Image processing apparatus, image processing method, program, and recording medium

An image processing apparatus comprising:

• a filtering process circuit that performs an image filtering process including a plurality of times of filtering processes with respect to original image data to acquire processed image data,
• wherein the plurality of times of filtering processes include at least a first filtering process and a second filtering process,
• wherein the filtering process circuit
• applies a filter to a processing target data to acquire filter application process data, applies a gain to the filter application process data to acquire gain application process data, and acquires filtering process data from the gain application process data, in each of the plurality of times of filtering processes,
• acquires, in the first filtering process, the filter application process data using a reference filter determined according to an average of frequency characteristics of the plurality of types of image filtering processes, which are frequency characteristics of the plurality of types of image filtering processes determined according to a pixel position in the original image data, and
• acquires, in the second filtering process, the filter application process data using a variance filter determined according to a variance of the frequency characteristics of the plurality of types of image filtering processes, which are the frequency characteristics of the plurality of types of image filtering processes determined according to the pixel position in the original image data, and
• wherein the gain applied to the filter application process data is determined according to the pixel position in the original image data, in each of the plurality of times of filtering processes.

An image processing method for performing an image filtering process including a plurality of times of filtering processes with respect to original image data to acquire processed image data, comprising:

• applying a filter to processing target data to acquire filter application process data, applying a gain to the filter application process data to acquire gain application process data, and acquiring filtering process data from the gain application process data, in each of the plurality of times of filtering processes,
• acquiring the gain applied to the filter application process data based on a target frequency characteristic of the image filtering process determined according to a pixel position in the original image data, in each of the plurality of times of filtering processes,
• storing gain table information obtained by associating candidate data of the gain applied to the filter application process data with the pixel position, in each of the plurality of times of filtering processes;
• and
• specifying, with reference to the gain table information, the candidate data associated with the pixel position according to the target frequency characteristic of the image filtering process as the gain applied to the filter application process data in each of the plurality of times of filtering processes,
• wherein applying the gain specified to the filter application process data to acquire the gain application process data in each of the plurality of times of filtering processes.

An image processing method for performing an image filtering process including a plurality of times of filtering processes with respect to original image data to acquire processed image data,

• wherein the plurality of times of filtering processes include at least a first filtering process and a second filtering process,
• wherein the method comprises:
• applying a filter to processing target data to acquire filter application process data, applying a gain to the filter application process data to acquire gain application process data, and acquiring filtering process data from the gain application process data, in each of the plurality of times of filtering processes;
• acquiring, in the first filtering process, the filter application process data using a reference filter determined according to an average of frequency characteristics of a plurality of types of image filtering processes, which are frequency characteristics of the plurality of types of image filtering processes determined according to a pixel position in the original image data;
• and
• acquiring, in the second filtering process, the filter application process data using a variance filter determined according to a variance of the frequency characteristics of the plurality of types of image filtering processes, which are the frequency characteristics of the plurality of types of image filtering processes determined according to the pixel position in the original image data, and
• wherein the gain applied to the filter application process data is determined according to the pixel position in the original image data, in each of the plurality of times of filtering processes.

A non-transitory computer-readable recording medium that stores a program that causes a computer to realize a function for performing an image filtering process including a plurality of times of filtering processes with respect to original image data to acquire processed image data, the program causing the computer to execute:

• a process of applying a filter to processing target data to acquire filter application process data, a process of applying a gain to the filter application process data to acquire gain application process data, and a process of acquiring filtering process data from the gain application process data, in each of the plurality of times of filtering processes,
• wherein the gain applied to the filter application process data is acquired based on a target frequency characteristic of the image filtering process determined according to a pixel position in the original image data, in each of the plurality of times of filtering processes,
• storing gain table information obtained by associating candidate data of the gain applied to the filter application process data with the pixel position, in each of the plurality of times of filtering processes;
• and
• specifying, with reference to the gain table information, the candidate data associated with the pixel position according to the target frequency characteristic of the image filtering process as the gain applied to the filter application process data in each of the plurality of times of filtering processes,
• wherein applying the gain specified to the filter application process data to acquire the gain application process data in each of the plurality of times of filtering processes.

A non-transitory computer-readable recording medium that stores a program that causes a computer to realize a function for performing an image filtering process including a plurality of times of filtering processes with respect to original image data to acquire processed image data,

• wherein the plurality of times of filtering processes include at least a first filtering process and a second filtering process,
• wherein the program causes the computer to execute:
• a process of applying a filter to processing target data to acquire filter application process data, a process of applying a gain to the filter application process data to acquire gain application process data, and a process of acquiring filtering process data from the gain application process data, in each of the plurality of times of filtering processes;
• a process of acquiring, in the first filtering process, the filter application process data using a reference filter determined according to an average of frequency characteristics of the plurality of types of image filtering processes, which are the frequency characteristics of the plurality of types of image filtering processes determined according to a pixel position in the original image data;
• and
• a process of acquiring, in the second filtering process, the filter application process data using a variance filter determined according to a variance of the frequency characteristics of the plurality of types of image filtering processes, which are the frequency characteristics of the plurality of types of image filtering processes determined according to the pixel position in the original image data, and
• wherein the gain applied to the filter application process data is determined according to the pixel position in the original image data, in each of the plurality of times of filtering processes.

An image processing apparatus comprising:

• a filtering process circuit that performs an image filtering process that includes a plurality of times of filtering processes with respect to original image data to acquire processed image data,
• wherein in each of the plurality of times of filtering processes, the filtering process circuit applies a filter to processing target data to acquire filter application process data, applies a gain to the filter application process data to acquire gain application process data, and acquires filtering process data from the gain application process data,
• wherein in each of the plurality of times of filtering processes, the gain applied to the filter application process data is acquired based on a target frequency characteristic of the image filtering process determined according to a pixel position in the original image data, and
• wherein the gain is acquired by fitting a frequency characteristic of the image filtering process to the target frequency characteristic of the image filtering process using a least squares method based on each frequency characteristic of the plurality of times of filtering processes.