JP2000209098A - Digital signal processor and digital signal processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital signal processor capable of burying digital watermark information in digital signals while hardly lowering the quality of sound and images. SOLUTION: The processor is provided with an FFT circuit 15 for frequency converting digital audio signals S9 with an FFT processing block composed of the prescribed amount of the digital signals as a unit, performing a frequency analysis processing and generating plural transformation coefficients for respectively indicating the level of a corresponding frequency component among the levels of the plural frequency components obtained by the frequency analysis processing and an MPU 19 for changing the value of at least one of the plural transformation coefficients obtained from the FFT processing block, burying the digital watermark information in the transformation processing block, which burying is executed for the plural FFT processing blocks positioned separately for more than a single FFT processing block on the digital audio signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a digital signal processing apparatus and a method for performing processing relating to digital watermark information.

[0002]

2. Description of the Related Art A digital audio (Digital Audio) signal and a digital image (Digital Image) signal are hardly deteriorated in quality compared to an original (MD).
Disk), CD (CmpactDisk) -R (Recordable) and DV
It can be recorded on a recording medium such as D (Digital Versatile Disk). Therefore, if the recording of the digital audio signal and the digital image signal on the recording medium is allowed without any restriction, the interest of the copyright holder is significantly impaired. From such a background, in recent years, information for restricting recording of the signal on a recording medium is embedded as digital watermark information (DigitalWatermark) in an original digital audio signal or an original digital image signal, and a recording apparatus uses the digital watermark information as the digital watermark information. A method of controlling recording on a recording medium based on the method has been proposed. Here, the digital watermark information is information that is embedded (embedded) in a signal in such a manner that it is hard to be perceived by human eyes and ears, and is difficult to remove or rewrite.

As a technique for embedding such digital watermark information in an original digital audio signal or an original digital image signal, for example, pseudorandom noise such as a PN (Pseudorandom Noise) sequence signal is superimposed on the original digital audio signal or the original digital image signal. There is something to do. According to this method, when recording a digital audio signal or a digital image signal on a recording medium, the recording apparatus detects pseudorandom noise superimposed on the digital audio signal or the digital image signal, and performs either copy prohibition or copy permission. It determines whether or not there is, and controls recording on the recording medium based on the determination result.

[0004]

However, when pseudo-random noise is superimposed as described above, a noise component is directly added to an original digital audio signal or an original digital image signal even though it is a small signal. In some cases, depending on the brightness, volume, distribution of the frequency spectrum, and the like of the digital image signal, deterioration of the sound and image quality due to the embedding of the digital watermark information may be perceived by human eyes and ears. Also, the recording device cannot detect the pseudo-random noise superimposed on the digital audio signal or digital image signal only after obtaining samples in a certain continuous section in time. It is necessary to superimpose pseudorandom noise on a signal for a relatively long time, and there is a problem that sound and sound quality degradation due to embedding of digital watermark information continues for a long time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been made in consideration of the above-described problems. It is an object to provide a processing device and a method thereof.

[0006]

In order to solve the above-mentioned problems of the prior art and achieve the above-mentioned object, a digital signal processing apparatus according to a first aspect of the present invention comprises a predetermined amount of digital signals. A frequency conversion process is performed by converting the frequency of the digital signal in units of the conversion processing block, and a plurality of conversion coefficients each indicating a level of a corresponding frequency component among a plurality of frequency component levels obtained by the frequency analysis process are generated. Embedding the digital watermark information in the conversion processing block by changing the value of at least one of the plurality of conversion coefficients obtained from the conversion processing block, and embedding the digital watermark information. An information embedding method performed on a plurality of the conversion processing blocks located apart from the single conversion processing block on the digital signal. With the door.

In the digital signal processing apparatus according to the first aspect of the present invention, first, the frequency analysis means performs frequency analysis processing by converting a digital signal into a unit of a conversion processing block comprising a predetermined amount of digital signals. Then, a plurality of transform coefficients each indicating the level of the corresponding frequency component among the levels of the plurality of frequency components obtained by the frequency analysis processing are generated. Next, in the information embedding means, digital watermark information is embedded in the conversion processing block by changing the value of at least one of the plurality of conversion coefficients obtained from the conversion processing block, Is embedded in a plurality of the conversion processing blocks located apart from the single conversion processing block by more than one on the digital signal.

As described above, by embedding digital watermark information by changing the value of one transform coefficient obtained by frequency conversion, it is not necessary to superimpose pseudorandom noise on a digital signal as in the related art. In addition, the time during which digital watermark information is embedded in a digital signal can be reduced. That is, in the digital watermark information detecting device, if the value of the conversion coefficient in which the digital watermark information is embedded is known, the digital watermark information can be embedded in the digital signal in a detectable manner by temporarily changing the value of the conversion coefficient for a short time. Can be.

A digital signal processing apparatus according to a second aspect of the present invention performs frequency analysis on a digital signal by performing frequency conversion on a conversion processing block comprising a predetermined amount of digital signals. Frequency analyzing means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and at least one of the plurality of transform coefficients obtained from the transform processing block An information embedding unit that embeds digital watermark information in the conversion processing block by changing a value of a conversion coefficient and embeds the digital watermark information in a plurality of conversion processing blocks in which the frequency analysis processing is continuously performed. .

A digital signal processing apparatus according to a third aspect of the present invention performs a frequency analysis process by converting a digital signal into a frequency in units of a conversion processing block composed of a predetermined amount of a digital signal. Frequency analyzing means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and at least one of the plurality of transform coefficients obtained from the transform processing block The digital watermark information is embedded in the conversion processing block by changing the value of the conversion coefficient, and the embedding of the digital watermark information is performed for the plurality of conversion processing blocks located closer to the digital signal than the single conversion processing block. Information embedding means for performing the information embedding.

A digital signal processing apparatus according to a fourth aspect of the present invention performs a frequency analysis process by frequency-converting a digital signal in units of a conversion processing block consisting of a predetermined amount of digital signals. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and at least one of the plurality of transform coefficients obtained from the first transform processing block The header of the digital watermark information is embedded by changing the value of one transform coefficient, and at least one transform coefficient among the plurality of transform coefficients obtained from the second transform processing block adjacent to the first transform processing block And an information embedding unit for embedding the data portion of the digital watermark information by changing the value of the digital watermark information.

Further, a digital signal processing apparatus according to a fifth aspect of the present invention includes a trigger signal detecting means for detecting a trigger signal included in the input digital signal based on an amplitude level of the input digital signal; After the trigger signal is detected, the input digital signal is subjected to frequency conversion by performing frequency conversion, and a plurality of levels respectively indicating the level of the corresponding frequency component among the levels of the plurality of frequency components obtained by the frequency analysis process Frequency analysis means for generating a conversion coefficient of the first and second conversion coefficients, and a header portion of the digital watermark information is embedded by changing a value of at least one of the plurality of conversion coefficients obtained from the first conversion processing block; Of at least one transform coefficient of the plurality of transform coefficients obtained from the second transform processing block following the transform processing block By changing the and an information embedding means for embedding the data portion of the digital watermark information.

A digital signal processing apparatus according to a sixth aspect of the present invention converts a digital signal into a frequency and performs a frequency analysis process in units of a conversion processing block composed of a predetermined amount of the digital signal. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and a reference based on a temporal change of the generated plurality of transform coefficients. A conversion coefficient change specifying means for specifying a conversion coefficient having a temporal change of an amount or more; and a conversion coefficient specified in common between a plurality of conversion processing blocks different from each other, and the specified conversion coefficient is specified in common. Information detecting means for detecting digital watermark information embedded in the digital signal based on the obtained conversion coefficient.

A digital signal processing apparatus according to a seventh aspect of the present invention converts a digital signal into a frequency and performs a frequency analysis process in units of a conversion processing block composed of a predetermined amount of the digital signal. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and a reference based on a temporal change of the generated plurality of transform coefficients. A conversion coefficient having a temporal change of an amount or more is specified, and based on the specified conversion coefficient, a header portion and a data portion of the digital watermark information embedded in the digital signal are detected, and the detected individual Information for performing error correction detection processing in units of the data portion corresponding to the header portion to detect digital watermark information embedded in the digital signal. And a detection means.

Further, a digital signal processing apparatus according to an eighth aspect of the present invention converts a digital signal into a frequency in a unit of a conversion processing block composed of a predetermined amount of the digital signal and performs a frequency analysis process. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and a reference based on a temporal change of the generated plurality of transform coefficients. A conversion coefficient having a temporal change equal to or more than the amount is specified, and based on the specified conversion coefficient, a header part and a data part of the digital watermark information embedded in the digital signal are detected. Information for performing error correction detection processing in units of the data portion corresponding to the header portion to detect digital watermark information embedded in the digital signal. And a detection means.

A digital signal processing apparatus according to a ninth aspect of the present invention converts a digital signal into a frequency and performs a frequency analysis process in units of a conversion processing block composed of a predetermined amount of the digital signal. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and a reference based on a temporal change of the generated plurality of transform coefficients. A conversion coefficient change specifying means for specifying a conversion coefficient having a temporal change of an amount or more; and a conversion coefficient specified in common between a plurality of conversion processing blocks different from each other, and the specified conversion coefficient is specified in common. Information detecting means for detecting digital watermark information embedded in the digital signal based on the obtained conversion coefficient, and outputting in accordance with the digital signal. And output means, on the basis of the detection result, and a control means for controlling whether the output of said digital signal by said output means.

A digital signal processing apparatus according to a tenth aspect of the present invention converts a digital signal into a frequency in units of a conversion processing block composed of a predetermined amount of the digital signal and performs a frequency analysis process. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels, and a reference based on a temporal change of the generated plurality of transform coefficients. A conversion coefficient change specifying means for specifying a conversion coefficient having a temporal change of an amount or more; and a conversion coefficient specified in common between a plurality of conversion processing blocks different from each other, and the specified conversion coefficient is specified in common. Information detecting means for detecting digital watermark information embedded in the digital signal based on the obtained conversion coefficient; and recording the digital signal on a recording medium. Recording means for, on the basis of the detection result, and a control means for controlling whether the output of said digital signal by said recording means.

Further, in the digital signal processing method according to the first aspect of the present invention, the digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of the digital signal to perform a frequency analysis process. A plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and a value of at least one transform coefficient among the plurality of transform coefficients obtained from the transform processing block Is changed to embed digital watermark information in the conversion processing block, and embeds the digital watermark information in a plurality of the conversion processing blocks that are located more than one conversion processing block apart on the digital signal.

Further, in a digital signal processing method according to a second aspect of the present invention, a digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing. A plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and a value of at least one transform coefficient among the plurality of transform coefficients obtained from the transform processing block Is changed, and the digital watermark information is embedded in the conversion processing block. The digital watermark information is embedded in a plurality of conversion processing blocks in which the frequency analysis processing is continuously performed.

Further, in a digital signal processing method according to a third aspect of the present invention, a digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals, and a frequency analysis process is performed. A plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and a value of at least one transform coefficient among the plurality of transform coefficients obtained from the transform processing block Is changed to embed digital watermark information in the conversion processing block, and embeds the digital watermark information in the plurality of conversion processing blocks located closer to the digital signal than the single conversion processing block.

In a digital signal processing method according to a fourth aspect of the present invention, a digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing. A plurality of transform coefficients each representing a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and at least one transform coefficient among the plurality of transform coefficients obtained from the first transform processing block , The header portion of the digital watermark information is embedded, and the value of at least one of the plurality of transform coefficients obtained from the second transform processing block adjacent to the first transform processing block is changed. To embed the data portion of the digital watermark information.

In a digital signal processing method according to a fifth aspect of the present invention, a trigger signal included in the input digital signal is detected based on an amplitude level of the input digital signal, and the trigger signal is detected. After that, the input digital signal is frequency-converted and subjected to frequency analysis processing, and a plurality of conversion coefficients each indicating a level of a corresponding frequency component among a plurality of frequency component levels obtained by the frequency analysis processing are generated. Then, the value of at least one of the plurality of transform coefficients obtained from the first transform processing block is changed to embed the header part of the digital watermark information, and the second transform processing block following the first transform processing block is embedded. The data part of the digital watermark information is embedded by changing the value of at least one of the plurality of transform coefficients obtained from the transform processing block. Writes.

In a digital signal processing method according to a sixth aspect of the present invention, a digital signal is frequency-converted and frequency-analyzed in units of a conversion processing block composed of a predetermined amount of digital signals. A plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and a time equal to or more than a reference amount is determined based on a temporal change of the generated plurality of transform coefficients. The conversion coefficient having a specific change is specified, the specified conversion coefficient is obtained in common between a plurality of conversion processing blocks different from each other, and based on the conversion coefficient specified in common, the digital Digital watermark information embedded in a signal is detected.

[0024] In a digital signal processing method according to a seventh aspect of the present invention, a digital signal is frequency-converted and frequency-analyzed in units of a conversion processing block composed of a predetermined amount of digital signals. A plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and a time equal to or more than a reference amount is determined based on a temporal change of the generated plurality of transform coefficients. Identifying a conversion coefficient having a specific change, detecting a header part and a data part of digital watermark information embedded in the digital signal based on the specified conversion coefficient, and corresponding to the detected individual header part The digital watermark information embedded in the digital signal is detected by performing error correction detection processing in units of the data portion.

In a digital signal processing method according to an eighth aspect of the present invention, a digital signal is frequency-converted and frequency-analyzed in units of a conversion processing block composed of a predetermined amount of digital signals. A plurality of transform coefficients each indicating a level of a corresponding frequency component among the obtained plurality of frequency component levels are generated, and a time equal to or more than a reference amount is determined based on a temporal change of the generated plurality of transform coefficients. A conversion coefficient having a specific change is identified, a header part and a data part of the digital watermark information embedded in the digital signal are detected based on the specified conversion coefficient, and the plurality of header parts correspond to the plurality of detected header parts. The digital watermark information embedded in the digital signal is detected by performing error correction detection processing in units of the data portion.

[0026]

Embodiments of the present invention will be described below. In the present embodiment, as a digital signal processing device of the present invention, a digital watermark information embedding device that embeds digital watermark information in a digital audio signal, a digital watermark information detecting device that detects digital watermark information from the digital audio signal, and a digital audio signal Although a recording device and a reproducing device are exemplified, the present invention detects digital watermark information from a digital image signal, and a digital watermark information embedding device that embeds digital watermark information in a digital image (image) signal, in addition to a digital audio signal. The present invention can be similarly applied to a digital watermark information detecting device, a digital image signal recording device, and a reproducing device.

First, a digital watermark information embedding device according to an embodiment of the present invention will be described. First Embodiment FIG. 1 is a configuration diagram of a digital watermark information embedding device 100 of the present embodiment. As shown in FIG. 1, the digital watermark information embedding device 100 includes a digital input I / F circuit 11, an analog input I / F circuit 12, an A / D conversion circuit 13, and a memory 14.
(Storage means), FFT (Fast Fourier Transform) circuit 1
5 (frequency analysis means), IFFT (Inverse Fast Fourie
r Transform) circuit 16 (orthogonal inverse transform means), signal compression circuit 17, digital output I / F circuit 18 (output means), M
It has a PU 19 (information embedding means), an internal bus 20 and an operation unit 21.

The digital input I / F circuit 11 outputs the input original digital audio signal S 9 to the memory 14 via the internal bus 20 based on the transfer control of the MPU 19. The analog input I / F circuit 12 outputs the input original analog audio signal S10 to the A / D conversion circuit 13. The A / D conversion circuit 13 converts the original analog audio signal S10 input from the analog input I / F circuit 12 into a digital audio signal, and outputs the digital audio signal to the memory 14 via the internal bus 20.

The memory 14 has a digital input I / F circuit 1
1 and a digital audio signal input from the A / D conversion circuit 13, and based on the control from the MPU 19, a digital audio signal constituting a FFT processing block serving as a unit of frequency analysis processing in the FFT circuit 15 (this embodiment) Now, when 512 samples are stored,
The stored digital audio signal is read out and output to the FFT circuit 15 via the internal bus 20.

The FFT circuit 15 converts the digital audio signal input from the memory 14 from the time domain to the frequency domain by performing frequency analysis by FFT processing, and converts the conversion coefficient obtained by the conversion under the control of the MPU 19. , To the MPU 19 via the internal bus 20. Here, FFT processing is often used when performing waveform analysis of digital signals such as digital audio signals and digital image signals because the arithmetic processing is fast and relatively easy. The FFT is basically performed on a sample of a power of two. For example, as shown in FIG. 2A, the digital audio signal is cut out by 512 (2 9) samples at a time and subjected to FFT processing. A frequency spectrum as shown in, for example, FIG. The frequency resolution is a value obtained by dividing the sampling frequency by the number of cut out samples. For example,
Referring to FIG. 3, when the sampling frequency fs of the audio signal is 44.1 kHz and the number of samples N is 512, the frequency resolution T is about 86.1 (= 441).
00/512) Hz.

The IFFT circuit 16 restores an audio signal by performing IFFT processing on the conversion coefficient input from the MPU 19 via the internal bus 20 based on the control from the MPU 19, and restores the restored audio signal via the internal bus 20. And outputs it to the digital output I / F circuit 18. At this time, as described later, among the conversion coefficients input from the MPU 19, the conversion coefficient of a predetermined frequency component is 0 based on the digital watermark information. That is, the IFFT circuit 1
The digital watermark information has already been embedded in the audio signal restored in step 6.

The digital output I / F circuit 18 is connected to the IFFT circuit 16 or the signal compression circuit 1 via the internal bus 20.
The digital audio signal input from 7 is recorded on a recording medium 30 such as an MD or CD-R.

The signal compression circuit 17 converts the digital audio signal embedded with the digital watermark information output from the IFFT circuit 16 into an MPEG (Movin
g Picture Experts Group) and outputs the compressed digital audio signal to a digital output I / F circuit 1
8 is output.

The MPU 19 includes the digital watermark information embedding device 1
Control of each component in 00 is performed in an integrated manner. MPU19
Has a built-in DMA (Direct Memory Access) controller and controls data transfer between components via the internal bus 20.

The MPU 19 monitors the storage state of the memory 14, and as described above, converts the digital audio signal of the data amount necessary for the FFT processing in the FFT circuit 15 into the digital input I / F circuit 11 or the A / D converter. After confirming that the digital audio signal is stored in the memory 14 from the circuit 13, control is performed so that the digital audio signal stored in the memory 14 is output to the FFT circuit 15.

The MPU 19 includes a RAM for storing information for specifying a frequency component to be varied based on digital watermark information to be embedded.
Of the transform coefficients input from the FFT circuit 15 via “0”, the transform coefficient corresponding to the frequency component specified from the information stored in the RAM is set to “0”. And
The MPU 19 stores the variation-added conversion coefficient and the variation-free conversion coefficient input from the memory 14 into the internal bus 2.
0 to the IFFT circuit 16. Here, in the present embodiment, one or more digital watermark information can be embedded in the digital audio signal, and the transform coefficient corresponding to one or more frequency components is set to “0” in one FFT processing block. When one piece of digital watermark information is embedded and no digital watermark information is embedded, the conversion coefficient is not changed. The digital watermark information includes, for example, information related to copyrights such as “copy prohibited” and “copy one generation only”.

FIGS. 4 and 5 are flowcharts for explaining the process of embedding digital watermark information in the MPU 19. Step S1: The MPU 19, for example, upon determining that a processing start indication has been issued by the operation of the operation unit 21 by the user, an internal variable count indicating the number of samples of the digital audio signal stored in the memory 14, and an FFT
Internal variable FET_ indicating the number of samples forming a unit (FFT processing block) for performing FFT processing in the circuit 15
Sample is initialized. Specifically, the internal variable c
"0" is substituted for "out" and the internal variable FET_samp
“512” is substituted for le.

Step S2: The MPU 19 receives an instruction to stop the processing by the operation of the operation unit 21 by the user, or inputs an audio signal from both the digital input I / F circuit 11 and the analog input I / F circuit 12. If at least one of the non-operations is detected, the process is terminated, and otherwise, the process of step S3 is executed.

Step S3: The MPU 19 outputs the digital audio signal S9 for one sample to the digital input I / F.
Each time the digital audio signal is input to the circuit 11, the digital audio signal for one sample is stored in the memory 14 via the internal bus 20, and the internal variable count is increased by one.

Step S4: The MPU 19 sets the internal variable c
It is determined whether or not “out” matches the internal variable FET_sample. If it is determined that they match, the process of step S5 is performed. If it is determined that they do not match, the process returns to step S2. That is, the MPU 19
Digital audio signals for 512 samples are stored in memory 1.
4, the processing of step S5 is performed.

Step S5: The MPU 19 sets the internal variable c
“0” is substituted for “out”.

Step S6: The MPU 19 stores in the memory 14
Is transferred to the FFT circuit 15 via the internal bus 20. As a result, the FFT circuit 15 performs the FFT processing on the digital audio signal for 512 samples, and outputs the transform coefficients obtained by the FFT processing to the MPU 19 via the internal bus 20.

Step S7: The MPU 19 sets the conversion coefficient C _n corresponding to the frequency component corresponding to the digital watermark information to be embedded to “0”. Here, the conversion coefficient C
Various methods are conceivable for the pattern in which the electronic watermark information is embedded by setting _n to “0”, in relation to the electronic watermark information embedding pattern in the preceding and following FFT processing blocks. These methods will be described later.

Step S8: The MPU 19 executes step S8.
The conversion coefficient set to "0" in step 8 or S10 and the other conversion coefficients input from the memory 14 are output to the IFFT circuit 16 via the internal bus 20. As a result, the IFFT circuit 16 performs IFFT processing using the conversion coefficient input from the MPU 19 to restore the digital audio signal.

Step S 9: The MPU 19 outputs the digital audio signal restored in the IFFT circuit 16 to the digital output I / F circuit 18 via the internal bus 20. Thus, the digital audio signal output from the digital output I / F circuit 18 is recorded on the recording medium 30.

Step S10: The MPU 19 stores in the memory 1
4 after erasing (clearing) the stored contents of step S2.
Return to the processing of.

In the digital watermark information embedding apparatus 100, when “0” is substituted for the conversion coefficient C _fn of one frequency component f _n of the frequency spectrum of one FFT processing block (the digital watermark information is embedded). FF)
It is assumed that the transform coefficient C _fn of the same frequency component f _n of the FFT processing block before and after the T processing block does not change. This is because, as will be described later, the digital watermark information detection device determines whether or not digital watermark information is embedded based on the temporal change of the conversion coefficient.

Hereinafter, in step S7 shown in FIG.
Various methods adopted when the conversion coefficient C _{n is set} to “0” and the digital watermark information is embedded will be described. [First Method] FIG. 6 is a diagram for explaining a first method of embedding digital watermark information by the MPU 19.
For example, the digital audio signal shown in FIG.
FFT processing is performed in units of continuous FFT processing blocks 50, 51, 52, 53, and 54 each having 512 samples, and FIGS. 6B, 6C, 6D, and 6D, respectively.
Consider the case where frequency spectra as shown in (E) and (F) are obtained. In the first method, the MPU 19
Digital watermark information is embedded at one FFT processing block interval, and one frequency component is set to “0” to embed digital watermark information. One digital watermark information is embedded in one FFT processing block. Specifically, FIG.
As shown in (C) and (E), the FFT processing block 5
Frequency component f of the frequency spectrum obtained from
_The digital watermark information is embedded by substituting “0” into the transform coefficient C _f3 corresponding to ₃ , and the FFT processing blocks 50, 52, 5
No. 4 does not embed digital watermark information. That is, FF
The same FFT processing block is embedded in the T processing blocks 51 and 53, and the same digital watermark information is embedded in the FFT processing blocks 50, 52 and 54.

[Second Method] FIG. 7 is a diagram for explaining a second method of embedding digital watermark information by the MPU 19. For example, a digital audio signal shown in FIG.
The FFT processing is performed for each of the T processing blocks 50, 51, 52, 53, and 54, as shown in FIG.
Consider a case where frequency spectra as shown in (C), (D), (E), and (F) are obtained. In the second method, the MPU 19 performs the FFT processing blocks 50, 51, 5
Digital watermark information is embedded in all of 2, 53 and 54.
For the same frequency component, digital watermark information is embedded at one FFT processing block interval. One digital watermark information is embedded in one FFT processing block.

Specifically, FIGS. 6 (B), (D), (F)
As shown in FIG. 6, digital watermark information is embedded by substituting “0” for the transform coefficient C _f4 corresponding to the frequency component f ₇ of the frequency spectrum obtained from the FFT processing blocks 50, 52, and 54, and ) As shown in FIG.
The digital watermark information is embedded by substituting “0” into the conversion coefficient C _f3 corresponding to the frequency component f ₃ of the frequency spectrum obtained from the processing blocks 51 and 53. That is, the same digital watermark information is embedded in the FFT processing blocks 50, 52, and 54, and the same digital watermark information is embedded in the FFT processing blocks 51 and 53.

[Third Method] FIG. 8 is a diagram for explaining the numbers assigned to the frequency components of the frequency spectrum in the third method. In the third method, as shown in FIG. 8, numbers “0” to “15” are assigned to frequency components f _{0 to} f ₁₅ of the frequency spectrum, respectively.

FIG. 9 is a diagram for explaining a third technique of embedding digital watermark information by the MPU 19. For example, the digital audio signal shown in FIG. 9A is subjected to FFT processing in units of continuous FFT processing blocks 50, 51, 52, 53, and 54 each having 512 samples, and as shown in FIGS. C), (D),
Consider the case where frequency spectra as shown in (E) and (F) are obtained. In the third method, the MPU 19
Digital watermark information is embedded in a part or all of a plurality of temporally continuous FFT processing blocks, but digital watermark information is embedded at intervals of one FFT processing block for the same frequency component. Also, in one FFT processing block,
Embed one piece of digital watermark information.

At this time, one piece of digital watermark information is composed of 4-bit information. Specifically, FIGS. 9 (B), (C),
As shown in (D), (E) and (F), the frequency components f ₇ , f ₃ , and f _{3 of} the frequency spectrum obtained from the FFT processing blocks 50, 51, 52, 53 and 54, respectively.
transform coefficients corresponding to f _1, f ₁₂ and f ₆ C _f7, C _f3,
The electronic watermark information is embedded by substituting “0” into C _f1 , C _f12 and C _f6 . At this time, the FFT processing blocks 50 to
Each of the digital watermark information embedded in
11 "," 0011 "," 0001 "," 1100 "and" 0110 ". That is, digital watermark information of a total of 20 bits is embedded in the FFT processing blocks 50 to 54. According to the present method, if different consecutive numbers are assigned in advance to 2 n frequency components having different frequency spectra obtained from the FFT processing block, n-bit digital watermark information per single FFT processing block can be obtained. Can be embedded.

[Fourth Method] FIG. 10 is a diagram for explaining a fourth method of embedding digital watermark information by the MPU 19. For example, the digital audio signal shown in FIG. 10A is subjected to FFT processing in units of continuous FFT processing blocks 50, 51, 52, 53, and 54 each having 512 samples.
Consider a case where frequency spectra as shown in (C), (D), (E), and (F) are obtained. In the fourth method, the MPU 19 performs the FFT processing blocks 50, 51, 5
2, 53, 54, 1FF for the same frequency component
Digital watermark information is embedded so as to be apart from the T processing block interval or more. One digital watermark information is embedded in one FFT processing block.

Then, the MPU 19 compares the transform coefficient with the digital watermark information embedded therein and the transform coefficient without the digital watermark information input from the FFT circuit 15 with the FF.
IFFT via the internal bus 20 in units of T processing blocks
The digital audio signal is output to the circuit 16 and subjected to IFFT processing by the IFFT circuit 16 to decode the digital audio signal, and the decoded digital audio signal is stored in the memory 14. Next, the FF shown in FIGS. 10 (G), (H), (I) and (J)
T processing blocks 60, 61, 62, 63
The decoded digital audio signal is transmitted to the FFT circuit 15
And the FFT circuit 15 performs the FFT processing.
Then, the MPU 19 changes the transform coefficients obtained by the FFT processing to change the FFT processing blocks 60, 61, 6
2 and 63, digital watermark information is embedded such that the same frequency component is separated by 1 FFT processing block interval or more.

As described above, according to the third method, for example, as in the FFT processing blocks 50 and 60, the 1F
Digital watermark information can also be individually embedded in FFT processing blocks that are not separated by FT processing blocks or more. At this time, if the FFT processing blocks do not completely match, the same frequency spectrum cannot be obtained.
Even when digital watermark information is individually embedded in FFT processing blocks that are not separated by T processing blocks or more, the digital watermark information detection device can detect digital watermark information based on a temporal change of a conversion coefficient.

When the fourth method is used,
The memory 14 stores the digital input I / F circuit 11 or A
It is necessary to have an area for storing the digital audio signal input from the / D conversion circuit 13 and an area for storing the restored digital audio signal input from the IFFT circuit 16. The FFT circuit 15 and the IFFT
The circuit 16 includes the FFT processing blocks 50 to 5 shown in FIG.
4 and the processing of the FFT processing blocks 60 to 63 must be capable of processing in parallel.

As described above, according to the digital watermark information embedding apparatus 100, among the conversion coefficients of the frequency spectrum obtained by performing the FFT processing on the original digital audio signal S9, the predetermined frequency component Digital watermark information is embedded depending on whether the conversion coefficient is set to “0”. Therefore, according to the digital watermark information embedding device 100, compared to the conventional method of superimposing pseudorandom noise on the original digital audio signal, deterioration of sound quality due to embedding of digital watermark information is perceived by humans. Can be suppressed. That is, according to the digital watermark information embedding device 100, one FFT processing block (512 samples)
By setting a specific frequency component to “0”, digital watermark information can be embedded, and the time during which digital watermark information is embedded is significantly shorter than when conventional pseudo-random noise is superimposed. Not perceived.

Since the time for embedding the digital watermark information is short as described above, the digital watermark information is embedded at the timing when the amplitude of the original digital audio signal sharply increases. When outputting a sound corresponding to the digital audio signal, the masking effect makes it possible to make the influence of the embedded digital watermark information on the sound hardly perceived. At this time, in order to further enhance the masking effect, the masking effect is further enhanced by embedding the digital watermark information only in a peak portion having a certain degree of sharpness by observing how the amplitude of the original digital audio signal rises.

Second Embodiment FIG. 11 shows a digital watermark information embedding device 200 according to the second embodiment .
FIG. As shown in FIG. 11, the digital watermark information embedding device 200 includes a digital input I / F circuit 11, an analog input I / F circuit 12, an A / D conversion circuit 13, a memory 14 (storage means), and an FFT circuit 15 ( Frequency analysis means), IFFT circuit 16 (orthogonal inverse transformation means), signal compression circuit 17, digital output I / F circuit 18 (output means),
An MPU 219 (information embedding unit), an internal bus 20 and an operation unit 21 are provided.

Here, digital input I / F circuit 11, analog input I / F circuit 12, A / D conversion circuit 13, memory 14, FFT circuit 15, IFFT circuit 16, signal compression circuit 17, digital output I / F Circuit 18, internal bus 20
The operation unit 21 is the same as that described in the first embodiment. That is, the digital watermark information embedding device 200
Means that the processing in the MPU 219 is the MPU of the first embodiment.
19 is different.

The MPU 219 has, for example, a digital input I
The amplitude level of the sample of the digital audio signal input to the / F circuit 11 is monitored, and when it is determined that the amplitude level is the peak level, the sample is determined to be a trigger signal, and the sample is continued. Digital watermark information is embedded in two temporally continuous FFT processing blocks. At this time, the conversion coefficients of two or more frequency components of the frequency spectrum obtained from the FFT processing block immediately after the sample determined to be the trigger signal are simultaneously set to “0”, so that the digital watermark information of the FFT processing block is stored in the FFT processing block. Embed the header part. At this time, a plurality of types of header sections may be set by changing the conversion coefficient to be "0" at the same time. Also, FFT in which the header part is embedded
For one or a plurality of FFT processing blocks following the processing block, the data part of the digital watermark information is embedded by setting the conversion coefficient of one frequency component of the frequency spectrum to “0”.

In this case, as in the first embodiment described above, between the FFT processing blocks that are temporally adjacent to each other,
"0" is not substituted for the same conversion coefficient. This is because the digital watermark information detection device detects whether or not digital watermark information is embedded based on a temporal change of the conversion coefficient.

For example, as shown in FIG. 12, after detecting the first peak level, the FFT processing block 150 following the sample having the first peak level transforms the samples corresponding to the frequency components f ₀ and f _8. "0" for coefficients C _f0 and C _f8
Is embedded in the header portion of the first digital watermark information. Further, the data portion of the first digital watermark information is embedded in the FFT processing block 151 by substituting “0” into the transform coefficient C _f3 corresponding to the frequency component f ₃ . Subsequently, after detecting the second peak level, the FFT processing block 160 following the sample having the second peak level adds transform coefficients C ₁ and f 2 corresponding to the frequency components f ₁ and f _7.
By substituting "0" into _f1 and _Cf7 , the header part of the second digital watermark information is embedded. Further, the data portion of the first digital watermark information is embedded in the FFT processing block 161 by substituting “0” into the transform coefficient C _f6 corresponding to the frequency component f ₆ .

As a method for embedding digital watermark information, for example, as shown in FIG. 13, frequency components f _{0 to} f ₇ for embedding a data portion and frequency components f _{10 to} f ₁₃ for embedding a header portion are overlapped. By substituting “0” into the conversion coefficient corresponding to one of the frequency components f _{10 to} f ₁₃ , the data portion of the digital watermark information can be embedded. Further, a plurality of types of header portions may be embedded by changing the number of frequency components for which the conversion coefficient is “0” among the frequency components f _{10 to} f ₁₃ .

Hereinafter, the processing in the MPU 219 will be mainly described. FIG. 14 and FIG. 15 are flowcharts for explaining a process of embedding digital watermark information in the MPU 219. Step S21: When the MPU 219 determines that the processing start instruction is issued by the operation of the operation unit 21 by the user, for example, the internal variable count indicating the number of audio signal samples stored in the memory 14 and the FFT in the FFT circuit 15 Internal variable FET_s indicating the number of samples constituting a unit (FFT processing block) for performing processing
ample, an internal variable flag_peak indicating whether or not the input sample is a trigger signal, and data_c for counting the number of data portions following the header portion.
ont is initialized. Specifically, the internal variable coun
"0" is substituted for t, flag_peak and data_cont, and "5" is set for the internal variable FET_sample.
12 ”.

Step S22: The MPU 219 receives an instruction to stop the processing by operating the operation unit 21 by the user, or inputs an audio signal from both the digital input I / F circuit 11 and the analog input I / F circuit 12. If at least one of the non-operations has been detected, the process ends, otherwise, the process of step S23 is executed.

Step S23: The MPU 219 monitors the amplitude level of the sample of the digital audio signal input to the digital input I / F circuit 11, and when it is determined that the amplitude level is the peak level, the sample is triggered. If it is determined that the signal is a signal, the process of step S24 is executed, and if not, the process of step S25 is executed.

Step S24: The MPU 219 substitutes "1" for the internal variable flag_peak.

Step S25: The MPU 219 determines whether or not the internal variable flag_peak is "1".
If it is determined to be “1”, the process of step S26 is executed, and if it is not “1”, the process of step S39 shown in FIG. 15 is executed.

Step S39: The MPU 219 converts the digital audio signal input from the digital input I / F circuit 11 into the internal bus 20 and the digital output I / F circuit 1
The data is written to the recording medium 30 as it is via 8.

Step S26: The MPU 219 stores the audio signal S9 for one sample input to the digital input I / F circuit 11 in the memory 14 via the internal bus 20, and increases the internal variable count by "1". I do.

Step S27: The MPU 219 determines whether or not the internal variable count and the internal variable FET_sample match, and if so, executes the processing of step S28 and determines that they do not match. In this case, the process returns to step S22. That is, MPU
In step 219, when the audio signal of 512 samples is stored in the memory 14, the process of step S28 is performed.

Step S28: The MPU 219 substitutes "0" for the internal variable "count".

Step S29: The MPU 219 transfers the audio signals of 512 samples stored in the memory 14 to the FFT circuit 15 via the internal bus 20.
As a result, the FFT circuit 15 performs the FFT processing on the audio signal for 512 samples, and converts the transform coefficients obtained by the FFT processing into the internal bus 20.
Is output to the MPU 219 via the.

Step S30: The MPU 219 determines whether or not the internal variable data_cnt is "0".
If it is determined to be "0", the process of step S31 is executed, and if it is not "0", the process of step S32 is executed.

Step S31: The MPU 219 performs the processing shown in FIG.
As described above, “0” is substituted for the transform coefficients corresponding to two or more frequency components among the transform coefficients obtained from the FFT processing block, and the header part of the digital watermark information is embedded.

Step S32: The MPU 219 performs the FFT
Of the transform coefficients obtained from the processing block, “0” is substituted for the transform coefficient corresponding to one frequency component, and the data part of the digital watermark information is embedded.

Step S33: The MPU 219 outputs to the IFFT circuit 16 via the internal bus 20 the conversion coefficient to which "0" has been substituted in step S31 or S32 and the other conversion coefficients input from the memory 14.
As a result, the IFFT circuit 16 performs IFFT processing using the conversion coefficient input from the memory 14 to restore the digital audio signal.

Step S34: The MPU 219 determines whether the IFF
The digital audio signal restored in the T circuit 16 is output to the digital output I / F circuit 18 via the internal bus 20. Thereby, the digital output I / F circuit 18
Digital audio signal output from the recording medium 3
Recorded as 0.

Step S35: The MPU 219 deletes (clears) the contents stored in the memory 14 and then proceeds to step S35.
It returns to the process of 32.

Step S36: The MPU 219 increases the internal variable data_cnt by one.

Step S37: The MPU 219 determines whether or not the internal variable data_cnt matches the constant N, and determines that the internal variable data_cnt matches the constant N (when digital watermark information is embedded in all data portions following the header portion). In step S38, the process of step S38 is executed, and if it is determined that they do not match, the process returns to step S22. Where the constant N
Indicates the number of data sections arranged following the header section.

Step S38: The MPU 219 sets “0” in the internal variables flag_peak and data_cnt.
Is returned, and the process returns to step S22.

In the present embodiment, the embedding process is performed on data portions corresponding to a plurality of header portions which are embedded by changing the transform coefficient corresponding to the same frequency component while changing the same frequency component. To Further, in order to increase detection accuracy, at least one of a plurality of header sections and a plurality of data sections having the same information (in which a transform coefficient corresponding to the same frequency component is changed) may be embedded.

As described above, according to the digital watermark information embedding device 200, the digital watermark information is embedded only immediately after the trigger signal.
The operation of detecting the digital watermark information only needs to be performed immediately after the detection of the trigger signal, and the load is reduced. Also, according to the digital watermark information embedding device 300, the header part of the digital watermark information is embedded in the FFT processing block immediately after the trigger signal in the digital audio signal, and the digital watermark information is subsequently embedded in one or more FFT processing blocks. Embed the data section of At this time, various electronic watermark information can be embedded by including the characteristics and control contents of the data part in the header part.

Other Embodiments of Digital Watermark Information Embedding Device
State for example, in the electronic watermark information embedding apparatus 200 of the second embodiment described above, an error correction code unit for error correction of the data portion may be embedded in the electronic watermark information. Further, an error correction code section for error correction between the header section and the data section following the header section may be embedded in the digital watermark information.

For example, as shown in FIG.
₁ , E ₂ , D ₃ , D ₄ , D ₅
(Error Correction Code) ₁ , ECC ₂ , ECC ₃ , E
CC ₄ and ECC ₅ are respectively divided into data parts D ₁ , D ₂ ,
Embedding is performed after D ₃ , D ₄ , and D ₅ . In the example shown in FIG. 16, the error correction code unit EE is used for each data unit.
C is provided. In this case, the error correction code section ECC may be provided in units of a plurality of data sections following the common header section.

As shown in FIG. 17, a single error correction code section ECC may be provided for a plurality of header sections and a data section following the header section. FIG.
In the example shown in FIG. 7, a single error correction code section ECC is provided for data sections D _{1 to} D ₅ corresponding to mutually different header sections H _{1 to} H ₅ .

In the above-described first and second embodiments, the frequency analysis means is not limited to the FFT, but may be the DCT (D
iscrete Cosine Transform) and MDCT (Modified Disc
Digital watermark information may be embedded by adding variation to the coefficients of each frequency component obtained by (reteCosine Transform) or the like.

In the above-described embodiment, after the digital audio signal is stored in the memory 14 shown in FIG.
Although the case of outputting to the FFT circuit 15 has been illustrated, for example, the input digital audio signal S9 may be directly output to the FFT circuit 15 without passing through the memory 14.

Hereinafter, a digital watermark information detecting apparatus according to an embodiment of the present invention will be described. Third Embodiment In the present embodiment, a digital watermark information detecting device for detecting digital watermark information from a digital audio signal in which digital watermark information is embedded using the digital watermark information embedding device of the first embodiment will be described. I do.

FIG. 18 is a configuration diagram of a digital watermark information detecting device 400 according to the present embodiment. As shown in FIG. 18, the digital watermark information detection device 400 includes a digital input I / F circuit 411, a memory 412 (storage means), and an FFT circuit 41.
3 (frequency analysis means), signal decompression circuit 414, digital output I / F circuit 415 (output means), D / A conversion circuit 4
16, 417, analog output I / F circuits 418, 419
(Output means), internal bus 420, display 421,
An MPU 422 (information detecting means) and an operation unit 423 are provided.

The digital input I / F circuit 411 converts an audio signal input from a recording medium (package medium) 30 such as an MD, CD-R, or DVD, an internet, or the like into an internal bus 420 based on transfer control of the MPU 422. Is output to the memory 412 via. The digital input I / F circuit 411 converts an audio signal input via a digital broadcast network or the Internet into an audio signal.
The data may be output to the memory 412 via the internal bus 420 based on the transfer control of the MPU 422.

The memory 412 stores the digital audio signal input from the digital input I / F circuit 411 or the signal decompression circuit 414, and performs FFT processing as a unit of frequency analysis processing in the FFT circuit 413 based on control from the MPU 422. When an audio signal (512 samples in this embodiment) constituting a block is stored,
The stored digital audio signal is read and output to the FFT circuit 413 via the internal bus 420.

The FFT circuit 413 performs FFT processing on the digital audio signal input from the memory 412 in units of FFT processing blocks, performs frequency analysis, converts the time domain to the frequency domain, and performs conversion based on control from the MPU 422. The coefficient is transferred to the MPU 42 via the internal bus 420.
Output to 2.

The signal expansion circuit 414 has a digital input I /
If the digital audio signal input from the F circuit 411 is compressed, the input digital audio signal is expanded and stored in the memory 412.

When the digital audio signal S30 can be copied, the digital output I / F circuit 415
Based on the control from U422, the digital audio signal read from the memory 412 is input and output as a digital audio signal S415. The A / D conversion circuits 416 and 417 convert the digital audio signals input from the memory 412 into analog audio signals based on the control from the MPU 422, and convert the analog audio signals into analog output I / F circuits 418 and 41.
9 respectively.

The MPU 422 performs overall control of each component in the digital watermark information detection device 400. Also, M
The PU 422 has a built-in DMA (Direct Memory Access) controller and controls data transfer between components via an internal bus 420.

Further, the MPU 422 monitors the storage state of the memory 412, and as described above, the digital audio signal constituting the FFT processing block which is the unit of the FFT processing in the FFT circuit 413 is transmitted from the digital input I / F circuit 411. When it is confirmed that the digital audio signal is stored in the memory 412, control is performed so that the digital audio signal stored in the memory 412 is output to the FFT circuit 413.

The MPU 422 inputs a transform coefficient as a result of the FFT processing from the FFT circuit 413 via the internal bus 420 and stores it in a built-in RAM. And M
The PU 422, based on the information that specifies the transform coefficient of the frequency component in which the digital watermark information stored in the RAM is embedded in advance, is output from the FFT circuit 413 to the transform coefficient specified by the information among the transform coefficients stored in the RAM. Is calculated, and it is determined that variation is added to the conversion coefficient whose temporal change rate is equal to or more than a certain value in accordance with the embedding of the digital watermark information. And MPU422
Is based on the conversion factor we have determined that variation has been added,
Identifies the embedded digital watermark information. Note that M
PU 422, based on the detection result of the digital watermark information,
It is determined whether the audio signal input from the digital input I / F circuit 411 is directly output to the digital output I / F circuit 415 and the D / A conversion circuits 416 and 417 via the internal bus 420.

The display 421 displays the contents of the digital watermark information detected by the MPU 422, and also displays, for example, the track number and title of the digital audio signal read from the recording medium 30, as shown in FIG. Is also good. Here, as the display 421, for example, a display using a liquid crystal, a cathode ray tube, or a light emitting diode is used, and display by a GUI (Graphical User Interface) of a computer display may be used. Note that, instead of the display 421, a speaker that outputs the content of the digital watermark information by voice may be used.

FIG. 20 is a flowchart for explaining the process of decrypting digital watermark information in MPU 422. In the decoding process described below, the digital watermark information is embedded in the digital audio signal by setting the conversion coefficient of the corresponding predetermined frequency component to “0”, and the three temporally continuous FFT processes are performed. The figure illustrates an example in which digital watermark information is decoded based on a temporal change of a transform coefficient obtained by the FFT circuit 413 for a block (512 × 3 samples). Where one FFT
When digital watermark information is embedded in one frequency component of a processing block, it is assumed that digital watermark information is not embedded in the frequency components of the FFT processing blocks before and after the digital watermark information.

Step S51: If the MPU 422 determines that a reproduction instruction has been issued by a user's operation of the operation unit 423, for example, the internal variable count, FET
Initialize _sample. Specifically, the internal variable c
"0" is substituted for "out" and the internal variable FET_samp
“512” is substituted for le. The timing at which step S51 is executed is determined so that the processing is performed in units of the FFT processing blocks processed in the first embodiment described above.

Step S52: The MPU 422 detects at least one of the processing stop instruction issued by the user operating the operation unit 423 and the digital audio signal not being input from the digital input I / F circuit 411. If so, the process ends; otherwise, the process of step S53 is executed.

Step S53: Every time the digital audio signal S30 for one sample is input to the digital input I / F circuit 411, the MPU 422 transfers the digital audio signal for one sample to the memory 412 via the internal bus 420. Then, the internal variable count is increased by “1”.

Step S54: The MPU 422 determines whether or not the internal variable count and the internal variable FET_sample match, and if so, executes the process of step S55 and determines that they do not match. In this case, the process returns to step S52. That is, MPU
In step 422, when the audio signal for 512 samples is stored in the memory 412, the process in step S55 is performed.

Step S55: The MPU 422 substitutes “0” for the internal variable “count”.

Step S56: The MPU 422 converts the 512-sample digital audio signal stored in the memory 412 into the FFT circuit 41 via the internal bus 420.
Transfer to 3. Thus, the FFT circuit 413 performs the FFT processing on the digital audio signal for 512 samples, and outputs the transform coefficients obtained by the FFT processing to the MPU 422 via the internal bus 420. The conversion coefficient is stored in a RAM built in the MPU 422.

Step S57: The MPU 422 sets the F
It is determined whether digital watermark information is embedded in the FT processing block. Specifically, the MPU 422 determines the same frequency component in the RAM in the previous step S56.
Is stored in the RAM in step S56 of this time.
The conversion coefficient stored in the RAM and the RAM in step S56 two times before
Is smaller than a constant value C such as 1/10, for example, when the result of division by the value obtained by adding the conversion coefficient stored in
It is determined that digital watermark information is embedded in the conversion coefficient, and if the value is equal to or greater than the predetermined value C, it is determined that digital watermark information is not embedded in the conversion coefficient. This is F
This is a process for judging whether or not digital watermark information is embedded in each frequency component of the frequency spectrum of the 512 samples in which the FT process was performed last time. Have substantially the same value, and the result of the division is about 1/2. On the other hand, if the digital watermark information is embedded in the frequency components of the 512 samples on which the FFT processing was performed last time, the conversion coefficient of the frequency components is “0”,
The conversion coefficient of the frequency component before and twice before is "0"
Therefore, even if the error of the FFT processing is considered, the result of the division is, for example, 1/20 or less.

Step S58: After erasing the contents stored in the memory 412, the MPU 422 returns to the processing of step S62.

As described above, according to the digital watermark information detecting device 400, the original digital audio signal is subjected to the FFT processing as in the digital watermark information embedding device 100 of the first embodiment. The conversion coefficient of a predetermined frequency component among the conversion coefficients of the obtained frequency spectrum is set to “0” to embed the digital watermark information. For example, the conversion coefficient is generated using the digital watermark information embedding device of the first embodiment described above. Digital watermark information can be appropriately detected from a digital audio signal. Further, according to the digital watermark information detection device 400, by performing FFT processing on three consecutive FFT processing blocks, it is possible to detect whether or not digital watermark information is embedded in a specific frequency component. Can be detected in a short time.

Fourth Embodiment In this embodiment, digital watermark information detection for detecting digital watermark information from a digital audio signal in which digital watermark information is embedded using the digital watermark information embedding apparatus of the second embodiment described above. The device will be described. FIG. 21 is a configuration diagram of the digital watermark information detection device 500 of the present embodiment. As shown in FIG. 21, the digital watermark information detecting device 50
0 is a digital input I / F circuit 411 and a memory 412
(Storage means), FFT circuit 413 (frequency analysis means),
Signal decompression circuit 414, digital output I / F circuit 415
(Output means), D / A conversion circuits 416 and 417, analog output I / F circuits 418 and 419 (output means), an internal bus 420, a display 421, an MPU 522 (information detection means), and an operation unit 423.

In FIG. 21, the components denoted by the same reference numerals as those in FIG. 18 are the same as the components described in the third embodiment. That is, the digital watermark information detecting device 5
In the case of 00, the processing in the MPU 522 is different from the processing in the MPU 422 of the second embodiment described above.

Hereinafter, the processing in MPU 522 will be mainly described. FIG. 22 and FIG. 23 are flowcharts for explaining the embedding process of the digital watermark information in the MPU 522. Step S61: When the MPU 522 determines that the processing start instruction has been issued by the operation of the operation unit 421 by the user, for example, the internal variable count indicating the number of audio signal samples stored in the memory 412, and the FF
Internal variable FE indicating the number of samples constituting a unit (FFT processing block) for performing FFT processing in T circuit 413
Initialize T_sample, an internal variable flag_peak indicating whether or not the input sample is a trigger signal, and an internal variable data_cont for counting the number of data portions following the header portion. Specifically, the internal variables count, flag_peak and data
_Cont is substituted with “0”, and the internal variable FET_sam
“512” is substituted for ple.

Step S62: The MPU 522 detects at least one of the processing stop instruction issued by the user operating the operation unit 421 and the audio signal not being input from the digital input I / F circuit 411. In this case, the process ends, and otherwise, the process of step S63 is executed.

Step S63: The MPU 522 monitors the amplitude level of the sample of the digital audio signal input to the digital input I / F circuit 411, and when it is determined that the amplitude level is the peak level, the sample is triggered. If it is determined that the signal is a signal, the process of step S64 is executed, and if not, the process of step S65 is executed.

Step S64: The MPU 522 substitutes "1" for the internal variable flag_peak.

Step S65: The MPU 522 determines whether or not the internal variable flag_peak is "1".
If it is determined to be “1”, the process of step S66 is executed, and if it is determined that it is not “1”, step S66 is performed.
It returns to the process of 62.

Step S66: The MPU 522 stores the audio signal S30 for one sample input to the digital input I / F circuit 411 in the memory 412 via the internal bus 420, and increases the internal variable count by "1". I do.

Step S67: The MPU 522 determines whether or not the internal variable count and the internal variable FET_sample match, and if so, executes the processing of step S68 and determines that they do not match. In this case, the process returns to step S62. That is, MPU
522 performs the process of step S68 when 512 samples of the audio signal are stored in the memory 14.

Step S68: The MPU 522 substitutes "0" for the internal variable "count".

Step S69: The MPU 522 transfers the audio signal of 512 samples stored in the memory 412 to the FFT circuit 413 via the internal bus 420. Thereby, in the FFT circuit 413, 512
The FFT processing is performed on the audio signals for the samples, and the transform coefficients obtained by the FFT processing are output to the MPU 522 via the internal bus 420.

Step S70: The MPU 522 determines whether or not the internal variable data_cnt is "0".
If it is determined to be "0", the process of step S72 is executed, and if it is not "0", the process of step S71 is executed.

Step S71: Internal variable data_cn
The process is executed when t is determined to be “0”, that is, when it is determined that the t is the header of the digital watermark information,
The MPU 522 specifies a transform coefficient having a temporal change among the transform coefficients input from the FFT circuit 413, and detects digital watermark information embedded in the header from the specified transform coefficient.

Step S72: Internal variable data_cn
MPU 522 is executed when it is determined that t is not “0”, that is, when it is determined that it is the data portion of the digital watermark information, and the MPU 522 has a temporal change in the transform coefficients input from the FFT circuit 413. The transform coefficient is specified, and digital watermark information embedded in the data part is detected from the specified transform coefficient.

Step S73: The MPU 522 erases (clears) the data stored in the memory 412.

Step S74: The MPU 522 increases the internal variable data_cnt by “1”.

Step S75: The MPU 522 compares the internal variable data_cnt with a predetermined constant N indicating the number of data parts, and if it is determined that they match, executes the processing of step S76. If it is determined that they do not match, the process returns to step S62.

Step S76: Internal variable data_cn
The MPU 522 executes the process when the t and the constant N match, that is, when the process of step S72 is performed on all data portions following the header portion.
“0” is substituted for ag_peak and data_cnt.

Step S77: The MPU 522 determines whether or not the header part and the data part of all the digital watermark information subjected to the error correction processing as a unit have been stored in the built-in RAM.

Step S78: The MPU 522 determines whether or not an error (error) exists in the data portion of the digital watermark information by using the error correction code section ECC embedded in the digital audio signal. For example, FIG.
In the example shown, in between the data unit _{D 1, D 2, (f} 3,
f ₁ ), (f ₃ , f ₆ ), (f ₇ , f ₁ ), and all combinations of (f ₇ , f ₆ ) are determined, and an error detection process is performed for each combination using the contents of the ECC unit. Then, one correct combination is determined from these combinations. At this time, in the digital audio signal, as described above with reference to FIG. 16, the error correction code section EC is provided for each data section corresponding to each header section.
When C is added, error correction processing is individually performed on all data sections using the corresponding error correction code section ECC.

Step S79: This is executed when it is determined in step S78 that there is no error, and the contents corresponding to the digital watermark information detected in steps S71 and S72 are displayed on the display 421.

Step S80: This is executed when it is determined in step S78 that an error exists, and is executed by the MPU.
A step 522 determines whether or not an error has been detected for all the combinations. If it is determined that the error has been detected, the process ends. If it is determined that the error has not been detected, step S81 is performed.
Execute the processing of

Step S81: The MPU 522 changes the combination and performs the processing of step S78 again.

Other Embodiments of Digital Watermark Information Detecting Apparatus
State or less, for example, as shown in FIG. 25, after detecting the first peak level, to detect the header portion of the first electronic watermark information of the FFT processing block 150 subsequent to the sample having the first peak level After detecting the data portion of the first digital watermark information of the FFT processing block 151 following the FFT processing block 151 and detecting the second peak level, the FFT processing block 1 following the sample having the second peak level is detected.
Consider a case where the header part of the first digital watermark information at 60 is detected, and the data part of the first digital watermark information at the FFT processing block 161 is detected. That is, the first
After detecting the peak level and the second peak level, the same first digital watermark information is embedded.

In this case, as shown in FIG. 25, some noise occurs, and the frequency component f ₀ ,
It is detected that the transform coefficients C _f0 , C _f8 , C _f12 corresponding to f ₈ , f ₁₂ are “0”, and the FFT processing block 16
0, the conversion coefficients C _f0 , C _f2 , and C _f0 corresponding to the frequency components f ₀ , f ₂ , and f ₈ .
It has been detected that C _f8 is “0”. FIG.
As shown in FIG. 5, some noise occurs, and the transform coefficient C _f3 , corresponding to the frequency components f ₃ , f ₁₀ of the data part of the first digital watermark information of the FFT processing block 151 is obtained.
It is detected that C _f10 is “0”, and transform coefficients C _f3 and C _f3 corresponding to the frequency components f ₃ and f ₆ for the data portion of the first digital watermark information of the FFT processing block 161
It is detected that _f6 is "0".

In this case, the digital watermark information detecting apparatus of the present invention obtains the logical product of the conversion coefficients (C _f0 , C _f8 , C _f12 ) and the conversion coefficients (C _f0 , C _f2 , C _f8 ). It is determined that the conversion coefficients (C _f0 , C _f8 ) in the header portion of the first digital watermark information are “0”. Further, a logical product of the conversion coefficients (C _f3 , C _f10 ) and the conversion coefficients (C _f3 , C _f6 ) is obtained, and the conversion coefficient C _f3 of the header portion of the first digital watermark information becomes “0”. Judge that

According to the digital watermark information detecting apparatus, when the same digital watermark information is embedded following different peak levels, a logical product is obtained between the digital watermark information and the converted digital watermark information. By specifying the coefficient, the accuracy of detection of the digital watermark information can be improved.

Fifth Embodiment FIG. 26 is a block diagram of a digital audio signal reproducing apparatus 600 of the present embodiment. As shown in FIG. 26, the digital audio signal reproducing device 600 is the same as the digital output information detecting device 400 shown in FIG.
18 and 419 are connected to a speaker 501.

In the digital audio signal reproducing apparatus 600, the digital audio signal S30 read from the recording medium 30 is D / A converted in the digital watermark information detecting apparatus 400, and the analog audio signal S41
8, S419 is output to the speaker 501. And
From the speaker 501, the analog audio signal S41
8. Sound corresponding to S419 is output. At this time, in the digital watermark information detecting device 400, for example, the digital watermark information of “prohibition of reproduction” is transmitted to the digital audio signal S30.
If the speaker 5 is determined to be embedded in the
The output of the analog audio signals S418 and S419 to C.01 may be prohibited. The output to the speaker 501 may be a digital audio signal S415 shown in FIG.

Sixth Embodiment FIG. 27 is a block diagram of a digital audio signal recording device 700 of the present embodiment. As shown in FIG. 27, the digital audio signal recording device 700 is a digital output I / F circuit 4 of the digital watermark information detecting device 400 shown in FIG.
15 is connected to a recorder 601.

In the digital audio signal recording device 700, the digital audio signal S30 read from the recording medium 30 is input to the digital watermark information detecting device 400, and is embedded in the digital audio signal S30 in the digital watermark information detecting device 400. Digital watermark information is detected, and it is determined whether the digital watermark information indicates “recordable”. Then, when it is determined to indicate “recordable”, the digital output I / F circuit 415 and / or the analog output I / F circuit 41 shown in FIG.
8, 419 to the recorder 601 from the digital audio signal S415 and / or the analog audio signal S4.
18, S419 are output and recorded on a predetermined recording medium.

[0144]

As described above, according to the digital signal processing apparatus and method of the present invention, digital watermark information can be embedded in a digital signal without substantially lowering the quality of the digital signal. Further, according to the digital signal processing apparatus and method of the present invention, it is possible to detect digital watermark information embedded by changing a transform coefficient indicating a level of a predetermined frequency component. Further, according to the digital signal processing device of the present invention, it is possible to detect embedded digital watermark information by changing a conversion coefficient indicating a level of a predetermined frequency component, and control the output of a digital signal based on the detection result. According to the digital signal processing device of the present invention, digital watermark information embedded by changing a conversion coefficient indicating a level of a predetermined frequency component is detected, and a digital signal is recorded on a recording medium based on the detection result. Can be controlled.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a digital watermark information embedding device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining processing in the FFT circuit shown in FIG. 1;

FIG. 3 is a diagram for explaining a process in the FFT circuit shown in FIG. 1;

FIG. 4 is a flowchart for explaining an operation of the digital watermark information embedding device shown in FIG. 1 and a process of embedding digital watermark information in an MPU;

FIG. 5 is a flowchart for explaining an operation of the digital watermark information embedding device shown in FIG. 1 and a process of embedding digital watermark information in the MPU;

FIG. 6 is a diagram for explaining a first technique of embedding digital watermark information by the MPU shown in FIG. 1;

FIG. 7 is a diagram for explaining a second technique of embedding digital watermark information by the MPU shown in FIG. 1;

FIG. 8 is a diagram for explaining the number assigned to the frequency component of the frequency spectrum in the third method of embedding digital watermark information by the MPU shown in FIG. 1;

FIG. 9 is a diagram for explaining a third technique of embedding digital watermark information by the MPU shown in FIG. 1;

FIG. 10 is a diagram for explaining a fourth technique of embedding digital watermark information by the MPU shown in FIG. 1;

FIG. 11 is a configuration diagram of a digital watermark information embedding device according to a second embodiment of the present invention.

FIG. 12 is a diagram for explaining a case where a header section and a data section are provided in digital watermark information in the digital watermark information embedding apparatus shown in FIG. 11;

FIG. 13 is a diagram for explaining a case where a header section and a data section are provided in digital watermark information in the digital watermark information embedding apparatus shown in FIG. 11;

FIG. 14 is a flowchart for explaining the operation of the digital watermark information embedding device shown in FIG. 11 and a process of embedding digital watermark information in the MPU;

FIG. 15 is a flowchart for explaining the operation of the digital watermark information embedding device shown in FIG. 11 and a process of embedding digital watermark information in the MPU;

FIG. 16 is a diagram for explaining a case where an ECC unit is provided in digital watermark information;

FIG. 17 is a diagram for explaining a case where an ECC unit is provided in digital watermark information;

FIG. 18 is a configuration diagram of a digital watermark information detection device according to a third embodiment of the present invention.

FIG. 19 is a diagram for explaining an example of a screen displayed on the display shown in FIG. 18;

FIG. 20 is a flowchart for explaining the operation of the digital watermark information detecting device shown in FIG. 18 and a process of detecting digital watermark information in the MPU;

FIG. 21 is a configuration diagram of a digital watermark information detection device according to a fourth embodiment of the present invention.

FIG. 22 is a flowchart for explaining the operation of the digital watermark information detection device shown in FIG. 21 and the processing for detecting digital watermark information in the MPU.

FIG. 23 is a flowchart for explaining the operation of the digital watermark information detection device shown in FIG. 21 and the processing for detecting digital watermark information in the MPU;

FIG. 24 is a diagram for explaining an example of an error detection process of the MPU shown in FIG. 21;

FIG. 25 is a diagram for explaining another example of the error detection processing of the MPU shown in FIG. 21;

FIG. 26 is a configuration diagram of a digital audio signal reproduction device according to an embodiment of the present invention.

FIG. 27 is a configuration diagram of a digital audio signal recording device according to an embodiment of the present invention.

[Explanation of symbols]

11, 411: digital input I / F circuit, 12: analog input I / F circuit, 13: A / D conversion circuit, 14, 41
2: memory, 15,413: FFT circuit, 16: IFF
T circuit, 17 ... signal compression circuit, 18, 415, 415 ...
Digital output I / F circuit, 19, 219, 422, 52
2, MPU, 20, 420, internal bus, 21, 423,
Operation unit 30, 30 recording medium, 416, 417 D / A conversion circuit, 421 display, 418, 419 analog output I / F circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yumi Kato 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Corporation (reference) 5C053 FA23 GA11 GA20 GB06 GB07 GB11 GB15 GB23 HA27 JA07 JA21 KA05 KA24 KA25 LA06 LA20 5D044 AB06 AB07 BC01 BC04 CC04 DE50 DE58 GK11 HL08 5J064 AA00 BA16 BB08 BB13 BC01 BC06 BC29 BD03

Claims (34)

[Claims] A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform a frequency analysis process, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis process is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of a component, and changing the value of at least one of the plurality of transform coefficients obtained from the transform processing block to a digital watermark to the transform processing block A digital signal processing device comprising: information embedding means for embedding information and embedding the digital watermark information in a plurality of the conversion processing blocks located apart from the single conversion processing block on the digital signal. 2. The frequency analysis means is an orthogonal transformation means for transforming the digital signal from a time domain to a frequency domain, wherein the frequency analysis means changes the value of the transform coefficient and the value of the plurality of transform coefficients. 2. The digital signal processing device according to claim 1, further comprising orthogonal inverse transform means for orthogonally inverse transforming a digital signal represented in a frequency domain by a transform coefficient into a time domain. 3. A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of a component, and changing the value of at least one of the plurality of transform coefficients obtained from the transform processing block to a digital watermark to the transform processing block A digital signal processing device comprising: information embedding means for embedding information and embedding the digital watermark information for a plurality of conversion processing blocks in which the frequency analysis processing is continuously performed. 4. The information embedding means, for a plurality of conversion processing blocks in which the frequency analysis processing is continuously performed, changes the value of a conversion coefficient indicating a level of a mutually different frequency component to change the digital watermark information. The digital signal processing device according to claim 3, in which is embedded. 5. A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform a frequency analysis process, and a frequency corresponding to a corresponding one of a plurality of frequency component levels obtained by the frequency analysis process is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of a component, and changing the value of at least one of the plurality of transform coefficients obtained from the transform processing block to a digital watermark to the transform processing block An information embedding unit that embeds information and embeds the digital watermark information in a plurality of conversion processing blocks located closer to a single conversion processing block on the digital signal. 6. A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating a level of a component; and a header of digital watermark information by changing a value of at least one of the plurality of transform coefficients obtained from the first transform processing block. And embedding a data part of the digital watermark information by changing a value of at least one of the plurality of transform coefficients obtained from a second transform processing block adjacent to the first transform processing block. A digital signal processing device having information embedding means. 7. The digital signal processing device according to claim 6, wherein said information embedding means embeds said header part indicating at least one of characteristics and control contents of said data part. 8. The information embedding means includes: a number of transform coefficients that change the value among the plurality of transform coefficients obtained from the first transform processing block;
The digital signal processing device according to claim 6, wherein the value of the conversion coefficient is changed such that the number of the conversion coefficients that change the value among the plurality of conversion coefficients obtained from the conversion processing block is different. 9. The information embedding means includes: a frequency component indicated by a transform coefficient that changes the value among the plurality of transform coefficients obtained from the first transform processing block; The digital signal processing device according to claim 6, wherein the value of the conversion coefficient is changed such that a frequency component indicated by the conversion coefficient that changes the value among the obtained plurality of conversion coefficients is different. 10. The information embedding unit embeds a plurality of types of header sections by changing the number of transform coefficients that change the value among the plurality of transform coefficients obtained from the first transform processing block. The digital signal processing device according to claim 6. 11. The information embedding means, by changing a frequency component indicated by a transform coefficient for changing the value among the plurality of transform coefficients obtained from the first transform processing block, forms a plurality of types of header sections. The digital signal processing device according to claim 6, wherein the digital signal processing device is embedded. 12. The information embedding means, when embedding a plurality of header portions and a plurality of data portions corresponding to the plurality of header portions, changing a plurality of embeddings by changing the same frequency component. 7. The digital signal processing device according to claim 6, wherein the embedding is performed on a plurality of data portions respectively corresponding to the header portion while changing the same frequency component. 13. The digital signal processing apparatus according to claim 6, wherein said information embedding means embeds at least one of a plurality of header sections and a plurality of data sections by changing the same frequency component. 14. The digital signal processing apparatus according to claim 6, wherein said information embedding means embeds error correction codes individually generated for a plurality of data parts corresponding to different header parts. 15. The digital signal processing apparatus according to claim 6, wherein said information embedding means embeds an error correction code integrally generated for a plurality of data parts having different header parts. 16. The frequency analysis means according to claim 1, wherein at least one of a digital audio signal and a digital image signal is frequency-converted as the digital signal.
3. The digital signal processing device according to claim 1. 17. A trigger signal detecting means for detecting a trigger signal included in the input digital signal based on an amplitude level of the input digital signal; and detecting the input digital signal after detecting the trigger signal. Frequency analysis means for performing frequency conversion and frequency analysis processing, and generating a plurality of conversion coefficients each indicating a level of a corresponding frequency component among a plurality of frequency component levels obtained by the frequency analysis processing; The header portion of the digital watermark information is embedded by changing the value of at least one of the plurality of transform coefficients obtained from the transform processing block, and is obtained from the second transform process block following the first transform process block. Embedding the data portion of the digital watermark information by changing the value of at least one of the plurality of transform coefficients Digital signal processing apparatus and an information embedding means. 18. A digital signal is frequency-converted and subjected to frequency analysis processing in units of a conversion processing block consisting of a predetermined amount of digital signals, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of a component, and specifying a transform coefficient having a temporal change equal to or more than a reference amount based on a temporal change of the generated transform coefficients. The conversion coefficient change specifying means, and a plurality of conversion processing blocks different from each other, commonly obtains the specified conversion coefficient, and embeds in the digital signal based on the commonly specified conversion coefficient. A digital signal processing device having information detection means for detecting digital watermark information. 19. An input unit for inputting the digital signal, a trigger signal detecting unit for detecting a trigger signal included in the input digital signal based on an amplitude level of the input digital signal, and the frequency analyzing unit 19. The digital signal processing device according to claim 18, wherein the frequency analysis process is performed after the trigger signal is detected. 20. A digital signal is frequency-converted and subjected to frequency analysis processing in units of a conversion processing block composed of a predetermined amount of digital signals, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of the component, based on a temporal change of the generated plurality of transform coefficients, to identify a transform coefficient having a temporal change equal to or more than a reference amount Detecting a header portion and a data portion of the digital watermark information embedded in the digital signal based on the specified conversion coefficient, and performing error correction detection in units of the data portions corresponding to the detected individual header portions. A digital signal processing device comprising: an information detection unit that performs processing and detects digital watermark information embedded in the digital signal. 21. The digital signal processing apparatus according to claim 20, wherein the error correction processing is individually performed on the data portions corresponding to all the detected header portions. 22. An input unit for inputting the digital signal, a trigger signal detecting unit for detecting a trigger signal included in the input digital signal based on an amplitude level of the input digital signal, and the frequency analyzing unit The digital signal processing device according to claim 20, wherein the frequency analysis process is performed after the trigger signal is detected. 23. A digital signal is frequency-converted and frequency-analyzed in units of a conversion processing block composed of a predetermined amount of digital signals, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency-analysis processing is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of the component, based on a temporal change of the generated plurality of transform coefficients, to identify a transform coefficient having a temporal change equal to or more than a reference amount Detecting a header portion and a data portion of the digital watermark information embedded in the digital signal based on the specified conversion coefficient, and performing error correction detection in units of the data portions corresponding to the plurality of detected header portions. A digital signal processing device comprising: an information detection unit that performs processing and detects digital watermark information embedded in the digital signal. 24. An input unit for inputting the digital signal, a trigger signal detecting unit for detecting a trigger signal included in the input digital signal based on an amplitude level of the input digital signal, and the frequency analyzing unit 24. The digital signal processing device according to claim 23, wherein the frequency analysis process is performed after the trigger signal is detected. 25. A digital signal is frequency-converted and subjected to frequency analysis processing in units of a conversion processing block consisting of a predetermined amount of digital signal, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of a component, and specifying a transform coefficient having a temporal change equal to or more than a reference amount based on a temporal change of the generated transform coefficients. The conversion coefficient change specifying means, and a plurality of conversion processing blocks different from each other, commonly obtains the specified conversion coefficient, and embeds in the digital signal based on the commonly specified conversion coefficient. Information detecting means for detecting the digital watermark information being output; output means for performing output in accordance with the digital signal; and Control means for controlling whether or not the digital signal can be output by the input means. 26. A digital signal is frequency-converted and frequency-analysis-processed in units of a conversion processing block comprising a predetermined amount of digital signal, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency-analysis process is obtained. Frequency analysis means for generating a plurality of transform coefficients each indicating the level of a component, and specifying a transform coefficient having a temporal change equal to or more than a reference amount based on a temporal change of the generated transform coefficients. The conversion coefficient change specifying means, and a plurality of conversion processing blocks different from each other, commonly obtains the specified conversion coefficient, and embeds in the digital signal based on the commonly specified conversion coefficient. Information detecting means for detecting digital watermark information that is present; recording means for recording the digital signal on a recording medium; and Control means for controlling whether or not the digital signal is output by the recording means. 27. A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Generating a plurality of transform coefficients each indicating a component level, embedding digital watermark information in the transform processing block by changing a value of at least one transform coefficient among the plurality of transform coefficients obtained from the transform processing block, A digital signal processing method for embedding the digital watermark information for a plurality of the conversion processing blocks located at least a distance from the single conversion processing block on the digital signal. 28. A digital signal is frequency-converted in units of a conversion block composed of a predetermined amount of digital signals to perform a frequency analysis process, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis process is obtained. Generating a plurality of transform coefficients each indicating a component level, embedding digital watermark information in the transform processing block by changing a value of at least one transform coefficient among the plurality of transform coefficients obtained from the transform processing block, A digital signal processing method for embedding the digital watermark information in a plurality of conversion processing blocks in which the frequency analysis processing is continuously performed. 29. A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Generating a plurality of transform coefficients each indicating a component level, embedding digital watermark information in the transform processing block by changing a value of at least one transform coefficient among the plurality of transform coefficients obtained from the transform processing block, A digital signal processing method for embedding the digital watermark information in a plurality of the conversion processing blocks located closer to a single conversion processing block on the digital signal. 30. A digital signal is frequency-converted in units of a conversion processing block composed of a predetermined amount of digital signals to perform frequency analysis processing, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis processing is obtained. Generating a plurality of transform coefficients each indicating a component level, embedding a header part of digital watermark information by changing a value of at least one of the plurality of transform coefficients obtained from the first transform processing block, Digital signal processing method for embedding a data part of the digital watermark information by changing a value of at least one of the plurality of transform coefficients obtained from a second transform processing block adjacent to the first transform processing block . 31. A trigger signal included in the input digital signal is detected based on the amplitude level of the input digital signal. After the trigger signal is detected, the input digital signal is frequency-converted. Performing an analysis process, generating a plurality of transform coefficients each indicating a level of a corresponding frequency component among a plurality of frequency component levels obtained by the frequency analysis process, and obtaining the plurality of transform coefficients obtained from a first transform process block The header of the digital watermark information is embedded by changing the value of at least one of the transform coefficients among the transform coefficients, and among the plurality of transform coefficients obtained from the second transform processing block following the first transform processing block, A digital signal processing method for embedding a data portion of the digital watermark information by changing a value of at least one conversion coefficient. 32. A digital signal is frequency-converted and frequency-analyzed in units of a conversion block composed of a predetermined amount of digital signals, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis is obtained. Generating a plurality of transform coefficients each indicating a component level; identifying transform coefficients having a temporal change equal to or more than a reference amount based on a temporal change of the generated transform coefficients; A digital signal for obtaining the specified conversion coefficient in common among a plurality of conversion processing blocks and detecting digital watermark information embedded in the digital signal based on the commonly specified conversion coefficient. Processing method. 33. A digital signal is frequency-converted and frequency-analyzed in units of a conversion processing block composed of a predetermined amount of digital signals, and a corresponding frequency among a plurality of frequency component levels obtained by the frequency analysis is obtained. A plurality of transform coefficients each indicating the level of the component are generated, and a transform coefficient having a temporal change equal to or more than a reference amount is specified based on the temporal change of the generated plurality of transform coefficients, and the specified Based on the transform coefficient, a header part and a data part of the digital watermark information embedded in the digital signal are detected, and an error correction detection process is performed in units of the data part corresponding to the detected individual header parts. A digital signal processing method for detecting digital watermark information embedded in the digital signal. 34. A digital signal is frequency-converted and frequency-analyzed in units of a conversion processing block composed of a predetermined amount of digital signals, and a frequency corresponding to a corresponding one of a plurality of frequency component levels obtained by the frequency analysis is obtained. A plurality of transform coefficients each indicating the level of the component are generated, and a transform coefficient having a temporal change equal to or more than a reference amount is specified based on the temporal change of the generated plurality of transform coefficients, and the specified Based on the conversion coefficient, detecting a header portion and a data portion of the digital watermark information embedded in the digital signal, performing an error correction detection process in units of the data portion corresponding to the plurality of detected header portions. A digital signal processing method for detecting digital watermark information embedded in the digital signal.