JP2004056459A - Imformation signal processor, information signal processing method, iamge signal processor and image display, device and method generating correction data used therefor, program for each method, and computer readable medium recording program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfactorily reduce the coding noise (coding distortion) in information signals obtained by decoding the coded digital information signals. <P>SOLUTION: Using a plurality of pixel data of an image signal Va locating around an interested position on an image signal Vb, a classifier 130 generates a class code CL showing the class to which pixel data y at the interested position on the image signal Vb belong. Based on the class CL, a means reads difference data DF (corrected data of a coded noise) corresponding to the interested position on the image signal Vb from a storage table 131. A means feeds an adder 134 with pixel data (pixel values or DCT coefficients) x corresponding to the interested position on the image signal Vb via a changeover switch 133. The adder 134 adds the difference data DF read from the storage table to the pixel data to obtain the pixel data y at the interested position on the image signal Vb. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an information signal processing device, an information signal processing method, an image signal processing device and an image display device, a correction data generating device and a generating method used therein, and a program for executing each method and a recording of the program. Computer-readable medium.
[0002]
More specifically, the present invention detects a class to which pixel data of a target position in an output information signal belongs based on an input information signal, and detects information data corresponding to the target position in the output information signal among information data forming the input information signal. Is corrected using the correction data corresponding to the detected class to obtain the information data of the target position in the output information signal, and thereby the code of the information signal obtained by decoding the encoded digital information signal. The present invention relates to an information signal processing device and the like capable of favorably reducing formation noise.
[0003]
[Prior art]
As a compression encoding method of an image signal, there is an encoding method based on MPEG (Moving Picture Expert Group phase) using DCT (discrete cosine transform). DCT performs discrete cosine transform on pixels in a block, requantizes coefficient data obtained by the discrete cosine transform, and further performs variable length coding on the requantized coefficient data. is there. For this variable length coding, entropy coding such as Huffman coding is often used. The image data is divided into a large number of frequency data from low frequency to high frequency by orthogonal transformation.
[0004]
When performing requantization on the divided frequency data, low-frequency data, which is important in consideration of human visual characteristics, is finely quantized and the importance is determined in consideration of human visual characteristics. The low-frequency data is characterized in that high-quality data can be maintained and efficient compression can be realized by coarsely performing quantization.
[0005]
Conventional decoding using DCT converts the quantized data for each frequency component into a representative value of the code, and performs inverse DCT (IDCT: Inverse DCT) on those components to convert the reproduced data. obtain. When converting to this representative value, the quantization step width at the time of encoding is used.
[0006]
[Problems to be solved by the invention]
As described above, the encoding method based on MPEG using DCT has the advantage that high-quality images can be maintained and high-efficiency compression can be realized by performing encoding in consideration of human visual characteristics.
[0007]
However, since the encoding that performs DCT is a process in units of blocks, block-like noise, so-called block noise (block distortion), may occur as the compression ratio increases. Also, in a portion where there is a sharp change in luminance such as an edge, a rough noise caused by coarsely quantizing a high-frequency component, so-called mosquito noise, is generated.
[0008]
Such coding noise (coding distortion) may be generated not only by the MPEG coding method but also by other coding methods.
[0009]
Therefore, an object of the present invention is to provide an information signal processing device or the like that can satisfactorily reduce coding noise (coding distortion) of an information signal obtained by decoding a coded digital information signal. .
[0010]
[Means for Solving the Problems]
An information signal processing device according to the present invention converts a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information including a plurality of pieces of information data. An information signal processing device that converts a plurality of pieces of first information data located around a target position in the second information signal based on the first information signal; Class detecting means for detecting the class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means; and encoding corresponding to the class detected by the class detecting means. Correction data generating means for generating correction data for correcting noise; and a plurality of pieces of information data constituting the first information signal, which correspond to a position of interest in the second information signal. And correcting means for performing correction processing using the correction data generated by the correction data generating means on the second information data to obtain information data of a position of interest in the second information signal. .
[0011]
Further, the information signal processing method according to the present invention converts the first information signal including a plurality of pieces of information data generated by decoding the encoded digital information signal into a second information signal including a plurality of pieces of information data. An information signal processing method for converting a plurality of pieces of first information data located around a position of interest in a second information signal based on the first information signal. And a second step of detecting a class to which the information data of the position of interest belongs based on the plurality of pieces of first information data selected in the first step, and corresponding to the class detected in the second step. A third step of generating correction data for correcting coding noise, and a second step corresponding to a position of interest in the second information signal among a plurality of information data constituting the first information signal. Respect of the information data, the third by performing correction processing using the generated correction data was in step, in which and a fourth step of obtaining information data of the target position in the second information signal.
[0012]
Further, a program according to the present invention is for causing a computer to execute the above information signal processing method. A computer-readable medium according to the present invention stores the above-mentioned program.
[0013]
Also, the image signal processing device according to the present invention converts the first image signal composed of a plurality of pixel data, which is generated by decoding the encoded digital image signal, into a second image signal composed of a plurality of pixel data. An image signal processing device for converting a plurality of first pixel data located around a position of interest in a second image signal based on the first image signal; Class detecting means for detecting a class to which the pixel data at the target position belongs based on the plurality of first pixel data selected by the data selecting means; and a code corresponding to the class detected by the class detecting means. Correction data generating means for generating correction data for correcting quantization noise, and a plurality of pixel data constituting the first image signal, which correspond to a position of interest in the second image signal. And a correction unit that performs a correction process using the correction data generated by the correction data generation unit on the second pixel data to obtain pixel data of a target position in the second image signal. .
[0014]
Further, an image display device according to the present invention includes: an image signal input unit configured to receive a first image signal including a plurality of pixel data, which is generated by decoding an encoded digital image signal; Image signal processing means for converting the first image signal input to the image signal input means into a second image signal comprising a plurality of pixel data and outputting the second image signal, and a second image output from the image signal processing means Image display means for displaying an image based on the signal on the image display element. The image signal processing means has the same configuration as the image signal processing device described above.
[0015]
In the present invention, the first information signal including a plurality of pieces of information data is generated by decoding an encoded digital information signal. Based on the first information signal, a plurality of first information data located around the target position in the second information signal are selected, and based on the plurality of first information data, information on the target position is selected. The class to which the data belongs is detected. As the information signal, for example, an image signal or an audio signal can be considered.
[0016]
Correction data for correcting coding noise corresponding to the class detected as described above is generated. For example, the correction data for each class is stored in the storage means, and the correction data corresponding to the detected class is read out from the storage means. This correction data is generated in advance using a student signal corresponding to the first information signal and a teacher signal corresponding to the second information signal. For example, the student signal is obtained by decoding a digital information signal obtained by encoding the teacher signal. In this case, the student signal contains coding noise (coding distortion).
[0017]
The correction process using the correction data generated as described above is performed on the second information data corresponding to the target position in the second information signal among the plurality of pieces of information data forming the first information signal. Then, information data of the target position is generated.
[0018]
For example, the correction data is differential data of a number corresponding to the number of information data at the target position in the second information signal. In this case, when the number of pieces of information data at the position of interest in the second information signal is the same as the number of pieces of second information data corresponding to the position of interest, correction data corresponding to each of the pieces of second information data Are added to obtain corrected information data.
[0019]
In this case, when the number of pieces of information data at the target position in the second information signal is N times (N is an integer of 2 or more) the number of pieces of second information data corresponding to the target position, the correction data is output. By adding the corresponding second information data to each of the plurality of correction data included in each of the divided regions obtained by dividing into N, the corrected information data is obtained.
[0020]
As described above, the class to which the pixel data of the target position in the second information signal belongs is detected based on the first information signal, and the class corresponding to the target position in the output information signal among the information data constituting the first information signal. The obtained information data is corrected using the correction data corresponding to the detected class to obtain the information data of the position of interest in the second information signal, and is obtained by decoding the encoded digital information signal. The coding noise (coding distortion) of the obtained information signal can be reduced favorably.
[0021]
An information signal processing device according to the present invention converts a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information including a plurality of pieces of information data. An information signal processing device for converting a plurality of first information data located around a position of interest in a second information signal based on the first information signal. Class detecting means for detecting the class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means; and orthogonal transform corresponding to the class detected by the class detecting means. Correction data generating means for generating correction data for correcting coding noise relating to the obtained frequency coefficient; and among a plurality of information data constituting the first information signal, Orthogonal transform means for performing orthogonal transform on the second information data corresponding to the target position in the information signal of No. 2 and correction data generated by the correction data generating means for the frequency coefficient obtained by the orthogonal transform means And a reverse orthogonal transforming means for performing an inverse orthogonal transform on the frequency coefficient corrected by the correcting means to obtain information data of a position of interest in the second information signal. Things.
[0022]
Further, the information signal processing method according to the present invention converts the first information signal including a plurality of pieces of information data generated by decoding the encoded digital information signal into a second information signal including a plurality of pieces of information data. An information signal processing method for converting a plurality of pieces of first information data located around a position of interest in a second information signal based on the first information signal. A second step of detecting a class to which the information data of the target position belongs based on the plurality of first information data selected in the first step; A corresponding third step of generating correction data for correcting coding noise related to a frequency coefficient obtained by orthogonal transformation, and a plurality of information data forming a first information signal. A fourth step of performing an orthogonal transformation on the second information data corresponding to the position of interest in the second information signal, and a third step of generating the frequency coefficients obtained in the fourth step in a third step Fifth step of performing a correction process using the corrected data, and performing inverse orthogonal transformation on the frequency coefficient corrected in the fifth step to obtain information data of a target position in the second information signal. And a sixth step.
[0023]
Further, a program according to the present invention is for causing a computer to execute the above information signal processing method. A computer-readable medium according to the present invention stores the above-mentioned program.
[0024]
Also, the image signal processing device according to the present invention converts the first image signal composed of a plurality of pixel data, which is generated by decoding the encoded digital image signal, into a second image signal composed of a plurality of pixel data. An image signal processing device for converting a plurality of first pixel data located around a position of interest in a second image signal based on the first image signal; Class detecting means for detecting a class to which the pixel data at the target position belongs based on the plurality of first pixel data selected by the data selecting means; and a quadrature corresponding to the class detected by the class detecting means. Correction data generating means for generating correction data for correcting coding noise related to a frequency coefficient obtained by the conversion; and a correction data generation means for generating a plurality of pixel data constituting the first image signal. In addition, orthogonal transform means for performing orthogonal transform on the second pixel data corresponding to the target position in the second image signal, and correction data generating means for generating a frequency coefficient output from the orthogonal transform means. Means for performing a correction process using the corrected data, and an inverse orthogonal transform for performing an inverse orthogonal transform on the frequency coefficient output from the corrector to obtain pixel data of a target position in the second image signal. Means.
[0025]
Further, the image display device according to the present invention includes: an image signal input unit to which a first image signal including a plurality of pixel data generated by decoding an encoded digital image signal is input; Image signal processing means for converting the first image signal input to the signal input means into a second image signal composed of a plurality of pixel data and outputting the second image signal; and the second image output from the image signal processing means Image display means for displaying an image based on the signal on the image display element. The image signal processing means has the same configuration as the image signal processing device described above.
[0026]
In the present invention, the first information signal including a plurality of pieces of information data is generated by decoding an encoded digital information signal. Based on the first information signal, a plurality of first information data located around the target position in the second information signal are selected, and based on the plurality of first information data, information on the target position is selected. The class to which the data belongs is detected. As the information signal, for example, an image signal or an audio signal can be considered.
[0027]
Correction data for correcting coding noise corresponding to the detected class is generated as described above. For example, the correction data for each class is stored in the storage means, and the correction data corresponding to the detected class is read out from the storage means. This correction data is generated in advance using a student signal corresponding to the first information signal and a teacher signal corresponding to the second information signal. For example, the student signal is obtained by decoding a digital information signal obtained by encoding the teacher signal. In this case, the student signal contains coding noise (coding distortion).
[0028]
Orthogonal transform (discrete cosine transform, wavelet transform, discrete sine transform, etc.) is performed on the second information data corresponding to the position of interest in the second information signal among a plurality of pieces of information data constituting the first information signal. Is performed. The frequency coefficient obtained by the orthogonal transform is subjected to a correction process using the correction data generated as described above. Then, an inverse orthogonal transform is performed on the corrected frequency coefficient to generate information data of the position of interest.
[0029]
For example, the correction data is differential data of a number corresponding to the number of information data at the target position in the second information signal. In this case, when the number of pieces of information data at the target position in the second information signal is the same as the number of pieces of second information data corresponding to the target position, the second information data is obtained by orthogonal transformation. By adding the corresponding correction data to each of the frequency coefficients, a corrected frequency coefficient is obtained.
[0030]
In this case, when the number of pieces of information data at the target position in the second information signal is N times (N is an integer of 2 or more) the number of pieces of second information data corresponding to the target position, the correction data Correction by adding a frequency coefficient obtained by orthogonally transforming the second information data to a low frequency component corresponding to a frequency coefficient obtained by orthogonally transforming the second information data. A later frequency coefficient is obtained.
[0031]
Further, for example, the correction data is a number of frequency coefficients corresponding to the number of information data at the target position in the second information signal. In this case, when the number of information data at the target position in the second information signal is N times (N is an integer of 2 or more) the number of the second information data corresponding to the target position, at least the correction data Of the low frequency component corresponding to the frequency coefficient obtained by orthogonally transforming the second information data with the frequency coefficient obtained by orthogonally transforming the second information data. A later frequency coefficient is obtained.
[0032]
As described above, the class to which the pixel data of the target position in the second information signal belongs is detected based on the first information signal, and the class corresponding to the target position in the output information signal among the information data constituting the first information signal. The frequency coefficient obtained by orthogonally transforming the corrected information data is corrected using the correction data corresponding to the detected class, and the corrected frequency coefficient is inversely orthogonally transformed to determine the position of interest in the second information signal. Information data is obtained, and coding noise (coding distortion) of an information signal obtained by decoding an encoded digital information signal can be reduced favorably.
[0033]
A correction data generation device according to the present invention converts a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information including a plurality of pieces of information data. An apparatus for generating correction data for correcting coding noise used when converting into a signal, comprising the steps of: converting a digital information signal obtained by encoding a teacher signal corresponding to a second information signal; Decoding means for decoding to obtain a student signal corresponding to the first information signal; and a plurality of first signals located around the target position in the teacher signal based on the student signal output from the decoding means. Data selection means for selecting information data; and class detection means for detecting a class to which the information data at the target position belongs based on the plurality of first information data selected by the data selection means. Subtraction means for performing a subtraction process on the information data of the position of interest in the teacher signal using second information data corresponding to the position of interest among a plurality of pieces of information data constituting the student signal, and output data of the subtraction means And a calculating means for averaging each class based on the class detected by the class detecting means to obtain correction data for each class.
[0034]
Further, the correction data generation method according to the present invention converts the first information signal including a plurality of pieces of information data generated by decoding the encoded digital information signal into the second information signal including a plurality of pieces of information data. A method for generating correction data for correcting coding noise, which is used when converting into an information signal, wherein a digital signal obtained by encoding a teacher signal corresponding to a second information signal is obtained. A first step of decoding a signal to obtain a student signal corresponding to the first information signal, and a plurality of steps located around the target position in the teacher signal based on the student signal obtained in the first step. A second step of selecting the first information data, and a third step of detecting a class to which the information data of the target position belongs based on the plurality of first information data selected in the second step. And a fourth step of performing a subtraction process on the information data at the target position in the teacher signal using the second information data corresponding to the target position among the plurality of pieces of information data constituting the student signal; A fifth step of averaging the data obtained in the fourth step for each class based on the class detected in the third step to obtain correction data for each class.
[0035]
Further, a program according to the present invention is for causing a computer to execute the above-described correction data generation method. A computer-readable medium according to the present invention stores the above-mentioned program.
[0036]
In the present invention, the first information signal including a plurality of information data is an encoded digital information signal. The present invention is an apparatus for generating correction data for correcting coding noise, which is used when converting the first information signal into a second information signal including a plurality of pieces of information data.
[0037]
A digital information signal obtained by encoding the teacher signal corresponding to the second information signal is decoded, and a student signal corresponding to the first information signal is obtained. Based on the student signal, a plurality of first information data located around the target position in the teacher signal is selected, and a class to which the information data of the target position belongs is detected based on the plurality of first information data. Is done.
[0038]
A subtraction process is performed on the information data of the target position in the teacher signal using the second information data corresponding to the target position among the plurality of pieces of information data forming the student signal. The data obtained by the subtraction processing is averaged for each class based on the class detected as described above, and correction data for each class is obtained.
[0039]
As described above, the correction data used when converting the first information signal into the second information signal is generated. When the first information signal is converted into the second information signal, The correction data corresponding to the class to which the information data of the target position in the second information signal belongs is selectively used, and the information data of the target position is calculated. Thereby, the coding noise of the information signal obtained by decoding the coded digital information signal can be favorably reduced.
[0040]
A correction data generation device according to the present invention converts a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information including a plurality of pieces of information data. An apparatus for generating correction data for correcting coding noise used when converting into a signal, comprising the steps of: converting a digital information signal obtained by encoding a teacher signal corresponding to a second information signal; Decoding means for decoding to obtain a student signal corresponding to the first information signal; and a plurality of first information items located around the target position in the teacher signal based on the student signal output from the decoding means. Data selecting means for selecting data, class detecting means for detecting a class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means, First orthogonal transformation means for performing orthogonal transformation on information data at a target position in a signal to obtain a first frequency coefficient, and second information corresponding to the target position among a plurality of pieces of information data constituting the student signal A second orthogonal transform means for performing orthogonal transform on the data to obtain a second frequency coefficient, and a second orthogonal transform means for the first frequency coefficient obtained by the first orthogonal transform means. Subtraction means for performing a subtraction process using the obtained second frequency coefficient; and output data of the subtraction means are averaged for each class based on the class detected by the class detection means, and correction for each class is performed. Calculation means for obtaining data.
[0041]
The correction data generation method according to the present invention converts a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information including a plurality of pieces of information data. A method for generating correction data for correcting coding noise, which is used when converting into a signal, comprising: converting a digital information signal obtained by encoding a teacher signal corresponding to a second information signal; A first step of decoding to obtain a student signal corresponding to the first information signal, and a plurality of first signals located around the target position in the teacher signal based on the student signal obtained in the first step. A second step of selecting the information data of the target position, and a third step of detecting a class to which the information data of the target position belongs based on the plurality of first information data selected in the second step. A fourth step of performing orthogonal transformation on the information data at the target position in the teacher signal to obtain a first frequency coefficient, and a second information data corresponding to the target position among a plurality of information data constituting the student signal A fifth step of performing an orthogonal transform on the second frequency coefficient to obtain a second frequency coefficient obtained in the fifth step with respect to the first frequency coefficient obtained in the fourth step. A sixth step of performing a subtraction process using a coefficient, and averaging the data obtained in the sixth step for each class based on the class detected in the third step, and correcting for each class. And a seventh step of obtaining data.
[0042]
Further, a program according to the present invention is for causing a computer to execute the above-described correction data generation method. A computer-readable medium according to the present invention stores the above-mentioned program.
[0043]
In the present invention, the first information signal including a plurality of information data is an encoded digital information signal. The present invention is an apparatus for generating correction data for correcting coding noise, which is used when converting the first information signal into a second information signal including a plurality of pieces of information data.
[0044]
A digital information signal obtained by encoding the teacher signal corresponding to the second information signal is decoded, and a student signal corresponding to the first information signal is obtained. Based on the student signal, a plurality of first information data located around the target position in the teacher signal is selected, and a class to which the information data of the target position belongs is detected based on the plurality of first information data. Is done.
[0045]
An orthogonal transformation is performed on the information data of the position of interest in the teacher signal to obtain a first frequency coefficient. Similarly, orthogonal transform is performed on the second information data corresponding to the position of interest among the plurality of pieces of information data forming the student signal, and a second frequency coefficient is obtained.
[0046]
Then, a subtraction process using the second frequency coefficient is performed on the first frequency coefficient. The data obtained by the subtraction processing is averaged for each class based on the class detected as described above, and correction data for each class is obtained.
[0047]
As described above, the correction data used when converting the first information signal into the second information signal is generated. When the first information signal is converted into the second information signal, The correction data corresponding to the class to which the information data of the target position in the second information signal belongs is selectively used, and the information data of the target position is calculated. Thereby, the coding noise of the information signal obtained by decoding the coded digital information signal can be favorably reduced.
[0048]
A correction data generation device according to the present invention converts a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information including a plurality of pieces of information data. An apparatus for generating correction data for correcting coding noise used when converting into a signal, comprising the steps of: converting a digital information signal obtained by encoding a teacher signal corresponding to a second information signal; Decoding means for decoding to obtain a student signal corresponding to the first information signal; and, based on the student signal output from the decoding means, a plurality of pieces of information data located around the target position in the teacher signal. Data selecting means for selecting, class detecting means for detecting a class to which the information data of the target position belongs based on the plurality of information data selected by the data selecting means, Orthogonal transform means for performing an orthogonal transform on the information data at the position of interest to obtain a frequency coefficient, and a frequency coefficient obtained by the orthogonal transform means for each class based on the class detected by the class detecting means. Calculating means for averaging and obtaining correction data for each class.
[0049]
Further, the correction data generation method according to the present invention converts the first information signal including a plurality of pieces of information data generated by decoding the encoded digital information signal into the second information signal including a plurality of pieces of information data. A method for generating correction data for correcting coding noise, which is used when converting into an information signal, wherein a digital signal obtained by encoding a teacher signal corresponding to a second information signal is obtained. A first step of decoding a signal to obtain a student signal corresponding to the first information signal, and a plurality of steps located around the target position in the teacher signal based on the student signal obtained in the first step. A second step of selecting information data, a third step of detecting a class to which the information data of the target position belongs based on the plurality of information data selected in the second step, A fourth step of performing orthogonal transformation on the information data of the target position in the signal to obtain a frequency coefficient, and calculating the frequency coefficient obtained in the fourth step based on the class detected in the third step. , And averaging for each class to obtain correction data for each class.
[0050]
Further, a program according to the present invention is for causing a computer to execute the above-described correction data generation method. A computer-readable medium according to the present invention stores the above-mentioned program.
[0051]
In the present invention, the first information signal including a plurality of information data is an encoded digital information signal. The present invention is an apparatus for generating correction data for correcting coding noise, which is used when converting the first information signal into a second information signal including a plurality of pieces of information data.
[0052]
A digital information signal obtained by encoding the teacher signal corresponding to the second information signal is decoded, and a student signal corresponding to the first information signal is obtained. Based on the student signal, a plurality of information data located around the target position in the teacher signal are selected, and a class to which the information data of the target position belongs is detected based on the plurality of information data.
[0053]
An orthogonal transformation is performed on the information data of the target position in the teacher signal to obtain a frequency coefficient. The frequency coefficients are averaged for each class based on the class detected as described above, and correction data for each class is obtained.
[0054]
As described above, the correction data used when converting the first information signal into the second information signal is generated. When the first information signal is converted into the second information signal, The correction data corresponding to the class to which the information data of the target position in the second information signal belongs is selectively used, and the information data of the target position is calculated. Thereby, the coding noise of the information signal obtained by decoding the coded digital information signal can be favorably reduced.
[0055]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a digital broadcast receiver 100 as an embodiment.
The digital broadcast receiver 100 includes a microcomputer, and includes a system controller 101 for controlling the operation of the entire system, and a remote control signal receiving circuit 102 for receiving a remote control signal. The remote control signal receiving circuit 102 is connected to the system controller 101, receives a remote control signal RM output in response to a user operation from the remote control transmitter 200, and supplies an operation signal corresponding to the signal RM to the system controller 101. It is configured to
[0056]
Further, the digital broadcast receiver 100 is supplied with a receiving antenna 105 and a broadcast signal (RF modulated signal) captured by the receiving antenna 105, performs channel selection processing, demodulation processing, error correction processing, and the like, and executes a predetermined program. And a tuner unit 106 for obtaining an MPEG2 stream as an encoded image signal according to the above.
[0057]
Further, the digital broadcast receiver 100 decodes the MPEG2 stream output from the tuner unit 106 to obtain an image signal Va, and temporarily converts the image signal Va output from the MPEG2 decoder 107 into an image. And a buffer memory 108 for storing the data in the buffer memory 108.
[0058]
FIG. 2 shows the configuration of the MPEG2 decoder 107.
The decoder 107 has an input terminal 181 to which an MPEG2 stream is input, and a stream buffer 182 for temporarily storing the MPEG2 stream input to the input terminal 181.
[0059]
The decoder 107 extracts a DCT (Discrete Cosine Transform) coefficient as a frequency coefficient from the MPEG2 stream stored in the stream buffer 182, and the extraction circuit 183 extracts the DCT coefficient. And a variable-length decoding circuit 184 for performing variable-length decoding on DCT coefficients that have been subjected to variable-length coding, for example, Huffman coding.
[0060]
Further, the decoder 107 extracts the quantization characteristic designation information from the MPEG2 stream stored in the stream buffer 182, and extracts the quantization characteristic designation information based on the quantization characteristic designation information extracted by the extraction circuit 185. An inverse quantization circuit 186 that performs inverse quantization on the quantized DCT coefficient output from the variable length decoding circuit 184, and an inverse DCT circuit that performs inverse DCT on the DCT coefficient output from the inverse quantization circuit 186 187.
[0061]
The decoder 107 stores the I-picture (Intra-Picture) and P-picture (Predictive-Picture) image signals in a memory (not shown), and uses these image signals to generate a signal from the inverse DCT circuit 187. When a P-picture or a B-picture (Bidirectionally-predictive-Picture) image signal is output, a prediction memory circuit 188 that generates and outputs a corresponding reference image signal Vref is provided.
[0062]
Further, when an image signal of a P picture or a B picture is output from the inverse DCT circuit 187, the decoder 107 includes an addition circuit 189 that adds the reference image signal Vref generated by the prediction memory circuit 188 to the image signal. Have. Note that when the I-picture image signal is output from the inverse DCT circuit 187, the reference image signal Vref is not supplied from the prediction memory circuit 188 to the addition circuit 189, and is therefore output from the inverse DCT circuit 187 from the addition circuit 189. The image signal of the I picture is output as it is.
[0063]
The decoder 107 supplies the I-picture and P-picture image signals output from the addition circuit 189 to the prediction memory circuit 188 and stores them in the memory. It has a picture selection circuit 190 for rearranging the signals in the correct order and outputting them, and an output terminal 191 for outputting an image signal output from the picture selection circuit 190.
[0064]
Further, the decoder 107 has an extraction circuit 192 that extracts encoding control information, that is, picture information PI and motion vector information MI, from the MPEG2 stream stored in the stream buffer 182. The motion vector information MI extracted by the extraction circuit 192 is supplied to the prediction memory circuit 188, and the prediction memory circuit 188 performs motion compensation when generating the reference image signal Vref using the motion vector information MI. The picture information PI extracted by the extraction circuit 192 is supplied to a prediction memory circuit 188 and a picture selection circuit 190, and the prediction memory circuit 188 and the picture selection circuit 190 identify a picture based on the picture information PI. .
[0065]
The operation of the MPEG2 decoder 107 shown in FIG. 2 will be described.
The MPEG2 stream stored in the stream buffer 182 is supplied to an extraction circuit 183, where DCT coefficients as frequency coefficients are extracted. This DCT coefficient is subjected to variable length coding, and this DCT coefficient is supplied to a variable length decoding circuit 184 and decoded. Then, the quantized DCT coefficients output from the variable length decoding circuit 184 are supplied to an inverse quantization circuit 186, where the quantization is performed.
[0066]
The DCT coefficient output from the inverse quantization circuit 186 is subjected to inverse DCT by the inverse DCT circuit 183 to obtain an image signal of each picture. The image signal of each picture is supplied to the picture selection circuit 190 via the addition circuit 189. In this case, the reference image signal Vref output from the prediction memory circuit 188 is added by the adding circuit 189 to the image signals of the P picture and the B picture. Then, the picture signal of each picture is rearranged in the correct order by the picture selection circuit 190 and output to the output terminal 191.
[0067]
Returning to FIG. 1, the digital broadcast receiver 100 further reduces coding noise (coding distortion) such as block noise (block distortion) and mosquito noise from the image signal Va stored in the buffer memory 108. An image signal processing unit 110 that converts the image signal into an image signal Vb, and a display unit 111 that displays an image based on the image signal output from the image signal processing unit 110. The display unit 111 is configured by a display such as a CRT (cathode-ray tube) display or an LCD (liquid crystal display).
[0068]
The operation of the digital broadcast receiver 100 shown in FIG. 1 will be described.
The MPEG2 stream output from the tuner unit 106 is supplied to an MPEG2 decoder 107 and decoded. Then, the image signal Va output from the decoder 107 is supplied to the buffer memory 108 and is temporarily stored.
[0069]
Thus, the image signal Va stored in the buffer memory 108 is supplied to the image signal processing unit 110, and is converted into an image signal Vb in which coding noise (coding distortion) is reduced. In the image signal processing unit 110, pixel data forming the image signal Vb is obtained from pixel data forming the image signal Va.
[0070]
The image signal Vb output from the image signal processing unit 110 is supplied to a display unit 111, and an image based on the image signal Vb is displayed on a screen of the display unit 111.
[0071]
Next, details of the image signal processing unit 110 will be described.
The image signal processing unit 110 has an accumulation table 131. In the accumulation table 131, difference data DF as correction data for correcting coding noise (coding distortion) is stored in advance for each class. The difference data DF is difference data of pixel data or difference data of DCT coefficients (frequency coefficients) obtained by DCT processing.
[0072]
The storage table 131 is supplied with a class code CL output from the class classification unit 130 described later as read address information. From the accumulation table 131, difference data DF corresponding to the class code CL is read and supplied to an adding unit 134 described later.
[0073]
The difference data DF stored in the accumulation table 131 is generated in advance using a student signal corresponding to the image signal Va and a teacher signal corresponding to the image signal Vb. For example, a student signal is obtained by decoding an MPEG2 stream obtained by encoding a teacher signal by MPEG2.
[0074]
Further, the image signal processing unit 100 performs a DCT process on the image signal Va stored in the buffer memory 108 to obtain a DCT coefficient, and a DCT coefficient output from the DCT circuit 132 And a changeover switch 133 to which the image signal Va output from the buffer memory 108 is input to the fixed terminal on the b side thereof. The changeover switch 133 is connected to the b side when the difference data DF stored in the accumulation table 131 is the difference data of the pixel data, and is connected to the a side when the difference data DF stored in the accumulation table 131 is the difference data of the DCT coefficient obtained by the DCT processing. Connected to.
[0075]
Further, the image signal processing unit 110 converts the difference data DF read from the accumulation table 131 into data (pixel data or DCT coefficient) x corresponding to the target position in the image signal Vb output from the movable terminal of the changeover switch 133. An addition unit 134 is provided as a correction unit that generates the data y of the target position in the image signal Vb by performing the addition.
[0076]
Here, the data x and y are block data corresponding to a DCT block which is a unit of DCT processing. In the present embodiment, the number of data (pixel data or DCT coefficients) constituting data y is equal to the number of data (pixel data or DCT coefficients) constituting data x.
[0077]
In this case, the number of pixel data forming the image signal Vb is equal to the number of pixel data forming the image signal Va. For example, when the data x is composed of 8 × 8 data, the adder 134 generates 8 × 8 data as the data y. At this time, the difference data DF supplied from the accumulation table 131 to the adder 134 also includes 8 × 8 difference data.
[0078]
Further, the image signal processing unit 110 includes an inverse DCT circuit 135 that performs an inverse DCT process on an output signal of the adding unit 134, and an output signal of the inverse DCT circuit 135 is input to a fixed terminal on the a side, and a changeover switch 136 for inputting the output signal of the adder 134 to the fixed terminal on the b side. The changeover switch 136 is connected to the b side when the difference data DF stored in the accumulation table 131 is the difference data of the pixel data, and is connected to the a side when the difference data DF stored in the accumulation table 131 is the difference data of the DCT coefficient obtained by the DCT processing. Connected to. A signal output from the movable terminal of the changeover switch 136 is supplied to the display unit 111 as an image signal Vb.
[0079]
Further, the image signal processing unit 110 includes a class classification unit 130 as a class detection unit that detects a class to which the pixel data y of the target position in the image signal Vb belongs. The classifying unit 130 uses the plurality of pixel data, which are located around the position of interest in the image signal Vb, among the plurality of pixel data constituting the image signal Va stored in the buffer memory 108, A class code CL indicating the class to which the pixel data y of the target position in Vb belongs is generated.
[0080]
FIG. 3 shows a configuration of the class classification unit 130.
The classifying unit 130 classifies n types of classes to which the pixel data y of the target position in the image signal Vb belongs based on the input terminal 130A for inputting the image signal Va and the image signal Va input to the input terminal 130A. Tap selection circuit 130B for selectively extracting a plurality of pixel data of class taps used for detection ₁ ~ 130B _n have.
[0081]
Further, the class classification unit 130 includes a tap selection circuit 130B. ₁ ~ 130B _n Code CL indicating n kinds of classes using the pixel data extracted in ₁ ~ CL _n Generation circuit 130C that generates ₁ ~ 130C _n And the class generation circuit 130C ₁ ~ 130C _n Class code CL generated by ₁ ~ CL _n And a class integration circuit 130D that integrates the two into a single class code CL, and an output terminal 130E that outputs the class code CL.
[0082]
In the present embodiment, a class code CL indicating six types of classes ₁ ~ CL ₆ Is generated, and these class codes CL ₁ ~ CL ₆ Is output as one class code CL. The six classes are a spatial waveform class, a time variation class, an AC variation class, a flat class, a line correlation class, and a block edge class. Each class will be briefly described.
[0083]
(1) The spatial waveform class will be described. Tap selection circuit 130B ₁ And class generation circuit 130C ₁ Is assumed to constitute a detection system for this spatial waveform class.
Tap selection circuit 130B ₁ Extracts the pixel data of the block corresponding to the pixel data y of the target position in the image signal Vb (the target block shown in FIG. 4) from the current frame of the image signal Va. Class generation circuit 130C ₁ Divides the 8 × 8 pixel data of the block of interest into four, obtains an average pixel value of each divided region to obtain 2 × 2 upper-layer pixel data, and obtains 2 × 2 pixel data for each of the 2 × 2 pixel data. Is subjected to, for example, 1-bit ADRC (Adaptive Dynamic Range Coding) or the like, and a 4-bit class code CL indicating a spatial waveform class is processed. ₁ Generate
[0084]
The ADRC determines the maximum value and the minimum value of a plurality of pixel data of a class tap, obtains a dynamic range that is a difference between the maximum value and the minimum value, and requantizes each pixel value according to the dynamic range. . In the case of 1-bit ADRC, the pixel value is converted into 1 bit depending on whether it is larger or smaller than the average value of a plurality of pixel values of the class tap. The ADRC process is a process for making the number of classes representing the level distribution of pixel values relatively small. Therefore, the present invention is not limited to ADRC, and may use encoding such as VQ (vector quantization) for compressing the number of bits of a pixel value.
[0085]
(2) The time-varying class will be described. Tap selection circuit 130B ₂ And class generation circuit 130C ₂ Is assumed to constitute a detection system for this time-varying class.
Tap selection circuit 130B ₂ Extracts the pixel data of the block (target block shown in FIG. 4) corresponding to the target pixel data y in the image signal Vb from the current frame of the image signal Va, and extracts the pixel data from the past frame one frame before the image signal Va. Then, the pixel data of the block (the past block shown in FIG. 4) corresponding to the target block is extracted.
[0086]
Class generation circuit 130C ₂ Is subtracted for each corresponding pixel between the 8 × 8 pixel data of the block of interest and the 8 × 8 pixel data of the past block to obtain 8 × 8 difference values. The sum of squares of the eight difference values is obtained, and the sum of squares is determined as a threshold value, and a 2-bit class code CL indicating a time variation class is obtained. ₂ Generate
[0087]
(3) The AC fluctuation class will be described. Tap selection circuit 130B ₃ And class generation circuit 130C ₃ , Constitute a detection system of this AC fluctuation class.
Tap selection circuit 130B ₃ Extracts the pixel data of the block (target block shown in FIG. 4) corresponding to the target pixel data y in the image signal Vb from the current frame of the image signal Va, and extracts the pixel data from the past frame one frame before the image signal Va. Then, the pixel data of the block (the past block shown in FIG. 4) corresponding to the target block is extracted.
[0088]
Class generation circuit 130C ₃ Calculates a DCT coefficient (frequency coefficient) by performing DCT processing on each of the 8 × 8 pixel data of the target block and the 8 × 8 pixel data of the past block. Then, the class generation circuit 130C ₃ Is the number m of base positions at which a coefficient exists at each base position in the AC part. ₁ And the number m of the base positions of those whose sign is inverted and one whose coefficient is 0 ₂ And m ₁ / M ₂ Is determined as a threshold value, and a 2-bit class code CL indicating the AC fluctuation class ₃ Generate In a block having a small time variation, it is possible to perform a class classification corresponding to the mosquito distortion by using the AC variation class.
[0089]
(4) The flat class will be described. Tap selection circuit 130B ₄ And class generation circuit 130C ₄ Is assumed to constitute this flat class detection system.
Tap selection circuit 130B ₄ Extracts the pixel data of the block corresponding to the pixel data y of the target position in the image signal Vb (the target block shown in FIG. 4) from the current frame of the image signal Va. Class generation circuit 130C ₄ Detects the maximum value and the minimum value of 8.times.8 pixel data of the block of interest, determines the difference as a dynamic range as a threshold value, and determines a 1-bit class code CL indicating a flat class. ₄ Generate
[0090]
(5) The line correlation class will be described. Tap selection circuit 130B ₅ And class generation circuit 130C ₅ Is assumed to constitute a detection system for this line correlation class.
Tap selection circuit 130B ₅ Extracts the pixel data of the block corresponding to the pixel data y of the target position in the image signal Vb (the target block shown in FIG. 4) from the current frame of the image signal Va.
[0091]
Class generation circuit 130C ₅ Corresponds to the first and second lines, the third and fourth lines, the fifth and sixth lines, and the seventh and eighth lines of the 8 × 8 pixel data of the target block. Subtraction is performed for each pixel to obtain 8 × 4 difference values, further, the sum of squares of the 8 × 4 difference values is obtained, and the sum of squares is determined as a threshold value, and a 1-bit class indicating a line correlation class is determined. Code CL ₅ Generate This line correlation class indicates whether the correlation within a frame such as a still image is high or the motion is fast and the correlation within a field is higher than that within a frame.
[0092]
(6) The block edge class will be described. Tap selection circuit 130B ₆ And class generation circuit 130C ₆ Is assumed to constitute a block edge class detection system.
Tap selection circuit 130B ₆ Extracts the pixel data of the block (the block of interest shown in FIG. 4) corresponding to the pixel data y at the position of interest in the image signal Vb from the current frame of the image signal Va, The pixel data of the block adjacent to the left and right (the adjacent block shown in FIG. 4) is extracted.
[0093]
Class generation circuit 130C ₆ Is subtracted for each corresponding pixel between each of the eight pixel data of the four sides of the target block and the pixel data of the adjacent block adjacent thereto to obtain 4 × 8 difference values. The sum of squares of the difference values is determined, and the four sums of squares respectively corresponding to the four sides of the block of interest are determined as threshold values, and a 4-bit class code CL indicating the block edge class ₆ Generate
[0094]
In the present embodiment, the class integration circuit 130D includes a class generation circuit 130C ₁ ~ 130C ₆ Class code CL generated by ₁ ~ CL ₆ Are integrated into one class code CL.
[0095]
Where CL ₁ ~ CL ₆ Is simply integrated, the class code CL is 16 classes (spatial waveform class) × 4 classes (time fluctuation class) × 4 classes (AC fluctuation class) × 2 classes (flat class) × 2 classes (line correlation class) × 16 Class (block edge class) = 16384 class.
[0096]
However, in the present embodiment, the AC fluctuation class is integrated with the time fluctuation class as a tree structure. That is, when the time variation is small, there is a high possibility that the portion is a stationary portion. Therefore, the time variation class is performed, and when the time variation is small, the AC variation class is performed as a tree structure. Thereby, the number of classes after the integration of the time variation class and the AC variation class is 7 (= 4 + 4-1).
[0097]
In the present embodiment, the line correlation class is integrated with the flat class as a tree structure. In other words, flat classification is performed, and if not flat, line correlation classification is performed as a tree structure. Thus, the number of classes after integration of the flat class and the line correlation class becomes 3 (= 2 + 2-1).
[0098]
By performing the class integration using the tree structure in this manner, the class code CL is composed of 16 classes (spatial waveform class) × 7 classes (time variation class and AC variation class) × 16 classes (block edge class) × 3 classes (flat Class and line correlation class) = 5376 classes, and the number of classes can be greatly reduced.
[0099]
The operation of the image signal processing unit 110 will be described.
First, a case where the difference data DF stored in the accumulation table 131 is difference data of pixel data will be described. In this case, the changeover switches 133 and 136 are respectively connected to the b side.
[0100]
The class classification unit 130 uses a plurality of pieces of pixel data of the image signal Va located around the position of interest in the image signal Vb, and generates a class code CL indicating the class to which the pixel data y of the position of interest in the image signal Vb belongs. Generated.
[0101]
This class code CL is supplied to the storage table 131 as read address information. Based on the class code CL, the difference data DF corresponding to the target position in the image signal Vb is read from the accumulation table 131 and supplied to the adding unit 134.
[0102]
Further, of the image signals Va stored in the buffer memory 108, pixel data x corresponding to the target position in the image signal Vb is supplied to the adder 134 via the b side of the changeover switch 133. The adder 134 adds the difference data DF read from the accumulation table to the pixel data x to generate pixel data y at the target position in the image signal Vb.
[0103]
Here, the pixel data x and y are block data composed of, for example, 8 × 8 pieces of pixel data. Further, the difference data DF supplied from the accumulation table 131 to the adder 134 also includes, for example, 8 × 8 difference data. In the adding unit 134, each piece of difference data forming the difference data DF is added to each piece of pixel data forming the pixel data x, and each piece of pixel data forming the pixel data y is obtained.
[0104]
FIG. 5 shows an outline of the addition operation in the addition unit 134 on the assumption that the block data is composed of 2 × 2 pixel data for simplicity. Four pieces of difference data a to d forming the difference data DF are respectively added to four pieces of pixel data A to D forming the pixel data x, and four pieces of pixel data A ′ to D forming the pixel data y are added. 'Is required. That is, A '= A + a, B' = B + b, C '= C + c, and D' = D + d.
[0105]
The pixel data y generated by the addition unit 134 is output as an output signal of the image signal processing unit 110 via the b side of the changeover switch 136. That is, the image signal Vb is constituted by the pixel data y.
[0106]
Next, a case where the difference data DF stored in the accumulation table 131 is DCT coefficient difference data obtained by DCT processing will be described. In this case, the changeover switches 133 and 136 are respectively connected to the a side.
[0107]
In the class classification unit 130, from the image signal Va stored in the buffer memory 108, pixel data y of the target position in the image signal Vb is determined using a plurality of pixel data located around the target position in the image signal Vb. A class code CL indicating the class to which the class belongs is generated.
[0108]
This class code CL is supplied to the storage table 131 as read address information. Based on the class code CL, the difference data DF corresponding to the target position in the image signal Vb is read from the accumulation table 131 and supplied to the adding unit 134.
[0109]
The DCT coefficient x obtained by performing DCT processing on a plurality of pixel data of the image signal Va corresponding to the pixel data y at the target position in the image signal Vb and obtained by the DCT circuit 132 The signal is supplied to the adder 134 via the side a. The adder 134 adds the difference data DF to the DCT coefficient x to generate a DCT coefficient y corresponding to the pixel data of the target position in the image signal Vb.
[0110]
Here, the DCT coefficients x and y are block data including, for example, 8 × 8 DCT coefficients. Further, the difference data DF supplied from the accumulation table 131 to the adder 134 also includes, for example, 8 × 8 difference data. The adder 134 adds each of the difference data forming the difference data DF to each of the DCT coefficients forming the DCT coefficient x, and obtains each DCT coefficient forming the DCT coefficient y (see FIG. 5).
[0111]
The DCT coefficient y generated by the adding unit 134 is supplied to the inverse DCT circuit 135. The inverse DCT circuit 135 performs an inverse DCT process on the DCT coefficient y to obtain pixel data. Thus, the pixel data output from the inverse DCT circuit 135 is output as an output signal of the image signal processing unit 110 via the a side of the changeover switch 136.
[0112]
As described above, the image signal processing unit 110 corrects the data (pixel data or DCT coefficient) x related to the image signal Va to obtain the data (pixel data or DCT coefficient) y related to the image signal Vb, Detecting the class to which the data y belongs based on Va, adding the difference data DF corresponding to the detected class to the data x, and obtaining data y corrected so as to reduce coding noise; As the image signal Vb, it is possible to obtain a signal in which the coding noise is favorably reduced.
[0113]
FIG. 6 shows a configuration of the difference data generation device 210 that generates difference data DF to be stored in the accumulation table 131 of the image signal processing unit 110 in FIG.
The difference data generation device 210 includes an input terminal 151 to which a teacher signal ST corresponding to the image signal Vb is input, an MPE2 encoder 152 that encodes the teacher signal ST to obtain an MPEG2 stream, An MPEG2 decoder 153 for decoding the MPEG2 stream to obtain a student signal SS corresponding to the image signal Va.
[0114]
Further, the difference data generation device 210 performs a DCT process on the student signal SS output from the MPEG2 decoder 153 to obtain a DCT coefficient, and the DCT coefficient output from the DCT circuit 171 is a The switch 172 receives the student signal SS output from the MPEG2 decoder 153 at the fixed terminal on the b side while being input to the fixed terminal on the side b. The changeover switch 172 is connected to the b side when the difference data DF stored in the storage table 177 described later is the difference data of the pixel data, and is connected to the a side when the difference data DF is the difference data of the DCT coefficient obtained by the DCT processing. Connected to.
[0115]
Further, the difference data generation device 210 performs a DCT process on the teacher signal ST whose time has been adjusted by the delay circuit 159 to obtain a frequency coefficient, and a frequency coefficient output from the DCT circuit And a changeover switch 174 for inputting the teacher signal ST whose time has been adjusted by the delay circuit 159 to the fixed terminal on the b side thereof. The changeover switch 174 is connected to the b side when the difference data DF stored in the storage table 177 described later is the difference data of the pixel data, and is connected to the a side when the difference data DF is the difference data of the DCT coefficient obtained by the DCT processing. Connected to.
[0116]
Further, the difference data generation device 210 outputs from the movable terminal of the changeover switch 172 from the data (pixel data or DCT coefficient) y of the target position of the teacher signal ST, which is output from the movable terminal of the changeover switch 174. A subtraction unit 175 is provided to obtain difference data df by subtracting data (pixel data or DCT coefficient) x corresponding to the target position of the teacher signal ST.
[0117]
Here, the data x and y are block data corresponding to a DCT block which is a unit of DCT processing. In the present embodiment, the number of data (pixel data or DCT coefficients) constituting data y is equal to the number of data (pixel data or DCT coefficients) constituting data x.
[0118]
In this case, the number of pixel data forming the teacher signal ST is equal to the number of pixel data forming the student signal SS. For example, when the data x and y each include 8 × 8 image data, the subtraction unit 175 generates 8 × 8 difference data as the difference data df.
[0119]
FIG. 7 shows an outline of the subtraction operation in the subtraction unit 175 assuming that the block data is composed of 2 × 2 data for simplicity. The four data A to D forming the data x are respectively subtracted from the four data A 'to D' forming the data y, and four difference data a to d forming the difference data df are obtained. . That is, a = A'-A, b = B'-B, c = C'-C, and d = D'-D.
[0120]
Further, the difference data generation device 210 performs an averaging process for each class on the difference data df sequentially output from the subtraction unit 175 based on a class code CL generated by a class classification unit 178 described later. And a storage controller 176 for storing the result in the storage table 177 as difference data DF.
[0121]
Further, the difference data generation unit 210 includes a class classification unit 178 as a class detection unit that detects a class to which the pixel data of the target position in the teacher signal ST belongs. Although a detailed description is omitted, this classifying unit 178 has the same configuration as the classifying unit 130 in the image signal processing unit 110 shown in FIG. 1, and forms the student signal SS output from the MPEG2 decoder 153. A class code CL indicating a class to which the pixel data of the target position in the teacher signal ST belongs is generated using a plurality of pixel data located around the target position in the teacher signal ST among the plural pixel data to be processed.
[0122]
Next, the operation of the difference data generation device 210 shown in FIG. 6 will be described.
First, a case where the difference data DF stored in the accumulation table 177 is difference data of pixel data will be described. In this case, the changeover switches 172 and 174 are respectively connected to the b side.
[0123]
A teacher signal ST corresponding to the image signal Vb is supplied to an input terminal 151, and the teacher signal ST is encoded by an MPEG2 encoder 152 to generate an MPEG2 stream. This MPEG2 stream is supplied to the MPEG2 decoder 153. The MPEG2 decoder 153 decodes the MPEG2 stream and generates a student signal SS corresponding to the image signal Va. Since the student signal SS has undergone MPEG2 encoding and decoding, it includes encoding noise (encoding distortion).
[0124]
Of the teacher signal ST whose time has been adjusted by the delay circuit 159, the pixel data y at the target position is supplied to the subtractor 175 via the b side of the changeover switch 174. The pixel data x corresponding to the target position in the teacher signal ST among the student signals SS output from the MPEG2 decoder 153 is supplied to the subtraction unit 175 via the selector switch 172 via the b side. Then, the subtraction unit 175 subtracts the pixel data x from the pixel data y to generate difference data df. The difference data df corresponding to each target position in the teacher signal ST sequentially output from the subtraction unit 175 is supplied to the accumulation control unit 176.
[0125]
Here, the pixel data x and y are block data composed of, for example, 8 × 8 pieces of pixel data. In the subtracting unit 175, each pixel data forming the pixel data x is subtracted from each pixel data forming the pixel data y, and each difference data forming the difference data df is obtained.
[0126]
The classifying unit 178 uses the plurality of pixel data, which are located around the target position in the teacher signal ST, among the plurality of pixel data constituting the student signal SS output from the MPEG2 decoder 153, and A class code CL indicating the class to which the pixel data y of the target position in ST belongs is generated.
[0127]
This class code CL is supplied to the accumulation control unit 176. The accumulation control unit 176 performs an averaging process for each of the plurality of difference data df sequentially output from the subtraction unit 175 based on the class code CL, and stores the results in the accumulation table 177. Is stored as difference data DF.
[0128]
Next, a case where the difference data DF stored in the accumulation table 177 is DCT coefficient difference data will be described. In this case, the changeover switches 172 and 174 are respectively connected to the a side.
[0129]
A teacher signal ST corresponding to the image signal Vb is supplied to an input terminal 151, and the teacher signal ST is encoded by an MPEG2 encoder 152 to generate an MPEG2 stream. This MPEG2 stream is supplied to the MPEG2 decoder 153. The MPEG2 decoder 153 decodes the MPEG2 stream and generates a student signal SS corresponding to the image signal Va. Since the student signal SS has undergone MPEG2 encoding and decoding, it includes encoding noise (encoding distortion).
[0130]
Of the teacher signal ST time-adjusted by the delay circuit 159, the DCT circuit 173 performs DCT processing on the pixel data at the target position, and the obtained DCT coefficient y is subtracted through the a side of the changeover switch 174. 175. Further, of the student signal SS output from the MPEG2 decoder 153, DCT processing is performed by the DCT circuit 171 on the pixel data corresponding to the target position in the teacher signal ST, and the obtained DCT coefficient x is changed by a switch. 172 is supplied through the a side. Then, the subtractor 175 subtracts the DCT coefficient x from the DCT coefficient y to generate difference data df. The difference data df corresponding to each target position in the teacher signal ST sequentially output from the subtraction unit 175 is supplied to the accumulation control unit 176.
[0131]
Here, the DCT coefficients x and y are block data including, for example, 8 × 8 DCT coefficients. In the subtraction unit 175, each DCT coefficient forming the DCT coefficient x is subtracted from each DCT coefficient forming the DCT coefficient y, and each difference data forming the difference data df is obtained.
[0132]
The classifying unit 178 uses the plurality of pixel data, which are located around the target position in the teacher signal ST, among the plurality of pixel data constituting the student signal SS output from the MPEG2 decoder 153, and A class code CL indicating the class to which the pixel data of the target position in ST belongs is generated.
[0133]
This class code CL is supplied to the accumulation control unit 176. The accumulation control unit 176 performs an averaging process for each of the plurality of difference data df sequentially output from the subtraction unit 175 based on the class code CL, and stores the results in the accumulation table 177. Is stored as difference data DF.
[0134]
As described above, the difference data generation device 210 illustrated in FIG. 6 can generate the difference data DF for each class, which is stored in the accumulation table 131 of the image signal processing unit 110 in FIG.
[0135]
Note that the processing in the image signal processing unit 110 in FIG. 1 can be realized by software using, for example, an image signal processing device 300 as shown in FIG.
[0136]
First, the image signal processing device 300 shown in FIG. 8 will be described. The image signal processing device 300 includes a CPU 301 that controls the operation of the entire device, a read only memory (ROM) 302 in which a control program for the CPU 301, difference data, and the like are stored, and a RAM (random) that forms a work area of the CPU 301. access memory) 303. The CPU 301, the ROM 302, and the RAM 303 are connected to a bus 304, respectively.
[0137]
Further, the image signal processing device 300 includes a hard disk drive (HDD) 305 as an external storage device, and a drive (FDD) 307 for driving a floppy (registered trademark) disk 306. These drives 305 and 307 are connected to the bus 304, respectively.
[0138]
In addition, the image signal processing device 300 includes a communication unit 308 that connects to a communication network 400 such as the Internet by wire or wirelessly. The communication unit 308 is connected to the bus 304 via the interface 309.
[0139]
Further, the image signal processing device 300 includes a user interface unit. The user interface unit includes a remote control signal receiving circuit 310 for receiving a remote control signal RM from the remote control transmitter 200, and a display 311 such as an LCD (liquid crystal display). The receiving circuit 310 is connected to the bus 304 via the interface 312, and similarly, the display 311 is connected to the bus 304 via the interface 313.
[0140]
Further, the image signal processing device 300 has an input terminal 314 for inputting the image signal Va and an output terminal 315 for outputting the image signal Vb. The input terminal 314 is connected to the bus 304 via the interface 316, and the output terminal 315 is similarly connected to the bus 304 via the interface 317.
[0141]
Here, instead of previously storing the control program, the difference data, and the like in the ROM 302 as described above, the control program and the difference data are downloaded from the communication network 400 such as the Internet via the communication unit 308 and stored in the hard disk or the RAM 303 for use. You can also. Further, these control programs, difference data, and the like may be provided on a floppy (registered trademark) disk 306.
[0142]
Instead of inputting the image signal Va to be processed from the input terminal 314, the image signal Va may be recorded in a hard disk in advance or downloaded from the communication network 400 such as the Internet via the communication unit 308. Further, instead of outputting the processed image signal Vb to the output terminal 315 or in parallel with the output, the image signal Vb is supplied to the display 311 for image display, further stored in the hard disk, the Internet via the communication unit 308, or the like. May be transmitted to the communication network 400.
[0143]
With reference to the flowchart of FIG. 9, a processing procedure for obtaining the image signal Vb from the image signal Va in the image signal processing device 300 shown in FIG. 8 will be described.
First, in step ST101, the process is started. In step S102, an image signal Va for one frame or one field is input into the apparatus from, for example, the input terminal 314. In this way, the pixel data constituting the image signal Va input from the input terminal 314 is temporarily stored in the RAM 303. When the image signal Va is recorded in advance in the hard disk drive 307 in the apparatus, the image signal Va is read from the drive 307, and pixel data constituting the image signal Va is temporarily stored in the RAM 303. I do.
[0144]
Then, in step ST103, it is determined whether or not processing of all frames or all fields of the image signal Va has been completed. If the processing has ended, the processing ends in step ST104. On the other hand, if the processing has not been completed, the process proceeds to step ST105.
[0145]
In this step ST105, from the image signal Va input in step ST102, pixel data of a class tap used for class classification is acquired corresponding to the target position in the image signal Vb. Then, in step ST106, a class code CL is generated from the pixel data of the class tap.
[0146]
Next, in step ST107, based on the class code CL generated in step ST106, difference data DF corresponding to the class code CL is read from the ROM 302 or the like, and temporarily stored in the RAM 303.
[0147]
Next, in step ST108, the difference data DF read out in step ST107 is added to the pixel data x corresponding to the target position in the image signal Vb among the plurality of pixel data constituting the image signal Va, and The pixel data y at the target position in the signal Vb is generated.
[0148]
Here, when the difference data DF stored in the ROM 302 or the like is the difference data of the DCT coefficient obtained by the DCT processing, the data y as the addition result is the DCT coefficient. I do. In this case, DCT processing is performed on the image signal Va input in step ST102, and data x corresponding to the target position in the image signal Vb is set as a DCT coefficient.
[0149]
Next, in step ST109, it is determined whether or not the process of obtaining the pixel data of the image signal Vb has been completed in the entire area of the pixel data of the image signal Va for one frame or one field input in step ST102. If the processing has been completed, the process returns to step ST102 to shift to the input processing of the image signal Va for the next one frame or one field. On the other hand, if the processing has not been completed, the process returns to step ST105, and the same processing as described above is repeated for the next target position.
[0150]
As described above, by performing the processing according to the flowchart illustrated in FIG. 9, the pixel data of the input image signal Va can be processed, and the pixel data of the image signal Vb can be obtained. As described above, the image signal Vb obtained by the above-described processing is output to the output terminal 315, supplied to the display 311 to display an image based thereon, and further supplied to the hard disk drive 305 to be supplied to the hard disk drive 305. Or recorded in
Although illustration of the processing device is omitted, the processing in the difference data generation device 210 in FIG. 6 can also be realized by software.
[0151]
The processing procedure for generating the difference data will be described with reference to the flowchart in FIG.
First, in step ST121, the process is started. In step ST122, the teacher signal ST is input for one frame or one field. Then, in step ST123, it is determined whether or not processing of all frames or all fields of the teacher signal ST has been completed. If the processing has been completed, the difference data DF of each class is stored in the memory in step ST124, and then the processing ends in step ST125. On the other hand, if the processing has not been completed, the process proceeds to step ST126.
[0152]
In step ST126, the teacher signal ST input in step ST122 is subjected to MPEG encoding, and the encoded data is subjected to MPEG decoding to generate a student signal SS.
[0153]
Next, in step ST127, from the student signal SS generated in step ST126, pixel data of a class tap used for class classification is acquired corresponding to the target position in the teacher signal ST. Then, in step ST128, a class code CL is generated from the pixel data of the class tap.
[0154]
Next, in step ST129, the difference data df is obtained by subtracting the pixel data x of the student signal SS corresponding to the target position of the teacher signal ST from the pixel data y of the target position of the teacher signal ST. Further, in step ST129, averaging processing is performed for each class based on the class code CL generated in step ST128 to generate difference data DF.
[0155]
Next, in step ST130, it is determined whether or not the generation processing of the difference data DF has been completed in all regions of the teacher signal ST input in step ST122. If the generation processing of the difference data DF has been completed, the process returns to step ST122, where the teacher signal for the next one frame or one field is input, and the same processing as described above is repeated. On the other hand, if the difference data generation processing has not been completed, the process returns to step ST127, and the same processing as described above is repeated for the next target position.
[0156]
Here, when generating the difference data of the DCT coefficient obtained by the DCT processing as the difference data DF, the difference data df as the subtraction result needs to be the difference data of the DCT coefficient. In that case, DCT processing is performed on the teacher signal ST input in step ST122, and pixel data y corresponding to the target position in the teacher signal ST is converted into DCT coefficients. Further, DCT processing is performed on the student signal SS generated in step ST126, and the pixel data x of the student signal SS corresponding to the target position in the teacher signal ST is converted into DCT coefficients.
[0157]
In this way, by performing the processing according to the flowchart shown in FIG. 10, the difference data DF can be obtained by the same method as that of the difference data generation device 210 shown in FIG.
[0158]
In the image signal processing unit 110 of the digital broadcast receiver 100 shown in FIG. 1 as the above-described embodiment, the data x and y are block data corresponding to a DCT block serving as a unit of DCT processing, and the data y The number of pieces of data (pixel data or DCT coefficients) to be processed is equal to the number of pixel data (pixel data or DCT coefficients) forming the data x, and the number of pixel data forming the image signal Vb is equal to the number of pixels forming the image signal Va. It was equal to the number of data.
[0159]
However, the number of pixel data constituting the image signal Vb may be N times (N is an integer of 2 or more) the number of pixel data constituting the image signal Va. In this case, the number of data (pixel data or DCT coefficients) constituting data y is N times the number of data (pixel data or DCT coefficients) constituting data x. In this case, the difference data DF supplied from the accumulation table 131 to the adder 134 includes the same number of pieces of difference data as the number of pieces of data constituting the data y. For example, when N = 4, the data x is composed of 8 × 8 data, and the data y is composed of 16 × 16 data.
[0160]
In this case, the adding unit 134 differs depending on whether the difference data DF stored in the accumulation table 131 is difference data of pixel data or difference data of DCT coefficients (frequency coefficients) obtained by DCT processing. Perform addition processing.
[0161]
First, a case where the difference data DF stored in the accumulation table 131 is difference data of pixel data will be described.
In this case, the corresponding pixel data forming the pixel data x is added to each of the difference data included in each divided region obtained by dividing the difference data DF into N, and each pixel forming the pixel data y is obtained. Data is required.
[0162]
In FIG. 11, for example, N = 4, and for simplicity, it is assumed that the pixel data x is composed of 2 × 2 pixel data and the pixel data y is composed of 4 × 4 pixel data, and the adding operation in the adding unit 134 is performed. The outline is shown. If the difference data DF is a ₁ ~ A ₄ , B ₁ ~ B ₄ , C ₁ ~ C ₄ , D ₁ ~ D ₄ Is divided into four. And the difference data a ₁ ~ A ₄ Is added to the pixel data A constituting the pixel data x, and the pixel data A constituting the pixel data y ₁ ~ A ₄ Is required.
[0163]
Also, the difference data b ₁ ~ B ₄ Is added to the pixel data B constituting the pixel data x, and the pixel data B constituting the pixel data y ₁ ~ B ₄ Is required. Also, the difference data c ₁ ~ C ₄ Are added to the pixel data C constituting the pixel data x, and the pixel data C constituting the pixel data y ₁ ~ C ₄ Is required. Further, the difference data d ₁ ~ D ₄ Are added to the pixel data D constituting the pixel data x, and the pixel data D constituting the pixel data y ₁ ~ D ₄ Is required.
[0164]
Further, the difference data DF in this case can be generated by the difference data generation device 210 shown in FIG. In this case, for example, after performing the decoding process in the MPEG encoder 153, the thinning process is performed, and the number of the pixel data constituting the student signal SS is reduced to 1 / the number of the pixel data constituting the teacher signal ST. N times. Accordingly, the number of pixel data constituting the pixel data y is N times the number of pixel data constituting the pixel data x. For example, when N = 4, the pixel data x is composed of 8 × 8 pixel data, and the pixel data y is composed of 16 × 16 pixel data.
[0165]
In this case, the subtraction unit 175 subtracts the corresponding pixel data constituting the pixel data x from each of the pixel data included in each of the divided regions obtained by dividing the pixel data y into N, thereby forming the difference data df. Are obtained.
[0166]
In FIG. 12, for example, N = 4, and for simplicity, the pixel data x is composed of 2 × 2 pixel data and the pixel data y is composed of 4 × 4 pixel data, and the subtraction operation in the subtraction unit 175 is performed. The outline is shown. If the pixel data y is A ₁ ~ A ₄ , B ₁ ~ B ₄ , C ₁ ~ C ₄ , D ₁ ~ D ₄ Is divided into four. Then, the pixel data A ₁ ~ A ₄ Are subtracted from the pixel data A constituting the pixel data x, and the difference data a constituting the difference data df is obtained. ₁ ~ A ₄ Is required.
[0167]
Also, pixel data B ₁ ~ B ₄ Are subtracted from the pixel data B constituting the pixel data x, and the difference data b constituting the difference data df ₁ ~ B ₄ Is required. The pixel data C ₁ ~ C ₄ Are subtracted from the pixel data C constituting the pixel data x, and the difference data c constituting the difference data df ₁ ~ C ₄ Is required. Further, the pixel data D ₁ ~ D ₄ Is subtracted from the pixel data D constituting the pixel data x, and the difference data d constituting the difference data df is obtained. ₁ ~ D ₄ Is required.
[0168]
Next, the case where the difference data DF stored in the accumulation table 131 of the image signal processing unit 110 (see FIG. 1) is the difference data of the DCT coefficient obtained by the DCT processing will be described.
In this case, the DCT coefficient corresponding to the DCT coefficient x is added to the low frequency component corresponding to the DCT coefficient x in each of the difference data configuring the difference data DF, and the DCT coefficient y Are obtained.
[0169]
FIG. 13 shows, for example, that N = 4, and for simplicity, the DCT coefficient x is composed of 2 × 2 DCT coefficients and the DCT coefficient y is composed of 4 × 4 DCT coefficients, The outline is shown.
[0170]
Of the difference data a to p constituting the difference data DF, DCT coefficients A to D constituting the DCT coefficient x are respectively added to low frequency components a to d corresponding to the DCT coefficient x, and a DCT coefficient y Are obtained. Further, other difference data ep of the difference data DF become DCT coefficients ep constituting the DCT coefficient y as they are.
[0171]
Further, the difference data DF in this case can be generated by the difference data generation device 210 shown in FIG. In this case, for example, after performing the decoding process in the MPEG encoder 153, the thinning process is performed, and the number of the pixel data constituting the student signal SS is reduced to 1 / the number of the pixel data constituting the teacher signal ST. N times. Thus, the number of DCT coefficients constituting DCT coefficient y is N times the number of DCT coefficients constituting DCT coefficient x. For example, when N = 4, the DCT coefficient x is composed of 8 × 8 DCT coefficients, and the DCT coefficient y is composed of 16 × 16 DCT coefficients.
[0172]
In this case, the subtraction unit 175 subtracts the corresponding DCT coefficient constituting the DCT coefficient x from the low frequency component corresponding to the DCT coefficient x among the DCT coefficients constituting the DCT coefficient y, The respective difference data constituting the difference data df are obtained.
[0173]
FIG. 14 shows, for example, that N = 4, and for simplicity, it is assumed that the DCT coefficient x is composed of 2 × 2 DCT coefficients and the DCT coefficient y is composed of 4 × 4 DCT coefficients, and the subtraction operation in the subtraction unit 175 is performed. The outline is shown. Among the DCT coefficients A ′ to p constituting the DCT coefficient y, the DCT coefficients A to D constituting the DCT coefficient x are respectively subtracted from the low frequency components A ′ to D ′ corresponding to the DCT coefficient x, Difference data a to d constituting the difference data df are obtained. The other DCT coefficients ep of the DCT coefficient y become difference data ep constituting the difference data df as they are.
[0174]
Instead of storing the difference data of the DCT coefficient (frequency coefficient) obtained by the DCT processing in the accumulation table 131, the DCT coefficient itself may be stored. In this case, the DCT coefficient stored in the accumulation table 131 is, for example, the difference data generation device 210 shown in FIG. Can be obtained.
[0175]
In this case, in the adding unit 134 in the image signal processing unit 110, at least the part of the low frequency component corresponding to the DCT coefficient x in the DCT coefficient (correction data) from the accumulation table 131 constitutes the DCT coefficient x. The corresponding DCT coefficient is replaced with the corresponding DCT coefficient, and each DCT coefficient constituting the DCT coefficient y is obtained.
[0176]
FIG. 15 shows, for example, that N = 4, and for simplicity, the DCT coefficient x is composed of 2 × 2 DCT coefficients and the DCT coefficient y is composed of 4 × 4 DCT coefficients, The outline is shown.
[0177]
Of the frequency coefficients a to p constituting the DCT coefficient (correction data), parts of low frequency components a to d corresponding to the DCT coefficient x are replaced with DCT coefficients A to D constituting the DCT coefficient x, respectively. DCT coefficients A to D and ep forming the DCT coefficient y are obtained. Note that not all of the parts e to p may be used, but part or all of them may be used depending on, for example, the class.
[0178]
In the above-described embodiment, the case of handling an MPEG2 stream accompanied by DCT has been described. However, the present invention can be similarly applied to a case of handling other encoded digital information signals. Also, instead of DCT, coding involving other orthogonal transform such as wavelet transform and discrete sine transform may be used.
[0179]
Further, in the above embodiment, the case where the information signal is an image signal has been described, but the present invention is not limited to this. For example, the present invention can be similarly applied to a case where the information signal is a voice signal.
[0180]
【The invention's effect】
According to this invention, the class to which the pixel data of the target position in the output information signal belongs is detected based on the input information signal, and the information data corresponding to the target position in the output information signal among the information data constituting the input information signal is determined. Is used to obtain information data of the position of interest in the output information signal by performing correction using correction data corresponding to the detected class, and encodes the information signal obtained by decoding the encoded digital information signal. Noise (encoding distortion) can be favorably reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a digital broadcast receiver as an embodiment.
FIG. 2 is a block diagram illustrating a configuration of an MPEG2 decoder.
FIG. 3 is a block diagram illustrating a configuration of a class classification unit.
FIG. 4 is a diagram showing a tap selection block.
FIG. 5 is a diagram for explaining the operation of an adding unit.
FIG. 6 is a block diagram illustrating a configuration of a difference data generation device.
FIG. 7 is a diagram for explaining an operation of a subtraction unit.
FIG. 8 is a block diagram illustrating a configuration example of an image signal processing device realized by software.
FIG. 9 is a flowchart illustrating image signal processing.
FIG. 10 is a flowchart illustrating a difference data generation process.
FIG. 11 is a diagram for explaining the operation of an adding unit.
FIG. 12 is a diagram illustrating the operation of a subtraction unit.
FIG. 13 is a diagram for explaining the operation of the addition unit.
FIG. 14 is a diagram for explaining the operation of the subtraction unit.
FIG. 15 is a diagram for explaining the operation of the addition unit.
[Explanation of symbols]
100: Digital broadcast receiver, 101: System controller, 102: Remote control signal receiving circuit, 105: Receiving antenna, 106: Tuner unit, 107: MPEG2 decoder, 108 ..Buffer memory, 110 image signal processing unit, 111 display unit, 130 class classification unit, 130A input terminal, 130B ₁ ~ 130B _n ... Tap selection circuit, 130C ₁ ~ 130C _n ... Class generation circuit, 130D ... Class integration circuit, 130E ... Output terminal, 210 ... Difference data generation device, 151 ... Input terminal, 152 ... MPEG2 encoder, 153 ... MPEG2 decoder, 159 delay circuit, 171 DCT circuit, 172, 174 changeover switch, 173 DCT circuit, 175 subtraction unit, 176 accumulation control unit 177, an accumulation table, 178, a class classification unit, 200, a remote control transmitter, 300, an image signal processing device

Claims (35)

An information signal processing device for converting a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information signal including a plurality of pieces of information data. hand,
Data selection means for selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
Class detecting means for detecting a class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means;
Correction data generating means for generating correction data for correcting coding noise, corresponding to the class detected by the class detecting means,
The correction data generated by the correction data generating means is used for the second information data corresponding to the target position in the second information signal among the plurality of information data constituting the first information signal. An information signal processing device comprising: a correction unit that performs a correction process to obtain information data of a target position in the second information signal. The correction data generating means includes:
Storage means for storing correction data for each class;
2. The information signal processing apparatus according to claim 1, further comprising: a data reading unit that reads correction data corresponding to the class detected by the class detection unit from the storage unit. The correction data stored in the storage means is
The information signal processing apparatus according to claim 2, wherein the information signal processing apparatus is generated in advance using a student signal corresponding to the first information signal and a teacher signal corresponding to the second information signal. The information signal processing device according to claim 3, wherein the student signal is obtained by decoding a digital information signal obtained by encoding the teacher signal. The number of pieces of information data at a position of interest in the second information signal is N times (N is an integer of 2 or more) the number of pieces of second information data corresponding to the position of interest. 2. The information signal processing device according to 1. The correction data is differential data of a number corresponding to the number of information data at the position of interest in the second information signal,
The correction means,
The output information data is obtained by adding corresponding second information data to each of a plurality of correction data included in each of the divided areas obtained by dividing the correction data into N to obtain output information data. The information signal processing device according to the above. An image signal processing device for converting a first image signal composed of a plurality of pixel data generated by decoding an encoded digital image signal into a second image signal composed of a plurality of pixel data. hand,
Data selecting means for selecting a plurality of first pixel data located around a target position in the second image signal based on the first image signal;
Class detecting means for detecting a class to which the pixel data at the target position belongs based on the plurality of first pixel data selected by the data selecting means;
Correction data generating means for generating correction data for correcting coding noise, corresponding to the class detected by the class detecting means,
The correction data generated by the correction data generating means is used for the second pixel data corresponding to the position of interest in the second image signal among the plurality of pixel data constituting the first image signal. An image signal processing apparatus comprising: a correction unit that performs correction processing to obtain pixel data of a target position in the second image signal. Image signal input means for receiving a first image signal composed of a plurality of pixel data, which is generated by decoding the encoded digital image signal;
Image signal processing means for converting the first image signal input to the image signal input means into a second image signal comprising a plurality of pixel data and outputting the second image signal;
Image display means for displaying an image based on the second image signal output from the image signal processing means on an image display element,
The image signal processing means includes:
Data selecting means for selecting a plurality of first pixel data located around a target position in the second image signal based on the first image signal;
Class detecting means for detecting a class to which the pixel data at the target position belongs based on the plurality of first pixel data selected by the data selecting means;
Correction data generating means for generating correction data for correcting coding noise, corresponding to the class detected by the class detecting means,
The correction data generated by the correction data generating means is used for the second pixel data corresponding to the position of interest in the second image signal among the plurality of pixel data constituting the first image signal. An image display device comprising: a correction unit that performs correction processing to obtain pixel data of a target position in the second image signal. An information signal processing method for converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data. hand,
A first step of selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
A second step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the first step;
A third step of generating correction data for correcting coding noise corresponding to the class detected in the second step;
The correction data generated in the third step is used for the second information data corresponding to the target position in the second information signal among the plurality of information data constituting the first information signal. Performing a correction process to obtain information data of the position of interest in the second information signal. In order to convert a first information signal composed of a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal composed of a plurality of pieces of information data,
A first step of selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
A second step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the first step;
A third step of generating correction data for correcting coding noise corresponding to the class detected in the second step;
The correction data generated in the third step is used for the second information data corresponding to the target position in the second information signal among the plurality of information data constituting the first information signal. And a fourth step of performing a correction process to obtain information data of a target position in the second information signal. A computer-readable medium storing a program for causing a computer to execute the information signal processing method. In order to convert a first information signal composed of a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal composed of a plurality of pieces of information data,
A first step of selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
A second step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the first step;
A third step of generating correction data for correcting coding noise corresponding to the class detected in the second step;
The correction data generated in the third step is used for the second information data corresponding to the target position in the second information signal among the plurality of information data constituting the first information signal. Performing a correction process to obtain information data of the position of interest in the second information signal. An information signal processing device for converting a first information signal including a plurality of pieces of information data generated by decoding an encoded digital information signal into a second information signal including a plurality of pieces of information data. hand,
Data selection means for selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
Class detecting means for detecting a class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means;
Correction data generating means for generating correction data for correcting coding noise related to a frequency coefficient obtained by orthogonal transformation, corresponding to the class detected by the class detecting means,
Orthogonal transform means for performing orthogonal transform on second information data corresponding to a position of interest in the second information signal, among a plurality of information data constituting the first information signal;
Correction means for performing a correction process using the correction data generated by the correction data generation means on the frequency coefficient obtained by the orthogonal transformation means,
An information signal processing apparatus comprising: an inverse orthogonal transform unit that performs an inverse orthogonal transform on the frequency coefficient corrected by the correction unit to obtain information data of a target position in the second information signal. The correction data generating means includes:
Storage means for storing correction data for each class;
13. The information signal processing apparatus according to claim 12, further comprising: data reading means for reading correction data corresponding to the class detected by the class detecting means from the storage means. The correction data stored in the storage means is
14. The information signal processing apparatus according to claim 13, wherein the information signal processing apparatus is generated in advance using a student signal corresponding to the first information signal and a teacher signal corresponding to the second information signal. The information signal processing device according to claim 14, wherein the student signal is obtained by decoding a digital information signal obtained by encoding the teacher signal. The number of pieces of information data at a position of interest in the second information signal is N times (N is an integer of 2 or more) the number of pieces of second information data corresponding to the position of interest. 13. The information signal processing device according to item 12. The correction data is difference data of a number of frequency coefficients corresponding to the number of information data at the position of interest in the second information signal,
The correction means,
An output frequency coefficient is obtained by adding a frequency coefficient output from the orthogonal transform means to a low frequency component corresponding to a frequency coefficient output from the orthogonal transform means in the correction data. Item 17. An information signal processing device according to Item 16. The correction data is a number of frequency coefficients corresponding to the number of information data at the position of interest in the second information signal,
The correction means,
An output frequency coefficient is obtained by replacing at least a part of a low-frequency component of the correction data corresponding to a frequency coefficient output from the orthogonal transform means with a frequency coefficient output from the orthogonal transform means. 17. The information signal processing device according to item 16. An image signal processing device for converting a first image signal composed of a plurality of pixel data generated by decoding an encoded digital image signal into a second image signal composed of a plurality of pixel data. hand,
Data selecting means for selecting a plurality of first pixel data located around a target position in the second image signal based on the first image signal;
Class detection means for detecting a class to which the pixel data at the target position belongs based on the plurality of first pixel data selected by the data selection means;
Correction data generating means for generating correction data for correcting coding noise related to a frequency coefficient obtained by orthogonal transformation, corresponding to the class detected by the class detecting means,
Orthogonal transformation means for performing orthogonal transformation on second pixel data corresponding to a position of interest in the second image signal, among a plurality of pixel data constituting the first image signal;
Correction means for performing a correction process using the correction data generated by the correction data generation means on the frequency coefficient output from the orthogonal transformation means,
An image signal processing apparatus comprising: an inverse orthogonal transform unit that performs an inverse orthogonal transform on a frequency coefficient output from the correction unit to obtain pixel data of a target position in the second image signal. Image signal input means for inputting a first image signal composed of a plurality of pixel data generated by decoding the encoded digital image signal;
Image signal processing means for converting the first image signal input to the image signal input means into a second image signal comprising a plurality of pixel data and outputting the second image signal;
Image display means for displaying an image based on the second image signal output from the image signal processing means on an image display element,
The image signal processing means includes:
Data selecting means for selecting a plurality of first pixel data located around a target position in the second image signal based on the first image signal;
Class detection means for detecting a class to which the pixel data at the target position belongs based on the plurality of first pixel data selected by the data selection means;
Correction data generating means for generating correction data for correcting coding noise related to a frequency coefficient obtained by orthogonal transformation, corresponding to the class detected by the class detecting means,
Orthogonal transformation means for performing orthogonal transformation on second pixel data corresponding to a position of interest in the second image signal, among a plurality of pixel data constituting the first image signal;
Correction means for performing a correction process using the correction data generated by the correction data generation means on the frequency coefficient output from the orthogonal transformation means,
An image display apparatus comprising: an inverse orthogonal transform unit that performs an inverse orthogonal transform on a frequency coefficient output from the correction unit to obtain pixel data of a target position in the second image signal. An information signal processing method for converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data. hand,
A first step of selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
A second step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the first step;
A third step of generating correction data for correcting coding noise related to frequency coefficients obtained by orthogonal transform, corresponding to the class detected in the second step;
A fourth step of performing orthogonal transformation on second information data corresponding to a position of interest in the second information signal, among a plurality of information data constituting the first information signal;
A fifth step of performing a correction process using the correction data generated in the third step on the frequency coefficient obtained in the fourth step;
A sixth step of performing an inverse orthogonal transform on the frequency coefficient corrected in the fifth step to obtain information data of a position of interest in the second information signal. Method. In order to convert a first information signal composed of a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal composed of a plurality of pieces of information data,
A first step of selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
A second step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the first step;
A third step of generating correction data for correcting coding noise related to frequency coefficients obtained by orthogonal transform, corresponding to the class detected in the second step;
A fourth step of performing orthogonal transformation on second information data corresponding to a position of interest in the second information signal, among a plurality of information data constituting the first information signal;
A fifth step of performing a correction process using the correction data generated in the third step on the frequency coefficient obtained in the fourth step;
Performing an inverse orthogonal transform on the frequency coefficient corrected in the fifth step to obtain information data of a position of interest in the second information signal. A computer-readable medium storing a program for causing a computer to execute the program. In order to convert a first information signal composed of a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal composed of a plurality of pieces of information data,
A first step of selecting, based on the first information signal, a plurality of pieces of first information data located around a target position in the second information signal;
A second step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the first step;
A third step of generating correction data for correcting coding noise related to frequency coefficients obtained by orthogonal transform, corresponding to the class detected in the second step;
A fourth step of performing orthogonal transformation on second information data corresponding to a position of interest in the second information signal, among a plurality of information data constituting the first information signal;
A fifth step of performing a correction process using the correction data generated in the third step on the frequency coefficient obtained in the fourth step;
Performing an inverse orthogonal transform on the frequency coefficient corrected in the fifth step to obtain information data of a position of interest in the second information signal. Program to let you. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; An apparatus for generating correction data for correcting coding noise,
Decoding means for decoding a digital information signal obtained by encoding the teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
Data selection means for selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal output from the decoding means;
Class detecting means for detecting a class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means;
Subtraction means for performing a subtraction process on the information data of the target position in the teacher signal using second information data corresponding to the target position among a plurality of information data constituting the student signal;
A correction data generating apparatus, comprising: calculation means for averaging output data of the subtraction means for each class based on the class detected by the class detection means, and obtaining correction data for each class. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; A method for generating correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the second step;
A fourth step of performing a subtraction process on the information data of the position of interest in the teacher signal using second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal;
A fifth step of averaging the data obtained in the fourth step for each class based on the classes detected in the third step to obtain correction data for each class. Correction data generation method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; To generate correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the second step;
A fourth step of performing a subtraction process on the information data of the position of interest in the teacher signal using second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal;
A fifth step of averaging the data obtained in the fourth step for each class based on the classes detected in the third step to obtain correction data for each class. A computer-readable medium storing a program for causing a computer to execute the method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; To generate correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the second step;
A fourth step of performing a subtraction process on the information data of the position of interest in the teacher signal using second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal;
A fifth step of averaging the data obtained in the fourth step for each class based on the classes detected in the third step to obtain correction data for each class. A program that causes a computer to perform the method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; An apparatus for generating correction data for correcting coding noise,
Decoding means for decoding a digital information signal obtained by encoding the teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
Data selection means for selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal output from the decoding means;
Class detecting means for detecting a class to which the information data of the target position belongs based on the plurality of first information data selected by the data selecting means;
First orthogonal transform means for performing an orthogonal transform on the information data at the position of interest in the teacher signal to obtain a first frequency coefficient;
A second orthogonal transform unit that performs an orthogonal transform on second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal, to obtain a second frequency coefficient;
Subtraction means for performing a subtraction process on the first frequency coefficient obtained by the first orthogonal transformation means using the second frequency coefficient obtained by the second orthogonal transformation means;
A correction data generating apparatus, comprising: calculation means for averaging output data of the subtraction means for each class based on the class detected by the class detection means, and obtaining correction data for each class. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; A method for generating correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the second step;
A fourth step of performing orthogonal transformation on the information data of the position of interest in the teacher signal to obtain a first frequency coefficient;
A fifth step of performing orthogonal transformation on second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal to obtain a second frequency coefficient;
A sixth step of performing a subtraction process on the first frequency coefficient obtained in the fourth step using the second frequency coefficient obtained in the fifth step;
Averaging the data obtained in the sixth step for each class based on the classes detected in the third step to obtain correction data for each class. Correction data generation method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; To generate correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the second step;
A fourth step of performing orthogonal transformation on the information data of the position of interest in the teacher signal to obtain a first frequency coefficient;
A fifth step of performing orthogonal transformation on second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal to obtain a second frequency coefficient;
A sixth step of performing a subtraction process on the first frequency coefficient obtained in the fourth step using the second frequency coefficient obtained in the fifth step;
Averaging the data obtained in the sixth step for each class based on the classes detected in the third step to obtain correction data for each class. A computer-readable medium storing a program for causing a computer to execute the method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; To generate correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of first information data located around a target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of first information data selected in the second step;
A fourth step of performing orthogonal transformation on the information data of the position of interest in the teacher signal to obtain a first frequency coefficient;
A fifth step of performing orthogonal transformation on second information data corresponding to the position of interest among a plurality of pieces of information data forming the student signal to obtain a second frequency coefficient;
A sixth step of performing a subtraction process on the first frequency coefficient obtained in the fourth step using the second frequency coefficient obtained in the fifth step;
Averaging the data obtained in the sixth step for each class based on the classes detected in the third step to obtain correction data for each class. A program that causes a computer to perform the method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; An apparatus for generating correction data for correcting coding noise,
Decoding means for decoding a digital information signal obtained by encoding the teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
Data selection means for selecting a plurality of information data located around the position of interest in the teacher signal based on the student signal output from the decoding means;
Class detecting means for detecting a class to which the information data of the target position belongs, based on the plurality of information data selected by the data selecting means;
Orthogonal transform means for performing orthogonal transform on the information data of the position of interest in the teacher signal to obtain a frequency coefficient;
An arithmetic unit for averaging the frequency coefficients obtained by the orthogonal transform unit for each class based on the class detected by the class detection unit, and obtaining correction data for each class. Data generator. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; A method for generating correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of information data located around the target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of information data selected in the second step;
A fourth step of performing orthogonal transformation on the information data of the position of interest in the teacher signal to obtain a frequency coefficient;
A fifth step of averaging the frequency coefficient obtained in the fourth step for each class based on the class detected in the third step to obtain correction data for each class. Characteristic correction data generation method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; To generate correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of information data located around the target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of information data selected in the second step;
A fourth step of performing orthogonal transformation on the information data of the position of interest in the teacher signal to obtain a frequency coefficient;
A fifth step of averaging the frequency coefficients obtained in the fourth step for each class based on the classes detected in the third step to obtain correction data for each class. A computer-readable medium recording a program for causing a computer to execute the generation method. Used when converting a first information signal including a plurality of pieces of information data, which is generated by decoding an encoded digital information signal, into a second information signal including a plurality of pieces of information data; To generate correction data for correcting coding noise,
A first step of decoding a digital information signal obtained by encoding a teacher signal corresponding to the second information signal to obtain a student signal corresponding to the first information signal;
A second step of selecting a plurality of pieces of information data located around the target position in the teacher signal based on the student signal obtained in the first step;
A third step of detecting a class to which the information data of the target position belongs based on the plurality of pieces of information data selected in the second step;
A fourth step of performing orthogonal transformation on the information data of the position of interest in the teacher signal to obtain a frequency coefficient;
A fifth step of averaging the frequency coefficients obtained in the fourth step for each class based on the classes detected in the third step to obtain correction data for each class. A program that causes a computer to execute the generation method.

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