Signal converter and signal conversion method

A signal converter for converting a low-definition input image signal into a high-definition image signal, said signal converter comprising:

• frequency characteristic determination means for evaluating a frequency characteristic of the input image signal with respect to each of predetermined unit blocks;
• pixel pattern setting means for setting a pixel pattern from the input image signal for each of the unit blocks;
• classification means for forming a class code representing a class to which the input image signal forming the pixel pattern belongs by setting a quantization condition with respect to the input image signal according to the evaluated frequency characteristic and data compressing the input image signal;
• prediction coefficient storage means for storing, in correspondence with each class code, prediction coefficients for predicting and forming pixels from pixels of the input image signal;
• and
• prediction calculation means for forming a high-definition image signal with respect to the input image signal by prediction calculation processing the input image signal using the prediction coefficients read out of said prediction coefficient storage means according to the class code.

A signal converter for converting a low-definition input image signal into a high-definition image signal, said signal converter comprising:

• frequency characteristic determination means for evaluating a frequency characteristic of the input image signal with respect to each of predetermined unit blocks;
• selecting means for selecting a pixel pattern according to the evaluated frequency characteristic to determine a class;
• classification means for forming a class code representing a class to which the input image signal forming the pixel pattern selected by said selecting means belongs by setting a quantization condition with respect to the input image signal according to the evaluated frequency characteristic, and data compressing the input image signal;
• prediction coefficient storage means for storing, in correspondence with each class and class code, prediction coefficients which are read out for predicting and forming pixels from pixels of the input image signal;
• and
• prediction calculation means for forming a high-definition image signal with respect to the input image signal by prediction calculation processing of the input image signal using the prediction coefficients read out of said prediction coefficient storage mans according to the class and class code.

A signal conversion method for converting a low-definition input image signal into a high-definition image signal, said method comprising the steps of:

• evaluating frequency characteristics of the input image signal with respect to predetermined unit blocks;
• selecting a pixel pattern according to the evaluated frequency characteristics;
• forming a class based on the selected pixel pattern;
• and
• converting the input image signal into a high-definition image signal by reading out previously-obtained prediction coefficients stored for each class in a memory according to the class and prediction calculation processing the input image signal using the read out prediction coefficients such that pixels from pixels of the input image signal are formed.

A signal conversion method for converting a low-definition input image signal into a high-definition image signal, said method comprising the steps of:

• evaluating frequency characteristics of the input image signal with respect to predetermined unit blocks;
• setting a pixel pattern from the input image signal with respect to each of the unit blocks;
• forming a class code representing a class to which the input image signal forming the pixel pattern belongs by setting a quantization condition with respect to the input image signal according to the evaluated frequency characteristics and data compressing the input image signal;
• and
• converting the input image signal into a high-definition image signal by reading out previously-obtained prediction coefficients stored for each class in a memory according to the class code and prediction calculation processing the input image signal using the read out prediction coefficients such that interpolated pixels are formed from pixels of the input image signa.

A signal conversion method for converting a low-definition input image signal into a high-definition image signal, said method comprising the steps of:

• evaluating frequency characteristics of the input image signal with respect to predetermined unit blocks;
• setting a spatial class by selecting a pixel pattern according to the evaluated frequency characteristic;
• forming a class code representing a class to which the input image signal forming the selected pixel pattern belongs by setting a quantization condition with respect to the input image signal according to said evaluated frequency characteristic and data compressing the input image signal;
• and
• converting the input image signal into a high-definition image signal by reading out previously-obtained prediction coefficients stored for each class in a memory according to the class and the class code and prediction calculation processing the input image signal using the read out prediction coefficients such that interpolated pixels are formed from pixels of the input image signal.

A signal conversion method for converting a low-definition input image signal into a high-definition image signal, said method comprising the steps of:

• evaluating frequency characteristics of the input image signal with respect to predetermined unit blocks;
• selecting a pixel pattern according to the evaluated frequency characteristic;
• forming a class based on the input image signal forming the selected pixel pattern;
• and
• converting the input image signal into a high-definition image signal by reading out previously-obtained prediction data stored for each class in a memory according to the class and by using the read out prediction data as pixels of the high-definition image signal.

A signal conversion method for converting a low-definition input image signal into a high-definition image signal, said method comprising the steps of:

• evaluating frequency characteristics of the input image signal with respect to predetermined unit blocks;
• setting a pixel pattern from the input image signal with respect to each of the unit blocks;
• forming a class code representing a class to which the input image signal forming the pixel pattern belongs by setting a quantization condition with respect to the input image signal according to the evaluated frequency characteristic and data compressing the input image signal;
• and
• converting the input image signal into a high-definition image signal by reading out previously-obtained prediction data stored for each class in a memory according to the class code and using the prediction data as pixels of the high-definition image signa.

A signal conversion method for converting a low-definition input image signal into a high-definition image signal, said method comprising the steps of:

• evaluating frequency characteristics of the input image signal with respect to predetermined unit blocks;
• setting a class by selecting a pixel pattern according to the evaluated frequency characteristic;
• forming a class code representing a class to which the input image signal forming the selected pixel pattern belongs by setting a quantization condition with respect to the input image signal according to the evaluated frequency characteristic and data compressing the input image signa;
• and
• converting the input image signal into a high-definition image signal by reading out previously-obtained prediction data stored for each class in a memory according to the class and the class code and using the prediction data as interpolated pixels of the input image signal.

An apparatus for converting a first image signal formed of pixels into a second image signal formed of pixels and having a resolution greater than the first image signal, said apparatus comprising:

• means for detecting a frequency characteristic with respect to pixels in the first image signal in a vicinity close to a target pixel of the second image signal;
• means for selecting pixels in said vicinity in said first image signal as a function of the detected frequency characteristic for determining a class in accordance with the selected pixels;
• a memory for storing a respective set of predicted coefficients for each class, each set of predicted coefficients having been generated using a training image signal corresponding to said second image signal;
• means for retrieving a set of predicted coefficients from said memory in response to the determined class;
• and
• means for generating the target pixel of the second image signal in accordance with the retrieved set of predicted coefficients and pixels in the first image signal in a vicinity close to the target pixel.

Apparatus for converting a first image signal into a second image signal having a resolution greater than the first image signal, said apparatus comprising:

• means for detecting a frequency characteristic with respect to pixels in the first image signal in a vicinity of a target pixel of the second image signal;
• means for selecting pixels in said vicinity in said first image signal for determining a class in accordance with the selected pixels and in response to the detected frequency characteristics;
• a memory for storing a respective predicted value for each class, each predicted value having been generated using a training image signal corresponding to said second image signal;
• and
• means for retrieving a predicted value from said memory in response to the determined class to output the predicted value as the target pixel of the second image.

A method for converting a first image signal formed of pixels into a second image signal formed of pixels and having resolution greater than the first image signal, said method comprising the steps of:

• detecting a frequency characteristic with respect to pixels in the first image signal in a vicinity close to a target pixel of the second image signal;
• selecting pixels in said vicinity in said first image signal as a function of the detected frequency characteristic for determining a class in accordance with the selected pixels;
• retrieving a set of predicted coefficients stored in a memory in response to the determined class, each stored set of predicted coefficients having been generated using a training image signal corresponding to said second image signal;
• and
• generating the target pixel of the second image signal in accordance with the retrieved set of predicted coefficients and pixels in the first image signal in a vicinity close to the target pixel.

A method for converting a first image signal into a second image signal having a resolution greater than the first image signal, said method comprising the steps of:

• detecting a frequency characteristic with respect to pixels in the first image signal in a vicinity of a target pixel of the second image signal;
• selecting pixels in said vicinity in said first image signal as a function of the detected frequency characteristic for determining a class in accordance with the selected pixels;
• and
• retrieving a predicted value stored in a memory in response to the determined class, each stored predicted value having been generated using a training image signal corresponding to said second image signal to output the predicted value as the target pixel of the second image.