JP2000184377A - Image replacement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image replacement system where part of image data that is high efficiency-coded can be replaced with other image not attended with deterioration in image quality. SOLUTION: A 1st area indication section 20 and a 2nd area indication section 24 indicate a replaced area. A 1st coding section 16 of a 1st code converter 101 applies slice division to an image corresponding to the replaced area to encode the image. A 2nd coding section 34 of a 2nd code converter 103 applies encode to a partial image so that the code quantity of the replaced area of the image transmitted from the 1st code converter 101 is coincident with the code quantity of the partial image desired to be replaced and a conversion section 32 conducts replacement processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for replacing a part of image data compressed by a high efficiency coding method.

[0002]

2. Description of the Related Art Conventional techniques for replacing a part of an image with another image in a code generated using a high-efficiency coding method, for example, MPEG2, include: There is an image combining / encoding method and an image combining apparatus disclosed in Japanese Patent Application Laid-Open No. 7-250329. This is a method of synthesizing image data in a case where inter-frame differential encoding is used, and image data compressed by encoding is once decoded. Then, the decoded image is added to the image to be synthesized to obtain a synthesized image. Then, the composite image is encoded again, and encoded image data in which the image is replaced is obtained.

[0003] For example, consider a case in which coded image data is generated at broadcast station A, transmitted to broadcast station B, and broadcasted at different time zones by broadcast station B. When the time display of the A broadcast station is included in the image, since the broadcast time is different, the time display of the B broadcast station needs to be deleted or corrected to the time display of the B broadcast station. . In such a case, replacement of the image in the encoded image data is performed.

However, according to the above-described prior art, when an image in a partial area is replaced with another image, a part that is not replaced is re-encoded every time replacement is performed. There is a disadvantage that the image quality is degraded every time.

The present invention, which focuses on the above points, provides an image replacing apparatus which can replace a part of highly efficient encoded image data with another image without deteriorating the image quality. Is to do so.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an image replacing apparatus for replacing a part of an image coded on a slice-by-slice basis with another image. Replacement region instructing means for instructing; first encoding means for performing a slice division corresponding to the replacement region and encoding a replacement target image while prohibiting prediction over the replacement region designated thereby; ; Characterized by having;

Another invention is a second encoding means for encoding the other image so as to have the same code amount as the code amount of the replacement area in the encoded data; Conversion means for replacing the data of the replacement area in the encoded data obtained by the encoding means with the encoded data obtained by the second encoding means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. In FIG.
An example of an image encoded in the present embodiment is shown. FIG.
In this example, the processing target image PA before replacement
Are composed of 720 × 480 pixels. Then, the replacement area PB designated for replacement in the processing target image PA
For example, the starting point is (210, 20) and the size is 18
Assume 0x28 pixels. The specification of the area PB to be replaced uses area index data as shown in FIG. 5, for example. In the index data, a replacement part is represented by a logical value “1” in a bit map of a logical value “0”.

The image PA to be processed in FIG. 2 is divided into slices 1 to m formed by macroblocks, which are units of encoding, when data processing is performed. At the beginning of each slice, a header is provided. That is, data processing is performed in units of slices. In a normal case where replacement is not performed, the image is horizontally divided into m as shown in FIG. However, in the present embodiment, division is performed in consideration of the replacement part. That is, the slice unit is subdivided in consideration of the replacement part. For example, when the replacement area PB shown in FIG. 2 is designated, the slice configuration is as shown in FIG. More specifically, the replacement area PB
Spans slices 2 and 3, as shown by the dotted lines in FIG. Therefore, slices 2 and 3 are subdivided into a slice configuration as shown in FIG. That is, a portion corresponding to the replacement area PB is sliced along slices 2 to 7 along the replacement area PB.
And divided.

As described above, if the processing target image PA has a slice configuration corresponding to the replacement area PB, the slices 3 and 6 can be replaced, and the image can be replaced without decoding.

Next, an example of an apparatus for replacing an image by the above-described method will be described. In FIG. 1, an image replacement device according to the present embodiment includes a first code conversion device 101.
And the second code conversion device 103. The first transcoder 101 is arranged, for example, at a first broadcast station, and the second transcoder 103 is arranged, for example, at a second broadcast station.

To begin with, from the first transcoder 101, the image signal of the image PA to be replaced is supplied to the first motion vector detector 12. First
The output side of the motion vector detecting unit 12 is the first motion compensating unit 1
4 is connected. The output side of the first motion compensation unit 14 is
It is connected to the first encoding unit 16. First encoding unit 16
Is connected to the code amount control unit 18, the first decoding unit 22, and further to the second code conversion device 103 side. The output side of the first decoding unit 22 is connected to the first motion vector detection unit 12 and the first motion compensation unit 14.

On the other hand, the area designation input is made by the first area designating section 2
0 and the second area designating section 24. The output side of the first area indicator 20 is the first
They are connected to the motion vector detection unit 12 and the first encoding unit 16, respectively.

Next, the second code converter 103 will be described. A signal including a replacement image is supplied to a second motion vector detector 28. Second motion vector detection unit 2
The output side of 8 is connected to the second motion compensator 30.
The output side of the second motion compensator 30 is connected to the second encoder 34. The second encoding unit 34 converts the conversion unit 32, the second
Each is connected to the decoding unit 36. The output side of the second decoding unit 36 is connected to the second motion vector detecting unit 28 and the second
It is connected to the motion compensator 30. The second encoding unit 3
4 and the conversion unit 32 are connected to the second code amount control unit 26, respectively. The second where the above-mentioned area designation input is performed
The output side of the first code conversion device 101 is connected to the area instruction unit 24 and the conversion unit 32. The second area instruction unit 24 further includes a second motion vector detection unit 28,
They are connected to the motion compensation unit 30 and the conversion unit 32, respectively.

Next, the operation of the image replacing apparatus thus configured will be described. First, the normal operation in which the image is not replaced will be described. In this case, neither the area designation input nor the signal input of the replacement image is performed. The image signal to be transmitted is supplied to the first motion vector detection unit 12. The first motion vector detection unit 12 detects a motion vector between images in macroblock units based on the input image and the reference image from the first decoding unit 22. The macroblock to be processed and the detected motion vector are supplied to the first motion compensator 14. In the first motion compensation unit 14, a process corresponding to either inter-frame prediction or intra-frame prediction is performed. That is, a reference macroblock indicated by a motion vector is read from the first decoding unit 22 and subjected to motion compensation processing, a macroblock image to be processed, a motion vector, and a prediction error are generated. Sent to

In the first encoding unit 16, the slice processing is performed as shown in FIG. 3, and a slice header is inserted into each slice to perform the encoding processing. At this time, encoding according to the target code amount by the first code amount control unit 18 is performed. The encoded data is transmitted to the conversion unit 32 of the second code conversion device 103. The conversion unit 32 outputs the input coded data as it is.

As described above, normally, a high-efficiency encoding process according to a general MPEG system is performed, and encoded data is transmitted from the first code conversion device 101 to the second code conversion device 103. Then, in the second code conversion device 103, the input coded data is output as it is without performing the image replacement process.

Next, the operation in the case of image replacement according to this embodiment will be described. To explain from the first code conversion device 101, first, an area to be replaced is input to the first area designating unit 20. For example, in the example shown in FIG. 2, the start point (210, 20) and the size (180 × 28) of the replacement area PB are input. In the area instruction unit 20,
Based on the input area designation information, area index data as shown in FIG. 5 is generated. The generated region index data is supplied to the first motion vector detection unit 12.

The first motion vector detecting section 12 is supplied with an image signal of an image PA to be replaced. The first motion vector detection unit 12 detects a motion vector between images based on an input image and a reference image from the first decoding unit 22. At this time, if the region index data corresponding to the macroblock for which the detection process is being performed is different from the region index data of the pixel of the reference image, the region index data is not adopted as a motion vector. As a result, detection of a motion vector indicating a reference image over an area is prohibited.

If the area index data corresponding to the macroblock for which the detection process is being performed is the same as the area index data of the pixel of the reference image, it is adopted as a motion vector. The detected motion vector and the corresponding macroblock are supplied to the first motion compensation unit 14. In the first motion compensation unit 14, the reference macroblock indicated by the motion vector is read from the first decoding unit 22, and a known motion compensation process is performed. The prediction error obtained by this processing, the macroblock image to be processed, and the motion vector are sent to the first encoding unit 16.

The first encoding unit 16 performs an encoding process on a slice basis based on the input. At this time, if the macroblock to be processed is at the beginning of the slice, the first region instructing unit 20 determines whether the first encoding unit 1
6 is instructed to insert a slice header. Also,
A slice division in consideration of the replacement area PB is instructed.

The first encoder 16 refers to the area index data shown in FIG. 5 and performs slice division as shown in FIG. That is, slices 2 to 7 are set so that the replacement area PB can be replaced. For the other parts, the normal slice shown in FIG. 3 is set. Then, a slice header is inserted into each slice, and encoding processing is performed for each slice.
At this time, encoding according to the target code amount by the first code amount control unit 18 is performed. As described above, in the first transcoder 101, the slice of the replacement target image PA is set corresponding to the replacement area. Then, the encoding process is performed in units of the slice set as described above,
The encoded data is transmitted to the second code conversion device 103.

Next, the operation of the second code conversion device 103 will be described. Similarly, an area to be replaced (see FIG. 2) is input to the second area designating section 24, and area index data is generated (see FIG. 5). Then, the second motion vector detecting unit 28, the second motion compensating unit 30, and the converting unit 3
2 is instructed to indicate a replacement area. At this time, the second
The region instruction unit 24 detects whether the processing target frame is an I frame, a P frame, or a B frame based on the encoded data input from the first encoding unit 16, and Processing according to the type is instructed to the second motion vector detection unit 28 and the second motion compensation unit 30.

On the other hand, an image to be replaced (a signal is input to a second motion vector detecting unit 28. In the second motion vector detecting unit 28, an area to be replaced is cut out from the input image signal, and within the area, , A motion vector is detected in macroblock units with reference to the image from the first decoding unit 22. Then, the macroblock to be processed, the detected motion vector and the error image corresponding thereto are 2 It is output to the motion compensation unit 30.

The second motion compensator 30 determines whether to use inter-frame prediction or intra-frame prediction, and performs a motion compensation process. Then, the macroblock to be processed, the motion vector, and the prediction error
It is output to the encoding unit 34. In the second encoding unit 34, an input encoding process is performed while the code amount is controlled by the second code amount control unit 26. This control will be described later.

The coded data of the image PA to be replaced and the coded data of the partial image to be replaced are input to the converter 32. The conversion unit 32 obtains the code amount of the area PB to be replaced from the input coded data of the image PA with reference to the area index data specified by the second area specifying unit 24. The obtained code amount is output to the second code amount control unit 26. The second code amount control unit 26 controls the code amount of the partial image in the second encoding unit 34 using the code amount input from the conversion unit 32 as a target code amount. As a result, encoded data of a partial image having the same code amount as the code amount of the replacement area PB is generated.

In the conversion section 32, slices 3 and 6, which are code portions corresponding to the replacement area PB specified by the second area specification section 24, are encoded data of the partial image input from the second coding section 34. Is replaced by And
The coded data after the replacement is output from the conversion unit 32.

[0028]

As described above, according to the present invention,
The following effects can be obtained. (1) When a part of an encoded image is replaced with another image, a series of processes of replacing the image at the image level by decoding the entire image and encoding the image are not performed.
By designating the area to be replaced and encoding the image to be replaced, a part of the image can be easily replaced. (2) Since the re-encoding is not performed on the image portion that is not replaced, there is no deterioration in image quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of an image encoded in the embodiment of the present invention.

FIG. 3 is a diagram showing a normal slice configuration.

FIG. 4 is a diagram showing a slice configuration according to the embodiment of the present invention.

FIG. 5 is a diagram showing area designation index data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Image signal to be converted 12 ... First motion vector detecting unit 14 ... First motion compensating unit 16 ... First encoding unit 18 ... Code amount control unit 20 ... First area designating unit 22 ... First decoding Unit 24 second region instructing unit 26 second code amount control unit 28 second motion vector detection unit 30 second motion compensation unit 32 conversion unit 34 second encoding unit 36 second decoding unit 38 ... area input 40 ... image signal to be converted 101 ... first encoding conversion apparatus 103 ... second encoding conversion apparatus PA ... processing target image PB ... replacement area

Claims (2)

[Claims] 1. An image replacement device for replacing a part of an image coded in units of slices with another image, a replacement area designating means for designating an area to be replaced; A first encoding unit that performs slice division corresponding to the replacement area while prohibiting straddling prediction, and codes a replacement target image;
An image replacement device comprising: A second encoding unit for encoding the other image so as to have the same code amount as the code amount of the replacement area in the encoded data; 2. The image replacement device according to claim 1, further comprising: a conversion unit that replaces data of the replacement area in the obtained coded data with the coded data obtained by the second coding unit.