JP2002135772A - Image transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of the loss of the continuity of images and reproducibility of the images is reduced due to the fact that in a transmission of video signals by splitting them into more than one image area, when compressing pixels at boundary parts of an area, it is impossible to use elements information of the boundary parts of neighboring areas. SOLUTION: In an image transmitting system, a screenful of the area of the signals captured by imaging with an imaging device 1 is split, for example, into four parts by a screen frame enlarging part 6 of a camera control device 2, each split image area is added with a block-widthful area of the boundary parts of neighboring split image arras, so that, as a whole, each split image area is an enlarged split image area. A compression processing is allowed by using the block-widthful area of the boundary portion of the split image area, so that the continuity of the video signals of split image areas before division is ensured in spite of compressing of the pixels at the boundary parts. An image frame correcting part 7 outputs the video signals of the split image areas before division by deleting the information of the boundary parts of the neighboring split image areas from the video signals of the enlarged-split image area to composite and display the result on a display device 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission system, and more particularly to a method of dividing an output video signal of an image pickup apparatus using a solid-state image pickup device having a number of pixels equal to or larger than that of a high definition television (HDTV) by dividing the image signal. The present invention relates to an image transmission system for transmitting and displaying an image on a transmission path.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of a conventional image transmission system. In the figure, a solid-state imaging device having a number of pixels equal to or larger than the number of HDTV (high-vision) pixels is used, and an imaging device 1 for imaging an optically continuous image with a set of solid-state imaging devices and converting the image into an electric signal. The output video signal is subjected to a compression process by the image compression / transmission device 3 for each divided video signal after, for example, one screen is divided by the camera control device 2 into four, and then the transmission path (spatial transmission path,
Recording medium).

[0003] The compressed video signal transmitted through the transmission path is received by the receiving / decompressing device 4, decompressed to restore each divided video signal, and further combined to produce a video image equivalent to the output video signal of the imaging device 1. The signal is displayed on a large screen by the display device 5.

Here, image compression in the image compression / transmission device 3 is for reducing the amount of information and improving transmission efficiency. One example of an image compression method is a small block unit (for example, 16 × 16 pixel unit). It has been conventionally known that an arithmetic process is performed to reduce the amount of image information (for example,
JP-A-11-341498). The image compression device described in this publication includes a frame determination unit that searches for motion of an image in small block units, a frequency conversion unit that converts an image of a small block into a spatial frequency, and an image signal that is frequency-converted by the frequency conversion unit. The compression is performed using a quantization unit that performs quantization. That is, the compression efficiency is increased by making the image into small blocks, the image information having a large amount of information is reduced, and more information is transmitted.

[0005]

However, when an image is handled in units of small blocks as described above, the processing content of information differs particularly between a boundary portion (image frame portion) of the image and another portion. For example, it is clear that the comparison conditions are greatly different between the case where an image is present in an adjacent block and the end of an image frame where there is no image, even if the image is the same. Especially when there is no image, continuity is lost.

For this reason, when one large image is divided, compressed, and transmitted, there is no information at the division position. Therefore, when the image is expanded and reproduced after transmission, the continuity of the image is divided into blocks at the division position. Disappears, and the vertical and horizontal streak portion becomes a display screen including an image with no continuity.

That is, the image area of one screen shown in FIG.
The camera control device 2 divides the image into four as indicated by # 1 to # 4. When the image compression / transmission device 3 performs image compression processing on the divided image regions, the divided image regions # 2 and # 4
The compressed image B0 of one block of the divided image region # 1 adjacent to the compression region B1 should be subjected to compression processing in comparison with the surrounding four blocks B1 to B4 of the divided image region # 1. As shown in FIG. 8B, block 1 lacks blocks B3 and B4 in divided image areas # 2 and # 4 different from compressed image B0, and thus loses the continuity of the boundary portion.

For this reason, the image displayed on the display device 5 after being received and expanded by the receiving and expanding device 4 has the continuity of the image shown in FIG.
As shown by I in (C), the image is lost one block at a time at the boundary of the divided part, and the reproducibility of the image is degraded.

The present invention has been made in view of the above points,
It is an object of the present invention to provide an image transmission system that obtains a display image having continuity at a boundary portion even when transmission is performed while performing image compression.

It is another object of the present invention to provide an image transmission system capable of sufficiently correcting frequency characteristics even when an image area is divided into a plurality of areas.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an image pickup device for picking up an optically continuous image with a set of image pickup devices and converting the image into a video signal, and an image output from the image pickup device. Divides the image area of one screen by the video signal into a plurality of image areas, and adds the video signal of the boundary between other divided image areas adjacent to one divided image area to the video signal of one divided image area The signal of the enlarged divided image area
A plurality of video signal generating means for generating each of the video signals of the plurality of divided image areas; and a video signal of the plurality of enlarged divided image areas output from the plurality of video signal generating means, which is compressed and then transmitted to the transmission path. Receiving / expanding means for receiving and expanding video signals of a plurality of enlarged divided image areas compressed via a transmission path to obtain video signals of the original plurality of enlarged divided image areas;・
After removing the video signal at the boundary between the added adjacent divided image regions from the video signals of the plurality of enlarged divided image regions output from the decompression means and returning to the video signals of the plurality of divided image regions This is configured to include an image frame correcting / displaying means for combining and displaying.

According to the present invention, when compressing the video signal of the divided image area before the enlargement, the compression processing can be performed by using the video signal at the boundary between the adjacent divided image areas before the enlargement.
Since the video signal at the boundary portion is also transmitted after being compressed, the decompression process using the compressed video signal at the boundary portion can be performed at the time of decompression, so that the continuity of the video signal at the boundary portion of the divided image area before enlargement can be improved. Can be secured.

According to another aspect of the present invention, there is provided an image pickup apparatus for picking up an optically continuous image with a set of image pickup elements and converting the image into a video signal, and a video signal output from the image pickup apparatus. An enlarged divided image obtained by dividing an image region of one screen into a plurality of image regions, and adding a video signal at a boundary portion of another divided image region adjacent to one divided image region to a video signal of one divided image region A plurality of video signal generating means for generating a signal of an area for each of the video signals of the plurality of divided image areas; and a transmission for transmitting the video signals of the plurality of enlarged divided image areas output from the plurality of video signal generating means to a transmission path. Means, receiving means for receiving video signals of a plurality of enlarged divided image areas compressed through a transmission path, and other adjacent signals added to the video signals of the enlarged divided image areas output from the receiving means. Correcting means for correcting the frequency characteristic of the video signal of the divided image area before enlargement by contour compensation using the video signal at the boundary portion of the divided image area for each of the video signals of the plurality of enlarged divided image areas; and And display means for synthesizing and displaying the video signals of the plurality of divided image areas before enlargement corrected by the correction means.

According to the present invention, the video signal of the enlarged divided image area in which the video signal of the boundary part of the adjacent divided image area before the enlargement is added to the video signal of the divided image area before the enlargement is transmitted. In addition, the frequency characteristic of the video signal of the divided image area before the enlargement can be corrected using the video signal of the boundary part of the adjacent divided image area before the enlargement.

Here, the video signal added to the video signal of the enlarged divided image area at the boundary between adjacent divided image areas is determined by the number of pixels of the transmitted video signal in the normal horizontal scanning period. With the number of pixels less than half the difference from the number of pixels,
The number of effective scanning lines is not transmitted with the number of scanning lines that is less than half the difference between the normal number of horizontal scanning lines and the number of effective scanning lines of the video signal transmitted during the period in which the effective pixels are not transmitted. Transmission during the period is desirable because the existing synchronization system can be used as it is.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image transmission system according to the present invention. In the figure,
The same components as those in FIG. 7 are denoted by the same reference numerals. In FIG. 1, a solid-state imaging device having a number of pixels equal to or larger than the number of HDTV (high-definition) pixels is used, and an image pickup apparatus 1 that takes an optically continuous image with a set of solid-state imaging devices and converts the image into an electric signal. The output video signal is converted into, for example, an enlarged / divided processed image in which an image for one screen is divided into four by a frame enlarging unit 6 of the camera control device 2 and a boundary portion is added by one adjacent block width.

An image area for one screen of a video signal obtained by imaging by the imaging device 1 is
As shown in FIG. 2A, for example, the image frame enlarging unit 6 divides the image into four parts. However, since each divided image area has a boundary portion added by one block width of the adjacent divided image area, the divided image area #
1B, as shown in FIG. 2B, it is composed of one conventional divided image area # 1 and one block width of an adjacent divided image area indicated by oblique line II. The same applies to the other three divided image areas.

The image enlargement amount is, for example, 16 × 16 for image compression.
When the processing is performed in units of small blocks of pixels, the boundary portion is set to 16
Enlarge by pixel. That is, when the divided image is the upper left quarter divided image in FIG. 2A in the image frame enlarging unit 6, adjacent images are added to the right and lower sides by 16 pixels each. Similarly, in the case of the upper right quarter-divided image, the left and lower sides, and in the case of the lower left quarter-divided image, the right and upper sides, lower right 1
In the case of a ４ divided image, adjacent images are added to the right side and the upper side, respectively, and enlarged. That is, the image enlargement amount may be obtained by adding adjacent pixels of the number of vertical and horizontal pixels in small block units to the boundary portions of the divided images.

Next, the camera control device 2 creates a camera output signal based on a standard signal used for transmission for each divided image. For example, a high definition SDI signal (BT
AS-004B). This SDI signal is created for each divided image, and after being compressed by the image compression / transmission device 3, is transmitted through the transmission path. When compressing this image,
The video signal of the divided image area before the enlargement is compressed using the video signal of the boundary between adjacent divided image areas,
The video signal at the boundary between adjacent divided image areas is also compressed, and transmitted as the video signal of the enlarged image area.

After the transmitted SDI signal is received by the receiving / decompressing device 4, the image is decompressed and restored. Next, a display image in which the enlarged portion added to the boundary portion by the image frame correction unit 7 is deleted is set. If this display image is sent to the display device 5 and displayed, the division boundary portion can be displayed as an image having continuity as shown in FIG.

Next, a specific example of image frame enlargement will be described with reference to FIG.
This will be described with reference to FIG. In the high definition SDI signal (BTAS-004B), as shown in FIG. 3A, the number of lines in the vertical period is set to 1125, and the number of lines for actually forming an image is set to 1080. Further, the number of pixels in the horizontal period is set to 2200 pixels as shown in FIG. 3B, and the effective pixels are set to 1920 pixels. Therefore, there is a gap between the vertical and horizontal periods, and by adding an image for enlargement to this gap, without adding a new synchronization system,
Existing synchronization schemes can be used.

The small block unit of the image compression is set to half or less of the number of pixels in the gap. That is, in the vertical period, 2
The number of pixels transmitted by 2.5 (= (1125-1080) / 2) or less lines is assumed to be 140 (=
(2200-1920) / 2) or less.

Next, an example of creating an enlarged portion using an image memory will be described. FIG. 4A schematically shows, at a high level, a video signal recording period of the second image memory in which the image of the divided image area # 2 ′ shown in FIG. 2A is stored and read, and FIG. ) Stores the image of the divided image area # 1 ′ shown in FIG. 2A and schematically shows, at a high level, the video signal recording period of the first image memory to be read out. As shown by W in FIG. 4 (C), the video signal A (for example, B3 in the example of FIG. 2) for the first block written to the second image memory is written in parallel with the second image memory, and After writing the video signal B (for example, B0 in the example of FIG. 2) of the last block of the divided image area (# 1 in FIG. 8A) into the image memory of
Subsequently, the video signal A is read from the image memory as indicated by R in FIG. 4 (C), and is read into the first image memory as a video signal A ′ for the last one block of the divided image area # 1 ′. Write as shown in FIG. Thus, the video signal of the divided image area # 1 'is written to the first image memory.

Similarly, a certain image memory has W in FIG.
As shown by, the video signal B for one block written in the first image memory (for example, B0 in the example of FIG. 2) is transmitted to the first image memory.
Immediately before writing the video signal A (for example, B3 in the example of FIG. 2) for the first block of the divided image area (# 2 in FIG. 8A) to the second image memory. The video signal B is read out from the image memory as indicated by R in FIG. 4D, and is read into the second image memory as a video signal B ′ for the first block of the divided image area # 2 ′ in FIG. Write as shown in A). Thereby, the second
The video signal of the divided image area # 2 ′ is written in the image memory of “1”. The above operation is performed in the same manner in both the horizontal period and the vertical period of the video signal.

Next, the configuration and operation of the image frame enlarging unit 6 will be further described. FIG. 5 is a block diagram showing an example of the image frame enlarging unit in FIG. 5, the memory 11 _H Out of before expansion divided into four divided image areas # 1 of the video signal, storing the video signals of one block adjacent to the divided image areas # 2 in the horizontal direction, the memory 11 _V is The video signal for one block adjacent to the divided image area # 4 in the vertical direction is stored. Also, the memory 12 _H stores the video signal of one block adjacent to the horizontal divided image area # 1 among the four divided image signals of the divided image area # 2 before enlargement.
_V stores a video signal for one block adjacent to the divided image area # 3 in the vertical direction.

[0026] Similarly, the memory 13 _H Out of before expansion divided into four divided image areas # 3 of the video signal, storing the video signals of one block horizontally adjacent divided image area # 4, the memory 13 _V stores a video signal for one block adjacent to the vertical divided image area # 2,
_H stores the video signal of one block adjacent to the horizontal divided image region # 3 among the video signals of the divided divided image region # 4 before the enlargement, and the memory _14V stores the vertical divided image region. The video signal for one block adjacent to the area # 1 is stored.

The enlargement unit adding device 15 receives the video signal of the divided image area # 1 before the enlargement, and in addition to this video signal, the video signal adjacent to the divided image area # 2 from the memory _{12H in} the horizontal direction. And the divided image area # from the memory 13 _V
By adding a vertically adjacent video signal and a part of the video signal from the memory _14V , a video signal of the enlarged divided image area # 1 'is generated and output.

Further, the enlargement unit adding device 16 adds the video signal adjacent to the video signal of the divided image area # 2 before the enlargement from the memories _11H and _{14V in} the horizontal and vertical directions, and the memory 13
By adding a part of the video signal from _V , a video signal of the enlarged divided image area # 2 'is generated and output. Similarly, the enlargement unit adding device 17 outputs a video signal of the divided image region obtained by enlarging the divided image region # 3 by one block in each of the horizontal and vertical directions,
Outputs a video signal of the divided image area obtained by enlarging the divided image area # 4 by one block in each of the horizontal and vertical directions.

The video signal of each divided image area obtained as described above is transmitted after being compressed for each divided image area by the image compression / transmission device 3 of FIG. The image is received and decompressed, and only the enlarged portion is deleted by the image frame correcting unit 7 to return to the original image. In this way, a display image without deterioration of the adjacent portion due to compression / decompression can be obtained.

The present invention is not limited to the above embodiment, and other embodiments are also conceivable.
For example, if the blurring of the subject light image occurs in an optical system such as a lens in the imaging apparatus 1 and the frequency characteristics of the image are deteriorated due to the blur, in another embodiment, the deterioration of the frequency characteristics is corrected. In this embodiment, as shown in FIG. 6, a difference between adjacent pixels is emphasized and added to correct a deteriorated frequency component.

That is, assuming that FIG. 6A is an original image waveform a, an image signal b (FIG. 6B) obtained by advancing this original image waveform a by one pixel period using a delay circuit or the like, and an original image waveform a a
After generating an image signal c (FIG. 6 (C)) delayed by one pixel period, a difference signal d between these two signals a and b and a difference signal e between both signals a and c are generated. The difference signal d is shown in FIG. 6D, and the difference signal e is shown in FIG.
Subsequently, the difference signals d and e are added to generate an addition signal shown in FIG. This addition signal is a contour emphasis signal.

A coefficient K is determined according to the degree of blurring of the light image of the object, and the contour emphasizing signal shown in FIG. 4F is multiplied by 1 / K, and a signal obtained by adding this to the original image waveform a is shown in FIG. The corrected image waveform is shown in which the outline is emphasized. Actually, FIG.
Since the video signal whose high frequency component has deteriorated is output as an image pickup signal as shown in FIG. 6, contour correction is performed by the above-described method to obtain a corrected video signal close to the original image as shown in FIG. Can be.

In the above description, the correction is performed by enhancing the contour in the horizontal direction. In the vertical direction, the contour is enhanced by generating the contour enhancing signal in the same manner as described above. However, in this case, the above 1
Instead of the signal advanced and delayed in the pixel period, a signal advanced and delayed in one line period are used. The frequency characteristic correction itself by the above-described contour enhancement is conventionally known. However, as described above, the present invention can be applied to a case where one screen image is divided into a plurality of pieces and transmitted.

That is, when correcting a video signal having deteriorated frequency characteristics using adjacent pixels, the image at the boundary of the image division area loses the adjacent pixel information and the adjacent line information. When the image is transmitted after adding the adjacent pixel information and the adjacent line information of the adjacent image divided area in advance and the outline is emphasized on the receiving side (reproducing side) by the method described with reference to FIG. 6, the adjacent information of the divided image area is damaged. Since an edge-enhanced signal is obtained without being corrected, an image with sufficiently corrected frequency characteristics can be obtained.

[0035]

As described above, according to the present invention,
Since the video signal at the boundary between the adjacent pre-enlarged divided image areas is added to the video signal of the pre-enlarged divided image area and transmitted as the video signal of the enlarged divided image area, the video signal is compressed and transmitted. In some cases, compression transmission can be performed while ensuring continuity of a video signal without losing information of an image at a boundary portion between adjacent divided image regions, and correction processing of a frequency characteristic in which contour enhancement is performed on a receiving side can be performed. For this reason, according to the present invention, even if a high-resolution large-screen video signal is divided into video signals of an image region of an existing standard and transmitted, a good image without image quality degradation can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a divided image and an example of a composite image of each unit in FIG. 1;

FIG. 3 is a diagram showing the number of effective pixels, the number of effective scanning lines, and the like of a HDTV synchronization signal.

FIG. 4 is a diagram illustrating a method for transmitting a video signal at a boundary portion between adjacent image areas according to the present invention.

FIG. 5 is a block diagram illustrating an example of an image frame enlarging unit in FIG. 1;

FIG. 6 is a waveform diagram illustrating an example of frequency characteristic correction by contour enhancement used in another embodiment of the present invention.

FIG. 7 is a block diagram of an example of the related art.

FIG. 8 is a diagram showing an example of a conventional divided image and an example of a composite image.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 imaging device 2 camera control device 3 image compression / transmission device 4 reception / expansion device 5 display device 6 image frame enlargement unit 7 image frame correction unit 11H, 11L, 12H, 12L, 13H, 13L, 1
4H, 14L Memory 15-18 Enlargement unit addition device # 1- # 4 Divided image area before enlargement # 1 ', # 2' Enlarged divided image area

Claims (3)

[Claims] An image pickup apparatus that picks up an optically continuous image with a set of image pickup elements and converts the image into a video signal, and converts an image area of one screen by a video signal output from the image pickup apparatus into a plurality of image areas. Dividing and adding a video signal of a boundary portion of another divided image region adjacent to one divided image region to a video signal of the one divided image region, a signal of an enlarged divided image region into a plurality of divided image regions. A plurality of video signal generating means for generating each of the video signals, and a compression / transmission for compressing and transmitting each of the video signals of the plurality of enlarged divided image areas output from the plurality of video signal generating means to a transmission path. Means for receiving and decompressing after receiving the compressed video signals of the plurality of enlarged divided image areas via the transmission path to obtain video signals of the original plurality of enlarged divided image areas; Of the video signals of the plurality of enlarged divided image areas output from the receiving / expanding means, the video signals of the boundary between the added adjacent divided image areas are removed to remove the video of the plurality of divided image areas. An image transmission system, comprising: an image frame correcting / displaying means for returning the signal to a signal and combining and displaying the combined signal. 2. An image pickup apparatus for picking up an optically continuous image with a set of image pickup devices and converting the image into a video signal, and converting an image area of one screen by a video signal output from the image pickup apparatus into a plurality of image areas. Dividing and adding a video signal of a boundary portion of another divided image region adjacent to one divided image region to a video signal of the one divided image region, a signal of an enlarged divided image region into a plurality of divided image regions. A plurality of video signal generating means for generating each of the video signals, transmitting means for transmitting video signals of a plurality of enlarged and divided image areas output from the plurality of video signal generating means to a transmission path, via the transmission path Receiving means for receiving the compressed video signals of the plurality of enlarged divided image areas; and the other adjacent divided picture added to the video signals of the enlarged divided image areas output from the receiving means. Using a video signal of the boundary portion of the region, correcting means for correcting the frequency characteristics of the video signal of the divided image region before enlargement by contour compensation, for each of the video signals of the plurality of enlarged divided image regions, Display means for combining and displaying the video signals of the plurality of divided image areas before enlargement corrected by the correction means. 3. The video signal at the boundary between the adjacent divided image areas added to the video signal of the enlarged divided image area is determined by the number of pixels of a transmitted video signal in a normal horizontal scanning period. The difference between the normal number of horizontal scanning lines and the number of effective scanning lines of the video signal transmitted during a period in which the effective pixels are not transmitted, and which is less than half the difference from the number of effective pixels. The image transmission system according to claim 1, wherein the transmission is performed in a period in which the number of effective scanning lines is not transmitted with the number of scanning lines being １ ／ or less.