Image processing method and apparatus using trained dictionary
First Claim
1. An image processing method that uses a processor to convert an image, the method comprising:
- performing, on each of multiple first dictionaries produced by dictionary learning, a process to approximate a first image by linear combination of elements of the first dictionary so as to produce a linear combination coefficient and thereby acquiring multiple linear combination coefficients;
calculating, by the processor and for each of the multiple linear combination coefficients, a ratio between a largest coefficient element and a second-largest coefficient element among respective coefficient elements of the respective linear combination coefficients, the largest coefficient element having an absolute value that is largest among the respective coefficient elements and the second-largest coefficient element having an absolute value that is second-largest among the respective coefficient elements, thereby obtaining respective ratios of the multiple linear combination coefficients;
selecting a specific linear combination coefficient, among the multiple linear combination coefficients, having the ratio that is largest among the respective ratios of the multiple linear combination coefficients;
selecting, from multiple second dictionaries corresponding to the first dictionaries, a specific dictionary corresponding to the first dictionary for which the specific linear combination coefficient is selected; and
converting the first image into a second image by using linear combination of the specific linear combination coefficient and elements of the specific dictionary.
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Abstract
The image processing method includes providing first dictionaries produced by dictionary learning and second dictionaries corresponding to the first dictionaries, performing, on each first dictionary, a process to approximate the first image by linear combination of elements of the first dictionary so as to produce a linear combination coefficient and thereby acquiring multiple linear combination coefficients, and calculating, for each linear combination coefficient, a ratio between a largest coefficient element and a second-largest coefficient element and selecting a specific linear combination coefficient in which the ratio is largest among the multiple linear combination coefficients. The method further includes selecting, from the multiple second dictionaries, a specific dictionary corresponding to the first dictionary for which the specific linear combination coefficient is produced, and producing the second image by using linear combination of the specific linear combination coefficient and elements of the specific dictionary.
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Citations
9 Claims
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1. An image processing method that uses a processor to convert an image, the method comprising:
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performing, on each of multiple first dictionaries produced by dictionary learning, a process to approximate a first image by linear combination of elements of the first dictionary so as to produce a linear combination coefficient and thereby acquiring multiple linear combination coefficients; calculating, by the processor and for each of the multiple linear combination coefficients, a ratio between a largest coefficient element and a second-largest coefficient element among respective coefficient elements of the respective linear combination coefficients, the largest coefficient element having an absolute value that is largest among the respective coefficient elements and the second-largest coefficient element having an absolute value that is second-largest among the respective coefficient elements, thereby obtaining respective ratios of the multiple linear combination coefficients; selecting a specific linear combination coefficient, among the multiple linear combination coefficients, having the ratio that is largest among the respective ratios of the multiple linear combination coefficients; selecting, from multiple second dictionaries corresponding to the first dictionaries, a specific dictionary corresponding to the first dictionary for which the specific linear combination coefficient is selected; and converting the first image into a second image by using linear combination of the specific linear combination coefficient and elements of the specific dictionary. - View Dependent Claims (2, 3, 4, 5)
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6. A non-transitory computer-readable storage medium storing an image processing program as a computer program to cause a computer to execute image processing, the image processing comprising:
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performing, on each of multiple first dictionaries produced by dictionary learning, a process to approximate a first image by linear combination of elements of the first dictionary so as to produce a linear combination coefficient and thereby acquiring multiple linear combination coefficients; calculating, for each of the multiple linear combination coefficients, a ratio between a largest coefficient element and a second-largest coefficient element among respective coefficient elements of the respective linear combination coefficients, the largest coefficient element having an absolute value that is largest among the respective coefficient elements and the second-largest coefficient element having an absolute value that is second-largest among the respective coefficient elements, thereby obtaining respective ratios of the multiple linear combination coefficients; selecting a specific linear combination coefficient, among the multiple linear combination coefficients, having the ratio that is largest among the respective ratios of the multiple linear combination coefficients; selecting, from multiple second dictionaries corresponding to the first dictionaries, a specific dictionary corresponding to the first dictionary for which the specific linear combination coefficient is selected; and converting the first image into a second image by using linear combination of the specific linear combination coefficient and elements of the specific dictionary. - View Dependent Claims (7)
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8. An image processing apparatus configured to perform image processing to convert an image, the image processing apparatus comprising:
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a coefficient calculator configured to perform, on each of multiple first dictionaries produced by dictionary learning, a process to approximate a first image by linear combination of elements of the first dictionary so as to produce a linear combination coefficient and thereby acquiring multiple linear combination coefficients; a coefficient selector configured to calculate, for each of the multiple linear combination coefficients, a ratio between a largest coefficient element and a second-largest coefficient element among respective coefficient elements of the respective linear combination coefficients, the largest coefficient element having an absolute value that is largest among the respective coefficient elements and the second-largest coefficient element having an absolute value that is second-largest among the respective coefficient elements, thereby obtaining respective ratios of the multiple linear combination coefficients, and to select a specific linear combination coefficient, among the multiple linear combination coefficients, having the ratio that is largest among the respective ratios of the multiple linear combination coefficients; a dictionary selector configured to select, from multiple second dictionaries corresponding to the first dictionaries, a specific dictionary corresponding to the first dictionary for which the specific linear combination coefficient is selected; and an image producer configured to convert the first image into a second image by using linear combination of the specific linear combination coefficient and elements of the specific dictionary. - View Dependent Claims (9)
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Specification