ENCODING DEVICE, DECODING DEVICE, CONTROL METHOD FOR AN ENCODING DEVICE, CONTROL METHOD FOR A DECODING DEVICE, TRANSMISSION SYSTEM, AND COMPUTER-READABLE RECORDING MEDIUM HAVING A CONTROL PROGRAM RECORDED THEREON

• US 20120207226A1
• Filed: 06/23/2010
• Published: 08/16/2012
• Est. Priority Date: 11/17/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Gohshi, Seiichi
• Granted Patent: US 8,811,765 B2
• Time in Patent Office: Days
• US Class Current: 375/240.25
• CPC Class Codes: G10L 19/0212 using orthogonal transformation

Abstract

Disclosed is an encoding device, which is an encoding device that outputs an encoded signal including a signal in which an original signal is encoded, the original signal indicative of at least one of image and audio, which encoding device includes a frequency component extraction section that extracts a part of frequency components of the original signal from the original signal to generate a frequency component extraction signal and an encoding process section that encodes the frequency component extraction signal and the original signal while switching between the frequency component extraction signal and the original signal, and making the signal thus encoded be included in the encoded signal.

Claims

1. An encoding device that outputs an encoded signal, the encoded signal including a signal in which an original signal is encoded, the original signal being indicative of contents of at least one of image and audio, the encoding device comprising:

frequency component extracting means for extracting, from the original signal, a part of frequency components included in the original signal, to generate a frequency component extraction signal; and

encoding means for encoding the frequency component extraction signal and the original signal in such a manner that the encoding is carried out while switching over between the frequency component extraction signal and the original signal, and making the signal thus encoded be included in the encoded signal.

2. The encoding device according to claim 1, wherein

the frequency component extracting means includes:

high-frequency component removing means for removing a high-frequency component from frequency components of the original signal, to generate a high-frequency-free signal;

high-frequency component generation means for generating harmonics of the high-frequency-free signal; and

subtraction means for subtracting the harmonics of the high-frequency-free signal from the original signal, to generate the frequency component extraction signal,

the high-frequency component generation means including;

low-frequency component removing means for removing, from frequency components of the high-frequency-free signal, a low-frequency component at least including a direct current component, to generate a low-frequency-free signal;

nonlinear process means for generating a nonlinear process signal (i) in which positive and negative signs of the low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the low-frequency-free signal when values of the low-frequency-free signal are at least in the vicinity of 0; and

addition means for adding the nonlinear process signal to the high-frequency-free signal, to generate the harmonics.

3. The encoding device according to claim 2, wherein

the contents is constituted of a plurality of frames that are consecutive in terms of time,

the encoding means further (i) makes, for each frame, any one of a first signal and a second signal be included in the encoded signal, the first signal being a signal in which the original signal is encoded and the second signal being a signal in which the frequency component extraction signal is encoded, and (ii) outputs motion vector information for carrying out motion compensation prediction among the frames,

the encoding device further comprising:

decoding means for decoding the encoded signal, to generate a decoded signal;

second high-frequency component generation means for generating harmonics of the decoded signal; and

second subtraction means for subtracting the harmonics of the decoded signal from the original signal, to generate a difference signal,

the decoding means further (i) generating, as the decoded signal when the first signal is decoded, a signal in which the first signal is decoded, and (ii) generating, as the decoded signal when the second signal is decoded, a signal by adding (a) a signal of a decoded signal generated immediately before that has been subjected to motion compensation with use of the motion vector information and (b) a signal in which the second signal is decoded,

the second high-frequency component generation means including;

second low-frequency component removing means for removing, from frequency components of the decoded signal, a low-frequency component at least including a direct current component, to generate a second low-frequency-free signal;

second nonlinear processing means for generating a second nonlinear process signal (i) in which positive and negative signs of the second low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the second low-frequency-free signal when values of the second low-frequency-free signal are at least in the vicinity of 0; and

second addition means for adding the second nonlinear process signal to the decoded signal, to generate harmonics generated by the second high-frequency component generation means,

each of the high-frequency component removing means, the low-frequency component removing means, and the second low-frequency component removing means increasing and reducing the frequency components to be removed, in response to an instruction received from outside,

the encoding device further comprising;

a frequency component control section that controls, depending on a value of the difference signal, the increase and reduction in the frequency components to be removed by at least one of the high frequency component removing means, the low frequency component removing means, and the second low-frequency component removing means.

4. The encoding device according to claim 3, wherein

when a total of an absolute value of signals included in the difference signal is greater than a predetermined threshold, the frequency component control section controls so as to reduce a high-frequency component removed by the high-frequency component removing means, controls so as to increase a low-frequency component to be removed by the low-frequency component removing means, and controls so as to increase a low-frequency component to be removed by the second low-frequency component removing means, and

when the total is not more than the predetermined threshold, the frequency component control section controls so as to increase the high-frequency component to be removed by the high-frequency component removing means, controls so as to reduce the low-frequency component to be removed by the low-frequency component removing means, and controls so as to reduce the low-frequency component to be removed by the second low-frequency component removing means.

5. The encoding device according to claim 4, further comprising:

signal decimation means for decimating the original signal and the frequency component extraction signal; and

signal interpolation means for interpolating the decoded signal.

6. The encoding device according to claim 2, wherein

the nonlinear process means includes:

even exponentiation operation means for generating an even exponentiation signal by raising the low-frequency-free signal to an even exponent not less than 2; and

sign changing means for generating the nonlinear process signal by reversing positive and negative signs of a part of the even exponentiation signal which part is different in sign from the low-frequency-free signal.

7. The encoding device according to claim 2, wherein

the nonlinear process means includes:

even exponentiation operation means for generating an even exponentiation signal by raising the low-frequency-free signal to an even exponent not less than 2;

differentiation means for generating a differential signal by differentiating the even exponentiation signal; and

sign changing means for generating the nonlinear process signal by reversing positive and negative signs of a part of the differential signal which part is different in sign from the low-frequency-free signal.

8. The encoding device according to claim 2, wherein

the nonlinear process means includes odd exponentiation operation means for generating the nonlinear process signal by raising the low-frequency-free signal to an odd exponent not less than 3.

9. The encoding device according to claim 2, wherein

the nonlinear processing means includes

square root operation means for generating a square root signal by multiplying (i) a square root of an absolute value of a value calculated by dividing the low-frequency-free signal by a possible maximum value of the low-frequency-free signal, by (ii) the maximum value;

and

sign changing means for generating the nonlinear process signal by reversing positive and negative signs of a part of the square root signal which part is different in sign from the low-frequency-free signal.

10. The encoding device according to claim 2, wherein

the nonlinear process means further includes amplitude adjustment means for adjusting an amplitude of the nonlinear process signal by multiplying the amplitude by a predetermined magnification value.

11. The encoding device according to claim 2, wherein

when the values of the low-frequency-free signal are around 0, the nonlinear process means generates the nonlinear process signal so that the nonlinear process signal has an absolute value larger than that of the low-frequency-free signal.

12. The encoding device according to claim 2, wherein the low-frequency component removing means is a high-pass filter having 3 or more taps.

13. The encoding device according to claim 2, wherein

the low-frequency component removing means further includes:

low-level signal removing means for changing, out of signal values of the low-frequency-free signal, signal values whose absolute values are lower than a predetermined lower limit to 0, and

high-level signal removing means for changing, out of the signal values of the low-frequency-free signal, signal values whose absolute values are higher than a predetermined upper limit in such a manner that the absolute values are not higher than the predetermined upper limit while maintaining signs of that signal values.

17. A transmission system, comprising:

an encoding device as set forth in claim 1 as a transmitting device; and

a decoding device as a receiving device, the decoding device being one that generates a decoded signal by receiving, as an input, an encoded signal including a signal in which an original signal is encoded, the original signal being indicative of contents of at least one of image and audio,

the contents being constituted of a plurality of frames that are consecutive in terms of time,

the encoding of the original signal causing an output of motion vector information for carrying out motion compensation prediction among the frames,

the encoded signal including, in each frame, any one of a first signal or a second signal, the first signal being a signal in which the original signal is encoded and the second signal being a signal in which a part of frequency components included in the original signal is encoded, and the decoding device comprising

decoding means for generating, as the decoded signal when the first signal is decoded, a signal in which the first signal is decoded, and generating, as the decoded signal when the second signal is decoded, a signal by adding (a) a signal of a decoded signal generated immediately before that has been subjected to motion compensation with use of the motion vector information and (b) a signal in which the second signal is decoded;

the contents being constituted of a plurality of frames that are consecutive in terms of time,

the encoding means further (i) makes, for each frame, any one of a first signal and a second signal be included in the encoded signal, the first signal being a signal in which the original signal is encoded and the second signal being a signal in which the frequency component extraction signal is encoded, and (ii) outputs motion vector information for carrying out motion compensation prediction among the frames.

18. A transmission system, comprising

an encoding device as set forth in claim 3 as a transmitting device;

and

a decoding device as a receiving device, the decoding device further including third high-frequency component generation means for generating harmonics of the decoded signal, the decoding device being one that generates a decoded signal by receiving, as an input, an encoded signal including a signal in which an original signal is encoded, the original signal being indicative of contents of at least one of image and audio,

the contents being constituted of a plurality of frames that are consecutive in terms of time,

the encoding of the original signal causing an output of motion vector information for carrying out motion compensation prediction among the frames,

the encoded signal including, in each frame, any one of a first signal or a second signal, the first signal being a signal in which the original signal is encoded and the second signal being a signal in which a part of frequency components included in the original signal is encoded, and the decoding device comprising

decoding means for generating, as the decoded signal when the first signal is decoded, a signal in which the first signal is decoded, and generating, as the decoded signal when the second signal is decoded, a signal by adding (a) a signal of a decoded signal generated immediately before that has been subjected to motion compensation with use of the motion vector information and (b) a signal in which the second signal is decoded;

the third high-frequency component generation means including;

third low frequency component removing means for removing, from frequency components of the decoded signal, a low-frequency component at least including a direct current component, to generate a third low-frequency-free signal;

third nonlinear processing means for generating a third nonlinear process signal (i) in which positive and negative signs of the third low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the third low-frequency-free signal when values of the third low-frequency-free signal are at least in the vicinity of 0; and

third addition means for adding the third nonlinear process signal to the decoded signal, to generate harmonics generated by the third high-frequency component generation means,

the decoding means included in the decoding device increasing and reducing the low-frequency component to be removed by the third low-frequency-component removing means, so that the low-frequency component removed by the second low-frequency component removing means included in the encoding device agrees with the low-frequency components removed by the third low frequency component removing means.

19. A computer-readable recording medium in which a control program is recorded, the control program causing a computer included in an encoding device as set forth in claim 1 to operate as means of the encoding device.

14. A decoding device that generates a decoded signal by receiving, as an input, an encoded signal including a signal in which an original signal is encoded, the original signal being indicative of contents of at least one of image and audio,

the contents being constituted of a plurality of frames that are consecutive in terms of time,

the encoding of the original signal causing an output of motion vector information for carrying out motion compensation prediction among the frames,

the encoded signal including, in each frame, any one of a first signal or a second signal, the first signal being a signal in which the original signal is encoded and the second signal being a signal in which a part of frequency components included in the original signal is encoded,

the decoding device comprising:

decoding means for generating, as the decoded signal when the first signal is decoded, a signal in which the first signal is decoded, and generating, as the decoded signal when the second signal is decoded, a signal by adding (a) a signal of a decoded signal generated immediately before that has been subjected to motion compensation with use of the motion vector information and (b) a signal in which the second signal is decoded.

20. A computer-readable recording medium in which a control program is recorded, the control program causing a computer included in a decoding device as set forth in claim 14 to operate as means of the decoding device.

15. A method of controlling an encoding device that outputs an encoded signal, the encoded signal including a signal in which an original signal is encoded, the original signal being indicative of contents of at least one of image and audio, the method comprising:

extracting from the original signal a part of frequency components included in the original signal, to generate a frequency component extraction signal;

encoding the frequency component extraction signal and the original signal in such a manner that the encoding is carried out while switching over between the frequency component extraction signal and the original signal; and

making the signal thus encoded be included in the encoded signal.

16. A method of controlling a decoding device that generates a decoded signal by receiving, as an input, an encoded signal including a signal in which an original signal is encoded, the original signal being indicative of contents of at least one of image and audio,

the contents being constituted of a plurality of frames that are consecutive in terms of time,

the encoding of the original signal causing an output of motion vector information for carrying out motion compensation prediction among the frames,

the encoded signal including, in each frame, any one of a first signal or a second signal, the first signal being a signal in which the original signal is encoded and the second signal being a signal in which a part of frequency components included in the original signal is encoded,

the method comprising:

generating, as the decoded signal when the first signal is decoded, a signal in which the first signal is decoded; and

generating, as the decoded signal when the second signal is decoded, a signal by adding (a) a signal of a decoded signal generated immediately before that has been subjected to motion compensation with use of the motion vector information and (b) a signal in which the second signal is decoded.