11, is added to this system. A feature of the present invention is that the collision in the LAN 13 caused by the newly added image transmission device 14 is controlled by the image transmission devices 11 and 14. A plurality of image transmission apparatuses 11 and image reception apparatuses 12 are connected to the LAN 13.
[0012]
As shown in FIG. 2, the image transmission apparatus includes a collision detection storage unit 21, a collision state change notification unit 22, an image LAN transmission unit 23, an image compression unit 24, a frame deletion unit 25, an image size change unit 26, and a color gradation change. Means 27, image data increase / decrease means 28, image input means 29, and image A / D converter 30 are provided.
[0013]
The collision detection storage unit 21 sets a predetermined time interval as the LAN collision detection sampling time P, and the collision detection rate CR = N / P from the number N of collisions detected when the image LAN transmission unit 23 transmits within P. The calculated value is stored and held.
[0014]
The collision state change notification means 22 compares the collision detection rate threshold value CRt designated in advance with the CR held in the collision detection storage means 21, and when the state changes from CR <CRt to CR ≧ CRt, or from CR ≧ CRt to CR <The case of changing to CRt is detected and notified to the image LAN sending means 23.
[0015]
The image LAN sending means 23 sends the image data sent from the image data increasing / decreasing means 28 to the LAN 13 from the CR value notified from the collision state change notifying means 22 and the state change notified from the collision state change notifying means 22. The image transmission band is determined, notified to the image data increasing / decreasing means 28, and transmitted to the LAN 13.
[0016]
The image compression unit 24 changes the image compression rate from the image transmission band notified from the image LAN transmission unit 23 by the image compression method such as Motion JPEG or MPEG from the image data transmitted from the image D / A converter 30. Increase or decrease the amount of image data.
[0017]
The frame deleting unit 25 increases or decreases the amount of image data by increasing or decreasing the number of frames of the image data sent from the image D / A convertor 30 from the image transmission band notified from the image LAN sending unit 23.
[0018]
The image size changing unit 26 increases or decreases the image data amount by increasing or decreasing the image size of the image data sent from the image D / A converter 30 from the image transmission band notified from the image LAN sending unit 23.
[0019]
The color gradation changing unit 27 increases / decreases the image data amount by increasing / decreasing the color gradation of the image data sent from the image D / A converter 30 from the image transmission band notified from the image LAN transmitting unit 23.
[0020]
The image data increasing / decreasing means 28 includes an image compressing means 24, a frame deleting means 25, an image size changing means 26, and a color gradation changing means 27, and image data sent from the image D / A convert 30 by these means. To increase or decrease the amount of image data.
[0021]
The image input unit 29 inputs a moving image to the image transmission apparatuses 11 and 14.
The image D / A converter 30 performs digital / analog conversion on the analog image input from the image input unit 29 and transmits it to the image data increase / decrease unit 28.
[0022]
Next, the operation will be described.
First, an analog image is input to the image transmission device 11 by the image input means 29, and is taken into the image data increase / decrease means 28 as a digital image by the image D / A converter 30. At this stage, LAN collision detection has not yet been performed, and if the digital image data does not exceed the entire transmission band X of the LAN 13, the image is not particularly processed, but the image is processed at a prespecified image compression rate. Compression by the compression means 24, frame reduction by the frame reduction means 25 at a predesignated frame rate, image size change by the image size change means 26 at a predesignated image size, or with a predesignated color gradation The color gradation change means 27 changes the color gradation.
[0023]
If the digital image data exceeds the entire transmission band X of the LAN 13, the image compression unit 24 compresses the image to a specified compression rate or more in accordance with the entire transmission band X and transmits it to the image LAN transmission unit 23. And sent to the LAN 13. At this time, in order to generate a constant image transmission rate, the image LAN sending means 23 transmits the transmission band X within the reference time for rate generation as shown in the upper diagram of FIG. At this stage, since the collision of the LAN 13 is not detected yet, the digital image data reaches the image receiving apparatus 12 as it is. This is repeated, and the image is constantly transmitted from the image transmission device 11 at a constant rate.
[0024]
On the other hand, when the image transmission apparatus 14 is connected to the LAN 13 for this steady state, the image transmission apparatus 14 captures an image in the same manner as the image transmission apparatus 11 and tries to start transmission by the image LAN transmission means 23. Since the transmission band of the image transmission apparatus 11 has been used, instead of increasing the reference time for rate generation as shown in the lower diagram of FIG. All data of the generated data is transmitted within a short time that is initially biased in time, a collision occurs in a short time, and the image transmission apparatus 11 detects the collision.
[0025]
The image transmission apparatus 11 increases the number N of times that the image LAN transmission means 23 cannot transmit an image due to a collision, and the collision detection storage means 21 calculates the collision detection rate CR = N / P from the sampling time p. The calculation result is notified to the collision state change notifying means 22, and the collision state change notifying means 22 compares it with a collision detection rate threshold value CRt specified in advance, and when this threshold value CRt is exceeded, to the image LAN sending means 23. The notification and the image LAN sending means 23 reduce Y from the current sending rate X by the band Y designated in advance, and send it again.
[0026]
At this time, the image LAN sending means 23 also notifies the image data increasing / decreasing means 28 that the image transmission band has become XY, and the image compression means 24 increases the compression rate to reduce the data amount. By repeating this in the image transmission device 11, collision detection is avoided and the image is transmitted in a stable state. On the other hand, the image transmission device 14 increases the image transmission bandwidth in the reverse procedure to that of the image transmission device 11 to avoid the collision detection, and the LAN 13 becomes stable. For example, when this is repeated three times, the graph shown in FIG. 4 is obtained. The band of the image transmission device 11 is repeated three times to obtain an X-3Y transmission band, while the image transmission device 14 transmits in the 3Y band.
[0027]
As described above, in addition to performing the image data increase / decrease by the image compression means 24, if the compression rate exceeds a predetermined compression rate according to the image quality, the data amount reduction by the image compression means 24 is stopped, If the number of frames is reduced by the frame reduction unit 25 and the number of frames is less than or equal to a predetermined number, the image size is reduced by the image size changing unit 26. By reducing the number of color gradations by the gradation changing means 27, four stages of image data amount reduction means are provided.
[0028]
【The invention's effect】
As described above, according to the present invention, since the collision detection is performed by the image transmission apparatus and the transmission rate is changed, the LAN bandwidth can be used efficiently.
[0029]
In addition, since the optimum bandwidth is determined by gradually changing the transmission rate in the image transmission device, and the image transmission amount is increased or decreased by providing the image data increase / decrease means, the transmission amount can be adjusted to the optimal transmission rate. Is possible.
[0030]
Further, since the collision is detected by the image transmission apparatus and the transmission rate is changed, it is possible to automatically control the transmission band even if the number of image transmission apparatuses increases in the system.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an image transmission automatic band control system according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of an image transmission apparatus constituting the image transmission automatic band control system according to the first embodiment of the present invention.
FIG. 3 is a diagram showing band control of an image transmission apparatus constituting the image transmission automatic band control system according to the first embodiment of the present invention.
FIG. 4 is a diagram showing band control of an image transmission apparatus constituting the automatic image transmission band control system according to Embodiment 1 of the present invention.
[Explanation of symbols]
11, 14 Image transmission device, 12 Image reception device, 13 LAN, 21 Collision detection storage means, 22 Collision state change notification means, 23 Image LAN transmission means, 24 Image compression means, 25 Frame deletion means, 26 Image size change means, 27 color gradation changing means, 28 image data increasing / decreasing means, 29 image input means, 30 image D / A conversion.

Claims (6)

A moving picture analog / digital conversion, and images transmitting device you sent to the network, receives the image to be sent the image transmission apparatus, wherein the image receiving apparatus for reproducing or accumulation, and the image transmission apparatus image A local area network (LAN) of a CSMA / CD system having a predetermined transmission band (X) for connecting to a receiving device, and detecting a LAN collision by the image transmitting device to control image transmission. An automatic image transmission bandwidth control system characterized in that,
The image transmission device includes:
A collision detection storage means for storing a collision detection rate CR (= N / P) from the number N of collisions in the P as a LAN collision detection sampling time P, which is a predetermined time interval T;
Compared to the collision detection rate threshold CRt specified in advance and the collision detection rate CR,
(A) When the state changes from CR <CRt to CR ≧ CRt
(B) When the state changes from CR ≧ CRt to CR <CRt
State determining means for determining
When the image data is sent to the LAN using the transmission band X when CR = 0, in the case of the state (a), the transmission band interval X−Y is reduced by a predetermined transmission band interval Y. In the case of the state (a) even at the next sampling time P, the transmission is further reduced by Y. On the other hand, in the case of the state (b), the transmission band is increased by Y and transmitted. In the case of the state (b) even at the next sampling time P, an image LAN sending means for further sending Y and transmitting,
A collision state change notifying unit for transmitting a determination result by the state determining unit to the image LAN transmitting unit;
The image LAN sending means
When the number of image transmission devices is increased to the LAN with respect to a constant-rate image transmission device that transmits moving images in packets and transmits the packets at regular time intervals, the constant transmission without changing the image transmission bandwidth. An image characterized in that the time interval is temporarily extended, and the packet is transmitted at the beginning within the temporarily extended time, and the transmission band is lowered by causing another image transmission device to detect a collision. Transmission automatic bandwidth control system. Image transmission apparatus, when the transmission band is increased or decreased, the image transmission automatic bandwidth control system according to claim 1, characterized in that it comprises an image compression means for image compression by increasing or decreasing the image compression rate. The image transmission automatic band control system according to claim 1 or 2 , wherein the image transmission apparatus includes frame deletion means for deleting the image frame by increasing or decreasing the frame rate when the transmission band increases or decreases. Image transmission apparatus, when the transmission band is increased or decreased, either by increasing or decreasing the raster vertical and horizontal image from claim 1, characterized in that it comprises an image size changing means for changing an image size of one of claims 3 1 The image transmission automatic band control system according to the item. Image transmission apparatus, when the transmission band is increased or decreased, either increase or decrease the color tone of the image to be provided with color gradation changing means for changing the color tone of claims 1, wherein one of claims 4 An automatic image transmission bandwidth control system according to claim 1. The image transmission apparatus includes image data increase / decrease means for selecting a method for increasing / decreasing image data based on the maximum compression rate by the image compression means, the minimum number of frames by the frame deletion means, and the minimum image size by the image size changing means. The image transmission automatic band control system according to any one of claims 1 to 5 , wherein:

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