JPH0818954A - Image transmitter - Google Patents

Abstract

PURPOSE:To obtain the image transmitter for dynamic images and still images in which the circuit scale is reduced through the reduction of A/D converters and D/A converters into one system respectively and interference between two kinds of clock signals whose frequencies are close to each other is eliminated. CONSTITUTION:A received image is A/D-converted at an A/D converter 1 at a sampling frequency of a dynamic picture in the case of transmission. A still image after A/D conversion is converted by a picture element structure conversion section 4 from 720 picture elements per one line into 768 picture elements per line and the converted signal is fed to a multiplexer section 7 via an image memory 5 and a still image compression section 6. On the other hand, in the case of reception, the image data demultiplexed by a multiplexer section 7 are expanded by a dynamic picture expansion section 9 or a still image expansion section 12 respectively. The expanded still dynamic is once stored in an image memory 13 and the picture elements of the picture are converted by a picture element structure conversion section 14 from 768 picture elements into 720 picture elements and the signal is converted into an analog video signal by a D/A converter 11 whose sampling frequency is a frequency for a dynamic picture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission device for transmitting and receiving moving images and still images, and more particularly to an image transmission device suitable for videophones and videoconferences.

[0002]

2. Description of the Related Art Due to recent technological progress and international standardization, the spread of videophones and videoconferencing is expected. Although analog transmission has been used for long-distance transmission of image signals, noise and distortion will not accumulate in the future, and transmission cost can be reduced by incorporating band compression coding. It is considered that digital transmission will become the mainstream due to the rapid progress of digitalization.

FIG. 4 is a block diagram showing the configuration of the main part of a conventional image transmission device for transmitting moving images and still images. In the figure, 1 is an analog / digital NTSC television signal (hereinafter analog / digital is abbreviated as A / D).
A moving image A / D converter for conversion, 2 is an NTSC-CIF conversion unit for converting a digital moving image into an international standard screen configuration, and 3 is a moving image compression unit. Reference numeral 15 is a still image A / D converter, 5 is a still image transmission memory, and 6 is a still image compression unit. Further, 7 is a multiplexing unit that multiplexes data and separates data, 8 is an I interface unit that is an interface with a line, and 23 is an ISDN line. Further, 9 is a moving image decompression unit, and 10 is a C which converts an international standard screen configuration into an NTSC format.
The IF-NTSC conversion unit 11 is a moving image digital / digital
An analog (hereinafter, digital / analog is abbreviated as D / A) converter, 12 is a still image expansion unit, 13 is a still image receiving memory, and 18 is a still image D / A conversion unit.

In the conventional image transmission apparatus having the above structure,
When transmitting a moving image, the A / D converter 1 converts the moving image into digital data. The sampling frequency at this time is 1
Performing at 3.5 MHz, the number of effective pixels in the horizontal direction is 720 pixels. In the vertical direction, 240 lines are converted into fields and 480 lines are converted into frames. The digitally converted data is sent to the ITU-T H.264 by the NTSC-CIF converter 2. Two
61 CIF (Common Intermediat)
e Format, pixel configuration is 352 (H) × 288 (V)),
QCIF (Quarter CIF, pixel configuration is 172 (H) x 1
44 (V)). H. Two
The data converted to the pixel configuration based on the 61 Recommendation is
H. It is compressed by the moving image compression unit 3 conforming to H.261, combined with the audio data by the multiplexing unit 7, and added to the H.264 standard. 221 compliant 6
The frame structure is 4 kbit / s and is transmitted to the ISDN line 23 via the I interface unit 8.

On the other hand, when the above image transmission device transmits a still image, it is converted into digital data by the A / D converter 15. The sampling frequency at this time is 14.32M
The number of effective pixels in the horizontal direction is 768 pixels. The vertical direction is the same as the moving image, and there are 240 fields and 480 frames. The digitally converted data is stored in the transmission memory 5 and compressed by the still image compression unit 6. At this time, TTC domestic standard [JJ41.10] J
It is compressed in conformity with PEG, combined with the audio data in the multiplexing unit 7, and added to the H.264 standard. A frame structure of 64 kbit / s conforming to 221 is obtained and transmitted to the ISDN line 23 via the I interface unit 8.

When the above image transmission apparatus receives a moving image, the I interface unit 8 receives it, and the multiplexing unit 7 separates it into audio and image data. The image data is decompressed by the moving image decompression unit 9 and converted into data having a screen configuration of CIF (352 × 288) or QCIF (176 × 144). The converted data is converted into the NTSC format by the CIF-NTSC converter 10 and converted into a video signal via the D / A converter 11 for display.

Further, when the above image transmission apparatus receives a still image, the I interface unit 8 receives it, and the multiplexing unit 7 separates it into audio and image data. The image data is decompressed by the still image decompression unit 12, and the still image receiving memory 1
3 is stored. The stored data is the D / A converter 1
At 8, it is converted into an analog signal and output as a still image.

[0008]

However, in the above conventional apparatus, the A / D converter and the D / A converter require two systems, one for moving images and one for still images, respectively.
Since different sampling frequencies are used for each, there is a problem that the circuit design becomes difficult because the circuit scale increases and interference is prevented between two clock operations whose frequencies are similar to each other, and unnecessary radiation is suppressed. there were. In view of the above problems, an object of the present invention is to provide an A / D converter and a D
2 / A / A converters are provided for each system, and the frequencies are similar.
An object of the present invention is to provide an image transmission device capable of transmitting and receiving a moving image and a still image without using any kind of clock.

[0009]

In order to solve the above problems, the present invention has the following constitution. That is, the first invention is an image transmission device for digitally encoding and transmitting a moving image and a still image, and an analog / digital converter for analog / digital converting the moving image and the still image with a pixel configuration of the digital moving image. A first pixel configuration converting means for converting the pixel configuration of the digitally converted image into a pixel configuration of a digital still image, and a second pixel configuration for converting the pixel configuration of the digital still image into a pixel configuration of a digital moving image. An image transmission apparatus comprising: a conversion unit; and a digital / analog converter for performing digital / analog conversion of a digital moving image and a digital still image whose pixel configuration has been converted.

The second aspect of the present invention is an image transmission device for digitally encoding and transmitting a moving image and a still image, wherein an analog / digital conversion of the moving image and the still image is carried out with a pixel configuration of the digital still image.
A digital converter and first for converting the pixel structure of the digitally converted image into the pixel structure of a digital moving image
Pixel configuration conversion means, second pixel configuration conversion means for converting the pixel configuration of the digital moving image into the pixel configuration of the digital still image, digital still image and the digital moving image with the pixel configuration converted. And a digital / analog converter.

The third aspect of the present invention is an image transmission apparatus for digitally encoding and transmitting a moving image and a still image, and an analog / digital converter for analog / digital converting the moving image and the still image at a common sampling frequency. First selecting means for selecting pixels required for moving image transmission from the digitally converted image, and second selecting means for selecting pixels required for still image transmission from the digitally converted image. The image transmission device is characterized by being provided.

[0012]

According to the first aspect of the present invention, the A / D converter and the D / A converter each have only one system for moving images, and the still images are transmitted at the sampling frequency for moving images when transmitting still images. After the A / D conversion is performed by using the A / D converter, the first pixel configuration conversion means converts the pixel configuration of the still image. There is no difference from the conventional method when transmitting moving images. When receiving a still image, the pixel configuration of the still image read from the still image receiving memory is set to the second
After the pixel configuration conversion means of (1) has converted the pixel configuration of the moving image, the D / A converter that uses the sampling frequency for the moving image performs D / A conversion. When receiving a moving image, there is no difference from the conventional method. As a result, the A / D converter and the D / A converter can be provided as one system, respectively, and the difficulty of using two clocks whose frequencies are close to each other is eliminated.

In the present invention according to claim 2, the A / D
The converter and the D / A converter each have only one system for still images, and when transmitting a moving image, the moving image is A / D converted using the A / D converter that uses the sampling frequency for still images.
After the conversion, the first pixel configuration conversion means converts the pixel configuration of the moving image. When transmitting a still image, there is no difference from the conventional method. Further, when receiving a moving image, after the pixel configuration of the decoded moving image is converted into the pixel configuration of the moving image by the second pixel configuration conversion means, the D / A converter using the sampling frequency for still image is used. D / A conversion.
When receiving a still image, it is the same as before. As a result, the A / D converter and the D / A converter can be provided as one system, respectively, and the difficulty of using two clocks whose frequencies are close to each other is eliminated.

According to the present invention of claim 3, only one system is provided for each of the A / D converter and the D / A converter which are shared between the moving image and the still image, and the sampling frequency is set to the moving image and the still image. Common frequency. The common frequency is preferably a frequency capable of sampling the number of pixels corresponding to the least common multiple of the number of moving image pixels and the number of still image pixels. When transmitting a moving image, the shared A / D converter is used to perform A / D conversion, and then the first pixel selecting means converts the pixel configuration of the moving image. When transmitting a still image, after A / D conversion using the shared A / D converter,
The second pixel selecting means converts the pixel configuration of the still image. As a result, the A / D converter and the D / A converter can be provided as one system, respectively, and the difficulty of using two clocks whose frequencies are close to each other is eliminated.

[0015]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a first image transmission device according to the present invention.
FIG. 3 is a block diagram showing a main part configuration of an embodiment, and corresponds to claim 1. In FIG. 1, 1 is an A / D converter that performs A / D conversion at a sampling frequency of a moving image, and 2 is an NTSC.
NTSC-CIF conversion unit for converting the signal format into the screen structure of the international standard screen structure CIF, 3 is a moving image compression unit, and 4 is the first pixel for converting the moving image pixel configuration to the still image pixel configuration. A configuration conversion unit, 5 is a still image transmission memory, 6 is a still image compression unit, 7 is a multiplexing unit that multiplexes or separates audio data and image data,
8 is an I interface unit for exchanging data with the line, 23 is an ISDN line, 9 is a moving image decompression unit, 10
Is a CIF-NTSC conversion unit that converts the CIF screen configuration into an NTSC screen configuration, 11 is a D / A converter that performs D / A conversion at the sampling frequency of the moving image, 12 is a still image expansion unit, and 13 is , Still image reception memory, 14 is
The second that converts the screen structure of a still image into the screen structure of a moving image
The respective pixel configuration conversion units are shown.

Next, the operation of the first embodiment having the above structure will be described. First, the input video signal is converted into digital data by the A / D converter 1, regardless of whether it is a moving image or a still image. The sampling frequency at this time conforms to the format that handles moving images, and the number of effective pixels in the horizontal direction is 720 pixels. When transmitting moving images, NTSC-C is used as usual.
The screen configuration 352 (H) × (V) (CIF
Mode) or 176 (H) X (V) (QCIF mode). The digital conversion result is converted into H.264 by the moving picture compression unit 3. It is compressed in accordance with the H.261 recommendation and is combined with the voice in the multiplexing unit 7 to be H.264. 221 compliant 6
It has a frame structure of 4 kbit / s and is transmitted to the other side through the ISDN line 23 via the I interface 8.

When transmitting a still image, the first pixel configuration conversion unit 4 converts horizontal 720 pixels to 768 pixels. Although various methods have been proposed for the conversion method,
Here, an example using pixel interpolation will be described. When making 768 pixels from 720 pixels, 48 pixels must be increased. This means that the original data may be increased by one pixel every 15 pixels. In this case, a new pixel may be created from left and right pixel (temporally preceding and following pixels) data, or a method may be created from left and right upper and lower pixel (temporally preceding and succeeding pixels and one line before and after) data. .

First, when the pixel is made from the left and right pixels, the half value of the front pixel data and the half value of the rear pixel data of the pixel to be made are added. When making from the left and right top and bottom pixels,
The values of the pixel data on the upper, lower, left and right sides are set to 1/4, and the sum of the values is taken as the data for that pixel. By performing this operation for every 15 pixels, the pixel configuration of the horizontal 720 pixel format can be converted to the 768 pixel format. Here, the data converted into the still image pixel format is once recorded in the still image transmission memory 5, and the still image compression unit 6 performs JPEG-compliant compression,
Similar to the moving image, it is combined with the voice in the multiplexing unit 7 to generate H.264. 221
It has a compliant 64 kbit / s frame structure and is transmitted to the other party through the I interface 8.

When a moving image is received, the received data is I
The interface 8 receives the data, the multiplexing unit 7 separates the audio data and the image data, and the moving image expansion unit 9 receives the H.264 data. Decompression, which is the inverse conversion of H.261 compression, is performed. The extension result is CI
The F-NTSC conversion unit 10 converts it into the NTSC format, the moving picture D / A converter 11 converts it into analog data, and outputs it as an NTSC signal.

When a still image is received, it is received by the I interface unit 8 like the moving image and separated from the audio data by the multiplexing unit 7. The image data is JPEG by the still image expansion unit 12.
Decompression, which is the inverse conversion of compliant compression, is performed and is temporarily recorded in the still image reception memory 13. Memory for receiving still images 1
The still image read from No. 3 is converted from horizontal 768 pixels to 720 pixels by the second pixel configuration conversion unit 14.

Since the conversion here may be changed from 16 pixels to 15 pixels, the simplest method is to thin one pixel in units of 16 pixels or to filter after that to maintain continuity of data change. There is a method of thinning out. There is also a method of thinning out the thinning position for each line at continuous data or a place where the amount of change is small. By doing so, the image format can be converted while maintaining the continuity of the images. Here, after being converted into 720 horizontal pixels, it is converted into analog data by the moving picture D / A converter 11 and output as a video signal.

Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram showing a main configuration of a second embodiment of the image transmission apparatus according to the present invention, and corresponds to claim 2. In FIG. 2, 15 is an A / D converter that performs A / D conversion at the sampling frequency of a still image, 16 is a first pixel configuration conversion unit that converts the pixel configuration of a still image for a moving image, and 17 is A second pixel configuration conversion unit for converting a pixel configuration of a moving image into a still image, a D / A converter for converting a digital image signal into an analog signal at a sampling frequency of a still image, and 2 for an NTSC signal format. NTSC to convert the international standard screen structure CIF screen structure
-CIF conversion unit, 3 is a moving image compression unit, 5 is a still image transmission memory, 6 is a still image compression unit, and 7 is a multiplexing unit that multiplexes or separates audio data and image data. , 8 is an I interface unit for exchanging data with the line, 23 is an ISDN line, 9 is a moving image expansion unit,
Reference numeral 10 denotes a CIF-NTSC conversion unit that converts a CIF screen configuration into an NTSC screen configuration, 12 denotes a still image expansion unit, and 13 denotes a still image reception memory. Reference numerals 2 to 13 and 23 are the same components as those of the first embodiment.

In the second embodiment, the image to be transmitted is
Regardless of the still image / moving image, the A / D converter 15 converts the still image into digital data of 768 horizontal pixels at the sampling frequency of the still image. Then, when a still image is transmitted, the digital data is recorded in the still image transmitting memory 5, and the recorded content is the still image compression unit 6.
Is JPEG-compressed by H.264 and is combined with voice by the multiplexing unit 7 in H.264. It has a frame structure of 64 kbit / s conforming to 221 and is transmitted to the other party via the I interface 8.

When transmitting a moving image, the number of horizontal pixels converted into digital data is 768 pixels like the still image, and it is necessary to convert this into 720 pixels. This conversion is performed by the first pixel configuration conversion unit 16. In the case of conversion from the pixel configuration of the still image to the pixel configuration of the moving image, it is sufficient to change from 16 pixels to 15 pixels. Therefore, the simplest method is to thin one pixel in 16 pixel units, and then There is a method of filtering and thinning while maintaining the continuity of data changes. There is also a method of thinning out the thinning position for each line at continuous data or a place where the amount of change is small. By doing so, the image format can be converted while maintaining the continuity of the images.

The data is converted into a moving picture format by the conversion of the horizontal pixel configuration, and the NTSC-CIF converter 2 converts the NTSC digital data into the screen mode (CIF, QCIF) of the international standard. Next, the moving picture compression unit 3 performs H.264. 261 compressed, similar to still image transmission,
The audio is combined with the voice in the multiplexer 7. 221 compliant 64k
It has a bit / s frame structure and is transmitted via the I interface unit 8.

When receiving a still image, first, the I interface unit 8 receives it, and the multiplexing unit 7 separates the image data and the audio data. The image data is the still image expansion unit 12
Then, decompression, which is the reverse conversion of JPEG compression, is performed and is temporarily recorded in the still image receiving memory 13. Then, it is converted into analog data by the D / A converter 18 and output as a video signal.

When a moving image is received, it is received by the I interface unit 8 as in the case of a still image, and separated by the multiplexing unit 7 into audio data and image data. The moving image data is transmitted by the moving image expansion unit 9 to the H.264 format. Decompression, which is the inverse conversion of H.261 compression, is performed and converted to the original data. The converted data is C
Since the image format is IF or QCIF, it is converted to the NTSC image format by the CIF-NTSC conversion unit 10. The image converted into the NTSC format has 720 pixels in the horizontal direction, and D /
Since the A converter 18 has a sampling frequency for a still image, it is necessary to convert the number of pixels of a moving image into the number of pixels of a still image. Therefore, the second pixel configuration conversion unit 17 converts the horizontal pixels from 720 pixels to 768 pixels. As a result, the signal is normally converted by the D / A converter 18 and output as a video signal.

When making 768 pixels from 720 pixels, 4
Must increase by 8 pixels. This means that the original data may be increased by one pixel every 15 pixels. In this case, a new pixel may be created from left and right pixel (temporally preceding and following pixels) data, or a method may be created from left and right upper and lower pixel (temporally preceding and succeeding pixels and one line before and after) data. .

First, when the pixel is made from the left and right pixels, the half value of the front pixel data and the half value of the rear pixel data of the pixel to be made are added. When making from the left and right top and bottom pixels,
The values of the pixel data on the upper, lower, left and right sides are set to 1/4, and the sum of the values is taken as the data for that pixel. By performing this operation for every 15 pixels, the pixel configuration of the horizontal 720 pixel format can be converted to the 768 pixel format.

Next, a third embodiment of the present invention will be described. FIG. 3 is a block diagram showing the configuration of the essential parts of a third embodiment of the image transmission apparatus according to the present invention, and corresponds to claim 3. In FIG. 3, 19 is an A / D converter, 20 is a moving image data selection unit, 21 is a still image data selection unit, 2
2 is a D / A converter, and 2 is an NT that converts the NTSC signal format into an international standard screen configuration CIF screen configuration.
SC-CIF conversion unit, 3 is a moving image compression unit, 5 is a still image transmission memory, 6 is a still image compression unit, and 7 is multiplexing for separating or separating audio data and image data. Reference numeral 8 is an I interface unit for exchanging data with the line, 23 is an ISDN line, 9 is a moving image decompression unit, and 10 is a CIF-NTSC conversion unit for converting a CIF screen configuration into an NTSC screen configuration. , 12 are still image expansion units, and 13 is a still image reception memory.
Reference numerals 2 to 13 and 23 are the same components as those of the first embodiment.

In the third embodiment, when transmitting an image, the A / D converter 19 converts analog data into digital data. The sampling frequency at this time is
It has the same frequency for moving images and still images. For example,
When the moving image is about 13 MHz and the still image is about 14 MHz, the frequency here is about 182 MHz. Also, the number of effective pixels at that time is 768 pixels for a still image,
Since it is 720 pixels for a moving image, the least common multiple of 115
It has 20 pixels.

When transmitting a moving image, the A / D converter 19
Then, effective pixels in the horizontal direction are sampled at 11520 pixels and passed to the moving image data selection unit 20. Since the number of effective pixels in the horizontal direction required for a moving image is 720 pixels, the moving image data selection unit 20 takes out one pixel data for every 16 pixels to form a screen of 720 pixels. After that, the NTSC-CIF conversion unit 2 converts the NTSC standard screen configuration into the international standard CIF [352 (H) × 288].
(V)] (or QCIF [176 (H) × 144
(V)]) Convert to screen configuration. The conversion result is converted into H.264 by the moving image compression unit 3. H.261-based compression is performed, and the data is combined with the voice in the multiplexing unit 7 and H.264. 221 compliant 64 kbit
It has a frame structure of / s and is transmitted to the other party via the I interface unit.

When transmitting a still image, the A / D converter 1
At 9, the effective pixels in the horizontal direction are sampled at 11520 pixels and passed to the still image data selection unit 20. Since the effective pixels in the horizontal direction are 768 pixels, pixel data is taken out every 15 pixels to form a screen of 768 pixels. The result is temporarily stored in the still image transmission memory 5, compressed by the still image compression unit 6 in accordance with JPEG, and combined with voice by the multiplexing unit 7 similarly to the moving image. 221 compliant 64k
It has a bit / s frame structure and is transmitted to the other party via the I interface unit 8.

When receiving a moving image, the I interface unit 8 receives it, and the multiplexing unit 7 separates it from audio data. The image data after separation is H.264 in the moving image expansion unit. The CIF-NTSC conversion unit 10 performs the decompression, which is the inverse conversion of the H.261 compression, and converts it into the image format of the NTSC standard. Then, it is converted into analog data by the D / A converter 22 and output as a video signal.

When a still image is received, it is received by the I interface unit 8 and separated from the audio data by the multiplexing unit 7 as in the case of receiving a moving image. Then, in the still image decompression unit, JPEG
Decompression, which is an inverse conversion of compression, is performed, is temporarily stored in the still image receiving memory 13, converted into analog data by the D / A converter 22, and output as a video signal.

[0036]

As described above, according to the first aspect of the present invention, an A / D having a sampling frequency for moving images is used.
By using only the converter and the D / A converter, it is possible to transmit and receive the moving image and the still image, and the A / D converter and the D / A conversion, which are conventionally provided separately for the moving image and the still image, respectively. This has the effect of reducing the circuit scale to about 1/2. At the same time, there is an effect that interference between clock operations and unnecessary radiation due to the use of clock frequencies that are close to each other is eliminated, and the circuit design is simplified.

Further, according to the second invention, by using only the A / D converter and the D / A converter having the sampling frequency for the still image, the moving image and the still image can be transmitted and received. The A / D converter and D / A converter, which were separately provided for moving images and still images, are about 1 /
This has the effect of reducing the circuit scale to 2. at the same time,
There is an effect that interference between clock operations and unnecessary radiation due to the use of clock frequencies that are close to each other is eliminated, and the circuit design is simplified.

Further, according to the third invention, a moving image and a still image are transmitted and received by using only an A / D converter and a D / A converter having a common sampling frequency for a moving image and a still image. A / D converter and D / which are separately provided for moving images and still images
There is an effect that the A converter can be reduced to a circuit size of about 1/2. At the same time, there is an effect that interference between clock operations and unnecessary radiation due to the use of clock frequencies that are close to each other is eliminated, and the circuit design is simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an image transmission apparatus according to the present invention, which is an example in which a moving image sampling frequency is used for an A / D converter and a D / A converter.

FIG. 2 is a block diagram showing a configuration of a second embodiment of an image transmission apparatus according to the present invention, which is an example in which a still image sampling frequency is used for an A / D converter and a D / A converter.

FIG. 3 is a block diagram showing a configuration of a third embodiment of an image transmission apparatus according to the present invention, in which an A / D converter and a D / A converter use sampling frequencies for both moving and still images. Is.

FIG. 4 is a block diagram showing a configuration of a conventional image transmission device.

[Explanation of symbols]

 1 A / D converter for moving images 2 NTSC-CIF conversion unit 3 Moving image compression unit 4 First pixel configuration conversion unit 5 Still image transmission memory 6 Still image compression unit 7 Multiplexing unit 8 I interface unit 9 Moving image Expansion unit 10 CIF-NTSC conversion unit 11 Moving image D / A converter 12 Still image expansion unit 13 Still image reception memory 14 Second pixel configuration conversion unit 15 Still image A / D converter 16 First pixel Number conversion unit 17 Second pixel number conversion unit 18 Still image D / A converter 19 Shared A / D converter 20 First selection means 21 Second selection means 22 Shared D / A converter 23 ISDN line

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Claims (3)

[Claims] 1. An image transmission device for digitally encoding and transmitting a moving image and a still image, comprising: an analog / digital converter for analog / digital converting the moving image and the still image into a pixel structure of the digital moving image; First pixel configuration conversion means for converting the pixel configuration of the digitally converted image into the pixel configuration of the digital still image, and second pixel configuration conversion means for converting the pixel configuration of the digital still image into the pixel configuration of the digital moving image. An image transmission device comprising: a digital moving image; and a digital / analog converter for performing digital / analog conversion on the digital still image whose pixel configuration has been converted. 2. An image transmission device for digitally encoding and transmitting a moving image and a still image, comprising: an analog / digital converter for analog / digital converting the moving image and the still image with a pixel configuration of the digital still image; First pixel configuration conversion means for converting the pixel configuration of the digitally converted image into the pixel configuration of the digital moving image, and second pixel configuration conversion means for converting the pixel configuration of the digital moving image into the pixel configuration of the digital still image. An image transmission device comprising: a digital still image; and a digital / analog converter that performs digital / analog conversion on the digital still image and the digital moving image whose pixel configuration has been converted. 3. An image transmission device for digitally encoding and transmitting a moving image and a still image, and an analog / digital converter for analog / digital converting the moving image and the still image at a common sampling frequency, and the digital conversion. A first selecting means for selecting pixels required for moving image transmission from the image, and a second selecting means for selecting pixels required for still image transmission from the digitally converted image. Image transmission device.