Image processing apparatus, recording medium having image processing program recorded thereon, and image processing method

A non-transitory computer-readable recording medium having an image processing program recorded thereon, the image processing program causing a computer to execute:

• deriving a color distribution degree that is a distribution degree of pixel values of respective sets of pixel data included in input image data;
• deriving a photograph area ratio that is a ratio of photograph area pixel data forming a photograph area to the pixel data;
• deriving a color uniformity area ratio that is a ratio of color uniformity area pixel data forming a color uniformity area where the pixel values may be regarded as being uniform to the pixel data;
• and
• determining whether it is appropriate to perform either an index color process to perform a compression process using a lossless compression method after performing a color reduction process on the input image data or a full-color process to perform a compression process using a lossy compression method without performing the color reduction process on the input image data based on the color distribution degree, the photograph area ratio, and the color uniformity area ratio.

An image processing method comprising:

• deriving a color distribution degree that is a distribution degree of pixel values of respective sets of pixel data included in input image data;
• deriving a photograph area ratio that is a ratio of photograph area pixel data forming a photograph area to the pixel data;
• deriving a color uniformity area ratio that is a ratio of color uniformity area pixel data forming a color uniformity area where the pixel values may be regarded as being uniform to the pixel data;
• and
• determining whether it is appropriate to perform either an index color process to perform a compression process using a lossless compression method after performing a color reduction process on the input image data or a full-color process to perform a compression process using a lossy compression method without performing the color reduction process on the input image data based on the color distribution degree, the photograph area ratio, and the color uniformity area ratio.