Image processing apparatus, image processing method, and program

An image processing method executed in an image processing apparatus, the image processing method including:

• accepting, by a signal processing unit, an input of a subsampled image obtained by copying an adjacent pixel value to a pixel value thinning position, as an input image;
• calculating, by the signal processing unit, a correction target signal global gain which is a ratio between a slope of a correction target signal and a slope of a luminance signal of a global region made up of a plurality of consecutive pixels including a pixel position of a correction target pixel of the input image;
• calculating, by the signal processing unit, a luminance local slope which is a slope of the luminance signal of a local region smaller than the global region, the local region being a region within the global region, including the pixel position of the correction target pixel of the input image;
• and
• calculating, by the signal processing unit, a corrected pixel value of the correction target pixel by multiplying the luminance local slope by the correction target signal global gain and applying a multiplication result.

A program stored in a non-transitory computer readable medium that executes an image process in an image processing apparatus, the program causing a signal processing unit to:

• accept an input of a subsampled image obtained by copying an adjacent pixel value to a pixel value thinning position, as an input image;
• execute a calculation process for a correction target signal global gain which is a ratio between a slope of a correction target signal and a slope of a luminance signal of a global region made up of a plurality of consecutive pixels including a pixel position of a correction target pixel of the input image;
• execute a calculation process for a luminance local slope which is a slope of the luminance signal of a local region smaller than the global region, the local region being a region within the global region, including the pixel position of the correction target pixel of the input image;
• and
• execute a process of calculating a corrected pixel value of the correction target pixel by multiplying the luminance local slope by the correction target signal global gain and applying a multiplication result.