JP2004038393A - Image transferring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute highly precise image transfer while reducing a transmission capacity to a communication network. <P>SOLUTION: This image transferring device for transferring an image from a first device through a communication network to a second device is provided with an application for generating a control signal to instruct the plotting of an image, a device driver for generating plotting information based on a plotting parameter and plotting interface function for plotting an image according to the control signal, and a network interface for transmitting the plotting information to a communication network. A network display monitor is provided with a network interface for receiving a communication signal, a control part 109 for separating the plotting information from the received communication signal, and for executing plotting control based on the plotting information, a graphic accelerator 111 for generating the image information, and a display part 115 for displaying the image information. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image transfer device that transfers an image drawn based on predetermined drawing parameters from a first device to a second device via a communication network.
[0002]
[Prior art]
2. Description of the Related Art In recent years, digitalization of electronic devices and networking have been advanced, and an environment that enables seamless data communication by laying a network in a home is being prepared. According to this home network, for example, a digital video camera, a television, a video printer, and the like are connected, and it is possible to enjoy an image with a simple operation by plug and play. As the data transmission means, for example, there are a wired interface such as IEEE1394, USB, and Ethernet (registered trademark), and a wireless interface such as wireless LAN (IEEE802.11), PHS, and wireless 1394.
[0003]
However, as for the output of PC images at present, it is still mainstream that a dedicated RGB shielded cable is connected to a display monitor, and image information is transmitted and displayed by analog means. In addition, due to electrical restrictions, the RGB shielded cable cannot be elongated for a long time, and as a result, a display monitor is often arranged near a PC.
[0004]
As described above, the reason why the transmission means is analog at present is that since the amount of data of a high-resolution PC image such as VGA (640 × 480) and XGA (1024 × 768) is enormous, digital image data is directly transmitted. Cannot be transmitted.
[0005]
In transmitting data, it is necessary to compress the data to increase the transmission efficiency. Conventionally, techniques such as MPEG and JPEG exist as means for digitally compressing a video. However, these means are intended for natural images, and it is considered difficult to apply them to PC images because the images rarely change dynamically. Further, since a PC image must express characters and graphics in detail, it is considered inappropriate to perform compression processing to reduce image energy.
[0006]
FIG. 7 is a block diagram showing an internal configuration of a PC image output system according to the related art. As shown in the figure, the PC 701 includes a CPU 702, a memory 703, and an expansion bus bridge 704.
[0007]
The expansion bus bridge 704 is an interface through which the CPU 702 inputs and outputs data to and from an expansion card such as a video card or an Ethernet (registered trademark) card. Examples of the interface specification of the expansion bus include PCI and ISA.
[0008]
The graphic accelerator board 705 includes a graphic accelerator 706, a frame buffer 707, a clock generator 709, and a video DAC 708. The graphic accelerator 706 is a functional unit that performs drawing processing in place of the CPU 702, and is also called a video controller. The frame buffer 707 is a memory for temporarily storing image digital data, and is also called a VRAM or a video memory, and usually uses a DRAM.
[0009]
The clock generator 709 is a functional unit that generates a reference clock on the graphic accelerator board 705 and processing timing for a peripheral function unit, and generates a vertical / horizontal synchronization signal to be transmitted to the display monitor 711. The video DAC 708 is a functional unit that converts the image digital data in the frame buffer 707 into an analog signal (RGB signal) to be displayed on the display monitor 711.
[0010]
This board is usually inserted into a PCI or ISA bus expansion slot of a PC. Further, the display monitor 711 is connected to the graphic accelerator board 705 by the video cable 710.
[0011]
Next, a flow from when the application on the PC 701 starts control for drawing a certain figure to when it is displayed on the display monitor 711 will be described.
[0012]
First, the application to be processed on the PC 701 enters a step of drawing a certain figure. Usually, the drawing function to be called is determined by the specification (shape, character, etc.) of the object to be drawn, and the application calls the predetermined drawing function with information such as coordinates and colors attached to the predetermined drawing function. In a conventional OS, there is a drawing function called a GDI (Graphic Device Interface) function as this drawing function.
[0013]
In this GDI, the called drawing function passes the obtained drawing control information to the graphic device driver. For example, a structure called a device context is generated by a GDI function, drawing control information is written in the structure, and the drawing control information is passed to the graphic device driver. The graphic device driver analyzes the acquired drawing information and performs register setting for the graphic accelerator 706 which is in charge of the control.
[0014]
Normally, a device driver is software prepared for each expansion board and supplied together with the board from a manufacturer. The device driver transfers control information from an OS standard interface function (here, a GDI function) to a device on the expansion board. The buffer functions to transfer data or transfer data in the opposite direction, so that even if the type of expansion board is different, the application or OS can perform drawing processing without being aware of this by replacing the device driver. Can be.
[0015]
Since the graphic accelerator 706 is on the graphic accelerator 706 and is connected to an expansion bus (PCI, ISA, etc.), the graphic device driver makes settings through the expansion bus bridge 704.
[0016]
The above steps are processed by the CPU 702 and the memory 703 in the PC 701. Next, in the graphic accelerator board 705, the graphic accelerator 706 analyzes the register setting made by the graphic device driver, generates predetermined graphic bitmap data, and develops the graphic bitmap data on the frame buffer 707.
[0017]
Next, the video DAC 708 converts the graphic bitmap data in the frame buffer 707 into an analog video signal (RGB or the like) in accordance with the timing signal passed from the clock generator 709.
[0018]
The analog video signal and the horizontal / vertical synchronization signal from the clock generator 709 are transmitted to the display monitor 711 via the video cable 710. The display monitor 711 projects an image on an optical display device (CRT, liquid crystal, TFT) based on the transmitted signals.
[0019]
As described above, in the conventional OS, the PC can display a high-definition image on the display monitor.
[0020]
By the way, in the PC before performing the graphic acceleration, all the drawing to the frame buffer is performed by the CPU. Therefore, in a GUI (Graphical User Interface) environment of the conventional OS, a complex application and a graphic display function using multiple colors put a large burden on the CPU.
[0021]
On the other hand, the graphic accelerator directly interprets the command from the graphic device driver and performs the drawing process on behalf of the CPU, so that no burden is imposed on the CPU. Therefore, the data sent from the PC to the graphic board is not an actual image bitmap, but only a register operation instruction of several bytes, so that the CPU can perform other processing after transmitting the drawing command.
[0022]
It goes without saying that such processing is possible not only in the presence of a graphic accelerator as hardware, but also, as described above, largely depends on the graphic interface of a conventional OS.
[0023]
[Problems to be solved by the invention]
However, in the above method, the transmission of the image signal to the display monitor is performed by the RGB shielded cable.
[0024]
For this reason, in the above-mentioned method, there is a problem that the RGB shielded cable cannot be elongated for a long time due to electrical restrictions on signals such as noise, and as a result, a display monitor must be installed near the PC. In addition, some cables have a diameter exceeding 10 mm, which cannot be said to be excellent in design.
[0025]
Furthermore, in the above-mentioned conventional system, the transmission system is analog, and the signal system is different from the normal television video signal system (NTSC, etc.). Therefore, at present, one normal television receiver and one display monitor are prepared. It cannot be used for multimedia and networking of home and premises equipment in the future.
[0026]
On the other hand, there is a concept of transmitting a bitmap of a PC image directly. For this transmission method, for example, VGA has the following specifications.
[0027]
Resolution: 640x480
Color hierarchy: 16 (4 bits)
Horizontal deflection frequency: 31.5kHz
Vertical deflection frequency: 60Hz
According to this, the amount of data processed per second is
640 x 480 x 60 (picture / s) x 4 (bit) = 73,728,000 bits
Thus, a communication network having a transmission capacity of about 75 Mbps or more is required.
[0028]
Further, at present, graphic modes having higher resolutions are often used. For example, in SVGA, the following graphic modes are available.
[0029]
Resolution: 1024 × 768
Color hierarchy: 256 (8 bits)
Horizontal deflection frequency: 48.4 kHz
Vertical deflection frequency: 60Hz
According to this, the amount of data processed per second is
1024 x 768 x 60 (picture / s) x 8 (bit) = 377, 487, 360 bits, a communication network with a transmission capacity of about 380 Mbps or more is required, and direct transmission of PC image bitmaps is not realistic. I can say.
[0030]
In this case, even if the communication network has the minimum direct transmission capacity, if various types of devices are connected on the network and the direct transmission of PC images occupies a band, other communications are performed. Communication between connected devices may be hindered.
[0031]
Therefore, the present invention reduces the transmission capacity for a communication network when transferring an image drawn based on a predetermined drawing parameter from a first device to a second device via a communication network. It is an object of the present invention to provide an image transfer device capable of displaying a high-definition image.
[0032]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is an image transfer device that transfers an image drawn based on a predetermined drawing parameter from a first device to a second device via a communication network. A first drawing control means for generating a control signal for instructing drawing of an image, a drawing parameter for drawing an image according to the control signal, and a specification of an image to be drawn. A drawing information generating means for generating drawing information based on the drawn drawing interface function; a first communication means for converting the drawing information into a communication signal transferable on a communication network and transmitting the communication signal to the communication network; A second communication unit that receives a communication signal via a communication network, and a second communication unit that separates drawing information from the received communication signal and performs drawing control based on the separated drawing information. Comprising of a drawing control unit, and an image information generating means for generating image information based on the drawing control, and display means for displaying an optical image based on image information.
[0033]
In the above invention, the drawing information generating means includes: a drawing application that calls a predetermined drawing interface function with a drawing parameter attached thereto in accordance with the specification of an image to be drawn; and specification information and drawing parameters by the called drawing interface function. And a first drawing device driver for processing the data into a predetermined format to generate drawing information. The first communication means obtains drawing information from the first drawing device driver as transmission information, and obtains the obtained transmission information. A first communication device driver that generates a communication packet based on a predetermined protocol from a first communication interface, and a first network interface that generates a physical communication frame from the generated communication packet and transmits the physical communication frame over a communication network. preferable.
[0034]
Further, in the above invention, the second communication means monitors the communication network, and when there is transmission information for the second device, acquires a corresponding communication frame and separates the communication packet from the communication frame. A network interface; and a second communication device driver for separating transmission information as drawing information from the separated communication packet, wherein the image information generating means analyzes the separated drawing information and performs drawing based on the analysis result. A second drawing device driver that performs control, a storage unit that generates image information based on the drawing control, and temporarily stores the image information in an expanded state, reads image information from the storage unit, and outputs a predetermined image signal. Image signal conversion means for converting and outputting the converted image signal, wherein the image display means can display the converted image signal as an optical image. Masui.
[0035]
According to the present invention, image information to be drawn is not information obtained by converting pixels themselves such as bitmap data, but drawing information including drawing parameters is transmitted and received via a communication network. The amount of data to be transmitted can be reduced, the communication load can be reduced, and the processing speed can be improved.
[0036]
In particular, in the first device,
application
→ Drawing interface function
→ Drawing device driver
→ Communication device driver
→ Network interface
, Not the image bitmap data, but the drawing information for drawing the image is transferred on the communication network.
Network interface
→ Communication device driver
→ Drawing device driver
In order to draw an image via the device, the second device on the receiving side generates image bitmap data based on the drawing information, so that the communication load between the first and second devices can be reduced. it can.
[0037]
That is, the data transmitted on the communication network is drawing information for drawing an image, and the generation of image bitmap data is performed by the graphic accelerator on the second network display monitor. Even if used, the PC screen can be displayed on the display monitor.
[0038]
Furthermore, the transmission signal of the drawing data to be transferred is a digital signal, and the degree of freedom (layout length, cable volume, etc.) of the layability is increased as compared with the analog transmission path, and the installation of the display monitor is improved.
[0039]
Furthermore, by making the network display monitor compatible with the reception of ordinary television broadcasts, it becomes possible to view ordinary television images and PC images on a single display device, and to increase the number of home and premises equipment in the future. It can respond to media and networking.
[0040]
In the above invention, the first and second communication means use a protocol for transmitting and receiving data at an indefinite period, and transmit normal response information to the transmitting side when the receiving side normally receives data. However, when abnormal reception occurs on the receiving side, it is preferable that a retransmission request is made from the receiving side, and the transmitting side performs retransmission processing in response to this.
[0041]
In this case, the drawing information is transferred using an irregular protocol, and when a transfer error occurs, a retransmission request is made and the drawing data is transferred again. Since the transfer can be performed, and the drawing data is reliably transferred between the first and second devices, an error-free display can be performed.
[0042]
Further, in the above invention, there is provided a cycle master which is arranged on the communication network and periodically transmits the timing information to the first and second devices, wherein the first and second communication means are provided on the transmitting side. The transmitting device can also transmit the information in accordance with the timing information by using a protocol for unilaterally transmitting the transmission information to the receiving device.
[0043]
In this case, each time the cycle master device on the communication network transmits the timing information to the communication network, the first device keeps transmitting data intermittently in synchronization with the timing information. , Continue to receive this data intermittently. As a result, the transmission cycle of the drawing information can be made constant over time, and a constant bandwidth can be secured. That is, since the drawing data is intermittently transmitted in synchronization with the timing information output from the cycle master device, the transmission band is guaranteed, and the second device can display a screen having high responsiveness to the instruction of the first device. Display becomes possible.
[0044]
In the above invention, the first image drawing control means generates a first control signal and a second control signal, and transmits and receives data at an indefinite period for transmission information based on the first control signal. If the reception is normally performed on the reception side, normal response information is transmitted to the transmission side, and if an abnormal reception occurs on the reception side, a retransmission request is made from the reception side. The transmission side performs retransmission processing in accordance with the above, and for transmission information based on the second control signal, a cycle master arranged on the communication network using a protocol for transmitting the transmission information to the receiving side device unilaterally from the transmission side. It is preferable to transmit in accordance with the timing information transmitted from.
[0045]
In this case, in the first device, drawing is performed using two systems: a protocol in which the communication quality is guaranteed irregularly and a periodic protocol in which the bandwidth is secured, according to the type of drawing control instructed. The information can be transmitted to the second device, the data can be transmitted and received according to the priority or importance of the data included in the drawing information, and the communication quality and the communication load can be balanced. Image transfer processing can be performed. As a result, for example, drawing processing commands that require display quality, such as character notation, transfer drawing data according to a protocol that guarantees communication quality, and a fixed transmission bandwidth for dynamically changing drawing processing commands such as games. By transferring the drawing data according to the protocol in which is secured, highly flexible display corresponding to the multitask processing of the first device can be performed.
[0046]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
(Configuration of image transfer device)
Hereinafter, a first embodiment of the image transfer device according to the present invention will be described. In the present embodiment, an application example in which an IEEE 1394 interface is used as a means for realizing a communication network and an asynchronous transfer method is used as a transfer method will be described. FIG. 1 is a block diagram illustrating a configuration of an image transfer device according to the present embodiment, FIG. 2 is a functional hierarchy diagram of the image transfer device according to the present embodiment, and FIG. FIG. 4 is a time chart when drawing data is transferred on the communication network.
[0047]
As shown in FIG. 1, the image transfer device according to the present embodiment transmits an image drawn based on a predetermined drawing parameter from the first device 100 to the network display monitor 108 as the second device. This is transferred via the communication network 107.
[0048]
The first device 100 includes first drawing control means, drawing information generation means, and first communication means. Specifically, the first device 100 includes a PC 101 and a network board 105 for connecting the PC 101 to a communication network 107. The first device 100 is installed so as to be connectable to the communication network 107. Connected to the network display monitor 108. In the present embodiment, IEEE 1394 is adopted as the communication network 107.
[0049]
The PC 101 includes a CPU 102, a memory 103, and an expansion bus bridge 104. The expansion bus bridge 104 is an interface through which the CPU 102 inputs and outputs data to and from an expansion card such as a video card or an Ethernet (registered trademark) card. The interface specifications of the expansion bus include, for example, PCI and ISA. The PC 101 is connected to the network board 105 through an expansion bus interface such as PCI and ISA, and the network board 105 is connected to the network display monitor 108 through the IEEE 1394 communication network 107.
[0050]
The first drawing control unit generates a drawing parameter and a control signal for instructing drawing of an image, and is realized by the application 201 executed on the CPU 102 in the present embodiment.
[0051]
The drawing information generating means generates drawing information based on drawing parameters for drawing an image and a drawing interface function corresponding to the specification of the image to be drawn. In addition, an application 201 that calls a predetermined drawing interface function (GDI 202) with drawing parameters attached thereto, and a display that generates specification information by processing specification information and drawing parameters into a predetermined format by the called GDI 202. This is realized by the driver 203.
[0052]
On the other hand, the first communication unit converts the drawing information into a communication signal that can be transferred on the communication network 107 and transmits the communication signal to the communication network 107. The network driver 204 executed by the CPU 102 and the memory 103 includes: This is realized by the network interface 205.
[0053]
Specifically, the first communication unit acquires drawing information from the display driver 203 as transmission information, and generates a communication packet based on a predetermined protocol from the acquired transmission information; And a network board 105 for generating a physical communication frame from the communication packet and transmitting the generated communication frame on the communication network 107.
[0054]
The network board 105 has a network interface 106. As the network interface 106, for example, a device in which each functional unit such as an extended bus interface, a LINK, and a PHY is formed as a chip (LSI) can be used. In this embodiment, since the communication network is IEEE1394, a general-purpose IEEE1394 board is used as the network interface 106.
[0055]
The network display monitor 108 includes a second communication unit that receives a communication signal via the communication network 107 and a second communication unit that separates drawing information from the received communication signal and performs drawing control based on the separated drawing information. Drawing control means, image information generating means for generating image information based on the drawing control, and display means for displaying an optical image based on the image information. Specifically, the network display monitor 108 , A control unit 109, a network interface 110, a graphic accelerator 111, a frame buffer 112, a clock generator 113, and a signal conversion unit 114.
[0056]
The second communication means monitors a communication network, acquires a corresponding communication frame when there is transmission information for the second device, and separates a communication packet from the communication frame with a second network interface 110. And a second communication device driver for separating transmission information as drawing information from the separated communication packet. Note that the second communication device driver is realized by the network driver 207 executed by the control unit 109.
[0057]
The control unit 109 is a function unit that controls each function unit in the network display monitor 108, and uses a CPU, a memory, and the like. The graphic accelerator 111 is a functional unit that performs a direct drawing process, and is also called a video controller.
[0058]
The image information generating unit analyzes the separated drawing information, generates a display driver (second drawing device driver) 208 that performs drawing control based on the analysis result, and generates image information based on the drawing control. The image processing apparatus includes a frame buffer 112 for temporarily storing image information in a developed state, and a signal conversion unit 114 for reading image information from the frame buffer, converting the image information into a predetermined image signal, and outputting the image signal.
[0059]
The frame buffer 112 is a memory (storage means) for temporarily storing image digital data, and is also called a VRAM or a video memory, and usually uses a DRAM.
[0060]
The clock generator 113 is a functional unit that generates a reference clock on the network display monitor 108 and processing timing for peripheral function units, and generates a vertical / horizontal synchronization signal required by the display unit 115. The signal conversion unit 114 is a functional unit that converts image digital data in the frame buffer 112 into a signal for display on the display unit 115. The signal system differs depending on the specifications of the display unit 115, but is not particularly defined.
[0061]
(Operation of the image transfer device)
Next, the operation of the image transfer device having the above configuration will be described. FIG. 3 is a flowchart illustrating the operation of the image transfer device according to the present embodiment.
[0062]
As shown in the figure, first, the CPU 102 in the PC 101 and the application 201 processed on the memory 103 enter a step of drawing a certain figure. Normally, the drawing function to be called is determined by the specification (shape, character, etc.) of the drawing target, and the application calls the predetermined drawing function with data such as coordinates and colors attached to the predetermined drawing function. In the present embodiment, this drawing function is referred to as a GDI (Graphic Device Interface) function, and this functional hierarchy is referred to as GDI 202.
[0063]
The called drawing function passes the obtained drawing control data to the display driver 203. In the present embodiment, the GDI function generates a structure called a device context, writes drawing control data in the structure, and passes it to the display driver.
[0064]
The display driver 203 passes the obtained drawing data to the network driver 204 and instructs the network display monitor 108 to transmit the drawing data to the network display monitor 108 in the asynchronous transfer mode. The display driver 203 manages data and addresses of devices connected on the network, and the data is transmitted to the OS. Therefore, the display driver 203 knows the address of the destination device from the registry of the OS. Can be.
[0065]
Next, an IEEE 1394 asynchronous communication packet is generated based on the transmission data (drawing data) acquired from the display driver 203, and is transferred to the network board 105 via the expansion bus bridge 104.
[0066]
On the network board 105, the network interfaces 106 and 205 generate a physical transmission frame signal based on the obtained asynchronous communication packet and transmit it to the communication network 107. This time, since it is an asynchronous transfer method, it can be transmitted immediately without the need for synchronization processing. However, since the isochronous transfer is given priority by regulation, the asynchronous transfer packet actually flows after the isochronous transfer packet on the network. It takes shape.
[0067]
Next, in the network display monitor 108, the network interfaces 110 and 206 monitor communication data existing on the communication network 107, and when there is transmission data for its own address, receive this communication data frame. After receiving, the network interfaces 110 and 206 check for errors on the data frame. In IEEE 1394, since the transmitting side adds 32-bit CRC information to the data frame, the receiving side performs error detection by comparing it with its own 32-bit CRC calculation result.
[0068]
If no error is found, as shown in the data transmission phase A of the drawing information 1 in FIG. 4, the network interfaces 110 and 206 notify the network interfaces 106 and 205 of the normal reception. Send
[0069]
On the other hand, if an error is found, the network interfaces 110 and 206 request the network interfaces 106 and 205 to retransmit the communication data frame as shown in the data transmission phase B of the drawing information 2 in FIG. Send a signal. The network interfaces 106 and 205 that have received the retransmission request signal transmit the communication data frame again. This operation is performed until an error does not occur or a specified number of times.
[0070]
Next, the network interfaces 110 and 206 separate the communication packet from the communication data frame received normally and pass it to the network driver 207 operated by the control unit 109.
[0071]
The network driver 207 separates the data area from the acquired communication packet and passes the data area to the display driver 208 which is also operating by the control unit 109. The separated data area is data that the display driver 203 of the PC 101 attempts to transmit, that is, drawing data.
[0072]
The display driver 208 analyzes the acquired drawing data and sets registers for the graphic accelerators 111 and 209 which are in charge of the control. As described in the conventional example, the graphic device driver normally transfers control data from an OS standard interface function (here, a GDI function) to a device on the expansion board. In the present invention, the control data is received from the network driver 207. It takes shape. However, if the display driver 208 on the PC 101 side passes the drawing data from the GDI 202 to the network driver 204 without any conversion, the format of the drawing data acquired by the display driver 208 is the drawing data itself from the GDI 202. Therefore, the display driver 208 may perform the same processing as the conventional example. Alternatively, if there is a more efficient data transmission / reception method between the display driver 203 and the display driver 208, it may be performed by performing predetermined data conversion.
[0073]
Next, the graphic accelerators 111 and 209 analyze the register settings made by the display driver 208, generate predetermined graphic bitmap data, and expand the data on the frame buffer 112.
[0074]
Next, the signal conversion unit 114 performs a conversion operation for transferring an image signal to the display unit 115 in accordance with the timing signal passed from the clock generator 113, based on the graphic bitmap data in the frame buffer 112. The signal system to be converted has various specifications such as analog / digital and serial / parallel communication depending on the display unit 115.
[0075]
Further, a vertical / horizontal synchronization signal and the like are transmitted from the clock generator 113 to the display unit 115. Finally, the display unit 115 projects an image on an optical display device (CRT, liquid crystal, TFT) based on the transmitted signals.
[0076]
As described above, the PC 101 can display a high-definition image on the network display monitor 108 via the communication network 107.
[0077]
The communication of the drawing data guarantees the quality of the data by the retransmission processing, and thus is effective for, for example, drawing of a basic OS screen, drawing of a word processor, and drawing of CAD software.
[0078]
Furthermore, as for the method of realizing the function, in particular, on the PC 101 side, not only the GDI 202 but also the network board 105 and the network driver 204 for controlling the network board 105 need not be changed at all, and only the display driver 203 can correspond to the network. Good.
[0079]
(Action / Effect)
As described in detail above, according to the image transfer device according to the first embodiment, the data transmitted on the communication network 107 is drawing information data for drawing an image, and the generation of image bitmap data is Since the graphic accelerator 111 on the network display monitor 108 performs the processing, the screen of the PC 101 can be displayed on the display unit 115 even when a low-capacity communication network is used.
[0080]
Furthermore, the transmission signal of the drawing data to be transferred is a digital signal, and the degree of freedom (layout length, cable volume, etc.) of the layability is increased as compared with the analog transmission path, and the installation of the display monitor is improved.
[0081]
In addition, by making the network display monitor 108 correspond to the reception of ordinary television broadcasts, it becomes possible to view ordinary television images and PC images with one display device, and to monitor future home and premises equipment. Compatible with multimedia and networking.
[0082]
[Second embodiment]
As described above, in the first embodiment, the transfer of the drawing data by the asynchronous transfer method in the IEEE 1394 network has been described. By the way, in recent years, a dedicated API (Application Interface) for directly performing a drawing process from an application to a graphic accelerator has been prepared. This indicates, for example, functions such as DirectX, Direct3D, and DirectDraw in a conventional OS environment. By using this API (hereinafter referred to as DirectX function), the game software realizes high-speed drawing of 3D polygons and the like.
[0083]
During the operation of such software, a drawing function such as DirectX is called continuously. For this reason, in order to transfer drawing data via a communication network, a certain transmission band must be secured. By the way, in IEEE1394, there is an isochronous transfer method for transferring image data (DV stream, MPEG stream).
[0084]
This protocol is intended for use in digital AV equipment and measuring instruments at the beginning of the year, and is a protocol that guarantees transfer of a fixed amount of data within a fixed time. In the isochronous transfer, a common time is realized by the presence of a “cycle master” that supplies a constant cycle (8 kHz ± 100 ppm). The cycle master transmits (broadcasts) a packet called a cycle start, and writes a common time into a cycle timer register of each node (connected device). Among the nodes that have received the cycle start packet, the node that wishes to perform isochronous transfer starts arbitration (a procedure for obtaining the right to use a communication path) and transmits an isochronous packet. When the isochronous transmission is stopped, arbitration for asynchronous transfer is started, and asynchronous transfer is performed.
[0085]
Hereinafter, as a second embodiment of the present invention, an application example in which an IEEE 1394 interface is used as a means for realizing a communication network and an isochronous transfer method is used as a transfer method, as in the first embodiment, will be described.
[0086]
The configuration of the device according to the present embodiment is the same as that of the device described in the above-described first embodiment, the block diagram is the same as FIG. 1, and the functional hierarchy diagram is the same as FIG. FIG. 5 shows an operation flow of the apparatus according to the present embodiment, and FIG. 6 shows a time chart of drawing data transfer on the communication network.
[0087]
Next, the operation of the image transfer apparatus having the above configuration will be described with reference to the operation flowchart of FIG.
[0088]
As shown in the drawing, first, the CPU 102 in the PC 101 and the application 201 processed on the memory 103 enter a step of drawing a certain figure and call a drawing function. The called drawing function passes the obtained drawing control data to the display driver 203.
[0089]
The display driver 203 passes the acquired drawing data to the network driver 204 and instructs the network display monitor 108 to transmit the drawing data to the network display monitor 108 by the isochronous transfer method. Next, an IEEE 1394 isochronous communication packet is generated based on the transmission data (drawing data) acquired from the display driver 203, and is transferred to the network board 105 via the expansion bus bridge 104. On the network board 105, the network interfaces 106 and 205 temporarily store the acquired isochronous communication packets.
[0090]
In this embodiment, since the transmission method is the isochronous transfer method, the network interfaces 106 and 205 wait for a cycle start packet transmitted by a cycle mask on the network. The network interfaces 106 and 205, which have received the cycle start packet, use the stored isochronous communication packets as shown in FIG. A transmission frame signal is generated and transmitted on the communication network 107.
[0091]
After that, the same processing is performed on the network display monitor 108 except that the network interfaces 110 and 206 do not respond to reception of ACK or the like.
[0092]
As described above, the PC 101 can display a high-definition image on the network display monitor 108 via the communication network 107.
[0093]
Furthermore, since the communication of the drawing data is based on a transfer protocol that secures a certain transmission band, it is effective for applications such as drawing 2D polygons and 3D polygons and reproducing and displaying AVI data.
[0094]
Similarly to the first embodiment, in the method of realizing the functions, in particular, on the PC 101 side, not only the GDI 202 but also the network board 105 and the network driver 204 for controlling the GDI 202 without changing the display driver 203 only. Should correspond to the network.
[0095]
According to the present embodiment, since the PC 101 continuously transmits drawing data intermittently in synchronization with timing data output from the cycle master device, the transmission band is guaranteed, and the network display monitor 108 responds to the drawing command of the PC 101 Screen display with high responsiveness is possible.
[0096]
[Example of change]
Note that the present invention is not limited to the above-described embodiment, and various changes can be added.
[0097]
For example, depending on the application, there may be a specification in which both reliable image display and high-speed drawing are performed in a mixed manner.Therefore, when reliable image display is desired, a protocol whose communication quality is guaranteed, that is, an asynchronous transfer method is used. When it is desired to perform the transfer and perform the high-speed drawing, the transfer can be performed by a protocol in which a fixed transfer bandwidth is secured, that is, by the asynchronous transfer method.
[0098]
In this case, it is preferable to determine in advance which transfer method should be used for each GDI function. Based on this, when the display driver 203 receives a drawing instruction, it can be realized by instructing the display driver 203 on a transfer method together with transmission data.
[0099]
【The invention's effect】
According to the image transfer device of the present invention, when transferring an image drawn based on a predetermined drawing parameter from the first device to the second device via the communication network, the transmission capacity for the communication network , And high-resolution image display can be achieved.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an image transfer device according to the present invention.
FIG. 2 is a functional hierarchy diagram of the image transfer device according to the present invention.
FIG. 3 is an operation flow according to the first embodiment.
FIG. 4 is a time chart of drawing data transfer on the communication network according to the first embodiment.
FIG. 5 is an operation flow according to the second embodiment.
FIG. 6 is a time chart of drawing data transfer on a communication network according to a second embodiment.
FIG. 7 is a block diagram showing an internal configuration of a PC image output system according to the related art.
[Explanation of symbols]
100: first device
101 ... PC
102 ... CPU
103 ... Memory
104 ... expansion bus bridge
105 ... Network board
106 ... Network interface
107 ... Communication network
108 ... Network display monitor
109 ... Control unit
110 ... Network interface
111 ... Graphic accelerator
112 ... frame buffer
113 ... Clock generator
114 ... Signal conversion unit
115 ... Display unit
201… Application
202 ... GDI
(Graphic Device Interface)
203 ... Display driver
204: Network driver
205 ... Network interface
206 ... Network interface
207 ... Network driver
208: Display driver
209 ... Graphic accelerator
701 ... PC
702 ... CPU
703… Memory
704: Expansion bus bridge
705 ... Graphic accelerator board
706 ... Graphic accelerator
707 ... Frame buffer
708 ... Video DAC
709 ... Clock generator
710 ... Video cable
711: Display monitor

Claims (5)

An image transfer device for transferring an image drawn based on a predetermined drawing parameter from a first device to a second device via a communication network,
The first device comprises:
First drawing control means for generating a control signal for instructing drawing of the image,
In accordance with the control signal, a drawing parameter for drawing an image, and drawing information generating means for generating drawing information based on a drawing interface function according to the specification of the image to be drawn,
A first communication unit that converts the drawing information into a communication signal that can be transferred through the communication network, and transmits the communication signal to the communication network;
The second device comprises:
Second communication means for receiving the communication signal via the communication network;
Second drawing control means for separating the drawing information from the received communication signal and performing drawing control based on the separated drawing information;
Image information generating means for generating image information based on the drawing control;
Display means for displaying an optical image based on the image information. The drawing information generating means includes:
A drawing application that calls a predetermined drawing interface function with a drawing parameter attached to the specification of an image to be drawn;
A first drawing device driver for processing the specification information and the drawing parameter into a predetermined format by the called drawing interface function to generate the drawing information;
The first communication means includes:
A first communication device driver that acquires the drawing information as transmission information from the first drawing device driver, and generates a communication packet based on a predetermined protocol from the acquired transmission information;
A first network interface for generating a physical communication frame from the generated communication packet and transmitting the communication frame on the communication network;
The second communication means,
A second network interface that monitors the communication network and obtains a corresponding communication frame when there is transmission information for the second device, and separates a communication packet from the communication frame;
A second communication device driver for separating the transmission information as the drawing information from the separated communication packet,
The image information generating means,
A second drawing device driver that analyzes the separated drawing information and performs drawing control based on the analysis result;
A storage unit that generates image information based on the drawing control, and temporarily stores the image information in a developed state;
Image signal converting means for reading image information from the storage means, converting the image information into a predetermined image signal, and outputting the image signal;
The image transfer device according to claim 1, wherein the image display unit displays the converted image signal as an optical image. The first and second communication means use a protocol for transmitting and receiving data at an indefinite period,
When the reception is normally performed on the reception side, normal response information is transmitted to the transmission side,
The image transfer apparatus according to claim 1, wherein when an abnormal reception occurs on the receiving side, a retransmission request is issued from the receiving side, and the transmitting side performs retransmission processing in response to the request. A cycle master disposed on the communication network and periodically transmitting timing information to the first and second devices;
The first and second communication means use a protocol that unilaterally transmits transmission information from a transmitting side to a receiving side device,
4. The image transfer device according to claim 1, wherein the transmitting device transmits the image in accordance with the timing information. The first image drawing control means generates a first control signal and a second control signal,
Regarding the transmission information based on the first control signal,
Using a protocol that sends and receives data at irregular intervals,
If the receiving side normally receives, the normal response information is transmitted to the transmitting side, and if abnormal receiving occurs on the receiving side, a retransmission request is made from the receiving side. The sender performs retransmission processing,
Regarding the transmission information based on the second control signal,
Using a protocol to send transmission information to the receiving device unilaterally from the transmitting side,
The image transfer apparatus according to claim 1, wherein the transmission is performed in accordance with the timing information transmitted from a cycle master arranged on the communication network.

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