JP6609074B2 - Image output apparatus and output method - Google Patents

Description

  The technical field relates to transmission and reception of video information.

In recent years, the number of pixels handled in digital image processing is 4k2k (3
840 x 2160 pixels), broadcast HD (High Definition: 1920 x 1080 pixels)
Increasing year by year with the increase in pixels of digital video camera image sensors and displays.

Regarding the method of transmitting these image data between devices, HDMI (High-Definition Mul
timedia Interface (a registered trademark of HDMI Licensing, LLC) standard and VESA (Video Electron
There is DisplayPort (VESA registered trademark or trademark) standard established by ics Standards Association.

In the above-mentioned HDMI data transmission system, Patent Document 1 describes that “a non-compressed video signal or a compressed video signal obtained by compressing a non-compressed video signal with a compression system that can be supported by a receiving device”. For selective transmission, a video signal having a desired bit rate can be satisfactorily transmitted within the transmission bit rate of the transmission path ”(see Patent Document 1 [0048]), and for the compression method,“ data compression ” The units 121-1 to 121-n are respectively codec 117.
The uncompressed video signal output from is compressed with a predetermined compression ratio, and the compressed video signal is output. The data compression units 121-1 to 121-n constitute a video signal compression unit. Each of the data compression units 121-1 to 121-n performs data compression processing using different compression methods. For example, as a compression method, “RLE (Run Length Encoding)”, “Wavel”
et "," SBM (Super Bit Mapping (registered trademark of Sony)) "," LLVC (Low Lat
ency Video Codec) ”,“ ZIP ”, etc.” (see Patent Document 1 [0077]).

In HDMI, image data is TMDS (Transition Minimized Different
The data transmission format of the ial Signaling (registered trademark of Silicon Image, Inc.) method is employed, and Patent Document 2 is shown as an example.

JP 2009-213110 A JP 2005-514873 A

However, in any of the prior art documents, there is no consideration regarding transmission of image data of a larger size (also referred to as “video”, hereinafter the same) data while maintaining more faithfulness.

  In order to solve the above problems, for example, the configuration described in the claims is adopted.

The present application includes a plurality of means for solving the above-described problems. To give an example, an image transmission apparatus that transmits image data includes a compression processing unit that compresses image data and a compression processing unit that compresses the image data. An output unit that outputs compressed image data, and the output unit outputs the compressed image data divided into a first period and a second period different from the first period.

As another example, an image transmission apparatus that transmits image data includes: a compression processing unit that compresses image data including a plurality of components; and a data transfer unit that outputs compressed image data. The data transfer unit changes the image data output method based on each component of the image data.

As another example, an image transmission apparatus that transmits image data, the image data being compressed, and a compression processing unit that generates compressed image data and compressed code information related to the compression process; A data transfer unit that outputs compressed image data and compressed code information, and the redundancy of the compressed code information is higher than that of the compressed image data.

Another example is an image transmission apparatus that transmits image data, and includes a compression processing unit that compresses image data and an output unit that outputs compressed image data compressed by the compression processing unit. The output unit outputs the compressed image data divided into a first period and a second period different from the first period, and the compression processing unit outputs the image data based on the transmission error rate of the transmission path. The compression process is changed.

According to the above means, it is possible to transmit image data of a larger size while keeping it faithful.

1 illustrates an example of an image transmission device and an image reception device according to a first embodiment. An example of the validity / blanking period of the image data of 1st Example. An example of the unit of the image data to compress of 1st Example. An example of the unit of the image data to compress of 1st Example. An example of the structure of the main compression code information of 1st Example, subcompression code information, and compression image data. An example of the timing of the data transfer of 1st Example. An example of the compression process part of 1st Example. An example of the compression process part of 1st Example. An example of the compression process part of 1st Example. An example of the compression part A of 1st Example. An example of the compression part A of 1st Example. An example of the error correction code generation part of 1st Example. An example of the data transmission part of 1st Example. An example of the header of the compression code information packet of 1st Example. An example of the data of the compression code information packet of 1st Example. An example of the header of the compression code information packet of 1st Example. An example of the data of the compression code information packet of 1st Example. An example of the compression code information of 1st Example. An example of EDID description of the image receiver of 1st Example. An example of the data reception process part of 1st Example. An example of the expansion | extension process part of 1st Example. An example of the expansion | extension process part of 1st Example. An example of the expansion | extension process part of 1st Example. An example of the expansion | extension process part of 1st Example. An example of the timing of the data transfer of 1st Example. An example of the timing of the data transfer of 1st Example. An example of the compression code information of 1st Example. An example of the compression code information of 1st Example. An example of the waveform of the serializer of 2nd Example. An example of the data structure of the serializer output of 2nd Example. An example of the packet structure of the audio | voice data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of the bit allocation of the transmission line with respect to each component of the compressed image data of 2nd Example. An example of a data structure when the redundancy of the main compression code information of 3rd Example is not added. An example of a data structure at the time of adding the redundancy of the main compression code information of 3rd Example. An example of a data structure at the time of adding the redundancy of the main compression code information of 3rd Example. An example of a data structure at the time of adding the redundancy of the main compression code information of 3rd Example. An example of a data structure at the time of adding the redundancy of the subcompression code information of 3rd Example. An example of allocation of the compression rate, the horizontal blanking period, and the redundancy to the transmission error rate of the fourth embodiment. An example of allocation of the compression rate, the horizontal blanking period, and the redundancy to the transmission error rate of the fourth embodiment. An example of allocation of a compression method, a horizontal blanking period, and a redundancy to the transmission error rate of the fourth embodiment. An example of allocation of the compression rate, the horizontal blanking period, and the redundancy for the content of the fifth embodiment. An example of transmission timing of main compression code information, sub-compression code information and compressed image data, and audio packets in the sixth embodiment. An example of transmission timing of main compression code information, sub-compression code information and compressed image data, and audio packets in the sixth embodiment.

Conventionally, there is an uncompressed image data transmission system as an image data transmission system that minimizes the delay time, but there is a problem that a high-speed transmission path is required to send large-size image data. To solve this problem, a method of compressing and transmitting image data has been proposed. However, when an error occurs on the transmission path, there is a problem that the display image is disturbed in units of compressed blocks composed of a plurality of pixels. It was. Further, there is a problem that the amount of data that can be transmitted in the blanking period in which high error tolerance is ensured is smaller than the amount of data that can be transmitted in the effective pixel period.

In this embodiment, in a transmission method in which image data is compressed and transmitted, compression is performed for each compression block unit to generate compression code information. Among the compression code information, compression code information (hereinafter referred to as main code information) having high importance. This problem was solved by transmitting the compression code information) in a blanking period with high error tolerance. Other compression code information (hereinafter referred to as sub-compression code information)
As with the compressed image data, it is transmitted with an effective period. Hereinafter, this embodiment will be described with reference to the drawings.

  Hereinafter, embodiments of the image transmission device and the image reception device according to the present embodiment will be described.

FIG. 1 is a block diagram illustrating an image transmission system according to this embodiment, in which an image transmission apparatus 100 and an image reception apparatus 200 are connected by a cable 300.

The image transmission device 100 is an image transmission device that transmits image data. The image transmission device 100 receives image data that has been decoded so that digital broadcasts can be received and viewed, image data recorded on a recording medium, and image data captured by a camera or the like. A device that outputs to other devices via a cable or the like. Examples of the image transmitting apparatus 100 include a recorder, a digital TV with a built-in recorder function, a personal computer with a built-in recorder function, a mobile phone with a camera function and a recorder function, and a camcorder.

The image receiving apparatus 200 is a display device that inputs image data and outputs an image to a monitor using an HDMI cable or the like. Examples of the image receiving apparatus 200 include a digital TV, a display, a projector, a mobile phone, and a signage device.

The cable 300 is a data transmission path for performing data communication such as image data between the devices of the image transmission device 100 and the image reception device 200. As an example of the cable 300, there is a wired cable corresponding to the HDMI standard or the DisplayPort standard, or a data transmission path for performing wireless data communication.

First, the configuration of the image transmission device 100 will be described.
The input units 101, 102, and 103 are input units for inputting image data to the image transmission apparatus 100. An example of image data that is input to the input unit 101 and processed by the tuner reception processing unit 105 is digital broadcasting that is input as radio waves from a relay station such as a broadcasting station or a broadcasting satellite. The input unit 101 receives radio waves from a relay station such as this broadcasting station or broadcasting satellite.

Examples of image data that is input to the input unit 102 and processed by the network reception processing unit 106 include digital broadcasts distributed via a network using an Internet broadband connection, information contents, and the like.

An example of image data that is input to the input unit 103 and processed by the recording media control unit 107 is content recorded on an external recording medium connected to the input unit 103. Further, as an example of the video data processed by the recording media control unit 107, there is content recorded in the recording media 108 built in the image transmission apparatus 100. Examples of an external recording medium connected to the input unit 103 or a recording medium 108 built in the image transmission apparatus 100 include an optical disk, a magnetic disk, and a semiconductor memory.

The tuner reception processing unit 105 is a reception processing unit that converts an input radio wave into a bit stream. Here, a radio frequency radio wave is an IF band (Intermediate Freque
The modulation operation applied to the demodulated bit stream for transmission is demodulated as a signal of a constant band that is frequency-converted to ncy) and does not depend on the reception channel.

As an example of the bit stream, an MPEG2 transport stream (hereinafter referred to as MPE)
G2-TS) and a bit stream having a format conforming to MPEG2-TS. The subsequent bit stream will be described with MPEG2-TS as a representative.

The tuner reception processing unit 105 further detects and corrects a code error occurring during transmission, and after the descrambling of the error-corrected MPEG2-TS, a program for viewing or recording is multiplexed. One transponder frequency is selected, and the bit stream in the selected one transponder is separated into audio and video packets of one program.

The MPEG2-TS from the tuner reception processing unit 105 is supplied to the stream control unit 111 via the data bus 181. The stream control unit 111 stores a PTS (Presentation Time Stamp) which is time management information from the received packet and a standard decoding of the MPEG system in order to maintain an interval when the tuner reception processing unit 105 receives the packet. An internal STC (System Time Clock) is detected, and a time stamp is added at a timing corrected based on the detection result.

The packet to which the time stamp is added is supplied to one or both of the decoder unit 112 and the recording media control unit 107. Data path 1 to the decoder unit 112
94 is used for processing when viewing image data, and a data path 193 to the recording media control unit 107 is used when recording image data on recording media.

The data bus 192 of the stream control unit 111 receives MPEG2-TS input from the input unit 102 via the network reception processing unit 106. The data path 192
Is an input unit for acquiring digital broadcast or digital content distributed via the network.

Further, the digital broadcast or digital content recorded on the external recording medium connected to the input unit 103 or the recording medium 108 built in the image transmission apparatus 100 is read out as MPEG2-TS by the recording medium control unit 107. And input to the stream control unit 111 via the data bus 193. The stream control unit 11
1 selects at least one of these inputs and outputs it to the decoder unit 112.

The decoder unit 112 decodes the MPEG2-TS input from the stream control unit 111 and outputs the generated image data to the display processing unit 113. The display processing unit 113
The input image data is subjected to, for example, OSD (On Screen Display) superimposition processing, rotation, enlargement / reduction processing, and frame rate conversion processing, and then output to the compression processing unit 114.

The compression processing unit 114 performs compression processing on the image data from the display processing unit 113 and outputs it to the data transfer unit 115.

The data transfer unit 115 converts the image data compressed by the compression processing unit 114 (hereinafter referred to as “compressed image data”) into a signal in a format suitable for transmission, and outputs the signal from the output unit 116. Regarding transmission of image data, an example of a signal in a format suitable for cable transmission is described in the HDMI standard. In HDMI, image data adopts a TMDS data transmission format.

The input unit 104 is an input unit for inputting a signal for controlling the operation of the image transmission apparatus 100. As an example of the input unit 104, there is a receiving unit for a signal transmitted from a remote controller, a button provided on the apparatus main body, or the like. The control signal from the input unit 104 is a user IF1.
09. The user IF 109 outputs a signal from the input unit 104 to the control unit 110. The control unit 110 controls the entire image transmission apparatus 100 according to the signal from the input unit 104. An example of the control unit 110 is a microprocessor. Image transmission device 10
The image data from 0 is supplied to the image receiving device 200 via the cable 300.

Next, the configuration of the image receiving apparatus 200 will be described.
The input unit 201 receives a signal in a format suitable for cable transmission. The signal input to the input unit 201 is supplied to the data reception processing unit 205.

The data reception processing unit 205 performs processing for converting a signal in a format suitable for cable transmission into predetermined digital data, and outputs the converted digital data to the expansion processing unit 206.

The decompression processing unit 206 decompresses the compression processing performed by the compression processing unit 114 in the image transmission apparatus 100, generates image data, and outputs the image data to the display processing unit 207.

The display processing unit 207 performs display processing on the input image data. Examples of display processing include OSD superimposition processing, enlargement / reduction processing for conversion to the resolution of the display unit 208, rotation processing, frame rate conversion processing, and the like. The output of the display processing unit 207 is the display unit 2
Output to 08.

The display unit 208 converts the input image data into a signal that matches the display method and displays it on the screen. Examples of the display unit 208 include display units such as a liquid crystal display, a plasma display, an organic EL (Electro-Luminescence) display, and a projector projection display.

The input unit 202 is an input unit for inputting a signal for controlling the operation of the image receiving apparatus 200. As an example of the input unit 202, there is a receiving unit for signals transmitted from a remote controller, buttons provided on the apparatus main body, and the like. The control signal from the input unit 202 is the user IF2
03. The user IF 203 outputs a signal from the input unit 202 to the control unit 204. The control unit 204 is a control unit that controls the entire image receiving apparatus 200 in accordance with a signal from the input unit 202.

FIG. 2 is a diagram illustrating an effective area in which image data for one frame period is transmitted and a blanking period in which image data is not transmitted.

A region indicated by 400 indicates a vertical period, and the vertical period 400 is a vertical blanking period 401.
And a vertical effective period 402. The VSYNC signal is a vertical blanking period 401.
This is a 1-bit signal in which 1 is defined between the number of lines defined from the head of 0 and 0 between the other vertical blanking periods and the vertical effective period 402. As an example of the prescribed number of lines,
There are 4 lines.

An area indicated by 403 indicates a horizontal period, and the horizontal period 403 is a horizontal blanking period 404.
And a horizontal effective period 405. The HSYNC signal is a horizontal blanking period 404.
This is a 1-bit signal in which the interval between the number of pixels defined from the head of the signal is 1 and the interval between the other horizontal blanking period and the horizontal effective period 405 is 0. As an example of the prescribed number of pixels, 40
There are pixels.

An effective period 406 indicates an area surrounded by a vertical effective period 402 and a horizontal effective period 405, and image data is allocated to this period. The blanking period 407 is an area surrounded by a vertical blanking period 401 and a horizontal blanking period 404.

In this embodiment, in the above configuration, the compressed image data and the sub-compression code information are transmitted during the effective period 406, and the main compression code information is transmitted during the blanking period 407.

In the blanking period 407, data obtained by packetizing audio data and other attached data is transmitted.

A method of sending a reliable packet of voice data or the like in the blanking period 407 is disclosed in, for example, Japanese translations of PCT publication No. 2005-514873.

With this configuration, since the error correction code is included in the packet data in the blanking period, it is possible to correct an error occurring in the transmission path, and the error resistance is enhanced. In addition, the data for data transmission of the packet in the blanking period is configured to be transmitted to two physically different channels, and the channel to be transmitted is switched every certain time. Since the other channel is not affected by the error, the data error can be corrected. Correction rate errors, the horizontal effective period ^10-9
On the other hand, the horizontal blanking period has an improvement effect of ^10-14 .

In this example, image data of 24 bits per clock is transmitted in the valid period 406, and one packet composed of a 3-byte header and 28-byte data is transmitted in a 32-clock period in the blanking period 407.

For example, when transmitting 12 bits each of horizontal 3840 effective pixels, vertical 2160 effective lines, and YCbCr luminance / chrominance signal at 444 format with a frame frequency of 60 Hz, 891M
A very high clock frequency of Hz is required. The high clock frequency not only increases the cost of the transmission / reception unit, but also shortens the cable length capable of stably sending an image, resulting in poor usability.

According to the present embodiment, it is possible to approach a practical clock frequency of 594 MHz with 2/3 compression and 297 MHz with 1/3 compression. In addition, each 8b of the YCbCr luminance color difference signal
In the it 444 format and the 12-bit 422 format, a practical clock frequency of 297 MHz can be obtained with 1/2 compression.

In the horizontal 3840 effective pixels and the vertical 2160 effective lines, for example, the horizontal blanking period is a horizontal 560 blanking pixel, and the vertical blanking period is a vertical 90 blanking line. Hereinafter, 12 bits each of horizontal 3840 effective pixels, vertical 2160 effective lines, YCbCr luminance color difference signal in 444 format, and a video signal with a frame frequency of 60 Hz is 1/3.
A case where compression is performed will be described as an example.

The compressed clock frequency is 297 MHz, and if the transmission is performed under the conditions of horizontal 1940 effective pixels, vertical 2160 effective lines, horizontal 280 blanking pixels, and vertical 90 blanking lines, the original clock 594 MHz, which is twice the frequency, is stabilized on the receiving side. Easy to play. In the horizontal effective pixel period, each 12-bit total 36 bits of YCbCr luminance color difference signal per pixel is 1
If compressed to 12 bits of / 3, 24 bits can be transmitted per compressed pixel, so that transmission of two original pixels is possible, and the compressed clock frequency is half that of the original clock.

Since one packet can be transmitted per 32 clocks, a maximum of 8 packets can be transmitted in the compressed horizontal 280 blanking pixels. On the other hand, audio data is 24 bits per packet
X8ch transmission is possible. The horizontal frequency of the image data is 135 kHz (= 60 Hz × (21
60 + 90)), therefore, when transmitting 24-channel linear PCM audio of 192 kHz sample for 8 channels, a maximum of 2 packets are required during one horizontal blanking period. It is desirable that the compression code method information can be described within the remaining 6 packets, 168 bytes (= 28 bytes × 6 packets).

On the other hand, when the 32 pixels described above are compressed as a unit block, since they are horizontal 3840 effective pixels, a total of 360 description spaces for each compression code method information of YCbCr luminance color difference signals for 120 blocks are required. If the main compression code information is expressed by 3 bits, for example, 135 bytes
It becomes a description space for te and can be transmitted in 5 packets, so that it can be compatible with large-capacity audio data transmission of 192 kHz and 8 ch.

3 and 4 are diagrams illustrating an example of image data input to the compression processing unit 114. A luminance signal of n pixels in the horizontal direction and m lines in the vertical direction is shown. In the case of the 444 format, the color difference signal has the same format as the luminance signal. As an example of the number of pixels n and the number of lines m,
There are so-called full HD images with n = 1920 and m = 1080 and so-called 4k2k images with n = 3840 and m = 2160.

Here, a unit block (hereinafter referred to as a compression block) of image data to be compressed by the compression processing unit 114 is assumed to be 1 pixel in the horizontal direction and k pixels in the vertical direction. In FIG. 3, 501 and 50
2 shows an example of l = 32 and k = 1, and is composed of data of 32 pixels continuous in the same line. The compression processing unit 114 performs compression in units of this image data.

In FIG. 4, reference numerals 503 and 504 denote examples where l = 16 and k = 2, and are constituted by data of 16 pixels continuous between upper and lower two lines. The compression processing unit 114 performs compression in units of this image data. As compression processing, image data unit blocks having k1 and k2 (k1 <k2) having a horizontal compression unit and a vertical compression unit and different in the number of k pixels (number of lines) in the vertical direction are prepared, and the horizontal compression unit is an image of k1. The data unit block may be compressed by the vertical compression unit 134 for the k2 image data unit block.

As an example of the unit of image data to be compressed, 32 pixels have been described as an example. However, a unit of 64 pixels or 128 pixels may be used.

When the input color difference signal is in the 422 format, the Cb component and the Cr component of the color difference signal become nested data for each pixel. For example, in a 4k2k image, the Cb component and the Cr component may be combined and handled as image data of n = 3840 and m = 2160. Generally, since the correlation between Cb components and Cr components is high, the Cb component and the Cr component are separated, and n = 1920, m
By treating as = 2160, it is possible to improve the compression efficiency by making the unit block of image data compressed with only the same component.

When the input color difference signal is in the 420 format, the Cb component and Cr component of the color difference signal are data for one pixel with respect to four Y signal pixels. For example, in a 4k2k image, the Cb component and the Cr component may be combined and handled as image data of n = 1920 and m = 2160. In general, since the correlation between the Cb component and the Cr component is high, the Cb component and the Cr component are separated, and n = 1
By treating as 920, m = 1080, the compression efficiency can be increased by setting the unit of image data to be compressed with only the same component.

The compression code information is composed of main compression code information and sub compression code information. Based on the main compression code information and the sub compression code information, decompression processing can be performed from the compressed image data to the original image data.

  Simple decompression processing or partial decompression processing can be performed with only the main compression code information.

The main compression code information is transmitted through a transmission path with higher error resistance than the sub compression code information. In this embodiment, compressed image data and sub-compression code information are transmitted during the effective period 406, and main compression code information is transmitted during the blanking period 407. Blanking period 407 of main compression code information
As an example of transmission in the same line, main compression code information common to each line is transmitted in the vertical blanking period 401, and main compression code information for the compressed blocks in the same line is transmitted in the horizontal blanking period 4.
There is a method of transmission in 04.

By adopting the above configuration, even if an error occurs in the sub-compression code information on a transmission line with a high transmission error rate, the probability that an error will occur in the main compression code information is greatly reduced. For this reason, when an error occurs in the sub-compression code information on a transmission line with a high transmission error rate, image data that is simply decompressed using the main compression code information or partially decompressed image data is used for error correction. Display disturbance can be suppressed. Further, by including the compression block size in the main compression code information, when an error occurs in the sub compression code information, display disturbance can be suppressed in the compression block.

  Further, the compression code information may be composed only of main compression code information or sub compression code information.

  A configuration example of the compression code information and the compressed image data is shown in FIG.

In this example, the unit of the compression block 600 is composed of sub-compression blocks 610 and 620, and each sub-compression block 610 and 620 includes pixels 611, 612, 613, 614, and
It is composed of pixels 621, 622, 623, and 624.

An example of the configuration of the compressed block after compression is shown at 630. The compression block 630 includes compression code information 631 and compressed image data 632. The compressed image data 632 is compressed image data generated by compressing the pixel data 611, 612, 613, 614, 621, 622, 623, and 624. The compression code information 631 is information generated by the compression process. In this configuration, when the compression code information is transmitted in the valid period 406, if the transmission error rate is high, the probability that an error will occur in the compression code information is also high, and as a result, the display is disturbed in units of compression blocks. There is a problem that it is likely to occur. In addition, when the compression code information is transmitted in the blanking period 407, the amount of data that can be transmitted is significantly smaller than that in the valid period 406, so that the amount of compression code information is reduced.

Another example of the configuration of the compressed block after compression is shown at 640. In this example, the compression code information is composed of two types of main compression code information 641 and sub compression code information 642 and 644. The compression block 640 includes main compression code information 641, sub compression code information 642 and 644, and compressed image data 643 and 645. The compressed image data 643 is stored in the sub-compression block 6
10 is compressed image data generated by compressing image data 611, 612, 613, and 614 belonging to 10. The sub-compression code information 642 includes pixel data 611, 612, 613, 6
14 is information generated by the compression processing for 14. The compressed image data 645 is compressed image data generated by compressing the image data 621, 622, 623, and 624 belonging to the sub-compression block 620. The sub compression code information 644 includes pixel data 621, 622, 62.
3 and 624 is generated by the compression process.

Another example of the configuration of the compressed block after compression is shown at 650. In this example, the compression code information is composed of two types of main compression code information 651 and sub compression code information 652. Compressed block 650
Is composed of main compression code information 651, sub compression code information 652, and compressed image data 653. The compressed image data 653 is image data 611 and 61 included in the compressed block 600.
2, 613, 614, 621, 622, 623, and 624. The main compression code information 651 and the sub compression code information 652 are information generated by the compression process for the compression block 600.

Another example of the configuration of the compressed block after compression is shown at 660. The difference between this example and the compressed block 650 after compression is that the sub-compression code information 662 is information obtained by further compressing the sub-compression code information 652 in the compressed block 650 after compression. Although not shown here, the transmission data amount may be reduced by further compressing the main compression code information 651.

When the compressed blocks 640, 650, and 660 after compression are configured, the main compression code information is transmitted to a transmission path with higher error resistance by transmitting the main compression code information through a transmission path with higher error resistance than the sub compression code information. It is possible to suppress the influence of transmission errors on the display image (restored image) while suppressing the data amount.

FIG. 6 is an explanatory diagram of transmission timings for the compressed blocks 640, 650, and 660 after compression shown in FIG. 700 and 702 are effective periods 406, and 701 is a horizontal blanking period 404. Reference numerals 710, 711, and 712 denote image data for one line before compression transmitted in the validity period 700. In this example, three compressed blocks 710, 711, 71
2 is compressed.
Reference numeral 730 denotes main compression code information generated by compression processing for the compression blocks 710, 711, and 712. Reference numerals 731, 732, and 733 are compression blocks generated by the compression process for the compression blocks 710, 711, and 712. The compression block is composed of compressed image data and sub-compression code information generated by compression processing. 740, 750, and 760 are shown as examples of the configuration of the compressed block 731 after compression. These correspond to the sub-compression blocks 640, 650, and 660 shown in FIG.

The main compression code information 730 is transmitted in the horizontal blanking period 701 having higher error resistance than the effective periods 700 and 702. In addition, compressed blocks 731, 732, 73 after compression composed of compressed image data generated by compression processing on the image data 710 and sub-compression code information.
3 is transmitted in the effective period 702 next to the horizontal blanking period 701. A part or all of the main compression code information may be transmitted in the vertical blanking period 401.

  An example of main compression code information and sub compression code information will be described with reference to FIG.

The unit of the compression block 920 is horizontal 32 pixels, and the sub compression blocks 921, 922,
Consider a case in which compression processing is performed in which the units of 923 and 924 are 8 pixels. The compression code information 926 for the first sub-compression block 921 is used as main compression code information, and the compression code information 927, 928, and 929 for the other three sub-compression blocks is used as sub-compression code information.

The main compression code information includes compression code information 926 for the head sub-compression block 921 and other compression code information used for decompression processing of the sub-compression block 921 (for example, common compression code information 925 common to each sub-compression block). Consists of.

The sub-compression code information includes compression code information 927, 928, and 929 for the second and subsequent sub-compression blocks 922, 923, and 924.

By adopting the configuration of this example, if an error occurs in the sub-compression code information on a transmission path with a high transmission error rate, the image data belonging to the first sub-compression block decompressed using the main compression code information is in error. By using it for correction, display disturbance can be suppressed. As an example of error correction, there is a method of generating and displaying a complementary image belonging to a sub-compression block in which an error has occurred from image data belonging to the first sub-compression block of each compression block expanded by main compression code information.

As an example of the transmission path, sub-compression code information (FIG. 28C) and compression unit output (FIG. 28D)
Is transmitted in the effective period 406, and the main compression code information is transmitted in the horizontal blanking period 404 with higher error tolerance.

  Another example of main compression code information and sub compression code information will be described with reference to FIG.

The unit of the compression block 900 is horizontal 32 pixels, and the sub compression blocks 901, 902,
Consider a case where compression processing is performed in which the units 903 and 904 are 8 pixels.

In the first compression unit (compression unit A133), the sub-compression blocks 901, 902, 903, 9
04 is subjected to the first compression processing in units of sub-compression blocks, sub-compression code information (first compression code information 905, 906, 907, 908) and compressed image data (sub-compression block units).
First compressed image data 909, 910, 911, 912) is generated. The second compression unit (compression unit B134) further performs second compression processing on the input compressed image data (first compressed image data 909, 910, 911, 912) in units of four sub-compression blocks. 1
Main compression code information (second compression code information 914), compressed image data (second compressed image data 914), and compressed image data (second compressed image data 915) are generated. The main compression code information is transmitted through a transmission path having higher error resistance than the transmission path of the sub compression code information (first compression code information 905, 906, 907, 908) and the compressed image data (second compressed image data 915). As a result, even in a transmission line with a high transmission error rate, it is possible to perform decompression processing up to the sub-compression block unit, and it is possible to suppress the error influence range within the sub-compression block range.

In addition to the second compression code information 914, the first compression code information 905, 906, 907, 908
By transmitting the common compression code information 913 as the main compression code information, error tolerance can be further improved.

As another example of the compression code information, consider a case where, for example, the compression block unit is horizontal 32 pixels, the sub-compression block unit is 8 pixels, and compression processing is performed in which size information is added for each sub-compression block unit. The sum of the size information for each sub-compression block unit, that is, the size information for each compression block is included in the main compression code information, and the size information for each sub-compression block unit is included in the sub-compression code information. By transmitting the main compression code information through a transmission path with higher error tolerance, when an error occurs in the sub compression code information in a transmission path with a high transmission error rate, the compression unit is compressed based on the main image code information. By generating a size and skipping the decompression process by that size, it is possible to prevent the influence of an error on the next compressed block.

When there is a margin in the amount of data that can be transmitted on a transmission line with high error resistance, all the size information for each sub-compression block may be transmitted as main compression code information. In this case, if an error occurs in the sub-compression code information, the size of the sub-compression block in which the error has occurred is generated based on the main image code information, and the other sub-compression is performed by not performing the decompression process for that size. The effect of errors on the block can be prevented.

FIG. 7 is a block diagram illustrating an example of the configuration of the compression processing unit 114.
The input unit 130 is an input unit for inputting image data to the compression processing unit 114.

The input image data is supplied to the compression unit A133, the compression unit B134, and the compression unit C135.
The compression unit A133, the compression unit B134, and the compression unit C135
Different compression processes are performed to generate compression code information and compressed image data. Note that power consumption can be reduced by not performing compression processing or stopping the operation clock itself except for the compression unit specified by the control signal 131.

The compression unit A133, the compression unit B134, and the compression unit C135 are configured by a compression circuit that compresses a plurality of pieces of image data constituting the compression block. As an example of the compression method,
A Wavelet transform is calculated in the horizontal direction, and the calculation result is configured by an encoded compression method or the like. As a compression method, Hadamard transform, run length coding, Huffman coding, differential coding, or the like may be applied.

As an example of another compression method, a compression circuit that compresses a plurality of pieces of image data in the vertical direction is configured. As an example of the compression method, as a unit block of image data for compressing image data of 2 lines in the vertical direction and 16 pixels in the horizontal direction, a difference is first taken in the vertical direction, and then a difference is taken in the horizontal direction. . The result is configured by a compression method for encoding the result.

Further, as an example of another compression method, when a 444 format or 422 format color difference signal is input, it is configured by a circuit that thins out to a 422 format or 420 format. When a 444 format or a 422 format is input, if a predetermined compression rate is exceeded in the configuration of the compression processing unit 114 shown in FIG. 8 to be described later, the thinning process may be performed to the 422 format or the 420 format.

Here, the compression rate is a ratio of the data amount before compression and the data amount after compression. For example, when the data amount before compression is 100 and the data amount after compression is 30, the compression rate is 30%. Therefore, the higher the compression rate, the greater the amount of data after compression and the less the image quality degradation.

  FIG. 10 is a block diagram illustrating an example of the configuration of the compression unit A133.

  The input unit 150 is an input unit for inputting image data to the compression unit A133.

The input unit 151 is an input unit for inputting a control signal for controlling the compression unit A133.

The first compression unit 153 is a block that performs compression processing on input image data to generate compression code information and compressed image data. The compression code information generated by the first compression unit 153 is supplied to the compression code information generation unit 155. The compressed image data generated by the first compression unit 153 is supplied to the selection unit 156.

The compression code information generation unit 155 is a block that generates main compression code information and sub compression code information from the input compression code information. The compression code information generation unit 155 may include a memory that temporarily stores the generated main compression code information and sub compression code information.

The selection unit 156 is a block that selects and outputs the compressed image data supplied from the first compression unit 153 and the main compression code information and sub compression code information supplied from the compression code information generation unit 155.

  FIG. 11 is a block diagram illustrating another example of the configuration of the compression unit A133.

  The input unit 160 is an input unit for inputting image data to the compression unit A133.

The input unit 161 is an input unit for inputting a control signal for controlling the compression unit A133.

The first compression unit 163 is a block that performs first compression processing on input image data and generates sub-compression code information and compressed image data. The sub compression code information generated by the first compression unit 163 is supplied to the selection unit 166. The compressed image data generated by the first compression unit 163 is supplied to the second compression unit 164.

The second compression unit 164 is a block that performs a second compression process on the input compressed image data to generate main compression code information and compressed image data. The main compression code information and the compressed image data generated by the second compression unit 164 are supplied to the selection unit 166.

The selection unit 166 is a block that selects and outputs the sub compression code information supplied from the first compression unit 163 and the main compression code information and compressed image data supplied from the second compression unit 164.

With the configuration of this example, the two-stage compression processing shown in FIG. 27 can be performed. In this example, two compression units have been described as an example, but three or more compression units may be provided.

The outputs of the compression unit A133, compression unit B134, and compression unit C135 whose operations have been described above are supplied to the selection unit 136.

In this example, the compression processing unit having the three compression units 133, 134, and 135 has been described. However, the compression unit may include only one or two compression units, or may include four or more compression units. May be.

The selection unit 136 selects a compression unit A133, compression unit B134, and compression unit C135 that satisfies a predetermined compression rate and has a high image quality index, and supplies the selected one to the error correction code generation unit 137.
The image quality index includes, for example, an index that indicates a better value as the difference between the image data restored from the compressed image data and the image data before compression is smaller. The highest value is when lossless compression does not occur and lossless encoding is possible. In order to simplify the calculation of the image quality index, a value of the image quality index may be prepared for each compression method. Compared to the case where compression loss occurs due to compression in the 444 format, 4
A case where lossless encoding can be performed after thinning out to 22 formats may be defined as a high image quality index.
Conversely, if the amount of data increases due to compression, a predetermined compression ratio can be achieved by thinning out to 422 format or 420 format and reducing the number of quantization bits. Set the appropriate image quality index.

Further, the compression unit A133 and the compression unit B13 are controlled by a control signal input from the input unit 131.
4. The operation of any one of the compression units C135 may be enabled, and the other two may stop operating. In this case, control information indicating a compression unit whose operation is valid is input from the input unit 131 to the selection unit 136. The selection unit 136 outputs an output signal of the compression unit whose operation is valid to the error correction code generation unit 137 based on the control information.

The error correction code generation unit 137 calculates an error correction code for each unit of the image data (compressed image data) compressed by the compression unit A133, the compression unit B134, and the compression unit C135, adds the error correction code to the compressed image data, and The data is output to the control unit 139. As one of the error correction methods,
There are a CRC (Cyclic Redundancy Check) method and a parity check method.

Whether or not to add an error correction code may be determined according to the data transmission capacity. This is because, when the data transmission capacity of the cable is limited, if an error correction code is given, more pixels or gradations are thinned out, leading to deterioration in image quality of the entire screen. If the transmission capacity is sufficient, an error correction code may be added to the compressed image data to improve error resistance. Whether or not error correction processing is to be performed may be determined on the receiving side by transmitting together with metadata indicating whether or not error correction is added to the compressed image data. Further, the error resistance processing level may be changed by changing the error correction processing depending on the compression method to be applied, and information indicating which error correction code is assigned may be added as metadata. Also, without error correction processing,
The input data may be output as it is.

The memory control unit 139 temporarily stores the compressed image data, the main compression code information, and the sub compression code information supplied from the error code generation unit 137 in the memory unit 140. Further, the sub-compression code information and the compressed image data are read from the memory unit 140 and output during the valid period 406. Also, the main compression code information is read from the memory unit 140 and output in the horizontal blanking period 404 immediately before the effective period 406 for outputting the compressed image data. Another method is 1
Any of the compressed image data with error correction code for the line, main compression code information, and sub-compression code information may be transmitted within the effective period 406 for one line to increase the transmission amount. In addition, the error correction reliability may be improved by including the error correction code in the main compression code information and outputting it in the horizontal blanking period 404.

The output unit 132 outputs the compressed image data, main compression code information, and sub compression code information from the memory control unit 139. Although not shown, the operation of each block in FIG. 7 is controlled according to the control signal of the control unit 110 in FIG.

FIG. 12 is a block diagram illustrating an example of the configuration of the error correction code generation unit 136. Compressed image data is input to the input unit 170. The compressed image data is input to the holding unit 175 and the error correction code calculation unit 173. The error correction code calculation unit 173 performs a cyclic calculation with the generator polynomial on the input compressed image data.

An example of a generator polynomial is
(Equation 1) G (X) = X ¹⁶ + X ¹² + X ⁵ +1
There is. This generator polynomial takes an exclusive OR for each bit in the input compressed image data and performs a cyclic operation. The unit of calculation is a unit of compressed image data.

The input unit 171 receives a signal indicating a period during which the compressed image data is input and supplies the signal to the timing generation unit 174. The timing generation unit 174 outputs a signal indicating that the calculation for the unit block of the image data to be compressed by counting the valid period of the compressed image data has been processed to the data holding unit 175 as an error correction calculation result output timing signal. . Further, the timing generation circuit 174 outputs a timing signal indicating the input period of the compressed image data and a timing signal for outputting the compressed image data and the error correction code calculation result to the data holding unit 175.

The data holding unit 175 temporarily stores the calculation result of the error correction code calculation unit 173 and the compressed image data by, for example, a memory, a flip-flop, a delay element, and the like according to the timing indicated by the timing generation unit 174, and sequentially outputs them. To the unit 132.

FIG. 13 is a block diagram illustrating an example of the configuration of the data transfer unit 115. The input unit 180 outputs the compressed image data to the serializer unit 184. The input unit 181 receives a clock of image data and outputs the clock to the PLL 186 and the output unit 182.

As the clock of the image data, a clock synchronized with the pixel clock used in the standard timing format of the uncompressed image data is used. For example, a clock obtained by dividing the pixel clock of uncompressed image data by two may be used. In this case, the uncompressed image data is 12 bits.
In the case of s quantized image data, the clock is ½ and the number of quantized bits is 8/12, so the predetermined compression rate must be set to 1/3 or less. The clock may be multiplied by 3/4 or 2/3, in addition to dividing by two. By using a clock synchronized with the pixel clock of the uncompressed image data for transmission of the compressed image data, when restoring the uncompressed image data on the receiving side, it is 2 times, 4/3 times, 3/2 times the transmission clock. By using the multiplied clock as the pixel clock. There is an advantage that the jitter of the restored data can be minimized.

The PLL 186 generates a clock obtained by multiplying or dividing the input clock. Examples of multiplication include 5 times and 10 times the frequency of the input clock. The clock generated by the PLL 186 may be one type of clock or two types of clocks. An example of one type of clock is 10 times the input clock. Examples of the two types of clocks include a first clock speed that prioritizes the amount of data transmission and a second clock speed that is slower than the first clock speed that prioritizes lowering the frequency of error occurrence. is there. As an example of the speed, the first clock speed is multiplied by 10 of the input clock, and the second clock speed is multiplied by 5 of the input clock.

  The multiplied clock generated by the PLL 186 is output to the serializer unit 184.

The serializer 184 converts the compressed image data of the input YCbCr luminance color difference signal to 10
Serialized 1 bit at a time with the multiplied clock and outputs to the level converter 185. TMDS transmission method that suppresses the DC component of a bit stream that is serialized by mapping the 8-bit data to 10 bits when there is 8 bits of data input to the input unit 180 for one clock input to the input unit 181 May be used. When there are three cables connected to the output unit 176, 24 bits of compressed image data can be sent per input clock by performing the serial processing for each cable.

The level conversion unit 185 outputs a signal in a format suitable for cable transmission via the output unit 182.

  FIG. 8 is a block diagram illustrating another example of the configuration of the compression processing unit 114.

The memory control unit 142 temporarily stores the compressed image data, main compression code information, and sub-compression code information supplied from the error code generation unit 137 in the memory unit 140. Further, the sub-compression code information and the compressed image data are read from the memory unit 140 and output during the valid period 406. Also, the main compression code information is read from the memory unit 140 and output in the horizontal blanking period 404 immediately before the effective period 406 for outputting the compressed image data. Furthermore, the compressed image data
The data can be read from the memory unit 140 and supplied to the selection unit 141.

The selection unit 141 selects either the image data input from the input unit 130 or the compressed image data 143 supplied from the memory control unit 142, and compresses the compression unit A133 or the compression unit B13.
4 is a block supplied to the compression unit C135. Further, the image data input from the input unit 130 may be output to a predetermined compression unit, and the compressed image data 143 may be output to another compression unit. With the configuration of this example, the two-stage compression processing shown in FIG. 27 can be performed. Further, a compression process of three or more stages may be performed.

  FIG. 9 is a block diagram illustrating another example of the configuration of the compression processing unit 114.

The selection unit 138 outputs the main compression code information and the sub compression code information supplied from the error code generation unit 137 to the memory control unit 145, and outputs the compressed image data supplied from the error code generation unit 137 to the selection unit 144. To do.

The memory control unit 145 temporarily stores the main compression code information and the sub compression code information supplied from the selection unit 138 in the memory unit 140. Also, the sub-compression code information is read from the memory unit 140 and output via the selection unit 144 during a later-described effective period 406. Also, the main compression code information is read from the memory unit 140 and output via the selection unit 144 to the horizontal blanking period 404 immediately before the effective period 406 for outputting the sub compression code information.

The selection unit 144 receives the compressed image data supplied from the selection unit 138 and the memory control unit 145.
The main compression code information and the sub compression code information supplied from are selected and output to the output unit 132.

In this example, the selection unit 138 may output the sub-compression code information together with the compressed image data directly to the selection unit 144 without passing through the memory control unit 145. In this case, the memory control unit 14
5 performs a memory write and read process for the main compression code information. By adopting the configuration of this example, the memory amount of the memory unit 140 on the transmitter 100 side can be reduced.

  14 to 17 show an example of a packet for transmitting a part of main compression code information.

FIG. 14 and FIG. 16 are examples of packet headers, and a common header type 0Bh is described in the first header block HB0, which indicates information related to the compression coding transmission system of the present invention. Each bit of HB1 and Bits 4-7 of HB2 are set to 0 for future expansion. HB
Eco_Packet # indicated by 2 bits 0 to 3 indicates identification within the frame. FIG. 15 and FIG. 17 are examples of 28-byte data transmitted following the header.

In the header of FIG. 14, Eco_Packet # is assigned 0h, and the packet configured by the header of FIG. 14 and the data of FIG. 15 is common information (main compression code information) in each frame.
Indicates that This packet is arranged during the vertical blanking period and is transmitted at least once for each image frame. Hereinafter, the contents of the data in FIG. 15 will be described.

Color_Sample indicates color sample information. For example, 0 is a YCbCr luminance color difference signal in 444 format (hereinafter referred to as YCbCr444), 1 is a YCbCr luminance color difference signal in 422 format (hereinafter referred to as YCbCr422), and 2 is a YCbCr luminance color difference signal. 420 format (hereinafter referred to as YCbCr420), 3 is RGB signal 4
44 format (hereinafter referred to as RGB444), and 4 to 7 are for future expansion. 4
In 22 format and 420 format, B indicates sample position information of CbCr.
It may be assigned additionally.

Eco_Mem is set to 0 when a packet that transmits a part of main compression code information shown in FIGS. 16 and 17 to be described later is transmitted in the horizontal blanking period immediately before the effective period 406 for transmitting compressed image data. It is set to 1 when transmitting in the horizontal blanking period immediately after the effective period 406 for transmitting the compressed image data.

CD is Color Depth, for example, 4h is a total of 2 bits for each YCbCr component of 8 bits.
4bit Color, 5h is a total of 30bit Color of 10bit for each YCbCr component,
6h indicates a total of 36 bits of each YCbCr component 12 bits, 7h indicates a total of 48 bits of each YCbCr component 16 bits, and the others are for future expansion. This definition conforms to the definition of Deep Color Mode defined by HDMI.

Eco_FLM is set to 1 when the compression code system of all the blocks in the frame is the same, and is set to 0 when set for each block. In the case of 1, Eco-CD0 and E described later
Co-CD1 and Eco-CD2 describe Y, Cb, and Cr compression code systems, respectively.

The ratio (CK_N / CM_M) of CK_N and CK_M indicates a frequency ratio between a pixel clock of uncompressed image data and a clock of a communication path for transmitting the compressed data, for example, a TMDS clock. For example, if CM_N = 1 and CK_M = 2, the TMDS clock of the transmission system is 297 which is 1/2 of the pixel clock 594 MHz of the uncompressed image data in the case of 4k2k.
MHz.

  Eco_Block indicates the number of pixels constituting the compressed block.

Eco_CD0 to Eco_CD3 indicate four types of compression encoding information candidates to be applied to each image data unit block. As shown in FIG. 18, four types are selected from compression code information Eco_Code in units of image data to be compressed.

One or more packets including the header of FIG. 16 and the data of FIG. 17 are transmitted in each horizontal blanking period. Eco_Packet # in the header of FIG. 16 indicates the serial number of the packet transmitted to each line, and starts from 1 and is incremented by 1.

Eco_length_0 to Eco_length_39 indicate size information of the compressed block that transmits the valid period 406. Examples of size information include the bit size and byte size of the compressed block. Moreover, the information which becomes the origin of the bit size and byte size of a compression block may be sufficient. For example, the compressed block size S_Block is changed from 32 bits to 6
There is a method of defining the bit size of the compressed block by the following formula when taking two skipped values up to 4 bits.
(Expression 2) S_Block = 32 + (2 × Eco_length_ #) (# is 0 to 39)
In the above example, Eco_length_ # is 4 bits.

Eco_length_ # may be defined for each of Y, Cb, and Cr, or Y, Cb, and Cr.
You may prescribe | regulate by the value which added the compression block size of. In the latter case, Eco_len
The transmission amount of gth_ # can be reduced to 1/3.

The compression code information defined in units of compressed blocks is transmitted as sub-compression code information during the effective period 406 together with the compressed image data. As the type of sub-compression code information, Eco_Er
lor_0-39 and Code_0-Code_39.

Eco_Error0 to Eco_Error39 indicate error encoding methods.
The error encoding method is an error correction encoding method in which the error correction code generation unit 137 calculates data transmitted during the valid period 406. As one of error correction coding systems, there are a CRC (Cyclic Redundancy Check) system, a parity check system, and the like.

Code_0 to Code_39 describe the Y, Cb, and Cr components in order in each image data unit block, with numbers selected from the four types of compression encoded information described in Eco_CD0 to Eco_CD3 in FIG. For example, if Code_0 indicating the compression code information of the Y component of the first image data unit block is 1, it indicates Eco_CD1. Eco_CD
If 1 indicates 10, it is shown in FIG. 18 that the data is the data obtained by compressing the 444 format Y component of the original image data by the differential encoding method.

When the two vertical lines shown in FIG. 4 are used as image data unit blocks, the first line Co
de_0 is the compression code information of the image data unit block 503, and Code_0 of the second line.
Indicates compression code information of the image data unit block 504.

When Color_Sample in FIG. 15 indicates 444 format, Cod
e_1 is Cb compression code information of the first image data unit block, Code_2 is Cr compression code information of the first image data unit, and Code_3 is Y compression code information of the second image data unit block. When Color_Sample indicates 420 format, Code_1 is Y compression code information of the second image data unit block, Code_2 is Cb compression code information of the first and second image data units (Cr in even lines), Code_3 indicates Y compression code information of the third image data unit block. Color_Sample is 4
In the case of the 22 format, Code_1 is Cb compression code information of the first and second image data unit blocks, Code_2 is Y compression code information of the second image data unit,
Code_3 indicates compression code information of Cb of the first and second image data unit blocks.

If Code_0 is 0, it indicates Eco_CD0, and if Eco_CD0 indicates 6, each Y, Cb, Cr component 12b of the 444 format of the data of the original image is obtained from FIG.
It shows that the it data is thinned out to 420 formats and 8 bits. In this case, since the transmission form of Cb and Cr is determined only by Y component Code_0, Cod indicating the Cb component
Information of Code_1 indicating e_1 and Cr component is not necessary, and 0 may be described.

Although not shown in FIG. 1, the image receiving apparatus 200 is equipped with a ROM that stores EDID (Enhanced Extended Display Identification Data) indicating the performance of the image receiving apparatus 200. Information for determining whether or not the image receiving apparatus 200 supports compression / decompression may be added to the ROM. As a result, the image transmission device 100 is connected to the image reception device 2.
Information for determining whether or not compression / decompression is supported is read from a ROM storing 00 EDID, and if the device is compatible, the compressed image data is transmitted. If the device is not compatible, By transmitting an image in a conventional size without compression, compatibility with an image receiving apparatus that does not support compression processing can be maintained. In addition, information for determining whether or not the error correction encoding method for transmitting the compression code information in the effective period 406 is supported is read, and if the device is compatible, an error correction encoding process is performed. If the device is transmitted as compressed code information and is incompatible with the device, transmission without performing the error correction encoding processing allows compatibility with an image reception device incompatible with the compression processing. In the case of a non-compliant device, the packet error correction function in the blanking period 407 may be used to increase resistance to transmission errors. In addition, the user can be notified by displaying on the display unit 208 that the image receiving apparatus is incompatible with compression, has a conventional image size, and incompatible with error correction coding.

A description example of the EDID is shown in FIG. FIG. 19 shows an example of extension to an area called HDMI-VSDB.

Eco_2 indicates whether or not the bit 2 of the 6th byte is compatible with the compression encoding transmission system of this embodiment.
A transfer flag is provided. Since this area has been treated as a reserved area, it is described as 0 for non-compliant legacy devices, and backward compatibility can be maintained by describing only 1 for compatible devices. If this Eco_transfer flag is 1, Byte9 and Byte
The description of e10 is valid.

Block_64 and Block_128 are flags indicating that the size of the image data unit block to be compressed corresponds to 64 pixels and 128 pixels, respectively. An image data unit block size of 32 pixels is defined as an essential mode for this compressed image data transmission, and E
DID description is not shown to save space.

Each of Eco-Codes 1 to 4 is a compression encoding method, Wav shown in FIG.
It is a flag indicating that it corresponds to elet transform, run-length coding, Huffman coding, and differential coding.

CLK_1, CLK_3 / 4, and CLK_1 / 2 are flags indicating that the mode corresponds to the mode in which the frequency of the TMDS transmission clock is 1 time, 3/4 time, and 1/2 time with respect to the uncompressed image data clock, respectively. is there.

Eco_Error_1 to 4 are flags that are set to 1 when they correspond to the respective error encoding schemes, and are set to 0 when they are not supported.

Eco_Mem is set to 1 when the main compression code information corresponds to the case where the main compression code information is transmitted in the horizontal blanking period immediately before the effective period 406 for transmitting the compressed image data, and is set to 1 in the effective period 406 for transmitting the compressed image data. It is set to 2 when transmitting in the immediately following horizontal blanking period. 3 indicates a case where both correspond, and 0 indicates a case where neither corresponds.

In addition, when the image transmission apparatus 100 is used as a portable device, the power consumption of the image transmission apparatus 100 affects the continuous use time because it is a battery-driven apparatus. In this case, image data can be compressed and transmitted to reduce the amount of data transmission and reduce power consumption. This effect is achieved by adding a function such as “power saving mode” as an operation mode of the image transmission apparatus 100, and when power is supplied from the outside, the image transmission apparatus 100 is transmitted by non-compressed image data and driven by a battery. In this case, the continuous use time can be set longer by compressing and transmitting the image data.

FIG. 20 is a block diagram illustrating an example of the configuration of the data reception processing unit 205. Input unit 22
0 represents the signal converted by the level conversion unit 175 of the image transmission apparatus 100 as the level conversion unit 22.
Output to.

The level conversion unit 224 converts the signal level-converted by the image transmission apparatus 100 into a digital signal and outputs the digital signal to the deserializer unit 225. An example of level conversion is conversion of a differential signal to a single-ended signal. The input unit 221 receives the clock output from the image transmission device 100 and outputs the clock to the PLL 226. The PLL 226 generates a clock 10 times the input clock and outputs the generated clock to the deserializer unit 225. Further, the PLL 226 outputs a pixel clock used in the image receiving apparatus 200 from the output unit 222. When the pixel clock of the uncompressed image data of the original image is used in the image display device 200, the input clock is shown in FIG.
Based on the packet data, the PLL 226 outputs a clock multiplied by (CK_M / CK_N) times from the output unit 223.

The deserializer unit 225 parallelizes the serialized data with the clock from the PLL 226 and outputs it from the output unit 222. The deserializer 225 parallelizes the 10-times clock data, and outputs the data from the output unit 222 as 8-bit parallel data by predetermined TMDS decoding, for example.

FIG. 21 is a block diagram illustrating an example of the configuration of the decompression processing unit 206. In addition, FIG.
FIG. 5 is a timing explanatory diagram showing a processing concept of a decompression processing unit 206 for the compressed block shown in FIG. 4.
The input unit 230 is a data input unit of the decompression processing unit 206. The data input to the input unit 230 includes HSYNC (FIG. 26 (a)) indicating a synchronization signal of image data and VSYNC.
Then, there is compressed image data and sub-compression code information 812 and 814 in the effective period 406, and main compression code information 811 and 813 in the horizontal blanking period 404. The input unit 231 receives a pixel clock of uncompressed image data after restoration, a compressed image data clock, and the like.

The HSYNC, VSYNC, compressed image data clock, and the pixel clock of the uncompressed image data after restoration are supplied to the timing generation unit 236. The timing generation unit 236 controls the counter based on the input HSYNC and VSYNC, and the vertical blanking period 401, the vertical valid period 402, the horizontal blanking period 404, the horizontal valid period 405, and the valid period 406.
The timing required for controlling each block in the decompression processing unit is generated and output.

The compression code information extraction unit 233 extracts the compression code information of each image data unit block sent during the horizontal blanking period and stores it in the compression code information storage unit 234.

The storage period is shown in FIG. The main compression code information 811 includes the subsequent compressed image data 8
Since the data corresponds to 12, the storage period 815 until the main compression code information 813 of the second line comes is sufficient. However, for example, when two lines of image data are vertically compressed, it is necessary to retain only the compression code information 816 for vertical expansion until a period during which the compressed image data of the second line is expanded.

The compressed image data sent within the horizontal effective period is subjected to transmission system error correction processing by the error correction unit 235. The error correction unit 235 calculates the same error correction code as the error correction code generation unit 137 for each compressed image data unit. The calculation result and compression code information extraction unit 233
Is compared with the error correction code input from the above, and if the comparison results are different, error correction processing is performed. An example of error correction processing is CRC calculation. Alternatively, only error detection may be performed, and errors may be interpolated in subsequent processing.

The input compressed image data is supplied to the expansion unit A237, the expansion unit B238, and the expansion unit C239. The decompression unit A237, the decompression unit B238, and the decompression unit C239 include a compression code information storage unit 234.
Based on the information, the input compressed image data is subjected to different decompression processes to generate decompressed image data, which is output to the selection unit 261.

26D and 26E show output data of each decompression unit when the decompression unit A237 performs horizontal decompression processing and the decompression unit B238 performs vertical decompression processing on the compressed block shown in FIG. Horizontally expanded image data 818 and 819 indicate output data of the expansion unit A237, and vertical expansion image data 820 and 821 indicate output data of the expansion unit B237.

The selection unit 261 appropriately selects the image data input to the input unit 230, the output of the decompression unit A237, the output of the decompression unit B238, and the output of the decompression unit C239 based on information in the compression code information storage unit 234. Then, it is output to the output unit 232 as restored image data 824 (FIG. 26 (
f)).

FIG. 25 is an explanatory timing diagram illustrating the processing concept of the decompression processing unit 206 when the decompression unit A237 performs horizontal decompression processing on the compressed block shown in FIG.

The input unit 230 is a data input unit of the decompression processing unit 206. The data input to the input unit 230 includes HSYNC (FIG. 26 (a)) indicating a synchronization signal of image data and VSYNC.
Then, there is compressed image data and sub-compression code information 802 and 804 in the effective period 406, and main compression code information 801 and 803 in the horizontal blanking period 404. The input unit 231 receives a pixel clock of uncompressed image data after restoration, a compressed image data clock, and the like.

The compression code information extraction unit 233 extracts the compression code information of each image data unit block sent during the horizontal blanking period and stores it in the compression code information storage unit 234.

The storage period is shown in FIG. The main compression code information 801 is the subsequent compressed image data 8
Since the data corresponds to 02, the storage period 805 until the main compression code information 803 of the second line comes is sufficient for the information.

The input compressed image data is subjected to horizontal expansion processing by the expansion unit A237 to generate horizontal expanded image data 806 and 807, which are expanded image data, and output to the selection unit 261 (FIG. 25 (d)). .

The selection unit 261 appropriately selects the image data input to the input unit 230, the output of the decompression unit A237, the output of the decompression unit B238, and the output of the decompression unit C239 based on information in the compression code information storage unit 234. Then, the restored image data 808 and 809 are output to the output unit 232 (FIG. 25 (f)).

FIG. 22 is a block diagram illustrating an example of the configuration of the decompression processing unit 206. This example is an example of a decompression processing unit in a case where a method of transmitting sub-compression code information together with compressed image data within the effective period 406 instead of the horizontal blanking period 404 is employed.

If the data to be sent within the valid period 406 is not only compressed image data but also compression code information, it may be necessary to reduce the compression rate of the compressed image data depending on the compression method. There is a concern that the image quality degradation of the image at the time of restoration becomes large. As a countermeasure, the horizontal blanking period is reduced to such an extent that two audio data transmission packets can be sent, and the horizontal effective period is extended. 4k2k image data is uncompressed image pixel clock 594MHz
In the first embodiment, the horizontal effective period 1920,
The horizontal blanking period was 280. Since it is sufficient that the horizontal blanking period is about 96 including the transmission period for two voice packets and the front and rear guard bands, the horizontal effective period can be increased with the remaining 184. There is an effect that the horizontal effective period 1920 can be expanded by about 9.5%.

In the case of this example, the position and width of the horizontal synchronizing signal are deviated from the standard timing of the predetermined uncompressed image data. Therefore, the SVD added to the image data when reproducing the uncompressed image data on the receiving side.
(Short Video Descriptor) The timing may be restored so that the standard timing format is obtained with reference to the metadata.

In FIG. 22, blocks having the same functions as those in FIG. The difference is that a second video code information extraction unit 250 is added to the output unit of the error correction circuit 255.
In the example of FIG. 21, the compression code information extraction unit 233 includes compression code information (packets of FIGS. 14 and 15) within the vertical blanking period and compression code information (packets of FIGS. 16 and 17) within the horizontal blanking period. ) Was extracted. In this example, the compression code information extraction unit 233 extracts only the main compression code information transmitted in the vertical blanking period or the horizontal blanking period, and stores it in the compression code information storage unit 234.

In this example, instead of sending compressed code information in a packet that has been subjected to error correction processing within the blanking period, error correction processing similar to that for other compressed image data is added. For this reason, the main compression code information after error correction processing of the error correction unit 255 output from the second compression code information extraction unit 250 and the sub compression code information output from the compression code information storage unit 234 are converted into an expansion unit. The data is output to A237, expansion unit B238, expansion unit C239, and selection unit 251.

In this example, since the compressed image data and the compression code information are close in timing, storage of the compression code information over one horizontal period is unnecessary except for the compression code information common in the frame. There is an effect that can be reduced.

  FIG. 23 is a block diagram illustrating another example of the configuration of the decompression processing unit 206.

In FIG. 23, blocks having functions similar to those in FIG. The difference is that a selection unit 260 is added in the preceding stage of each expansion unit.

The selection unit 261 appropriately selects the image data input to the input unit 230, the output of the decompression unit A237, the output of the decompression unit B238, and the output of the decompression unit C239 based on information in the compression code information storage unit 234. Then, the data is output to the output unit 232. The selection unit 261 further includes an extension unit A23.
7, the output of the expansion unit B 238, and the output of the expansion unit C 239 can be selected and output to the selection unit 260. By adopting the method of this configuration, it is possible to perform decompression processing of two or more methods on the compressed image data input to the input unit 230.

Although not shown, the output of the expansion unit A237, the output of the expansion unit B238, and the expansion unit C
Any one of the outputs of 239 may be selected and output to the compression code information storage unit 234. By adopting this configuration, for example, the decompression process of the compressed sub-compression code information 660 of FIG. 5 can be performed.

FIG. 24 is a block diagram illustrating another example of the configuration of the decompression processing unit 206. In FIG.
Blocks having the same functions as those in FIG. 22 are given the same numbers. The difference is the input unit 23.
The storage unit 270 is added after 0.

The selection unit 271 has a function of outputting selected data to the storage unit 270 in addition to the function of the selection unit 251 illustrated in FIG. The storage unit 270 temporarily stores main compression code information, sub-compression code information, compressed image data, and decompressed data supplied from the selection unit 271 that are input from the input unit 230, and is a block that is supplied to subsequent blocks It is. With such a configuration, a plurality of stages of decompression processing can be performed on the data input to the input unit 230.
In the case of only one-stage decompression processing, data supply from the selection unit 271 to the storage unit 270 may not be performed.

By adopting this configuration, for example, it is possible to perform decompression processing on compressed image data compressed by the method shown in FIGS.

Hereinafter, another embodiment of the image transmission device and the image reception device described in the first embodiment will be described.

FIG. 29 is a diagram illustrating an example of input and output waveforms of the serializer 184. The serializer 184 is a clock obtained by multiplying the input image data of YCbCr luminance color difference signal (hereinafter referred to as YCbCr image data) or image data of RGB signals (hereinafter referred to as RGB image data) by 10 times. The data is serialized into three 1-bit data and output to the level conversion unit 175.

As an example of serialization, 8-bit YCbCr luminance color difference signal or RGB signal image data is output in the order of MSB or LSB from the top with a 10-fold clock.

The level conversion unit 185 outputs the signal converted into the standardized data transfer format via the output unit 182. An example of a standardized data transfer format is TMDS
There are differential level signal formats. In this format, since it is not necessary to transmit image data during the image blanking period, the data to be serialized by the serializer 184 is used only for 4 bits in the clock multiplied by 10, and the remaining 6 bits are not used for transmission. It is possible to increase the strength against errors and transfer data other than image data. Further, by using two types of clocks, the same effect can be obtained by reducing the clock generated by the PLL 186 to ½ or less of the clock for transmitting image data.

FIG. 30 is a diagram illustrating an example of a data configuration of the serializer 184. Serializer 18
The output of 4 has three systems, one of which is composed of a synchronization signal (HSYNC, VSYNC), a packet header, and a fixed bit. Data is transferred using the remaining two systems. The packet size is 32 cycles of the transfer clock.

FIG. 31 is a diagram illustrating an example of a packet configuration of audio data superimposed in the horizontal blanking period. The voice packet generates 7-byte data using the same two bits for data transfer to the serializer, and an error correction code such as a parity check is attached to the data to form a subpacket. 4 sub-packets and packet header 4 bytes
A packet in the horizontal blanking period is formed in the format e.

With this configuration, since the error correction code is included in the subpacket data, an error occurring in the transmission path can be corrected and the error resistance is increased. In addition, since the data for subpacket data transfer is configured in a staggered manner by two physically different channels,
Data errors can be corrected because the other channel is not affected by an error that occurs in a burst manner in one channel. The error correction rate has an improvement effect of ^{10-14 in} the horizontal blanking period as compared to ^{10-9 in the} horizontal effective period.

The error correction code of the compressed image may be transmitted as a packet with high error tolerance. As an example of the number of packets that can be transmitted, the number of pixels in the horizontal period is 2200, and the number of pixels in the horizontal effective period is 19
The case of 20 will be described. The image format will be described by taking YCbCr 422 as an example.

If the size of the image to be compressed is 64 pixels (luminance 32 pixels, color difference 32 pixels), the size of 60 error correction codes (2 bytes) per line needs to be 120 bytes.

Since there is a capacity that can transfer 28 bytes per packet, there is a size that can be transferred if there are 5 packets. Since there are 280 pixels in the horizontal blanking period, 8 packets can be superimposed. With this configuration, even if a maximum of 2 packets are given to a voice packet as 192 kHz, 8ch, LPCM voice transmission, it is possible to transmit a maximum of 5 packets of the aforementioned error correction code in the horizontal period.

When the compressed image data for the RGB image data input to the data transfer unit 115 is output to a predetermined TMDS channel in units of compressed blocks, a non-transmission period of the compressed image data occurs between the compressed blocks. When considered in line units, there is a problem that the horizontal effective period cannot be significantly reduced as compared with the case of non-compression.

FIG. 32 is an example of an output waveform in each channel when the compressed image data for the RGB image data input to the data transfer unit 115 is output to the TMDS channel 0, the TMDS channel 1, and the TMDS channel 2.

In the present embodiment, a case will be described in which compression processing is performed on RGB image data for each of R, G, and B components to generate R compressed image data, G compressed image data, and B compressed image data, respectively. CR0 and CR1 in the figure are compressed image data in sub-compressed blocks, respectively, and the compressed blocks are composed of CR0 and CR1. CR2 is the first sub-block of the next compressed block. CG0, CG1, CG2, CB0, CB1, and CB2 are the same as CR0, CR1, and CR2.

In this embodiment, it is possible to reduce the non-transmission period of the compressed image data between the sub-compression block and the compression block by transmitting the R-compressed image data in the bit unit in the TMDS channel 0. .

FIG. 35 is another example of output waveforms in each channel when the compressed image data for the RGB image data input to the data transfer unit 115 is output to the TMDS channel 0, the TMDS channel 1, and the TMDS channel 2.

In this embodiment, the sub-compression blocks 1300, 1301, 1302, 1305, 1306
, 1309, 1310 are not divisible by 8 bits, stuffing data 1303, 1304, 1307, 1308, 1311 is added to the end so that the sub-compression block head bit is always located at the head bit of the channel. Yes. Thereby, it is possible to simplify the reception circuit of the sub-compression block on the image reception apparatus side. In this example, stuffing data is added in units of sub-compressed blocks, but may be performed in units of compressed blocks as shown in FIG.

In the embodiment described with reference to FIGS. 32 and 35, the compressed image data corresponding to the RGB image data input to the data transfer unit 115 is output to a predetermined TMDS channel, and thus the transmission band occupied by the transmitted compressed image data. TM with the largest amount of data after compression
There is a problem that the effective period becomes longer due to being limited to the DS channel.

FIG. 33 shows R compressed image data, G compressed image data, and B compressed image data, which are components of compressed image data for RGB image data input to the data transfer unit 115, as TMDS channel 0, TMDS channel 1, and TMDS channel. 6 is another example of an output waveform in each channel when outputting to 2;

In the present embodiment, R-compressed image data, G-compressed image data, and B-compressed image data are sequentially interleaved and output to TMDS channel 0, TMDS channel 1, and TMDS channel 2 in sub-compression block units. Here, the R compressed image data CR0 is 18 bi.
t, G compressed image data CG0 is 37 bits, B compressed image data CB0 is 8 bits, R compressed image data CR1 is 20 bits, G compressed image data CG1 is 18 bits, and B compressed image data CB1 is 14 bits. As a result, the compressed image data for the RGB image data input to the data transfer unit 115 can be transmitted to the three TMDS channels on average.
The effective period for transmitting the compressed image data can be shortened. In this example, output is performed in RGB order in units of sub-compression blocks, but may be performed in units of compression blocks as shown in FIG.

FIG. 37 shows compressed image data for YCbCr444 image data input to the data transfer unit 115 as TMDS channel 0, TMDS channel 1, and TMDS channel 2
It is another example of the output waveform in each channel when outputting to. The ratio of the data amount to each component of the image data of YCbCr444 is the same for Y image data, Cb image data, and Cr image data. Note that the ratio of the data amount to each component of the image data of YCbCr 422 is 1 for Cb image data and Cr image data for Y image data.

1500 is image data input to the compression processing unit 114. 1501, 1502,
Reference numeral 1503 denotes Y-compressed image data (luminance-compressed image data) and Cb-compressed image data (Cb color-difference-compressed images), which are components of compressed image data generated by compression processing on Y-image data, Cb image data, and Cr image data, respectively. Data), Cr compressed image data (Cr color difference compressed image data).

From the human visual characteristic that the sensitivity to the luminance (Y) component is higher than the color difference (Cb and Cr) component, the compression rate for the Y component is set higher than the compression rate for the Cb component and the Cr component, and the Y component The amount of Cb component compressed image data (hereinafter referred to as Cb compressed image data) and the amount of Cr component compressed image data (hereinafter referred to as Y compressed image data). The amount of data (referred to as Cr compressed image data) can be further reduced.

In this embodiment, an example is shown in which compression processing is performed at a high compression rate on image data having a high transmission priority for each component of the image data.

Specifically, the transmission priority of the Y compressed image data is set higher than the transmission priority of the Cb compressed image data and the Cr compressed image data, and the output bit width from the data transmission unit 115 is defined as Y
12 bits for compressed image data, 6 bits for Cb compressed image data, 6 for Cr compressed image data
Assign a bit.

Y-compressed image data 1501, Cb-compressed image data 1502, Cr-compressed image data 150
3 to TMDS channel 0 (8 bits / cycle) and TMDS channel 1 (
8bit / cycle), when outputting to TMDS channel 2 (8bit / cycle)
The transmission band occupied by the compressed image data to be transmitted is limited to the TMDS channel 0 having the largest amount of data after compression, and the effective period becomes long.

1505, 1506, 1507, 1508, and 1511 are Cb compressed image data (6bi
This is an example of output data when more channels (12 bits / cycle) are assigned to Y compressed image data than t / cycle) and Cr compressed image data (6 bits / cycle). By using the above output method, the effective period for transmitting the compressed image data can be shortened.

The assignment of the output bit width is instructed from the control unit 110 to the data transmission unit 115. Or an image format (for example, YCbCr444 etc.) instructed from the control unit
Depending on the data transmission unit 115, the data transmission unit 115 may allocate at a predetermined distribution ratio.
The distribution ratio may be set from the control unit 115.

In this embodiment, the case where the image data is YCbCr444 has been described as an example. However, in other image signals such as RGB signals, a transmission priority is given to each compressed image data to output transmission paths (for example, TMDS channel 0, 1, 2) may be assigned an output bit width. For example, when the image data is an RGB signal, there is a method of setting the transmission priority for the G component higher than the transmission priority for the R component and the B component. Specifically, there is a method in which 12 bits are assigned as the output bit width for the G component and 6 bits are assigned as the output bit widths for the R component and the B component.

As another example of the transmission priority when the image data is YCbCr444, 4
: 2: There is a method of assigning a higher transmission priority to the 2: 2 component than the remaining color difference components. Specifically, 20 bits are assigned as the output bit width for 4: 2: 2, and the remaining Cb component and C
There is a method of assigning 4 bits to the r component.

FIG. 38 shows the Y-compressed image data 1601, Cb-compressed image data 1602, and Cr-compressed image data 1603 input to the data transfer unit 115 in each channel when output to the TMDS channel 0, TMDS channel 1, and TMDS channel 2. It is another example of an output waveform. Note that 1600 is image data input to the compression processing unit 114. In this embodiment, bit 4, bit 5, bit 6, bit 7 of TMDS channel 0 and bit 0, bit 1, bit 6, bit 7 of TMDS channel 1 are the other data. bi
Consider a case where the transmission error rate is lower than t.

Reference numerals 1604, 1605, 1606, 1607, 1608, and 1609 are examples of output data when Y compressed image data is allocated to bits with a low transmission error rate of the TMDS channel. With the output method described above, it is possible to reduce the error occurrence rate for Y-compressed image data.

In this embodiment, Cb compressed image data is assigned to 1602, 1605 and 1607, and Cr compressed image data is assigned to 1603 and 1609.

Information on the transmission error rate is supplied from the control unit 110 to the data transmission unit 115. Alternatively, based on the transmission error rate, the control unit may specify bit allocation of the Y compressed image data, Cb compressed image data, and Cr compressed image data to the TMDS channel. In this example,
The YCbCr luminance color difference signal has been described as an example. However, in other image formats such as RGB signals, priority may be given to each compressed image data to assign bits to the TMDS channel.

The transmission priority of each component may be a compression rate for each component. In this case, the output bit width to be assigned is increased for components with a high compression rate, and the output bit width to be assigned is reduced for components with a low compression rate. As an example, each component of YCbCr444 (Y
, Cb, Cr) when the compression rate is 80%, 40%, 40%, the transmission priority is
There are a method of 2, 1, 1 respectively, and a method of setting the output bit width of each component (Y, Cb, Cr) to 12 bits, 6 bits, and 6 bits, respectively.

Hereinafter, another embodiment of the image transmission device and the image reception device described in the first embodiment will be described.

In this embodiment, main compression code information is transmitted in the packet area in the horizontal blanking period 406 shown in FIG. Although it is a packet area, it does not take a packet structure, and each channel 4
Bit data shall be transmitted. Also, the sub-compression code information 1740 is transmitted in the effective period.

FIG. 39 is a diagram illustrating an example of an output data configuration of the data transfer unit 115 when the main compression code information 1700 is transmitted in the horizontal blanking period 406.
By adopting this configuration, it is possible to enhance error resistance when transmitting the main compression code information 1700 as compared with transmission during the effective period. However, when transmitting on a transmission line with a high transmission error rate, further enhancement of error resistance becomes a problem.

FIG. 40 shows an example in which main compression code information 1710 that is the same as main compression code information 1700 is transmitted on the same transmission line during the horizontal blanking period. In this embodiment, main compression code information 1
Immediately after 700, main compression code information 1710 is output. The main compression code information 1710 is
It may not be immediately after the main compression code information 1700. With the above-described configuration, it is possible to increase the redundancy of the main compression code information and make the main compression code information highly resistant to transmission errors even on a transmission path with a high transmission error rate. In addition, the redundancy in this embodiment is the number of main compression code information that is additionally transmitted. The redundancy in this embodiment is 1.

FIG. 41 shows an example in which main compression code information 1720 that is the same as main compression code information 1700 is transmitted through different transmission paths in the horizontal blanking period. In this embodiment, the main compression code information 1720 is transmitted through a channel different from that of the main compression code information 1700, thereby suppressing a reduction in transmission error resistance due to channel variations in the transmission error rate.

For example, when the transmission error rate of channel 0 is higher than the transmission error rate of channel 1, when redundant main compression code information is assigned to channel 0 as shown in FIG. By transmitting the same main compression code information in multiple channels as shown in
It is possible to average the error occurrence rate with respect to the main compression code information. In this embodiment, two pieces of main compression code information are assigned to each channel, but may be assigned to each bit. For example, main compression code information 1700 is allocated to bit 0 and bit 1 of channel 0, bit 0 and bit 1 of channel 1, bit 2 and bit 3 of channel 0, bit 2 and b of channel 1
There is a method of assigning main compression code information 1700 to it3. Further, the bit allocation may be changed according to the transmission error rate information.

FIG. 42 is a diagram illustrating an example in which the redundancy is increased to 2 as compared with the embodiments of FIGS. 40 and 41. Main compression code information 1700 and main compression code information 1730 and main compression code information 1731 identical to main compression code information 1700 are output.

Depending on the transmission error rate, the redundancy of the main compression code information may be increased to increase the resistance to transmission line errors.

FIG. 43 shows an example in which the redundancy is increased to 2 as compared with the embodiments of FIGS. 40 and 41. Main compression code information 1700 and main compression code information 17 identical to main compression code information 1700
30 and main compression code information 1731 are output.

  Depending on the transmission error rate, the redundancy of the main compression code information may be increased.

The redundant main compression code information transmission when the main compression code information is transmitted in the horizontal blanking period has been described above. However, when the sub compression code image is transmitted in the effective period, the same redundancy as the sub compression code information is transmitted. The error resistance of the sub-compression code information may be increased by transmitting such sub-compression code information in the effective period.

FIG. 43 shows the sub-compression code information with a redundancy of 2 when the sub-compression code information is transmitted in the effective period.
It is a figure which shows an example of the output data structure of the data transfer part 115 in the case of becoming.

By adopting this configuration, it is possible to enhance error resistance when transmitting the sub-compression code information 1740.

  Depending on the transmission error rate, the redundancy of the main compression code information may be increased.

In the third embodiment, the redundancy of the main compression code information or the sub compression code information is increased according to the transmission error rate. However, the transmission amount of the transmission path for transmitting the redundant compression code information to be added is limited. There are challenges.

Therefore, in the fourth embodiment, the transmission rate of the transmission path for transmitting redundant compression code information is increased by extending or shortening the compression rate or compression method and the horizontal blanking period according to the transmission error rate. Adopt a possible method.

Information relating to the compression rate, compression method, horizontal blanking period extension / shortening instruction, and compression code information redundancy is supplied from the control unit 110 to the compression processing unit 114 and the data transfer unit 115.

The image reception apparatus side response status to the compression rate, compression method, horizontal blanking period extension / reduction instruction, and compression code information redundancy is transmitted from the image reception apparatus to the image transmission apparatus by EIDI or CEC communication. There is a way.

Compression rate, compression method, horizontal blanking period extension / shortening instruction for transmission error rate,
The control unit 110 may determine the redundancy of the compression code information, or the compression processing unit 1
14. The data transfer unit 115 may perform the processing individually.

FIG. 44 is a diagram illustrating an example of the compression rate, the horizontal blanking period, and the redundancy in each range, with the transmission error rate divided into three ranges. When the transmission error rate ER exceeds ERa (when the transmission error rate is high), the compression rate is set to 40%, the amount of generated compressed image data is reduced, the horizontal blanking period is shortened, and the effective period is extended. To do. As a result, it is possible to increase the transmittable amount of the sub-compression code information transmitted in the effective period. In this embodiment, the redundancy of the sub-compression code information is set to 2, and two pieces of redundant sub-compression code information having the same contents as the sub-compression code information are transmitted in the effective period, so that a transmission error of the sub-compression code information can be prevented. Increases tolerance.

When the transmission error rate ER is equal to or lower than ERb (when the transmission error rate is low), the compression rate is set to 80%, the amount of generated compressed image data is increased, and high-quality video transmission is enabled. Further, the non-transmission period of data is increased by not inserting redundant compression code information. In addition,
The non-transmission period is the total of the period during which neither the compressed image data nor the sub-compression code information is transmitted within the effective period 406 and the period during which neither the packet nor the main compression code information is transmitted within the blanking period period 407. During this non-transmission period, it is possible to save power by stopping the clock and operating at a lower clock frequency.

When the transmission error rate ER is larger than ERb and equal to or less than ERa (when the transmission error rate is normal), the compression rate is set to 60% and the redundancy of the sub-compression code information is set to 1, thereby increasing the transmission error tolerance. At the same time, we are trying to improve image quality.

FIG. 45 is a diagram illustrating another example of the compression rate, the horizontal blanking period, and the redundancy in each range, with the transmission error rate divided into three ranges. When the transmission error rate ER exceeds ERa (when the transmission error rate is high), the compression rate is set to 40%, the amount of compressed image data to be generated is reduced, the horizontal blanking period is extended, and the horizontal blanking period Is extended.
As a result, the transmittable amount of main compression code information transmitted in the horizontal blanking period can be increased. In this embodiment, the redundancy of the sub-compression code information is set to 1, and one piece of redundant sub-compression code information having the same content as the sub-compression code information is transmitted in the effective period, and the redundancy of the main compression code information is set to 1. As described above, by transmitting one piece of redundant main compression code information having the same content as that of the main compression code information in the horizontal blanking period, resistance against transmission errors of the sub compression code information and the main compression code information is enhanced.

In addition to the compression rates described with reference to FIGS. 44 and 45, the compression method may be changed. FIG.
It is a figure which divides | segments a transmission error rate into three ranges, and shows an example of the compression system, horizontal blanking period, and redundancy in each range. The compression method is switched between method A, method B, and method C depending on the transmission error rate ER. When the transmission error rate ER is larger than ERa, it is possible to increase resistance to transmission errors by adopting a compression method that can reduce the main compression code information and increase the redundancy. Also, by applying a compression method that can be expected to have a high compression rate (for example, the compression rate of 40% in FIG. 45), it is possible to increase the transmittable amount of sub-compression code information or main compression code information.

44 and 45, the compression rate has been described as an example, and in FIG. 46, the compression method has been described as an example. However, both the compression rate and the compression method may be switched depending on the transmission error rate.

In the present embodiment, in order to increase resistance to transmission errors, redundant main compression code information or redundant sub compression code information has been described as an example. However, depending on the transmission error rate, the error encoding method is switched. Also good. When the transmission error rate is high, as shown in FIG. 45, the amount of compressed image data after compression is reduced, the horizontal blanking period is extended, and a part of the sub-compression code information is transferred in the horizontal blanking period. By transmitting, tolerance to transmission errors may be increased.

In this embodiment, when the transmission error rate is higher than a predetermined value, the compression processing is performed using a method of reducing the compressed image data by performing compression processing at a low compression rate, or a compression method suitable for the low compression rate. A method of reducing the compressed image data, a method of increasing the transmission capacity of the transmission path for the main compression code information by extending the horizontal blanking period, or a transmission path of the sub compression code information by extending the effective period 406 Although the method of increasing the transmittable amount has been described, a method of reducing the number of voice packets transmitted in the horizontal blanking period by reducing the voice data may be used. Examples of methods for reducing audio data include a method of changing from uncompressed audio format to compressed audio, and a method of reducing the number of audio channels from 6 channels to 2 channels.

In the fourth embodiment, the compression rate, the horizontal blanking period, and the redundancy are increased according to the transmission error rate. However, the image quality and the error resistance with respect to the transmission error rate are determined regardless of the type of content of the image data. There are challenges. In this example, depending on the type of content,
By changing the reduction ratio, the horizontal blanking period, and the redundancy, it is possible to provide image quality and transmission error resistance suitable for the type of content. Although the transmission error rate is not described in this embodiment, switching according to the transmission error rate may be further performed in this embodiment.

FIG. 47 is a diagram illustrating an example of a method of switching the compression rate, the horizontal blanking period, and the redundancy according to the type of content. In this embodiment, when the content is a movie, in order to increase the image quality and error tolerance, the compression rate is increased by 80%, the horizontal blanking period is extended, the redundancy of the main compression code information is 2, and the sub compression code information is The redundancy is 1. On the other hand, if the content is Go / Shogi, the compression ratio is set to 40% because there are many stationary parts.
By shortening the horizontal blanking period, setting the redundancy of the main compression code information to 1, and setting the redundancy of the sub compression code information to 1, the tolerance to transmission errors is increased.

Also, if the content is sports, the image has many moving parts and is difficult to compress.
Considering that the visual sensitivity to errors is low, the horizontal blanking period is shortened while the compression rate is 80%, the redundancy of the main compression code information and the sub compression code information is both 0, that is, redundant compression code information is not inserted. Thus, the non-transmission period of data is increased while achieving high image quality.

In the fourth embodiment, when the transmission error rate is lower than the predetermined transmission error rate, the amount of compressed image data is increased at a high compression rate to improve the image quality. In the present embodiment, an example of a method for improving sound quality when the transmission error rate is lower than a predetermined transmission error rate will be described with reference to FIG.

1800 and 1802 are effective periods 406 for transmitting compressed image data or sub-compression code information, and 1801 is a blanking period 407 for transmitting main compression code information or audio packets as audio packets. Reference numeral 1810 denotes image data before compression. 1820,
1821 and 1822 transmit the main compression code information 1820 and the audio packet 1821 in the blanking period 1801, and transmit the sub compression code information or the compressed image data 1822 in the effective period 180.
This is an example of transmission with 2. In this case, the number of voice packets that can be transmitted within the blanking period 1801 is limited by the transmission amount of the main compression code information 1820.

Here, when the transmission error rate is lower than the predetermined transmission error rate, the main compression code information 1830 may also be transmitted in the effective period 1802. In this case, higher sound quality can be achieved by allocating more voice packets during the blanking period.

The blanking period has higher error resistance than the effective period, but the amount of data that can be transmitted is 1/3 or less when the transmission data rate is lower than a predetermined transmission error rate.

FIG. 49 shows another example of a method for realizing high sound quality. 1910, 1911, and 1912 are examples of transmitting the main compression code information 1910, the audio packet 1911, the sub compression code information, and the compressed image data 1912 when the effective period is not extended. In this example, there is no space in which the main compression code information 1910 can be transmitted during the effective period.

Therefore, if the transmission error rate is lower than the predetermined transmission error rate, the effective period is extended, and the main compression code information 1921 is transmitted in the extended effective period 1902. Valid period after extension 1
If it is within 902, the main compression code information 1921, the sub compression code information, and the compressed image data 19
The arrangement of 22 may be anywhere. In this method, the amount of data that can be transmitted in the effective period 1902 is three times or more the amount of data that can be transmitted in the blanking period, so the amount of extension of the effective period is the transmission of main compression code information in the blanking period. 1/3 of period
It becomes as follows. Therefore, as indicated by 1920, the blanking period during which voice packets can be transmitted can be lengthened. The sound quality can be improved by increasing the amount of audio data. As an example of improving the sound quality, there are an increase in the number of channels, an audio signal generation with a higher audio sampling frequency, an audio signal generation with a larger quantization bit, and relaxation of band restrictions for high and low frequencies.

According to the present embodiment described above, image data having a size larger than the currently specified image size is transmitted to the currently specified transmission path by compressing and transmitting the image data transmitted by the image transmission apparatus. Furthermore, by transmitting the main compression code information, which is a part of the compression code information, to a region where the error resistance is higher than the transmission region of the image data, a compressed image with high error resistance can be transmitted. Transmission can be performed.

In addition, when transmitting image data of the image size currently specified, the data transmission amount per predetermined time or the data transmission clock can be lowered, so that the frequency of occurrence of errors can be lowered, and A highly reliable system can be constructed against errors in the transmission path.

In addition, even when an error occurs in the transmission path and complete error correction cannot be performed, a system that performs error processing in which image quality deterioration due to an error is not noticeable can be realized.

DESCRIPTION OF SYMBOLS 100 Image transmission apparatus 101 Input part 102 Input part 103 Input part 104 Input part 105 Tuner reception process part 106 Network reception process part 107 Recording media control part 108 Recording medium 109 User IF part 110 Control part 111 Stream control part 112 Decoder part 113 Display Processing unit 114 Compression processing unit 115 Data transfer unit 116 Output unit 191 Data bus 192 Data bus 193 Data bus 200 Image receiving device 201 Input unit 202 Input unit 203 User IF unit 204 Control unit 205 Data reception processing unit 206 Decompression processing unit 207 Display Processing unit 208 Display unit 300 Cable

Claims (4)

An image output device that divides a two-dimensional image composed of the number of effective horizontal pixels and the number of effective vertical lines into unit blocks smaller than the two-dimensional image and outputs compressed image data compressed for each unit block,
A receiving unit that receives horizontal size candidate information capable of decompressing the compressed image data of the unit block from an image receiving device that is an output destination of the compressed image data;
A compression processing unit that generates compressed image data by compressing image data based on the horizontal size of the unit block selected based on the horizontal size candidate information of the unit block;
An output unit capable of outputting compressed image data generated by the compression processing unit and horizontal size information of the unit block;
The image output apparatus, wherein the output unit outputs horizontal size information of the unit block during a blanking period, and compressed image data during an effective period different from the blanking period. The image output apparatus according to claim 1,
The compression processing unit generates a CRC code for compressed image data,
The image output device, wherein the output unit outputs a CRC code during a blanking period. The image output apparatus according to claim 1,
The receiving unit further receives vertical size candidate information capable of decompressing the compressed image data of the unit block,
The compression processing unit generates compressed image data based on the vertical size of the unit block selected based on the vertical size candidate information of the unit block;
The image output apparatus, wherein the output unit outputs vertical size information of the unit block during a blanking period. An output method in an image output apparatus for dividing a two-dimensional image composed of the number of effective horizontal pixels and the number of effective vertical lines into unit blocks smaller than the two-dimensional image and outputting compressed image data compressed for each unit block There,
A compression processing step of compressing the image data to generate compressed image data and a CRC code;
An output step capable of outputting the generated compressed image data, CRC code, and size information of the unit block;
In the output step, there are a state in which the CRC code and the size information of the unit block are output in the blanking period, and a state in which the compressed image data is output in an effective period different from the blanking period,
The output method further comprises a selection step of obtaining size candidate information of the unit block from the image receiving apparatus which is an output destination of the compressed image data, and selecting the size of the unit block.

Images