JP2013085049A - Encoding device for transmitting information using code or value of orthogonal transformation coefficient, decoding device, method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To superimpose and transmit a control signal to a signal such as a video without increasing a code amount when the signal such as the video is transmitted to a decoder side from an encoder side.SOLUTION: An orthogonal transformation coefficient operating section 12 of an encoding device 1 inverts a code of an orthogonal transformation coefficient of a (0,0) component when a control signal s is 1, and does not change the code of the orthogonal transformation coefficient of the (0,0) component when the control signal s is 0. Thereby, the orthogonal transformation coefficient is generated on which the control signal s is superimposed. Generally, when a video signal is encoded, the video signal has properties that in the orthogonal transformation coefficient, low frequency information is much, and high frequency information is little. When the code of the low frequency information is inverted, signal variation in an encoding block boundary becomes extremely large. By making use of the properties of the video signal, a decoding device 2-1 extracts the control signal s for the orthogonal transformation coefficient on which the control signal s is superimposed based on a difference quantity between pixel signals in the block boundary.

Description

  The present invention relates to an encoding technology such as video or audio, and particularly relates to an encoding device, a decoding device, a method, and a program used for a broadcast or video distribution service.

  In an encoding technique such as video or audio, a plurality of signal processing techniques are combined to convert a signal into a smaller signal representation and realize signal compression. Although it is easy to perform each process in a predetermined procedure, it is necessary to add a control signal in order to determine by which process the signal is encoded when decoding. Such a control signal is not a signal obtained by converting the input signal by signal processing, but a newly added signal, and causes a code amount to increase in the encoding processing. In general, as a signal processing of an encoding method, a process that sufficiently obtains a compression effect is employed so that the code amount is not increased by a control signal, and there is no problem of an increase in the code amount. For example, MPEG-2, H.264. A process defined in H.264 / AVC or the like is employed.

  In addition, the development of digital encoding technology has made video distribution easier, and high-quality copying of video and audio signals has been performed, and the rights of content holders have been infringed. In order to solve such problems, from the viewpoint of copyright protection, research on data hiding technology that embeds management information for copyright protection in an encoded signal without increasing the code amount as much as possible has been conducted. Has been put into practical use (see, for example, Non-Patent Document 1). This data hiding technique is not (or is difficult to detect) the redundant part of the signal before encoding, or the human visual and auditory sense, so as not to affect the amount of information and encoding quality as much as possible. Management information is transmitted by embedding management information in the part. However, considering signal degradation due to irreversible encoding, such as video or audio encoding, the signal must be manipulated to some extent, which affects the amount of code and coding quality. End up. Also, since the embedded management information may change depending on the encoding process, it is not appropriate to apply the data hiding technique to a system that needs to reliably transmit a control signal such as management information.

  On the other hand, a technique for manipulating the encoded signal according to a specific procedure and transmitting information has been studied (see Non-Patent Document 2). In this technique, information is transmitted by incrementing or decrementing the value of the orthogonal transform coefficient by one. However, the encoded signal is a signal from which signal redundancy has been sufficiently removed, and even a slight signal operation greatly affects the encoding quality. Because of these problems, a system for transmitting a control signal using data hiding technology has not been put into practical use.

Toshinobu Yoshino, Toshiyuki Yoshida, “Data hiding based on integer programming problem for DCT coefficients of images”, 2002 Image Coding Symposium (PCSJ), November 11-13, 2002, P-5.06 JCTVC-E428, “Low Complexity Embedding of Information in Transform Coefficients”

  As described above, in the encoding process for the purpose of compression encoding, the control signal is a factor for increasing the code amount, and should not be given as much as possible. On the other hand, the data hiding technique generally embeds predetermined information in the signal before encoding, and when manipulating the signal after encoding, the influence on the encoding quality under ultra-high compression. Is big.

  However, in general, an encoding process for the purpose of compression reduces the average signal expression by using a statistical bias of an input signal, such as a Huffman code. That is, the input signal has a known signal property, and when the encoding quality is significantly deteriorated by manipulating the encoded signal, the signal property is easily broken.

  Therefore, the present invention has been made to solve the above-described problems, and the purpose of the present invention is to increase the amount of code without increasing the amount of code when transmitting a signal such as a video from the encoding side to the decoding side. Is to provide an encoding device, a decoding device, a method, and a program that can be transmitted by superimposing a control signal on this signal.

  In order to achieve the above object, an encoding apparatus according to claim 1 of the present invention is an encoding apparatus that performs orthogonal transform on a transmission target signal and transmits an encoded signal of an orthogonal transform coefficient. An orthogonal transform unit that performs orthogonal transform for each block composed of a plurality of element signals to generate orthogonal transform coefficients, and an orthogonal transform of preset components among the orthogonal transform coefficients generated by the orthogonal transform unit An orthogonal transform coefficient operation unit that manipulates and inverts the coefficient of the coefficient based on the control signal to invert the coefficient and superimposes the control signal on the orthogonal transform coefficient.

  An encoding apparatus according to a second aspect of the present invention is the encoding apparatus according to the first aspect, further comprising a binarized orthogonal transform coefficient operating unit instead of the orthogonal transform coefficient operating unit, and the binarized orthogonal The transform coefficient operation unit manipulates and inverts the most significant bit of the binarized orthogonal transform coefficient obtained by binarizing the orthogonal transform coefficient, and superimposes the control signal on the orthogonal transform coefficient.

  According to a third aspect of the present invention, there is provided a decoding apparatus according to a third aspect of the present invention, which receives the encoded signal of the orthogonal transform coefficient superimposed by the control signal and transmitted by the encoding apparatus of the first aspect, and receives the orthogonal transform coefficient of the encoded signal. A decoding apparatus that performs inverse orthogonal transformation on the original signal to be transmitted, performs inverse orthogonal transformation on the orthogonal transformation coefficient to generate a first element signal, and sets the code of the orthogonal transformation coefficient An inverse orthogonal transform unit that performs inversion by operation, performs inverse orthogonal transform on the inverted orthogonal transform coefficient to generate a second element signal, and a first element signal generated by the inverse orthogonal transform unit, The second difference generated by the inverse orthogonal transform unit is obtained while obtaining a predetermined first calculation result of a difference amount between the decoded signal to be transmitted, a sum of squares of the difference amount, or a correlation value. Element signal and transmission already decoded The difference between the first and second signals, the sum of squares of the difference, or the predetermined second calculation result of the correlation value is obtained, and the first calculation result is compared with the second calculation result. Thus, the comparison / determination is performed in which one of the first element signal and the second element signal is selected as the original transmission target signal, and the control signal superimposed on the orthogonal transform coefficient is determined. And a section.

  According to a fourth aspect of the present invention, there is provided the decoding apparatus according to the fourth aspect, wherein the transmission target signal is composed of a plurality of component signals, and the encoding apparatus according to the first aspect operates a code of an orthogonal transform coefficient in a predetermined component signal to perform the control. When the signal is superimposed, the encoded signal of the orthogonal transform coefficient in the component signal superimposed by the control signal transmitted by the coding device is received and in the other component signal not superimposed by the control signal A decoding device that receives encoded signals of orthogonal transform coefficients, performs inverse orthogonal transform on the orthogonal transform coefficients of each of the encoded signals, and decodes the original signal to be transmitted, the component on which the control signal is superimposed Inverse orthogonal transformation is performed on the orthogonal transformation coefficient of the signal to generate the 1-1st element signal, and the sign of the orthogonal transformation coefficient A first inverse orthogonal transform unit that performs inversion by operating, performs inverse orthogonal transform on the inverted orthogonal transform coefficient to generate a 1-2 element signal, and other component signals on which the control signal is not superimposed Inverse orthogonal transformation is performed on the orthogonal transformation coefficient to generate a 2-1st element signal, the sign of the orthogonal transformation coefficient is manipulated and inverted, and the inverse orthogonal transformation is performed on the inverted orthogonal transformation coefficient. A second inverse orthogonal transform unit that generates an element signal of 2-2, first and first element signals generated by the first inverse orthogonal transform unit, and a transmission target that has already been decoded A predetermined amount of difference between the first and second signals, a sum of squares of the difference amount, or a correlation value, and a first determination result obtained by comparing the calculated results. 2-1 and 2-2 generated by the inverse orthogonal transform unit The difference between the element signal and the signal to be transmitted that has already been decoded, the sum of squares of the difference, or the predetermined calculation result of the correlation value is obtained, and the calculation result is compared and The determination result of 2 is obtained, and based on the first and second determination results, the 1-1 or 1-2 element signal having the same determination result as the 2-1 element signal is used as the original result. A comparison / determination unit that selects a signal to be transmitted and determines a control signal superimposed on the orthogonal transform coefficient.

  According to a fifth aspect of the present invention, there is provided a decoding apparatus according to a fifth aspect of the present invention, which receives the encoded signal of the orthogonal transform coefficient superimposed on the control signal and transmitted by the encoding apparatus of the second aspect, and orthogonal transform coefficient of the encoded signal. Is a decoding device that performs inverse orthogonal transform on the original transmission target signal, decodes the binarized orthogonal transform coefficient decoded from the encoded signal into an orthogonal transform coefficient, and inverse orthogonally transforms the orthogonal transform coefficient Transform to generate a first element signal, add 1 to the most significant bit of the binarized orthogonal transform coefficient, decode the orthogonal transform coefficient from the binarized orthogonal transform coefficient with the 1 added, and An inverse orthogonal transform unit that performs orthogonal transform to generate a second element signal; a difference amount between the first element signal generated by the inverse orthogonal transform unit and a signal to be transmitted that has already been decoded; Or the sum of squares of the difference amount or the correlation value A predetermined first calculation result is obtained, and a difference amount between the second element signal generated by the inverse orthogonal transform unit and a signal to be transmitted that has already been decoded, or a sum of squares of the difference amount, Alternatively, by obtaining the predetermined second calculation result of the correlation values and comparing the first calculation result with the second calculation result, the first element signal or the second element signal A comparison / determination unit that selects one of the element signals as an original transmission target signal and determines a control signal superimposed on the orthogonal transform coefficient.

  According to a sixth aspect of the present invention, there is provided an encoding method according to a sixth aspect of the present invention, wherein the transmission target signal is configured by performing an orthogonal transform on a transmission target signal and transmitting an encoded signal of an orthogonal transform coefficient. Performing orthogonal transform for each block composed of a plurality of element signals and generating orthogonal transform coefficients; among the orthogonal transform coefficients, an orthogonal transform coefficient of a preset component based on the control signal Manipulating and inverting the sign of the transform coefficient and superimposing the control signal on the orthogonal transform coefficient.

  According to a seventh aspect of the present invention, there is provided an encoding method according to the seventh aspect of the present invention, wherein the signal to be transmitted is configured in an encoding method by an encoding device that performs orthogonal transform on a signal to be transmitted and transmits an encoded signal of orthogonal transform coefficients. Performing orthogonal transform for each block composed of a plurality of element signals to generate orthogonal transform coefficients, binarizing the orthogonal transform coefficients, generating binarized orthogonal transform coefficients, and binarized orthogonal Manipulating and inverting the most significant bit of the transform coefficient and superimposing the control signal on the orthogonal transform coefficient.

  According to the decoding method of claim 8 of the present invention, the encoded signal of the orthogonal transform coefficient superimposed by the control signal transmitted by the encoding method of claim 6 is received, and the original orthogonal transform is performed. A decoding method by a decoding device that decodes a signal to be transmitted, the step of performing inverse orthogonal transformation on the orthogonal transformation coefficient of the received encoded signal to generate a first element signal, and a code of the orthogonal transformation coefficient And performing the inverse orthogonal transform on the inverted orthogonal transform coefficient to generate a second element signal, and between the first element signal and the already decoded signal to be transmitted Between the step of obtaining a predetermined first calculation result of the difference amount, or the sum of squares of the difference amount or the correlation value, and the second element signal and the signal to be transmitted that has already been decoded The difference amount, or the difference amount The step of obtaining the predetermined second calculation result of the sum or the correlation value is compared with the first calculation result and the second calculation result, whereby the first element signal or the second calculation result is compared. Selecting one of the element signals as an original transmission target signal and determining a control signal superimposed on the orthogonal transform coefficient.

  According to a ninth aspect of the present invention, there is provided a decoding method according to a ninth aspect, wherein the encoded signal of the orthogonal transform coefficient superimposed by the control signal transmitted by the encoding method of the seventh aspect is received and the orthogonal transform coefficient of the encoded signal is received. Is a decoding method by a decoding device that performs inverse orthogonal transform and decodes the original signal to be transmitted, decoding a binarized orthogonal transform coefficient decoded from the encoded signal into an orthogonal transform coefficient, and the orthogonal transform coefficient The first orthogonal signal is added to the most significant bit of the binarized orthogonal transform coefficient, and the orthogonal transform coefficient is converted from the binarized orthogonal transform coefficient to which 1 is added. Decoding, performing inverse orthogonal transform, and generating a second element signal; a difference amount between the first element signal and a signal to be transmitted that has already been decoded; or a sum of squares of the difference amount Or a predetermined first of the correlation values A step of obtaining an output result; a difference amount between the second element signal and a signal to be transmitted that has already been decoded; a sum of squares of the difference amount; or the predetermined second of the correlation values The step of obtaining the calculation result and the first calculation result and the second calculation result are compared, thereby transmitting the element signal of either the first element signal or the second element signal to the original transmission. Selecting a target signal and determining a control signal superimposed on the orthogonal transform coefficient.

  An encoding program according to a tenth aspect of the present invention causes a computer to function as the encoding device according to the first or second aspect.

  A decoding program according to an eleventh aspect of the present invention causes a computer to function as the decoding device according to any one of the third to fifth aspects.

  As described above, according to the present invention, when a signal such as video is transmitted from the encoding side to the decoding side, the control signal is superimposed on the video signal and transmitted without increasing the code amount. It becomes possible. Further, by performing signal correction at the time of decoding, it is possible to transmit a control signal without deteriorating the quality of a signal such as a video, and it is possible to realize higher compression encoding.

It is a block diagram which shows schematic structure of the encoding apparatus by the 1st Embodiment (Example 1) of this invention. It is an example of the program which shows the process of an orthogonal transformation coefficient operation part. It is a flowchart which shows the process of an orthogonal transformation coefficient operation part. It is a block diagram which shows schematic structure of the decoding apparatus by Example 1. FIG. It is a flowchart which shows the process of an inverse orthogonal transformation part. It is a figure which shows the positional relationship of the pixel signal in a 4x4 pixel block. 7 is an example of a program illustrating processing of a comparison / determination unit according to the first embodiment. 6 is a flowchart illustrating processing of a comparison / determination unit according to the first embodiment. It is a block diagram which shows schematic structure of the decoding apparatus by the 2nd Embodiment (Example 2) of this invention. 10 is a flowchart illustrating processing of a comparison / determination unit according to the second embodiment. It is a block diagram which shows schematic structure of the decoding apparatus by the 3rd Embodiment (Example 3) of this invention. It is a block diagram which shows schematic structure of the encoding apparatus by the 4th Embodiment (Example 4) of this invention. It is a flowchart which shows the process of a binarization orthogonal transformation coefficient operation part. It is a block diagram which shows schematic structure of the decoding apparatus by Example 4. It is a flowchart which shows the process of an inverse orthogonal transformation part.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the first to third embodiments, taking a video signal to be transmitted as an example, when the encoded video signal is operated, the video signal is intentionally operated and decoded so that the statistical bias of the input signal is significantly broken. This is an example in which unnaturalness of statistical bias is sometimes detected and a video signal is restored by a predetermined procedure. Specifically, the orthogonal transform coefficient information (code information or / and value information) of the video signal is manipulated. In encoding video signals, it is known that the correlation between adjacent pixels of the video signal is high. Therefore, MPEG-2 or H.264 In block coding in which an image in accordance with the H.264 / AVC standard is divided into small regions and coded, the correlation between adjacent pixels is high at the block boundary. When the correlation between pixel signals in this region becomes extremely low, a significant signal change occurs at the block boundary, and streak-like deterioration is detected during decoding. Such deterioration is called block distortion, and encoding processing is performed so that normal block distortion does not occur. Therefore, in the encoding device and the decoding device according to the embodiment of the present invention, the control signal is obtained by manipulating the orthogonal transform coefficient information and performing a process of extremely reducing / not causing the correlation between adjacent pixels in the boundary portion at the time of decoding. Transmit the superimposed information.

  Even if the orthogonal transform coefficient is divided into the magnitude (absolute value) and the sign of the value, and the sign is manipulated, the amount of encoded information of the orthogonal transform coefficient is almost unchanged. It does n’t change that much. Also, when the value of the orthogonal transform coefficient is manipulated, that is, when the most significant bit signal of the orthogonal transform coefficient in the variable bit length signal binarized for entropy coding is inverted, the bit amount is also increased. Since there is almost no influence, the encoded information amount of the orthogonal transform coefficient does not change so much. Furthermore, by manipulating the code or / and value of the orthogonal transform coefficient in units of blocks, the overall bit fluctuation becomes 0 on average, so that information superimposed with the control signal is transmitted without increasing the amount of code. can do.

[Example 1 / Encoding device]
First, the encoding apparatus according to the first embodiment will be described. FIG. 1 is a block diagram illustrating a schematic configuration of the encoding apparatus according to the first embodiment. The encoding device 1 is a device that superimposes a control signal s by operating a code of an orthogonal transform coefficient of an image and transmits an encoded signal, and includes an orthogonal transform unit 11, an orthogonal transform coefficient operation unit 12, and an entropy code. The conversion unit 13 is provided. FIG. 1 shows only the components related to the present invention among the components of the encoding device 1.

  The orthogonal transform unit 11 receives an image (video signal) composed of pixel signals, performs orthogonal transform processing on the input pixel signals, generates a two-dimensional orthogonal transform coefficient, and generates an orthogonal transform coefficient operation unit 12. Output to. That is, the orthogonal transform unit 11 generates orthogonal transform coefficients of a plurality of components (bases) by orthogonal transform for each block composed of a plurality of pixel signals constituting the video signal. As orthogonal transform processing, for example, discrete cosine transform (DCT), discrete sine transform (DST), or the like is performed. Note that the present invention does not limit the type of orthogonal transform processing.

  The orthogonal transform coefficient operation unit 12 is provided between the orthogonal transform unit 11 and the entropy coding unit 13, and operates the code of the orthogonal transform coefficient based on the control signal s (= 0, 1). Invert. The orthogonal transform coefficient operation unit 12 inputs a two-dimensional orthogonal transform coefficient from the orthogonal transform unit 11 and also receives a control signal s to be superimposed on the orthogonal transform coefficient, and the input two-dimensional orthogonal transform coefficient is zigzag scanned or the like. Serialized by processing to generate a one-dimensional orthogonal transform coefficient. Then, based on the input control signal s, the orthogonal transform coefficient operation unit 12 inverts the sign of the orthogonal transform coefficient of the (0, 0) component, for example, or the sign is inverted and the sign is inverted. Alternatively, the orthogonal transform coefficient with the code as it is is output to the entropy encoding unit 13. Thereby, the control signal s is superimposed on the orthogonal transform coefficient, and the orthogonal transform coefficient on which the control signal s is superimposed is output to the entropy encoding unit 13.

  FIG. 2 is an example of a program (C language program) showing processing of the orthogonal transform coefficient operation unit 12, and FIG. 3 is a flowchart showing processing of the orthogonal transform coefficient operation unit 12, and the program of FIG. It is represented by. The input coefficient sequence serialized in the orthogonal transform coefficient operation unit 12 is a [i] (i = 0, 1,..., N−1), and the (0, 0) component is orthogonal based on the control signal s. B [i] (i = 0, 1,..., N−1) is performed on the output coefficient sequence in which the sign of the transform coefficient is inverted, or the output coefficient string in which the sign is left as it is, and a [0], b [0 ] Is an orthogonal transform coefficient of the (0, 0) component.

  First, the orthogonal transform coefficient operation unit 12 inputs an orthogonal transform coefficient from the orthogonal transform unit 11 and also receives a control signal s (= 0, 1) (step S301), serializes the orthogonal transform coefficient, and inputs an input sequence a. [I] (i = 0, 1,..., N−1) is generated (step S302). Then, the orthogonal transform coefficient operation unit 12 determines whether or not the control signal s is 1 (step S303), and determines that the control signal s is 1 (step S303: Y), (0, 0). ) The sign of the orthogonal transform coefficient a [0] of the component is inverted, and a new orthogonal transform coefficient (orthogonal transform coefficient with the sign inverted) b [0] of the (0, 0) component is generated (step S304). That is, the process b [0] = − a [0] is performed.

  On the other hand, when it is determined in step S303 that the control signal s is not 1 (the control signal s is 0) (step S303: N), the orthogonal transform coefficient operating unit 12 is the orthogonal transform coefficient of the (0, 0) component. An orthogonal transform coefficient b [0] is generated with the code of a [0] as it is (step S305). That is, the sign inversion process is not performed on the orthogonal transform coefficient a [0], and the process of b [0] = a [0] is performed. Then, the orthogonal transform coefficient operation unit 12 proceeds from step S304 and step S305, and the orthogonal transform coefficient a [i] (i = 1, 2,..., N−1) other than the (0, 0) component. The sign inversion process is not performed for the orthogonal transformation coefficient b [i] = a [i] is generated (step S306). Then, the orthogonal transform coefficient operation unit 12 supplies the orthogonal transform coefficient b [i] (i = 0, 1,..., N−1), that is, the orthogonal transform coefficient on which the control signal s is superimposed, to the entropy encoding unit 13. Output (step S307).

  Returning to FIG. 1, the entropy encoding unit 13 receives the orthogonal transform coefficient on which the control signal s is superimposed from the orthogonal transform coefficient operation unit 12 and performs entropy encoding. The orthogonal transform coefficient entropy-encoded by the entropy encoding unit 13 is transmitted as an encoded signal to the decoding device 2-1 described later.

  As described above, according to the encoding device 1 of the first embodiment, when the control signal s = 1, the orthogonal transform coefficient operation unit 12 inverts the sign of the (0, 0) component orthogonal transform coefficient and performs control. When the signal s = 0, the orthogonal transform coefficient on which the control signal s is superimposed is generated by keeping the sign of the orthogonal transform coefficient of the (0, 0) component as it is. Here, in general, when a video signal is encoded, there is a property that there is a lot of low-frequency information and low-frequency information in the orthogonal transform coefficient. The (0, 0) component, which is the first orthogonal transform coefficient generated by the orthogonal transform process, has a particularly large amount of information, and the orthogonal transform coefficient is set to 0 unless non-coding control is performed without sending any orthogonal transform coefficient. Very rarely. Further, the orthogonal transform coefficient of the (0, 0) component is the lowest frequency information, and in the case of the DCT used in the present embodiment, the signal fluctuation is extremely large at the coding block boundary because the sign is inverted. Become. Utilizing such a property of the video signal, by operating the code of the orthogonal transform coefficient in the encoding device 1, an orthogonal transform coefficient on which the control signal s is superimposed is generated and sent to the decoding device 2-1 described later. Is transmitted. Then, the decoding device 2-1 described later receives the encoded signal of the orthogonal transform coefficient on which the control signal s is superimposed, and extracts the control signal s based on the difference amount of the pixel signal at the block boundary. Details of the decoding device 2-1 will be described later. Thereby, when transmitting a video signal from the encoding apparatus 1 to the decoding apparatus 2-1 described later, the control signal s superimposed on the video signal can be transmitted without increasing the encoding amount.

[Example 1 / Decoding Device]
Next, the decoding device according to the first embodiment will be described. FIG. 4 is a block diagram illustrating a schematic configuration of the decoding apparatus according to the first embodiment. The decoding device 2-1 is a device that receives a coded signal from the coding device 1 and generates a decoded image, and extracts a control signal s superimposed on the orthogonal transform coefficient. The decoding device 2-1, the entropy decoding unit 21, the inverse orthogonal A conversion unit 22 and a comparison / determination unit 23 are provided. FIG. 4 shows only the components related to the present invention among the components of the decoding device 2-1.

  When the decoding device 2-1 receives the encoded signal transmitted from the encoding device 1, the entropy decoding unit 21 receives the encoded signal, performs entropy decoding, and performs orthogonal transform coefficient b [on which the control signal s is superimposed. i] is output to the inverse orthogonal transform unit 22.

  The inverse orthogonal transform unit 22 receives the orthogonal transform coefficient b [i] on which the control signal s is superimposed, leaves the code as it is for the (0, 0) component orthogonal transform coefficient b [0], and performs an inverse orthogonal transform process. To generate a pixel signal (the pixel signal as it is), invert the sign for the orthogonal transform coefficient b [0] of the (0, 0) component, perform an inverse orthogonal transform process, and perform the pixel signal (inverted) Pixel signal). Then, the inverse orthogonal transform unit 22 outputs the pixel signal as it is and the inverted pixel signal to the comparison / determination unit 23. As the inverse orthogonal transform process, for example, inverse discrete cosine transform (IDCT), inverse discrete sine transform (IDST), or the like is performed. Note that the present invention does not limit the type of inverse orthogonal transform processing.

  FIG. 5 is a flowchart showing the processing of the inverse orthogonal transform unit 22. First, the inverse orthogonal transform unit 22 receives the orthogonal transform coefficient b [i] from the entropy decoding unit 21 (step S501). Then, the inverse orthogonal transform unit 22 leaves the code as it is for the orthogonal transform coefficient b [0] of the (0,0) component (step S502), and the orthogonal transform coefficients b [0], b [1],. .., B [N−1] is subjected to inverse orthogonal transform processing to generate a pixel signal (as-is pixel signal) (step S503). Further, the inverse orthogonal transform unit 22 inverts the sign with respect to the orthogonal transform coefficient b [0] of the (0, 0) component to generate -b [0] (step S504), and generates the orthogonal transform coefficient -b [ 0], b [1],..., B [N−1] are subjected to inverse orthogonal transform processing to generate a pixel signal (inverted pixel signal) (step S505). Then, the inverse orthogonal transform unit 22 outputs the pixel signal generated in step S503 (as-is pixel signal) and the pixel signal generated in step S505 (inverted pixel signal) to the comparison / determination unit 23 (step). S506).

  Returning to FIG. 4, the comparison / determination unit 23 is generated from the inverse orthogonal transform unit 22 by the inverse orthogonal transform process while keeping the sign of the orthogonal transform coefficient of the pixel signal ((0, 0) component as it is. Pixel signal) and inverted pixel signal (pixel signal generated by inverting the sign of the orthogonal transform coefficient of the (0,0) component and generated by the inverse orthogonal transform process) and the adjacent pixel signal at the block boundary (the comparison) / Among the pixel signals of the decoded image that has already been processed and output by the determination unit 23, the closest pixel signal in the adjacent block to be processed) is input. Then, the comparison / determination unit 23 calculates the difference amount (absolute value of the difference amount) between the pixel signal as it is and the inverted pixel signal and the adjacent pixel signal, and compares the difference amount to calculate the difference amount. A small pixel signal (an intact pixel signal or an inverted pixel signal) is selected and output as a pixel signal of a decoded image. The comparison / determination unit 23 determines and outputs the control signal s = 0 when the pixel signal as it is is selected as the pixel signal having a small difference amount. Thereby, the control signal s = 0 is extracted. On the other hand, when selecting the inverted pixel signal as the pixel signal having a small difference amount, the comparison / determination unit 23 determines and outputs the control signal s = 1. Thereby, the control signal s = 1 is extracted.

  The comparison / determination unit 23 does not perform the above-described processing for extracting the control signal s for the video signal of the first block. This is because there is no adjacent pixel signal for the video signal of the first block. In this case, the orthogonal transform coefficient operation unit 12 of the encoding device 1 does not perform an operation on the code of the orthogonal transform coefficient for the video signal of the first block. In addition, the comparison / determination unit 23 selects a pixel signal with a small difference amount by comparing the difference amount and outputs it as a pixel signal of a decoded image. However, depending on the system, the pixel signal with a large difference amount is selected. It is possible that Whether the comparison / determination unit 23 selects a small pixel signal or a large pixel signal is set in advance according to the relative relationship determined by the system. The same applies to comparison / determination units 25 and 26 of Example 2, which will be described later, comparison / determination units 28-1, 28-2 and 29 of Example 3, and comparison / determination unit 23 of Example 4.

  6 is a diagram showing the positional relationship of pixel signals in a 4 × 4 pixel block, FIG. 7 is an example of a program (program in C language) showing processing of the comparison / determination unit 23, and FIG. FIG. 8 is a flowchart showing the processing of the comparison / determination unit 23, and shows the program of FIG. 7 in a flowchart. The pixel signal as input by the comparison / determination unit 23 from the inverse orthogonal transform unit 22 is B [i] [j], the inverted pixel signal is C [i] [j], and the adjacent pixel signal is d [j]. , E [i]. In addition, the absolute value sum of the difference amounts between the pixel signal B [i] [j] and the adjacent pixel signals d [j], e [i] is S [0], and the pixel signal C [i] [j] And S [1] is the absolute value sum of the difference amounts between the adjacent pixel signals d [j] and e [i]. i = 0-3, j = 0-3.

  In FIG. 6, the pixel signal B [0] [0], C [0] [0] exists in the number 1 in the 4 × 4 pixel block, and the pixel signal B [0] [1] exists in the numbers 2-4. ], C [0] [1] to B [0] [3], C [0] [3]. Similarly, pixel signal B [1] [0], C [1] [0] exists in number 5, and pixel signal B [3] [0], C [3] [0] exists in numbers 13-16. 0] to B [3] [3] and C [3] [3] exist. The adjacent pixel signals d [j] = d [0] to d [3] are adjacent pixel signals for the pixel signals of numbers 1 to 4, and the adjacent pixel signals e [i] = e [0] to e [ 3] are adjacent pixel signals for the pixel signals of numbers 1, 5, 9, and 13.

  7 and 8, S [0] and S [1] indicate the sum of absolute values of the calculated difference amounts. First, the comparison / determination unit 23 inputs the pixel signal B [i] [j] as it is and the inverted pixel signal C [i] [j] from the inverse orthogonal transform unit 22 and also the adjacent pixel signal d at the block boundary. [J] and e [i] are input (step S801). Then, the comparison / determination unit 23 calculates the sum of absolute values S [0], S of the difference amounts between the pixel signals B [i] [j], C [i] [j] and the adjacent pixel signal d [j]. [1] is calculated, the absolute value sums S [0] and S [1] of the calculated differences are added, and the pixel signals B [i] [j] and C [i] [j] are added. The absolute value sums S [0] and S [1] of the difference amounts between the pixel value and the adjacent pixel signal e [i] are respectively calculated, and the absolute value sums S [0] and S [1] of the calculated difference amounts are calculated. ], And the sum of absolute values S [0] and S [1] of the difference amount obtained by summing the addition results of the two is obtained (step S802).

  The comparison / determination unit 23 compares the absolute value sums S [0] and S [1] of the difference amounts obtained in step S802, and the absolute value sum S [0] of the difference amounts is the absolute value sum S of the difference amounts. It is determined whether or not it is [1] or more (step S803), and when it is determined that the absolute value sum S [0] of the difference amount is equal to or greater than the absolute value sum S [1] of the difference amount (step S803: Y ), Selecting and outputting the pixel signal C [i] [j] corresponding to the absolute value sum S [1] of the difference amount smaller than or equal to the absolute value sum S [0] of the difference amount, that is, the inverted pixel signal At the same time, the control signal s = 1 is determined and output (step S804). On the other hand, when the comparison / determination unit 23 determines in step S803 that the absolute value sum S [0] of the difference amount is not equal to or greater than the absolute value sum S [1] of the difference amount (step S803: N), the smaller one is determined. The pixel signal B [i] [j] corresponding to the sum of absolute values S [0] of the difference amounts, that is, the pixel signal as it is is selected and output, and the control signal s = 0 is determined and output (step S805). ).

  As described above, according to the decoding device 2-1 of the first embodiment, the inverse orthogonal transform unit 22 inputs the orthogonal transform coefficient on which the control signal s is superimposed, and the (0, 0) component orthogonal transform coefficient is input. Then, the inverse orthogonal transformation process is performed with the code as it is to generate a pixel signal (the original pixel signal), and the sign is inverted with respect to the orthogonal transformation coefficient of the (0, 0) component, and the inverse orthogonal transformation process is performed. A pixel signal (inverted pixel signal) is generated. Then, the comparison / determination unit 23 calculates a difference amount between the pixel signal as it is and the inverted pixel signal and an adjacent pixel signal at the block boundary, and a pixel signal with a small difference amount (a pixel signal as it is or an inverted pixel signal). Signal) is output as a pixel signal of the decoded image, and when the pixel signal is selected as it is, the control signal s = 0 is determined and output, and when the inverted pixel signal is selected, the control signal s = 1 was judged and output. Thereby, when transmitting a video signal from the encoding apparatus 1 to the decoding apparatus 2-1, the control signal s superimposed on the video signal can be extracted. In the encoding method, the control signal s can be transmitted without increasing the code amount of the control signal s, which causes the code amount to increase. In the decoding device 2-1, the video signal is corrected by performing signal correction, that is, by performing inverse orthogonal transform by inverting the sign of the orthogonal transform coefficient and performing the inverse orthogonal transform process without changing the code. Therefore, the control signal s can be transmitted without quality degradation, and higher-compression encoding can be realized.

  That is, in the decoding device 2-1, the transmitted control signal s can be restored without increasing the code amount. In addition, the control signal s can be superimposed on a color difference signal having a higher pixel correlation, instead of being superimposed on a luminance signal with high visual sensitivity. That is, when the encoding device 1 operates the encoded signal, the signal is intentionally manipulated so that the statistical bias of the input signal is significantly broken, and the decoding device 2-1 By detecting the unnaturalness and restoring the control signal s according to a predetermined procedure, quality deterioration of the video signal transmitted from the encoding device 1 to the decoding device 2-1 is prevented and superimposed on the video signal. It is possible to accurately extract the transmitted control signal s.

[Example 2]
Next, Example 2 will be described. As described above, the first embodiment extracts the control signal s by comparing and determining the component (either signal luminance or two-color difference signal) with reference to the difference amount between adjacent pixel signals. On the other hand, in the second embodiment, a video signal in which one pixel is composed of two component signals is taken as an example, and a pixel signal between adjacent pixel signals in a block of component signals in which the sign of the orthogonal transformation coefficient is manipulated. Is compared with the difference amount between the pixel signal at the same position in the block of the other component signal and the adjacent pixel signal, and the control signal s is extracted. According to the second embodiment, since the correlation between the pixel signals in the two component signals is extremely high, the control signal s can be extracted with higher accuracy than in the first embodiment. In particular, this is effective when the magnitude of the comparison result of the difference amount between the pixel signal as it is and the inverted pixel signal and the adjacent pixel signal is not constant, such as a prediction difference signal. The configuration and processing on the encoding side are the same as those of the encoding device 1 of the first embodiment shown in FIG. Also, the difference amount indicates the absolute value of the difference amount, as in the first embodiment.

  A decoding apparatus according to the second embodiment will be described. FIG. 9 is a block diagram illustrating a schematic configuration of the decoding apparatus according to the second embodiment. The decoding device 2-2 is a device that receives a coded signal from the coding device 1 and generates a decoded image, and extracts a control signal s superimposed on the orthogonal transformation coefficient of the component signal 1, and performs inverse orthogonal transformation. Units 24-1 and 24-2 and comparison / determination units 25 and 26 are provided. In FIG. 9, the entropy decoding unit is omitted, and only the components related to the present invention among the components of the decoding device 2-2 are shown.

  The inverse orthogonal transform unit 24-1 receives the component signal 1 that is an orthogonal transform coefficient on which the control signal s is superimposed. To generate a pixel signal (the pixel signal as it is), invert the sign with respect to the orthogonal transform coefficient of the (0,0) component, perform an inverse orthogonal transform process, and generate a pixel signal (inverted pixel signal) Generate. Then, the inverse orthogonal transform unit 24-1 outputs the pixel signal as it is and the inverted pixel signal to the comparison / determination unit 26.

  The inverse orthogonal transform unit 24-2 performs the same processing as the inverse orthogonal transform unit 24-1. Specifically, the inverse orthogonal transform unit 24-2 inputs the component signal 2 which is an orthogonal transform coefficient on which the control signal s is not superimposed, and directly codes the (0, 0) component orthogonal transform coefficient. Inverse orthogonal transform processing is performed to generate a pixel signal (as-is pixel signal), the sign is inverted with respect to the orthogonal transform coefficient of the (0, 0) component, and inverse orthogonal transform processing is performed to obtain the pixel signal ( Inverted pixel signal) is generated. The inverse orthogonal transform unit 24-2 then outputs the pixel signal (correct decoded signal) and the inverted pixel signal (incorrect decoded signal) as they are to the comparison / determination unit 25.

  The encoding device 1 transmits an encoded signal in the orthogonal transform coefficient of the component signal 1 on which the control signal s is superimposed, and also encodes in an orthogonal transform coefficient of the component signal 2 on which the control signal s is not superimposed. Transmit the signal. That is, the sign operation is not performed on the orthogonal transform coefficient of the component signal 2. The decoding device 2-2 receives the encoded signal in the orthogonal transform coefficient of the component signal 1 on which the control signal s is superimposed and the encoded signal in the orthogonal transform coefficient of the component signal 2 on which the control signal s is not superimposed. A decoding unit (not shown) performs entropy decoding on these encoded signals, outputs a component signal 1 that is an orthogonal transform coefficient on which the control signal s is superimposed, to the inverse orthogonal transform unit 24-1, and controls the control signal s. Is output to the inverse orthogonal transform unit 24-2. Therefore, the pixel signal as it is output from the inverse orthogonal transform unit 24-2 becomes a correct decoded signal, and the inverted pixel signal output from the inverse orthogonal transform unit 24-2 becomes an incorrect decoded signal. As described above, the component signal 2 is because the sign of the orthogonal transform coefficient is not operated in the encoding device 1.

  The comparison / determination unit 25 inputs the pixel signal (correct decoded signal) and the inverted pixel signal (incorrect decoded signal) as it is from the inverse orthogonal transform unit 24-2, and also inputs the adjacent pixel signal at the block boundary. The difference amount between the pixel signal as it is and the inverted pixel signal and the adjacent pixel signal (the difference amount of the correct decoded signal and the difference amount of the incorrect decoded signal) is calculated. When the difference amount of the correct decoded signal is equal to or less than the difference amount of the incorrect decoded signal, the comparison / determination unit 25 indicates that the difference amount is small (the smaller difference amount is the correct decoded signal) as the determination result. If the difference amount of the correct decoded signal is larger than the difference amount of the incorrect decoded signal, the difference amount is large (the larger the difference amount is the correct decoded signal). (Determination result indicating presence) is output to the comparison / determination unit 26. The comparison / determination unit 25 outputs the input pixel signal as it is as a pixel signal of the decoded image.

  FIG. 10 is a flowchart showing the processing of the comparison / determination unit 26. In FIG. 10, the difference amount indicates the sum of absolute values of the difference amounts. Referring to FIGS. 9 and 10, comparison / determination unit 26 inputs the pixel signal as it is and the inverted pixel signal from inverse orthogonal transform unit 24-1 and also determines the determination result (difference amount) from comparison / determination unit 25. Large, small), and adjacent pixel signals at the block boundary are input (step S901). Then, the comparison / determination unit 26 calculates the difference between the pixel signal as it is and the inverted pixel signal and the adjacent pixel signal (the difference between the pixel signal as it is and the difference between the inverted pixel signals) (step) In step S902, it is determined whether the determination result is a large difference amount or a small difference amount (step S903).

  When the comparison / determination unit 26 determines in step S903 that the determination result is a large difference amount (step S903: large difference amount), the pixel signal inverted from the difference amount of the pixel signal as calculated in step S902 is inverted. Are compared with each other to select a pixel signal (a pixel signal as it is or an inverted pixel signal) having a large difference (step S904). On the other hand, when the comparison / determination unit 26 determines in step S903 that the determination result is a small difference amount (step S903: small difference amount), the pixel signal having a small difference amount (an intact pixel signal or an inverted pixel signal). ) Is selected (step S905). Then, the comparison / determination unit 26 outputs the selected pixel signal as a pixel signal of the decoded image (step S906).

  The comparison / determination unit 26 determines whether or not the selected pixel signal is the pixel signal as it is (step S907). When it is determined that the selected pixel signal is not the pixel signal as it is (step S907: N), the control signal s = 1. Is determined and output (step S908). On the other hand, when the comparison / determination unit 26 determines in step S907 that the selected pixel signal is the pixel signal as it is (step S907: Y), the comparison / determination unit 26 determines and outputs the control signal s = 0 (step S909). . Thereby, the control signal s = 1, 0 is extracted.

  As described above, according to the decoding device 2-2 of the second embodiment, the inverse orthogonal transform unit 24-1 performs the inverse orthogonal while maintaining the code for the orthogonal transform coefficient of the component signal 1 on which the control signal s is superimposed. A conversion process is performed to generate a pixel signal (as-is pixel signal), a sign is inverted with respect to the orthogonal transform coefficient of the (0, 0) component, an inverse orthogonal transform process is performed, and a pixel signal (inverted pixel signal) ) And the inverse orthogonal transform unit 24-2 performs the same processing as the inverse orthogonal transform unit 24-1 on the orthogonal transform coefficient of the component signal 2 on which the control signal s is not superimposed. The comparison / determination unit 25 also compares the difference between the pixel signal (correct decoded signal) and the inverted pixel signal (incorrect decoded signal) from the inverse orthogonal transform unit 24-2 and the adjacent pixel signal at the block boundary. When the amount (correct decoded signal difference amount, incorrect decoded signal difference amount) is calculated, and the correct decoded signal difference amount is equal to or smaller than the incorrect decoded signal difference amount, a small difference amount is generated as a determination result. When the difference amount of the correct decoded signal is larger than the difference amount of the incorrect decoded signal, a large difference amount is generated as a determination result. Further, the comparison / determination unit 26 receives the pixel signal as it is from the inverse orthogonal transform unit 24-1 and the difference amount between the inverted pixel signal and the adjacent pixel signal (the difference amount of the pixel signal as it is, the inverted pixel signal). If the determination result is a large difference amount, a pixel signal having a large difference amount is selected from the difference amount of the pixel signal as it is and the difference amount of the inverted pixel signal, and the determination result is the difference amount. When the pixel signal is small, a pixel signal with a small difference amount is selected, and when the selected pixel signal is not the pixel signal as it is, the control signal s = 1 is determined and output, and the selected pixel signal is the pixel signal as it is The control signal s = 0 is determined and output. As a result, the control signal s = 0, 1 superimposed on the orthogonal transform coefficient can be extracted. Accordingly, as in the first embodiment, in the encoding method, the control signal s is not increased without increasing the code amount of the control signal s that causes the code amount to increase, and without accompanying the quality deterioration of the video signal. It is possible to transmit, and higher-compression encoding can be realized.

  In general, when the number of orthogonal transform coefficients for performing a code operation in the encoding device 1 increases, the possibility of erroneous detection of the control signal s in the decoding device 2-2 increases. According to the decoding device 2-2 of the second embodiment, the control signal s is extracted by the difference amount comparison process using the component signal 2 on which the control signal s is not superimposed, so that the code operation is performed. Even when the number of orthogonal transform coefficients is increased, the erroneous detection of the control signal s can be improved.

  The comparison / determination unit 25 calculates the difference amount (difference amount of the correct decoded signal) between the pixel signal (correct decoded signal) as it is and the adjacent pixel signal, and the comparison / determination unit 26 determines the pixel as it is. The difference amount between the signal and the inverted pixel signal and the adjacent pixel signal (the difference amount of the pixel signal as it is, the difference amount of the inverted pixel signal) is calculated, and the difference amount between the correct decoded signal and the pixel signal as it is The difference amount and the difference amount of the inverted pixel signal may be compared, and a pixel signal (an unchanged pixel signal or an inverted pixel signal) having a closer difference amount may be selected as the original transmission target signal. That is, if the difference amount of the correct decoded signal is close to the difference amount of the pixel signal as it is, the pixel signal is selected as it is, and if it is close to the difference amount of the inverted pixel signal, the inverted pixel signal is selected. The same applies to Example 3 described later. Further, as will be described later, the same applies to the case where a value indicating the sum of squares of the difference amount or a value (correlation coefficient) indicating the correlation is used instead of the difference amount.

Example 3
Next, Example 3 will be described. As described above, in the second embodiment, the control signal s is extracted by comparison and determination processing using two component signals. The third embodiment extends the second embodiment and extracts the control signal s by comparison and determination processing using three component signals. For example, there is application to color video signals. The configuration and processing on the encoding side are the same as those of the encoding device 1 of the first embodiment shown in FIG. The difference amount indicates the absolute value of the difference amount, as in the first and second embodiments.

  A decoding apparatus according to the third embodiment will be described. FIG. 11 is a block diagram illustrating a schematic configuration of the decoding apparatus according to the third embodiment. The decoding device 2-3 is a device that receives a coded signal from the coding device 1 to generate a decoded image, and extracts a control signal s superimposed on the orthogonal transformation coefficient of the component signal 1, and performs inverse orthogonal transformation. Units 27-1 to 27-3 and comparison / determination units 28-1, 28-2, and 29. In FIG. 11, the entropy decoding unit is omitted, and only the components related to the present invention among the components of the decoding device 2-3 are shown.

  The inverse orthogonal transform unit 27-1 receives the component signal 1 that is an orthogonal transform coefficient on which the control signal s is superimposed, performs the same processing as the inverse orthogonal transform unit 24-1 illustrated in FIG. The inverted pixel signal is output to the comparison / determination unit 29.

  The inverse orthogonal transform units 27-2 and 27-3 receive the component signals 2 and 3 that are orthogonal transform coefficients on which the control signal s is not superimposed, and are the same as the inverse orthogonal transform unit 24-2 illustrated in FIG. Processing is performed, and the pixel signal (correct decoded signal) and the inverted pixel signal (incorrect decoded signal) are output to the comparison / determination units 28-1 and 28-2.

  The comparison / determination units 28-1 and 28-2 receive the pixel signal (correct decoded signal) and the inverted pixel signal (incorrect decoded signal) from the inverse orthogonal transform units 27-2 and 27-3. The adjacent pixel signal at the block boundary is input, the same processing as that of the comparison / determination unit 25 shown in FIG.

  The comparison / determination unit 29 receives the pixel signal as it is and the inverted pixel signal from the inverse orthogonal transform unit 27-1, and also determines the determination result (large difference amount, small) from the comparison / determination units 28-1 and 28-2. And an adjacent pixel signal at the block boundary is input. Then, the comparison / determination unit 29 performs the same processing as that of the comparison / determination unit 26 shown in FIG. 9, and determines and outputs the control signal s. Here, since the determination results input from the comparison / determination units 28-1 and 28-2 are usually the same results, the comparison / determination unit 29 uses one of the predetermined determination results to control the control signal. Extract s.

  When the comparison / determination units 28-1 and 28-2 generate the determination result, the difference between the difference amount of the correct decoded signal and the difference amount of the incorrect decoded signal is equal to or less than a predetermined threshold value. Alternatively, it may be generated that the determination result is not determined and output to the comparison / determination unit 29. In this case, the comparison / determination unit 29 inputs the determination result (difference amount large or small) from either of the comparison / determination units 28-1 and 28-2, and the other comparison / determination units 28-1 and 28-. When a determination result that cannot be determined is input from 2, the determination result that cannot be determined is ignored, and the control signal s is extracted based on the determination result (difference amount is large or small). On the other hand, the comparison / determination unit 29 performs a predetermined error process and does not extract the control signal s when the determination result that cannot be determined is input from both of the comparison / determination units 28-1 and 28-2.

  Further, the comparison / determination units 28-1 and 28-2 may output the difference amount of the pixel signal as it is and the difference amount of the inverted pixel signal to the comparison / determination unit 29. In this case, the comparison / determination unit 29 inputs the difference amount of the pixel signal as it is and the difference amount of the inverted pixel signal from the comparison / determination units 28-1 and 28-2, and the difference amount of the input pixel signal as it is. Is added to obtain the total difference amount of the pixel signal as it is, and the difference amount of the input inverted pixel signal is added to obtain the total difference amount of the inverted pixel signal. If the total difference amount of the decoded signal) is equal to or less than the total difference amount of the inverted pixel signal (total difference amount of the incorrect decoded signal), a small difference amount is generated as a determination result, and the total difference amount of the pixel signal as it is If the (total difference amount of correct decoded signal) is larger than the total difference amount of inverted pixel signals (total difference amount of incorrect decoded signal), a large difference amount is generated as a determination result, and based on this determination result. Te, may be extracted control signal s by the same processing as described above.

  In the third embodiment, the control signal s is extracted by the comparison and determination process using three component signals. However, the control signal s may be extracted using more than three component signals. Good.

  As described above, according to the decoding apparatus 2-3 of the third embodiment, as in the first and second embodiments, in the encoding scheme, the code amount of the control signal s that causes the code amount to increase is increased. In addition, the control signal s can be transmitted without deteriorating the quality of the video signal, and higher-compression encoding can be realized. Similarly to the second embodiment, erroneous detection of the control signal s can be improved even when the number of orthogonal transform coefficients on which the code operation is performed increases.

[Embodiment 4 / Encoding device]
Next, an encoding apparatus according to the fourth embodiment will be described. As described above, in the first to third embodiments, the control signal s is superimposed by manipulating the sign of the orthogonal transform coefficient of the image. On the other hand, in Example 4, the control signal s is superimposed by manipulating the value of the orthogonal transform coefficient of the image. FIG. 12 is a block diagram illustrating a schematic configuration of the encoding apparatus according to the fourth embodiment. The encoding device 3 superimposes the control signal s by operating the value of the orthogonal transform coefficient of the image (the signal sequence of the orthogonal transform coefficient binarized for entropy coding), and transmits the encoded signal. The apparatus includes an orthogonal transform unit 11, a binarization unit 14, a binarized orthogonal transform coefficient operation unit 15, and an entropy encoding unit 13. FIG. 12 shows only the components related to the present invention among the components of the encoding device 3.

  The orthogonal transform unit 11 and the entropy coding unit 13 are the same as those in the first embodiment shown in FIG. The binarization unit 14, the binarized orthogonal transform coefficient operation unit 15 and the entropy coding unit 13 manipulate the binarized orthogonal transform coefficient obtained in the entropy encoding process and operate the binarized orthogonal transform coefficient. Are encoded by arithmetic encoding such as CABAC and CAVLC.

  The binarization unit 14 inputs the orthogonal transform coefficient from the orthogonal transform unit 11, binarizes the orthogonal transform coefficient by a binarization method, generates a binary orthogonal transform coefficient having a variable bit length, and binarized orthogonal The result is output to the conversion coefficient operation unit 15. For example, as a binarization technique, unary binarization, truncated unary binarization, or the like is used. When the binarization unit 14 uses the unary binarization method as a binarization method, for example, 0, 1, 2, 3 orthogonal transform coefficients are converted into 0, 10, 110, 1110 binary signal sequences. Each is converted into a certain binarized orthogonal transform coefficient. Since the techniques of unary binarization and truncated uninalization binarization are known, the description thereof is omitted here. For details, see “H.264 / AVC Textbook, Impress”. The present invention does not limit the binarization technique.

  The binarized orthogonal transform coefficient operation unit 15 inputs the binarized orthogonal transform coefficient from the binarization unit 14 and inputs the control signal s (= 0, 1) to be superimposed on the binarized orthogonal transform coefficient, Based on the control signal s, the most significant bit of the binarized orthogonal transform coefficient (the most significant bit of the binarized orthogonal transform coefficient having a variable bit length) is inverted, or the most significant bit is left as it is. The inverted binarized orthogonal transform coefficient or the binarized orthogonal transform coefficient with the most significant bit as it is is output to the entropy coding unit 13. Then, the encoded signal that has been entropy-encoded by the entropy encoding unit 13 is transmitted to the decoding device 4 described later.

  FIG. 13 is a flowchart showing the processing of the binarized orthogonal transform coefficient operation unit 15. Assume that the binarized orthogonal transform coefficient input by the binarized orthogonal transform coefficient operation unit 15 is E, and the binarized orthogonal transform coefficient output by the binarized orthogonal transform coefficient operation unit 15 is F.

  First, the binarized orthogonal transform coefficient operation unit 15 receives the binarized orthogonal transform coefficient E from the binarization unit 14 and also receives the control signal s (= 0, 1) (step S1301). Then, the binarized orthogonal transform coefficient operation unit 15 determines whether or not the control signal s is 1 (step S1302), and determines that the control signal s is 1 (step S1302: Y), The most significant bit of the binarized orthogonal transform coefficient E is inverted to generate a new binarized orthogonal transform coefficient F (step S1303). On the other hand, when the binarized orthogonal transform coefficient operation unit 15 determines that the control signal s is not 1 (the control signal s is 0) (step S1302: N), the most significant bit of the binarized orthogonal transform coefficient E And the binarized orthogonal transform coefficient E is generated as a new binarized orthogonal transform coefficient F (step S1304).

  For example, it is assumed that the binarization unit 14 binarizes the orthogonal transform coefficient “3” into the binarized orthogonal transform coefficient “1110” using a binarization technique based on unary binarization. When the input control signal s is 1 with respect to the binarized orthogonal transform coefficient E “1110”, the binarized orthogonal transform coefficient operating unit 15 inverts the most significant bit “1” to generate a new binarization. An orthogonal transform coefficient F “110” (a binarized orthogonal transform coefficient corresponding to the orthogonal transform coefficient “2” corresponding to the orthogonal transform coefficient “2”) is generated. Also, when the input control signal s is 0, the binarized orthogonal transform coefficient operation unit 15 keeps the most significant bit “1” as it is, and creates a new binarized orthogonal transform coefficient F “1110” (binarized orthogonal). The same value as the conversion coefficient E).

  The binarized orthogonal transform coefficient operation unit 15 proceeds from step S1303 and step S1304, and outputs a new binarized orthogonal transform coefficient F, that is, a binarized orthogonal transform coefficient F on which the control signal s is superimposed. In this way, the control signal s is superimposed on the orthogonal transform coefficient by manipulating the binarized orthogonal transform coefficient that is the value of the orthogonal transform coefficient of the image.

  As described above, according to the encoding device 3 of the fourth embodiment, when the binarized orthogonal transform coefficient operation unit 15 has the control signal s = 1, the binarization unit 14 binarizes the orthogonal transform coefficient. When the most significant bit of the binarized orthogonal transform coefficient is inverted and the control signal s = 0, the most significant bit of the binarized orthogonal transform coefficient is left as it is, so that the orthogonal transform coefficient on which the control signal s is superimposed is Was generated. Here, when the most significant bit of the binarized orthogonal transform coefficient is inverted, the signal fluctuation at the coding block boundary becomes extremely large. Accordingly, by operating the value of the orthogonal transform coefficient in the encoding device 3, an orthogonal transform coefficient on which the control signal s is superimposed is generated and transmitted to the decoding device 4 described later as an encoded signal. Then, the decoding device 4 described later receives the encoded signal of the orthogonal transform coefficient on which the control signal s is superimposed, and extracts the control signal s based on the difference amount of the pixel signal at the block boundary. Details of the decoding device 4 will be described later. Thereby, when transmitting the video signal from the encoding device 3 to the decoding device 4 described later, the control signal s superimposed on the video signal can be transmitted without increasing the encoding amount.

[Embodiment 4 / Decoding Device]
Next, a decoding device according to the fourth embodiment will be described. FIG. 14 is a block diagram illustrating a schematic configuration of a decoding apparatus according to the fourth embodiment. The decoding device 4 is a device that receives a coded signal from the coding device 3 shown in FIG. 12 to generate a decoded image, and extracts a control signal s superimposed on the orthogonal transform coefficient. The entropy decoding unit 21 The inverse orthogonal transform unit 30 and the comparison / determination unit 23 are provided. FIG. 14 shows only the components related to the present invention among the components of the decoding device 4.

  The inverse orthogonal transform unit 30 receives the binarized orthogonal transform coefficient on which the control signal s is superimposed from the entropy decoding unit 21, decodes the input binarized orthogonal transform coefficient into an orthogonal transform coefficient, and applies the orthogonal transform coefficient to the orthogonal transform coefficient Inverse orthogonal transform processing is performed (orthogonal transform processing is performed with the binarized orthogonal transform coefficient binarized as it is) to generate a pixel signal (as-is pixel signal) and binarized orthogonal “1” is added to the most significant bit of the transform coefficient, the binarized orthogonal transform coefficient with “1” added is decoded into an orthogonal transform coefficient, an inverse orthogonal transform process is performed on the orthogonal transform coefficient, and the pixel signal (A pixel signal to which “1” has been added) is generated, and the pixel signal as it is and a pixel signal to which “1” has been added are output to the comparison / determination unit 23.

  FIG. 15 is a flowchart showing the processing of the inverse orthogonal transform unit 30. First, the inverse orthogonal transform unit 30 inputs a binarized orthogonal transform coefficient (step S1501). Then, the inverse orthogonal transform unit 30 decodes the input binarized orthogonal transform coefficient into an orthogonal transform coefficient, performs an inverse orthogonal transform process, and generates a pixel signal as it is (step S1502).

  Then, the inverse orthogonal transform unit 30 adds “1” to the most significant bit of the binarized orthogonal transform coefficient, generates a new binarized orthogonal transform coefficient (step S1503), and creates a new binarized orthogonal transform. An inverse orthogonal transform process is performed on the coefficient (orthogonal transform coefficient with “1” added) to generate a pixel signal with “1” added (step S1504). Then, the inverse orthogonal transform unit 30 outputs the pixel signal as it is and the pixel signal to which “1” is added to the comparison / determination unit 23 (step S1505).

  Returning to FIG. 14, the comparison / determination unit 23 performs the same processing as in the first embodiment shown in FIG. That is, the comparison / determination unit 23 inputs the pixel signal as it is and the pixel signal added with “1” from the inverse orthogonal transform unit 30 and also receives adjacent pixel signals at the block boundary (already processed by the comparison / determination unit 23). Between the pixel signals of the decoded image that is output after being output and the pixel signal closest to the processing target adjacent block) is input, and the pixel signal obtained by adding “1” as it is and the adjacent pixel signal The difference amount (absolute value of the difference amount) is calculated, and by comparing the difference amounts, a pixel signal having a small difference amount is selected and output as a pixel signal of the decoded image. The comparison / determination unit 23 determines and outputs the control signal s = 0 when the pixel signal as it is is selected as the pixel signal having a small difference amount. On the other hand, the comparison / determination unit 23 determines and outputs the control signal s = 1 when the pixel signal to which “1” is added as the pixel signal having a small difference amount is selected.

  As described above, according to the decoding device 4 of the fourth embodiment, the inverse orthogonal transform unit 30 decodes the binarized orthogonal transform coefficient into the orthogonal transform coefficient, performs the inverse orthogonal transform process, and generates the pixel signal as it is. At the same time, “1” is added to the most significant bit of the binarized orthogonal transform coefficient, the inverse transform process is performed by decoding the orthogonal transform coefficient, and a pixel signal with “1” added is generated. Then, the comparison / determination unit 23 calculates a difference amount between the pixel signal as it is and the pixel signal to which “1” is added and the adjacent pixel signal at the block boundary, and a pixel signal with a small difference amount (a pixel signal as it is) Or a pixel signal to which “1” has been added) is selected and output as a pixel signal of the decoded image, and when the pixel signal is selected as it is, the control signal s = 0 is determined and output, and “1” is added. When the selected pixel signal is selected, the control signal s = 1 is determined and output. As a result, when the video signal is transmitted from the encoding device 3 to the decoding device 4, the control signal s superimposed on the video signal can be extracted. In the encoding method, the control signal s can be transmitted without increasing the code amount of the control signal s, which causes the code amount to increase. Further, in the decoding device 4, by performing signal correction, that is, performing inverse orthogonal transformation while leaving the most significant bit of the binarized orthogonal transform coefficient as it is, “1” is added to the most significant bit of the binarized orthogonal transform coefficient. ”And performing inverse orthogonal transform, the control signal s can be transmitted without deteriorating the quality of the video signal, and higher-compression encoding can be realized.

  That is, the decoding device 4 can restore the transmitted control signal s without increasing the code amount. In addition, the control signal s can be superimposed on a color difference signal having a higher pixel correlation, instead of being superimposed on a luminance signal with high visual sensitivity. That is, when the encoding device 3 operates the encoded signal, the signal is deliberately manipulated so that the statistical bias of the input signal is significantly broken, and the decoding device 4 causes the statistical bias to be unnatural. The quality of the video signal transmitted from the encoding device 3 to the decoding device 4 is prevented by restoring the control signal s in accordance with a determined procedure, and the control is transmitted while being superimposed on the video signal. The signal s can be extracted accurately.

  Although the present invention has been described with reference to the first to fourth embodiments, the present invention is not limited to the first to fourth embodiments, and various modifications can be made without departing from the technical idea thereof. For example, the decoding device 2-1 according to the first embodiment shown in FIG. 4, the comparison / determination unit 23 of the decoding device 4 according to the fourth embodiment shown in FIG. 14, and the decoding device 2-2 according to the second embodiment shown in FIG. Comparison / determination units 25 and 26 and comparison / determination units 28-1, 28-2, and 29 according to the third embodiment shown in FIG. 11 add the pixel signal as it is and the inverted pixel signal (or “1”). Although the difference amount between the pixel signal) and the adjacent pixel signal is calculated, the sum of squares of the difference amount may be calculated instead of the difference amount. Further, a value (correlation coefficient) indicating a correlation between the pixel signal as it is and the inverted pixel signal and the adjacent pixel signal may be calculated. In this case, a pixel signal having a large correlation coefficient (the pixel signal as it is or an inverted pixel signal) is selected and output as a pixel signal of a decoded image.

  Further, the orthogonal transform coefficient operation unit 12 of the encoding device 1 shown in FIG. 1 operates the code of the orthogonal transform coefficient of the (0, 0) component, which is the lowest frequency information, and controls the orthogonal transform coefficient to the control signal. Although s is superimposed, the present invention does not limit the operation target to the orthogonal transformation coefficient of the (0, 0) component, for example, the orthogonal transformation of the (0, 1) component or the (1, 0) component. The sign of the coefficient may be manipulated to superimpose the control signal s. Further, the component to be operated on which the control signal s is superimposed may be changed according to the property (for example, transmission quality) of the transmission system including the encoding device 1 and the decoding devices 2-1 to 2-3.

  In addition, the orthogonal transform coefficient operation unit 12 of the encoding device 1 operates the code of one orthogonal transform coefficient (orthogonal transform coefficient of (0,0) component), but orthogonal transform of two or more components The coefficient may be manipulated.

  In the first to fourth embodiments, the orthogonal transformation includes a case where orthogonality is lost in a strict sense by being converted to an integer. The present invention can be applied even if the orthogonal transform is an integer transform.

  In the second and third embodiments, the difference value between the pixel signal and the adjacent pixel signal in the component signal 1 on which the control signal s is superimposed and the component signal 2 (and 3) on which the control signal s is not superimposed is calculated. Thus, the control signal s is extracted. On the other hand, as a modification of the second and third embodiments, when the component signal 2 (or 3) other than the component signal 1 can be referred to, the fact that there is a strong correlation between the component signals is used. Thus, the control signal s may be extracted. Specifically, the comparison / determination unit of the decoding devices 2-2 and 2-3 does not superimpose the control signal s on the pixel signal as it is and the inverted pixel signal in the component signal 1 on which the control signal s is superimposed. A correlation value is calculated with the pixel signal (correct decoded signal) as it is in the other component signal 2 or component signal 3, and is defined by the system among the pixel signal as it is or the inverted pixel signal in the component signal 1. For example, a pixel signal having a large correlation value (high correlation) is selected and output as a pixel signal of a decoded signal. When the selected pixel signal is not the pixel signal as it is, the control signal s = 1 is determined and output, and when the selected pixel signal is the pixel signal as it is, the control signal s = 0 is determined and output. .

  Further, any one of the first to third embodiments may be combined with the fourth embodiment. That is, the control signal s is superimposed on the sign and value of the orthogonal transform coefficient by manipulating the sign and value of the orthogonal transform coefficient. Thereby, the determination accuracy of the control signal s can be increased.

  Further, in the fourth embodiment, as in the first embodiment, the case where there is one component signal has been described as an example. However, as in the second and third embodiments, the present invention can be applied to a case where there are a plurality of component signals. In this case, the encoding device 3 superimposes the control signal s on the binarized orthogonal transform coefficient for one component signal of the plurality of component signals. The decoding device 4 performs the same processing as the inverse orthogonal transform unit 30 illustrated in FIG. 14 on all of the plurality of component signals, and the comparison / determination units 25 and 26 illustrated in FIG. 9 or the processing illustrated in FIG. 11 is performed. The control signal s is extracted by performing the same processing as the comparison / determination units 28-1, 28-2, and 29.

  As hardware configurations of the encoding devices 1 and 3 and the decoding devices 2-1 to 2-3 and 4 according to the embodiment of the present invention, a normal computer can be used. The encoding devices 1 and 3 and the decoding devices 2-1 to 2-3 and 4 are configured by a computer having a CPU, a volatile storage medium such as a RAM, a nonvolatile storage medium such as a ROM, and an interface. The Each function of the orthogonal transform unit 11, the orthogonal transform coefficient operation unit 12, and the entropy coding unit 13 included in the encoding device 1 is realized by causing a CPU to execute a program describing these functions. In addition, each function of the orthogonal transform unit 11, the binarization unit 14, the binarized orthogonal transform coefficient operation unit 15 and the entropy coding unit 13 provided in the encoding device 3 also has a program describing these functions stored in the CPU. Each is realized by executing. Furthermore, the functions of the entropy decoding unit 21, the inverse orthogonal transform unit 22, and the comparison / determination unit 23 included in the decoding device 2-1 are also realized by causing the CPU to execute a program describing these functions. Inverse orthogonal transform units 24-1 and 24-2 and comparison / determination units 25 and 26 provided in the decoding device 2-2, and inverse orthogonal transform units 27-1 to 27-3 and comparison provided in the decoding device 2-3. The same applies to the determination units 28-1, 28-2, and 29. The same applies to the entropy decoding unit 21, the inverse orthogonal transform unit 30, and the comparison / determination unit 23 included in the decoding device 4. These programs can be stored and distributed in a storage medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory.

DESCRIPTION OF SYMBOLS 1,3 Encoding apparatus 2, 4 Decoding apparatus 11 Orthogonal transformation part 12 Orthogonal transformation coefficient operation part 13 Entropy encoding part 14 Binarization part 15 Binarization orthogonal transformation coefficient operation part 21 Entropy decoding part 22, 24, 27, 30 Inverse orthogonal transform unit 23, 25, 26, 28, 29 Comparison / determination unit

Claims (11)

In an encoding device that performs orthogonal transform on a transmission target signal and transmits an encoded signal of an orthogonal transform coefficient,
An orthogonal transform unit that performs orthogonal transform for each block including a plurality of element signals constituting the transmission target signal, and generates an orthogonal transform coefficient;
Among the orthogonal transform coefficients generated by the orthogonal transform unit, the orthogonal transform coefficient of a preset component is inverted by manipulating the sign of the orthogonal transform coefficient based on the control signal, and orthogonal transforming the control signal An orthogonal transform coefficient operation unit superimposed on the coefficient;
An encoding device comprising: The encoding device according to claim 1, wherein
A binarized orthogonal transform coefficient operation unit is provided instead of the orthogonal transform coefficient operation unit,
The binarized orthogonal transform coefficient operation unit manipulates and inverts the most significant bit of the binarized orthogonal transform coefficient obtained by binarizing the orthogonal transform coefficient, and superimposes the control signal on the orthogonal transform coefficient. An encoding device characterized by the above. The encoded signal of the orthogonal transform coefficient superimposed by the control signal transmitted by the encoding device according to claim 1 is received, inverse orthogonal transform is performed on the orthogonal transform coefficient of the encoded signal, and the original transmission target signal A decoding device for decoding
An inverse orthogonal transform is performed on the orthogonal transform coefficient to generate a first element signal, a sign of the orthogonal transform coefficient is manipulated and inverted, and an inverse orthogonal transform is performed on the inverted orthogonal transform coefficient to obtain a second An inverse orthogonal transform unit for generating an element signal;
The difference between the first element signal generated by the inverse orthogonal transform unit and the signal to be transmitted that has already been decoded, or the sum of squares of the difference, or a predetermined first of the correlation values While obtaining the calculation result, the difference amount between the second element signal generated by the inverse orthogonal transform unit and the signal to be transmitted that has already been decoded, or the sum of squares of the difference amount, or the correlation value The predetermined second calculation result is obtained, and the first calculation result is compared with the second calculation result, whereby either one of the first element signal and the second element signal is obtained. A comparison / determination unit that selects a signal as an original transmission target signal and determines a control signal superimposed on the orthogonal transform coefficient;
A decoding device comprising: The signal to be transmitted is composed of a plurality of component signals, and is transmitted by the coding device when the coding of the orthogonal transformation coefficient in the predetermined component signal is operated by the coding device of claim 1 and the control signal is superimposed. And receiving an encoded signal of an orthogonal transform coefficient in a component signal on which the control signal is superimposed, and receiving an encoded signal of an orthogonal transform coefficient in another component signal on which the control signal is not superimposed, A decoding device that performs inverse orthogonal transformation on the orthogonal transformation coefficient of the encoded signal and decodes the original signal to be transmitted,
The orthogonal transform coefficient of the component signal on which the control signal is superimposed is subjected to inverse orthogonal transform to generate the 1-1st element signal, and the sign of the orthogonal transform coefficient is manipulated to invert the inverted orthogonal transform coefficient. A first inverse orthogonal transform unit that performs inverse orthogonal transform to generate a 1-2 element signal;
An inverse orthogonal transform is performed on the orthogonal transform coefficients of other component signals not superimposed with the control signal to generate a 2-1 element signal, and the sign of the orthogonal transform coefficient is manipulated to invert the inverted signal. A second inverse orthogonal transform unit that performs inverse orthogonal transform on the orthogonal transform coefficient to generate a 2-2 element signal;
A difference amount between the 1-1 and 1-2 element signals generated by the first inverse orthogonal transform unit and a signal to be transmitted that has already been decoded, or a sum of squares of the difference amount, or Each of the predetermined calculation results of the correlation values is obtained, the calculation results are compared, the first determination result is obtained, and the 2-1 and 2-2 generated by the second inverse orthogonal transform unit are obtained. The difference between the element signal and the signal to be transmitted that has already been decoded, the sum of squares of the difference, or the predetermined calculation result of the correlation value is obtained, and the calculation result is compared and The determination result of 2 is obtained, and based on the first and second determination results, the 1-1 or 1-2 element signal having the same determination result as the 2-1 element signal is used as the original result. The control signal selected as the signal to be transmitted and superimposed on the orthogonal transform coefficient And determining comparing / judging unit,
A decoding device comprising: The encoded signal of the orthogonal transform coefficient superimposed by the control signal transmitted by the encoding device according to claim 2 is received, the orthogonal transform coefficient of the encoded signal is subjected to inverse orthogonal transform, and the original transmission target signal is obtained. A decoding device for decoding,
The binarized orthogonal transform coefficient decoded from the encoded signal is decoded into an orthogonal transform coefficient, the orthogonal transform coefficient is inversely orthogonal transformed to generate a first element signal, and the binarized orthogonal transform coefficient An inverse orthogonal transform unit that adds 1 to the most significant bit, decodes the orthogonal transform coefficient from the binarized orthogonal transform coefficient with the 1 added, performs inverse orthogonal transform, and generates a second element signal;
The difference between the first element signal generated by the inverse orthogonal transform unit and the signal to be transmitted that has already been decoded, or the sum of squares of the difference, or a predetermined first of the correlation values While obtaining the calculation result, the difference amount between the second element signal generated by the inverse orthogonal transform unit and the signal to be transmitted that has already been decoded, or the sum of squares of the difference amount, or the correlation value The predetermined second calculation result is obtained, and the first calculation result is compared with the second calculation result, whereby either one of the first element signal and the second element signal is obtained. A comparison / determination unit that selects a signal as an original transmission target signal and determines a control signal superimposed on the orthogonal transform coefficient;
A decoding device comprising: In the encoding method by the encoding device that performs orthogonal transform on the transmission target signal and transmits the encoded signal of the orthogonal transform coefficient,
Performing orthogonal transform for each block composed of a plurality of element signals constituting the signal to be transmitted to generate orthogonal transform coefficients;
Out of the orthogonal transform coefficients, the orthogonal transform coefficient of a preset component is manipulated and inverted based on the control signal, and the control signal is superimposed on the orthogonal transform coefficient;
An encoding method characterized by comprising: In the encoding method by the encoding device that performs orthogonal transform on the transmission target signal and transmits the encoded signal of the orthogonal transform coefficient,
Performing orthogonal transform for each block composed of a plurality of element signals constituting the signal to be transmitted to generate orthogonal transform coefficients;
Binarizing the orthogonal transform coefficient to generate a binarized orthogonal transform coefficient;
Manipulating and inverting the most significant bit of the binarized orthogonal transform coefficient and superimposing the control signal on the orthogonal transform coefficient;
An encoding method characterized by comprising: A decoding method by a decoding apparatus that receives an encoded signal of an orthogonal transform coefficient that is transmitted by the encoding method of claim 6 and on which the control signal is superimposed, performs inverse orthogonal transform, and decodes the original signal to be transmitted. There,
Performing an inverse orthogonal transform on the orthogonal transform coefficient of the received encoded signal to generate a first element signal;
Manipulating and inverting the sign of the orthogonal transform coefficient, performing inverse orthogonal transform on the inverted orthogonal transform coefficient to generate a second element signal;
Obtaining a predetermined first calculation result of a difference amount between the first element signal and a signal to be transmitted that has already been decoded, or a sum of squares of the difference amount, or a correlation value;
Obtaining the predetermined second calculation result of a difference amount between the second element signal and a signal to be transmitted that has already been decoded, or a sum of squares of the difference amount, or a correlation value;
By comparing the first calculation result and the second calculation result, one of the first element signal and the second element signal is selected as an original transmission target signal, Determining a control signal superimposed on the orthogonal transform coefficient;
A decoding method characterized by comprising: The encoded signal of the orthogonal transform coefficient superimposed by the control signal transmitted by the encoding method of claim 7 is received, the orthogonal transform coefficient of the encoded signal is subjected to inverse orthogonal transform, and the original transmission target signal is obtained. A decoding method by a decoding device for decoding,
Decoding a binarized orthogonal transform coefficient decoded from the encoded signal into an orthogonal transform coefficient, inverse orthogonal transforming the orthogonal transform coefficient, and generating a first element signal;
1 is added to the most significant bit of the binarized orthogonal transform coefficient, the orthogonal transform coefficient is decoded from the binarized orthogonal transform coefficient with the 1 added, and inverse orthogonal transform is performed to generate a second element signal Steps,
Obtaining a predetermined first calculation result of a difference amount between the first element signal and a signal to be transmitted that has already been decoded, or a sum of squares of the difference amount, or a correlation value;
Obtaining the predetermined second calculation result of a difference amount between the second element signal and a signal to be transmitted that has already been decoded, or a sum of squares of the difference amount, or a correlation value;
By comparing the first calculation result and the second calculation result, one of the first element signal and the second element signal is selected as an original transmission target signal, Determining a control signal superimposed on the orthogonal transform coefficient;
A decoding method characterized by comprising:   An encoding program for causing a computer to function as the encoding device according to claim 1.   A decoding program for causing a computer to function as the decoding device according to any one of claims 3 to 5.

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