JP2008051850A - Data transmission method, data transmission system, information processor, data transmission program and external device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transmission method capable of performing data transmission which is high-speed and bandwidth-guaranteed without using a specified hardware. <P>SOLUTION: In a transmission system 1 which transmits data to an external device 3 from an information processor 2 via an image data transmission means 4, the information processor 2 is provided with: a means 21 which gains functional information of the external device 3; a means 24 which converts data to be transmitted to the external device 3 to temporary image data; and a means 22 which transmits the temporary image data via the image data transmission means 4, wherein the external device 3 is provided with: a means 31 for receiving transmitted image data; a means 36 for transmitting such temporary display information as to inform that the external device itself is a display for the information processor 2; and a means 38 for reconstituting received temporary image data to original data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a data transmission method, a data transmission system, an information processing device, a data transmission program, and an external device.

Due to the development of the network environment, various peripheral external devices such as a large-capacity storage and a printer are connected to an information processing device such as a PC, and a so-called multimedia information processing device that controls each external device from the information processing device side. The importance has become higher in recent years.
The information processing capability of an information processing apparatus such as a PC has been remarkably increased due to an increase in operating frequency due to advances in semiconductor technology.

For example, in the technology disclosed in Patent Document 1, a projector and a computer are connected by a USB standard cable or the like, and image correction processing that is conventionally performed by a projector is performed on the PC side, and the corrected image data is transmitted via a cable. Output to the projector, and based on this, the projector projects an image. In this way, by causing a PC with dramatically improved information processing capability to perform complex image correction processing, it is not necessary to install an expensive graphic processor for drawing in the projector, thereby reducing the price of the projector. it can.
By the way, an information processing apparatus such as a current PC has several types of general-purpose data transmission means, for example, an IEEE 802.3 series network, USB (Universal Serial Bus), IEEE 1394, and the like are common.

JP 2004-69996 A

However, when data is transmitted by the general-purpose data transmission means, it may be insufficient depending on the purpose. For example, there is a case where a high transmission rate is required or a bandwidth guarantee is required.
Consider moving image data as an example that requires a high transmission rate. For example, a moving image requires a transmission rate of 1280 (width) × 720 (high) × 3 (RGB) × 30 (frame / second) × 8 (bit) = about 660 Mbit / second.
However, USB has a data transmission speed of about 480 Mbit / sec at the fastest. Similarly, IEEE 1394 has a transmission rate of about 400 Mbit / sec.
Furthermore, the effective transmission rate in a real environment is often a fraction of these values. That is, these general-purpose data transmission means are quite insufficient for transmitting moving image data.

Further, in order to transmit a lot of multimedia data, bandwidth guarantee is required. This is to ensure that the sound is not interrupted and the video is not interrupted.
Regarding bandwidth guarantee, USB and IEEE 1394 have an isochronous transfer mode. In the isochronous transfer mode, it is guaranteed that data transmission processing is assigned within an appropriate time interval, and the bandwidth is guaranteed.
However, when such a mode is used, the effective transmission rate is further reduced.

On the other hand, as for the network function of the IEEE 802.3 series, there is a 10 Gbit baseband IEEE 802.3ak and the like, but this is not yet widespread yet.
Also in this case, the effective transmission rate becomes a fraction of the theoretical maximum rate due to a load such as packetization. Further, in these cases, the bandwidth is not normally guaranteed.

The above is an example of moving image data, but the same can be said for still image data, for example.
For example, there are many digital cameras obtained by general consumers that exceed 10 million pixels. If this still image is stored in an uncompressed state in order to maintain quality, the number of still images is several hundred megabits.
In addition, due to the increase in the capacity of semiconductor memory, a memory card of more than gigabytes is not uncommon. A memory card having such a capacity can store about 100 uncompressed high-quality still images.
If data of such a capacity is to be output in about 1 minute, a data transmission means of about several hundreds to 1000 Mbits / second is required.

  An object of the present invention is to provide a data transmission method, a data transmission system, an information processing apparatus, a data transmission program, and an external apparatus that can perform high-speed band-guaranteed data transmission without using special hardware. It is in.

A data transmission method according to the present invention includes:
An information processing apparatus having an image transmission means for transmitting image data, an image data transmission means for transmitting the image data connected to an image output terminal provided in the information processing apparatus, and a connection to the image data transmission means A data transmission method executed on a data transmission system including an external device,
When the image output terminal of the information processing device and the external device are connected via the image transmission means, a procedure for transmitting virtual display information indicating that the device is a display from the external device;
The information processing device acquires the transmitted virtual display information and recognizes the external device as a display;
A procedure for converting data to be sent from the image output terminal to the external device into virtual image data that the image transmission means recognizes as image data;
A procedure for transmitting virtual image data converted by the image data transmission means to the external device;
A procedure for the external device to receive the transmitted virtual image data;
The virtual image data received by the external device is reconstructed into original data.

Here, as the external device, for example, a printer, a storage, and the like can be considered in addition to video equipment such as a projector.
The image data transmission means can be configured as a display connection board connected to an information processing device such as a video card, and includes a GPU (Graphics Processing Unit), a frame buffer, and the like. .
Further, as the image data transmission means, it is possible to adopt one that transmits image data by a digital signal or an analog signal. For a digital signal, for example, DVI (Digital Visual Interface) standard, HDMI (High-Definition Multimedia Interface) Standards and the like can be adopted.

According to the present invention, data to be transmitted to the external device can be converted into virtual image data and transmitted to the external device via the image data transmission means. For example, as a display, a standard 1280 (horizontal) × 1024 ( The transmission speed of (vertical) × 3 (RGB) × 60 (frame / second) × 8 bits = about 1.9 Gbit / second can be realized, and a large amount of data can be transmitted to an external device at high speed.
In addition, by transmitting data using the image output terminal of the information processing apparatus, the image data transmission means such as a display transmits image data in a state where the bandwidth is guaranteed so that the image is not interrupted. Bandwidth is guaranteed for transmission of.
Since image transmission means normally provided in an information processing apparatus such as a PC is used, it is not necessary to provide special hardware, and high-speed transmission and band-guaranteed data transmission can be realized.

In the present invention,
Transmission of image data by the image data transmission means is performed by analog signals,
After the procedure of converting the data to be sent to the external device into the virtual image data, and before the procedure of transmitting the virtual image data, a procedure for encoding the virtual image data with an error correction code is provided. Executed,
It is preferable that a procedure for decoding the encoded virtual image data is performed after the external device receives the virtual image data and before reconstructing the original image data.
Here, as the error correction code, an arbitrary code such as a Hamming code, a Reed-Solomon code, or an M-sequence code can be adopted.

When image data transmission by the image data transmission means is performed by an analog signal, it is necessary to perform DA (Digital-Analog) conversion on the information processing apparatus side and AD (Analog-Digital) conversion on the external apparatus side. Since several LSB (Least Significant Bit) errors occur at the time of conversion, the reliability of data received and converted on the external device side becomes low.
For this reason, by performing error correction processing as in the present invention, an error correction code is added to the lower bit portion of the virtual image data to make it redundant, so even if a conversion error occurs during DA conversion and AD conversion, The reliability of the decrypted data is not impaired.
In the case of an analog display image transmission system, the maximum display is 2048 (horizontal) × 1536 (vertical) × 3 (RGB) × 75 (frame / second) × 8 bits = approximately 5.7 Gbit / second. A transmission rate of 1.4 Gbit / s can be realized even if redundancy is performed in which 4 bits correspond to 1 bit of the original data.

Further, the present invention can be configured not only as the data transmission method described above but also as a data transmission system. Specifically, the data transmission system according to the present invention includes:
An information processing apparatus having an image data transmission means for transmitting image data, an image data transmission means connected to an image output terminal provided in the information processing apparatus for transmitting the image data, and an image data transmission means A data transmission system comprising an external device to be connected,
The information processing apparatus includes:
Function information acquisition means for acquiring function information of an external device connected to the image output terminal via the image transmission means;
Virtual image data conversion means for converting the data to virtual image data in order to cause the image data transmission means to recognize the data to be sent to the external device as image data,
The external device is
Image data receiving means for receiving image data transmitted from the information processing apparatus;
Virtual display information transmitting means for transmitting virtual display information to the function information acquisition means to the effect that it is a display;
Data reconstructing means for receiving the virtual image data transmitted from the image data transmitting means and reconstructing it into original data is provided.

In the above, when the image data transmission by the image data transmission means is performed by an analog signal,
The information processing apparatus includes data encoding means for attaching a code for error correction to image data to be transmitted,
The external device preferably includes data decoding means for decoding the encoded image data.
Such a data transmission system according to the present invention can also enjoy the same operations and effects as those described above.

  Furthermore, the present invention can be realized as an information processing apparatus as a sub-combination constituting the above-described data transmission system and an external apparatus. In addition, each functional means constituting the information processing apparatus is realized by a general-purpose computer. Therefore, it can also be configured as a data transmission program executed on a computer, and can also be configured as a computer-readable recording medium on which the data transmission program is recorded.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
[1] Configuration of Data Transmission System 1 FIG. 1 shows a schematic configuration of a data transmission system 1 according to the first embodiment of the present invention. This data transmission system 1 assumes a projector 3 as a peripheral external device, and includes a computer 2 as an information processing device, a projector 3 as an external device that projects a projection image on a screen Sc, and between the computer 2 and the projector 3. Are provided with a digital cable 4 as an image data transmission means.

In the data transmission system 1, the image correction processing necessary for the projector 3 is performed by the computer 2, and the corrected image data subjected to the correction processing is output to the projector 3 via the digital cable 4. A projected image is formed on the screen Sc based on the corrected image data that has been subjected to the correction process.
Here, the digital cable 4 employs a digital signal cable such as a DVI standard capable of transmitting image data by a digital signal. The DVI terminal for connecting the display of the computer 2 and the DVI terminal for connecting the display of the projector 3 are used. Connected to. This looks like a connection between a normal PC and projector, but differs in that the data transmitted by this connection is not image data in the normal sense. This will be described in detail later.

FIG. 2 schematically shows each functional block constituting FIG. 1 which is the first embodiment of the present invention. The computer 2 as an information processing device is configured as a general-purpose computer including an arithmetic processing device and a storage device such as a hard disk, and is operated via a digital cable 4 or the like by an OS (Operating System) executed on the arithmetic processing device. Communication control with various connected external devices is performed, or a necessary program is read from the storage device based on an instruction from the operator, and the read program is executed. The computer 2 includes a function information acquisition unit 21, an image data transmission unit 22, a display driver 23, and a virtual image data conversion unit 24.
Although not shown in FIG. 2, the computer 2 includes image processing means for performing correction specific to the projector 3 on the original image data in order to display an appropriate image on the projector 3. The corrected image data corrected by the computer 2 is configured to be displayed by the projector 3, and image processing by the projector 3 is minimized.

The function information acquisition unit 21 is configured as a so-called plug and play function that the OS of the computer 2 has. When an external device is connected to an image output terminal provided in the computer 2, the function information acquisition unit 21 is transmitted from the external device. The function information of the external device, for example, information such as supply vendor name and model number is acquired.
For example, when the display is connected to the DVI terminal for display connection, the function information acquisition unit 21 has information unique to the display conforming to VESA-DDC (Display Data Channel), for example, the name of the vendor to be supplied, the display Get information such as model number, resolution, refresh rate.

Although not shown, the image data transmission unit 22 is a part that converts the image data generated by the computer 2 into a predetermined format and transmits it to an external device such as a display connected via the digital cable 4. Although not shown in the figure, it is configured to include a GPU, a frame buffer for storing and holding the generated image data in units of frames, an encoder for encoding when transmitting via the digital cable 4, and the like.
The display driver 23 is software that controls the image data transmission unit 22.
The display driver 23 sets the image resolution, refresh rate, and the like of the image transmission unit 22 based on the display function information acquired by the function information acquisition unit 21.

The virtual image data conversion means 24 is a part that converts predetermined data from the computer 2 to the projector 3 as an external device via the digital cable 4 into virtual image data in frame units.
When executed, the virtual image data conversion unit 24 secures the entire screen area as a data storage area and stores data to be transmitted in the data storage area. This is to prevent data that is not intended to be transmitted from being written in the remaining portion when the entire screen area is not secured as a data area.
When the corrected data generated by the computer 2 is to be displayed on the connection destination projector 3 as in this embodiment, it is necessary to transmit data larger than the data before correction. That is, even if the data before correction has an 8-bit accuracy, for example, the corrected data requires 10-bit accuracy or 12-bit accuracy. Furthermore, in addition to the corrected data, other data and various control data may be transmitted. Also in this case, the size of the transmission data is larger than the original data. When transmitting such large data, the virtual image data conversion means 24 can synthesize virtual image data by the following two methods, for example.

(1) When setting a virtual image data area larger than the original display image data area As shown in FIG. 3, a virtual image data area G2 larger than the actual display image data area G1 actually displayed by the projector 3 is displayed. For example, audio data G3, control data G4, and the like are stored in a surplus portion other than the actual display image data area G1, and padding (margin) data G5 is stored in the surplus portion for conversion.
However, FIG. 3 schematically shows virtual image data for the sake of simplicity, and does not mean that such a data arrangement is actually used. For example, if the data accuracy before correction is 8 bits and the data accuracy after correction is 12 bits as described above, the size of the actual display image data is 1.5 times larger than the original data. In other words, it does not mean that the actual display image data and the arrangement of the displayed part have a one-to-one correspondence with the actually displayed data.
(2) When transmitting different data in frame units As shown in FIG. 4, a virtual image data area G6 is set with the same size as the actual display image data area G1, and the actual display image data and audio data, control, for example, are set. This is a method of converting the virtual image data area G6 in which data is stored and the base table self-image data G1 so as to be switched and output in units of one frame.
As described above, in this case as well, the vertical and horizontal sizes of the actual display image data area G1 do not correspond to the vertical and horizontal sizes of the actually displayed image. For example, assuming that the corrected data has increased 1.5 times, the virtual image data can be transmitted as shown in FIG. 4 by setting the horizontal side of the virtual image data to 1.5 times or twice the actual display. Can be realized.
Alternatively, assuming that the vertical and horizontal sizes of the virtual image data are the same as the actual display size, it is possible to divide and transmit the increased actual display image data after correction into a plurality of frames. .

As data stored as such virtual image data, for example, audio data can be considered in addition to the corrected display image data. According to this, it is possible to transmit audio with a single connection that can only transmit video signals in the prior art. In addition, it is advantageous for the lip sync that synchronizes the image and the sound to always transmit the display image data and the sound data as a pair.
In addition, as data stored as virtual image data, for example, light source modulation data of a projector can be considered. By appropriately controlling the light source modulation and the display image data, it is possible to display an image with a wider dynamic range.

In the above example, the virtual image data is naturally divided into frame units or integer multiple units of frames. However, in the present invention, this is not essential. That is, even if there is no natural delimiter in frame units, it is possible to transmit the data by the transmission means of the present invention by dividing the data into frame units. Specific examples include JPEG data and general data such as MPEG data.
In this embodiment, a projector is considered as an external peripheral device. However, for example, a printer may be considered as an external peripheral device, and JPEG data may be transmitted to the printer. Alternatively, a storage device may be considered as an external peripheral device, and MPEG data may be transmitted thereto. In such a case, there is no natural delimitation in units of frames in the data.

In such a case, specifically, as shown in FIG. 5, the virtual image data conversion unit 24 converts the transmission data 1 to be transmitted, for example, JPEG data, transmission data 2, for example, MPEG data, into a virtual frame unit. The virtual image data area is divided so as to correspond to typical image data, and padding data G5 is inserted into the remaining portion so that the data amount between the frames is the same, and a header H is added to each frame. To convert it into a series of virtual image data.
The header H records what type of data is included in the image data in units of frames.

Returning to the example of the first embodiment of the present invention shown in FIG. 1, the projector 3 as an external device converts a light beam emitted from a light source into a light modulation device such as a liquid crystal panel according to input image data. Is an optical device that forms an optical image by modulating the image and projects the enlarged image, and each part inside the apparatus is controlled by a built-in control means. As shown in FIG. 2, the projector 3 operates on the control means. The image data receiving means 31, the image processing means 32, the liquid crystal panel drive circuit 33, the light source control means 34, the light source drive circuit 35, the virtual display information. A transmission unit 36, a ROM 37, and a data reconstruction unit 38 are provided.
Although not shown in FIG. 2, the projector 3 is provided with sound output means such as a speaker, and the sound output means is controlled by the sound output control means provided on the control means described above.

The image data receiving means 31 is means for receiving image data input from the DVI terminal via the digital cable 4. The image data receiving means 31 decodes the encoded image data and restores it to image data, and sends it to the data reconstruction means 38. Output.
The image processing means 32 performs drive control of the liquid crystal panel drive circuit 33 based on the actual display image data and control data reconstructed by the data reconstruction means 38, and a projection image corresponding to the image data on the projection surface. Form. However, as described above, in this embodiment, image processing is performed on the computer 2 side, and the transmitted image data is already corrected, so that the transmitted data is displayed as it is. .

Similarly, the light source control means 33 controls the light source drive circuit 35 based on the control data reconstructed by the data reconstruction means 38. Specifically, as the light source control data by the light source control means 33, if the light source is an LED light source, it is light emission and dimming control by PWM control data or the like. It is possible to expand the dynamic range.
When connected to the computer 2 via the digital cable 4, the virtual display information transmitting unit 36 is a part that transmits virtual display information indicating that the display 2 itself is a display. The virtual display information is stored in a ROM provided in the projector 3. (Read Only Memory) 37, specifically, it is composed of information related to a virtual display conforming to VESA-DDC, such as the vendor name, model number, and refresh rate.

The data reconstruction unit 38 is a part that reconstructs the virtual image data transmitted from the image data reception unit 31 into original actual display image data, audio data, and control data.
As shown in FIG. 5, the data reconstruction unit 38 removes the header H and the padding data G5 from the virtual image data stored in units of frames, thereby converting the data 1 and data 4 into data 1 and data 4. 2 is reconstructed, data 3 and data 4 are reconstructed, and restored to transmission data 1 and transmission data 2 that were to be transmitted from the computer 2. At the time of data reconstruction, the data reconstruction unit 38 determines the type of data based on the information recorded in the header H, and performs data reconstruction based on the determination result.
If the data transmission format is uniquely determined by the virtual display information, such a header may not be necessary.
The restored transmission data 1 and transmission data 2 are processed by the image processing means 32 and the light source control means 34 in the projector 3, and the projector 3 performs projection based on the transmission data 1 and transmission data 2 generated by the computer 2. An image is formed on the screen Sc described above.

[2] Operation of Data Transmission System 1 Next, the operation of the data transmission system 1 configured as described above will be described.
(2-1) Establishing Protocol at Connection / Startup Establishment of a communication protocol between the computer 2 and the projector 3 at the time of connection / startup of the digital cable 4 of the data transmission system 1 is performed based on the flowchart shown in FIG. Is called.
(1) The virtual image data conversion unit 24 of the computer 2 starts a monitoring application and monitors display information of an external device connected to the DVI terminal of the computer 2 (step S1).
(2) When an operator or the like connects the computer 2 and the projector 3 with the digital cable 4, the virtual display information transmitting means 36 of the projector 3 reads the virtual display information in the ROM 37 and sends the virtual display information to the computer 2. Transmit (procedure S2), and then shift to a data reception operation (procedure S3).
In this case, the function information acquisition unit 21 of the computer 2 may read the virtual display information in the ROM 37 through the virtual display information transmission unit 36 of the projector 3.

(3) When the function information acquisition means 21 set as a function on the OS of the computer 2 acquires the virtual display information transmitted from the projector 3 (step S4), the display driver 23 is activated and set using the information. (Procedure S5), shift to a normal display control operation on the OS (procedure S6).
(4) When the display driver 23 is activated, the monitoring application of the virtual image data conversion unit 24 detects that the virtual display is connected (step S7), and activates the virtual image data conversion unit 24 (procedure). S8).

(5) The activated virtual image data conversion means 24 generates communication initial setting data for establishing a communication protocol with the data reconstructing means 38 of the projector 3 (step S9), and after conversion to the image data format, The image data transmission unit 22 transmits the image data to the projector 3 (step S10).
(6) When the communication initial setting data is received by the image data receiving means 31 of the projector 3 (procedure S11), the data reconstruction means 38 is activated based on the communication initial setting data (procedure S12). The compliance data indicating the activation is transmitted to the virtual image data conversion unit 24, and the activation / connection process is terminated (not shown).

(2-2) Data Transmission Method The virtual image data transmission from the computer 2 to the projector 3 after establishing the protocol at the time of activation / connection as described above will be described based on the flowchart shown in FIG.
(1) When a drawing process callback is made via the image data transmission means 22 (procedure S13), the virtual image data conversion means 24 converts the transmission data to be transmitted into virtual image data (procedure S14). .
(2) The display driver 23 waits for the transmission of the virtual image data from the image data transmission unit 22 according to the transmission timing (step S15). As the transmission timing, for example, a screen update timing such as a refresh rate included in the virtual display information may be employed.

(3) When the transmission timing is reached, the image data transmission means 22 encodes the virtual image data and transmits it to the projector 3 via the digital cable 4 (step S16). Received by the image data receiving means 31 (step S17).
(4) The image data receiving means 31 decodes the received virtual image data and outputs it to the data reconstruction means 38. The data reconstruction means 38 reconstructs transmission data from the virtual image data, and performs image processing. The information is output to the means 32, the light source control means 34, the sound output control means (not shown), and the like, and the image display output and sound output are performed from the projector 3 by each means (step S19).

In this way, the computer 2 and the projector 3 are connected by the digital cable 4 conforming to the DVI standard, and control data other than image data, audio data, and the like are output using this image transmission system, so that high speed and bandwidth guarantee can be achieved. Data transmission can be realized.
The DVI terminal is mounted on most computers 2, and the data transmission method described above can be realized on the data transmission system 1 simply by installing application software called virtual image data conversion means 24. Can be easily realized without the need to implement a high-speed and bandwidth-guaranteed data transmission.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the following description, the same parts as those already described are denoted by the same reference numerals and the description thereof is omitted.
In the first embodiment described above, data transmission between the computer 2 and the projector 3 is directly transmitted as a digital signal using the DVI standard digital cable 4.
In contrast, in the data transmission system 5 according to the second embodiment, as shown in FIG. 8, the computer 2 and the projector 3 are connected by an analog cable 14 connected to a terminal such as a D-sub 15 pin. The difference is that this is used as a data transmission means.

Therefore, the data transmission system of the computer 2 according to the second embodiment is provided with a converter 51 that performs digital-analog data conversion, a function information acquisition unit 52, and a data encoding unit 53. It differs from the form.
Further, the data transmission system of the projector 3 is different from the first embodiment in that it includes a converter 54, a virtual display information transmission unit 55, and a data decoding unit 56.

  When the image transmission means is an analog cable 14, when data is transmitted from the computer 2 to the projector 3, (digital data) → (digital-analog conversion) → (cable transmission) → (analog-digital conversion) → (digital data) ) And the high-speed converters 51 and 54 are used, a conversion error of several LSB (Least Significant Bit) occurs at the time of analog-to-digital conversion, and the analog cable 14 also has the same transmission path. Since an error occurs, the reliability of the received data is lowered.

Therefore, the computer 2 according to the present embodiment is provided with data encoding means 53 that adds an error correction code to the transmission data and encodes it redundantly, and the projector 3 receives the received encoded transmission data. By providing the data decoding means 56 for decoding the data, the reliability of the data is ensured.
Similarly, the function information acquisition unit 52 of the computer 2 performs data decoding, and the virtual display information transmission unit 55 of the projector 3 also performs data encoding to ensure the reliability of transmission data.

As an error correction processing method, various methods of error correction in data communication can be adopted. For example, assuming that the accuracy of the converters 51 and 54 is 8 bits and the average error is ± 4LSB, the lower 2 bits. An error occurs.
At this time, assuming that the data to be transmitted is DDDD, if this data is loaded with significant data only in the upper 4 bits, the lower 4 bits are added with the code 0111, and encoded into the data DDDD0111, −7LSB To + 8LSB, the upper 4 bits of transmission data DDDD are not affected.

In the above method, the hamming distance is simply increased to prevent the occurrence of errors, so that it is possible to cope with errors that occur due to DA and AD conversion. It is impossible to cope with burst errors that occur continuously and intensively.
Therefore, in order to further improve the reliability of transmission data, encoding may be performed using a Reed-Solomon code.
That is, the data encoding means 53 arranges the transmission data two-dimensionally, calculates the outer code by calculating the data in each column in the vertical direction, calculates the inner code by calculating in the horizontal direction, and attaches this to the transmission data. To encode.
When the virtual image data as shown in FIG. 3 in the first embodiment described above is encoded with an outer code and an inner code, the encoded virtual image data is as shown in FIG. In addition, the outer code G7 and the inner code G8 are added around the virtual image data area G2.

The transmission data is encoded by the data encoding unit 53 after the conversion by the virtual image data conversion unit 24, and the image data transmission unit 22 transmits the encoded virtual image data via the converter 51.
The transmitted encoded virtual image data is received by the image data receiving unit 31 via the converter 54 of the projector 3, decoded by the data decoding unit 56, and output to the data reconstruction unit 38.
In this way, when data transmission is performed using an analog signal, transmission data error correction can be performed by performing data encoding / decoding, thereby ensuring the reliability of transmission data. .

[Modification of Embodiment]
In addition, this invention is not limited to each embodiment mentioned above, The following deformation | transformation is included.
In the first embodiment described above, the virtual image data conversion means 24 converts the data into virtual image data by attaching a header H that records the type of data to each frame, but the present invention is not limited to this. .
That is, when establishing a protocol at the time of connection / startup, if the arrangement of transmitting control data, audio output data, etc. at the beginning of communication and outputting the image data after the transmission is completed, the header is set. It can be unnecessary, and can cope with various communication formats and transmission data.

In the above-described embodiment, data transmission is performed between the computer 2 and the projector 3. However, the present invention is not limited to this, and the present invention may be applied to a computer, a large-capacity storage, a printing device such as a printer, and the like.
In the first embodiment described above, error correction processing is not performed. However, error correction processing may be performed even when the image transmission unit transmits data using a digital signal.
In addition, the specific structure, shape, and the like in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

1 is a schematic perspective view illustrating a configuration of a data transmission system according to a first embodiment. The block diagram showing the structure of the data transmission system in the said embodiment. The schematic diagram showing the structure of the virtual image data in the said embodiment. The schematic diagram showing the structure of the virtual image data in the said embodiment. The schematic diagram showing the conversion to the virtual image data in the said embodiment, and the reconstruction of the data from virtual image data. The flowchart showing the effect | action of the data transmission system in the said embodiment. The flowchart showing the effect | action of the data transmission system in the said embodiment. The outline perspective view showing the composition of the data transmission system concerning a 2nd embodiment. The schematic diagram showing the structure of the virtual image data in the said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 5 ... Data transmission system, 2 ... Computer, 3 ... Projector, 4 ... Digital cable, 14 ... Analog cable, 21, 52 ... Function information acquisition means, 22 ... Image data transmission means, 24 ... Virtual image data conversion means, 31: Image data receiving means, 36, 55 ... Virtual display information transmitting means, 53 ... Data encoding means, 56 ... Data decoding means

Claims (8)

An information processing apparatus having an image transmission means for transmitting image data, an image data transmission means for transmitting the image data connected to an image output terminal provided in the information processing apparatus, and a connection to the image data transmission means A data transmission method executed on a data transmission system including an external device,
When the image output terminal of the information processing device and the external device are connected via the image transmission means, a procedure for transmitting virtual display information indicating that the device is a display from the external device;
The information processing device acquires the transmitted virtual display information and recognizes the external device as a display;
A procedure for converting data to be sent by the information processing device to the external device into virtual image data that the image transmitting means recognizes as image data;
A procedure for transmitting virtual image data converted by the image data transmission means to the external device;
A procedure for the external device to receive the transmitted virtual image data;
And a procedure for reconstructing virtual image data received by the external device into original data. The data transmission method according to claim 1,
Transmission of image data by the image data transmission means is performed by analog signals,
After the procedure of converting the data to be sent to the external device into the virtual image data, and before the procedure of transmitting the virtual image data, a procedure for encoding the virtual image data with an error correction code is provided. Executed,
A data transmission method comprising: a step of decoding the encoded virtual image data after the external device receives the virtual image data and before reconstructing the original data. An information processing apparatus having an image data transmission means for transmitting image data, an image data transmission means connected to an image output terminal provided in the information processing apparatus for transmitting the image data, and an image data transmission means A data transmission system comprising an external device to be connected,
The information processing apparatus includes:
Function information acquisition means for acquiring function information of an external device connected to the image output terminal via the image transmission means;
Virtual image data conversion means for converting the data to virtual image data in order to cause the image data transmission means to recognize the data to be sent to the external device as image data,
The external device is
Image data receiving means for receiving image data transmitted from the information processing apparatus;
Virtual display information transmitting means for transmitting virtual display information to the function information acquisition means to the effect that it is a display;
A data transmission system comprising: data reconstructing means for receiving virtual image data transmitted from the image data transmitting means and reconstructing the original data. The data transmission system according to claim 3, wherein
Transmission of image data by the image data transmission means is performed by analog signals,
The information processing apparatus includes data encoding means for attaching a code for error correction to image data to be transmitted,
The data transmission system, wherein the external device includes data decoding means for decoding encoded image data. An information processing apparatus comprising image data transmitting means for transmitting image data, wherein an external device is connected to an image output terminal via the image data transmitting means for transmitting the image data,
Function information acquisition means for acquiring function information of an external device connected to the image output terminal via the image transmission means;
Information comprising virtual image data conversion means for converting the data to be transmitted to the external device into virtual image data so that the image data transmission means recognizes the data as image data Processing equipment. A data transmission program executed on an information processing apparatus including an image data transmission unit that transmits image data, and an external device is connected to an image output terminal via the image data transmission unit that transmits the image data,
The information processing apparatus;
Function information acquisition means for acquiring function information of an external device connected to the image output terminal via the image transmission means;
A data transmission program for causing data to be sent to the external device to function as virtual image data conversion means for converting the data into virtual image data so that the image data transmission means recognizes the data as image data. .   A computer-readable recording medium on which the data transmission program according to claim 6 is recorded. An external device connected to an information processing apparatus having an image data transmission means for transmitting image data via an image data transmission means for transmitting the image data,
Image data receiving means for receiving image data transmitted from the information processing apparatus;
Virtual display information transmitting means for transmitting virtual display information indicating that the information processing apparatus is provided with the function information acquisition means;
Data reconstructing means for receiving virtual image data converted and transmitted to the original data and reconstructing the original data so that the information processing apparatus recognizes data to be sent to the external apparatus as image data And an external device.

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