Image processing apparatus, image processing method, photographic imaging apparatus, and recording device recording image processing program

An image processing method comprising:

• setting reference image data from a plurality of input image data obtained by shooting an identical object with a different amount of exposure;
• deriving a gray-scale conversion characteristic from the reference image data;
• and
• deriving a new pixel value for each pixel using a pixel value of one or more input image data selected from a plurality of the input image data based on the gray-scale conversion characteristic to create synthesized image data.

A computer readable recording device having an image processing program encoded and recorded in a computer readable format to create synthesized image data having an improved gray scale by synthesizing a plurality of input image data obtained by shooting an identical object with a different amount of exposure,

• wherein the image processing program causes a computer to execute a method including:
• setting reference image data from a plurality of input image data;
• deriving a gray-scale conversion characteristic from the reference image data;
• and
• deriving a new pixel value for each pixel using a pixel value of one or more input image data selected from a plurality of the input image data based on the gray-scale conversion characteristic to create synthesized image data.

A photographic imaging apparatus comprising:

• an image pickup unit capable of photoelectrically converting an object image formed by a photographic lens to output an image signal;
• a shooting control unit configured to obtain a plurality of input image data by shooting an identical object with a different amount of exposure using the image pickup unit;
• a grayscale conversion characteristic deriving unit configured to set reference image data out of a plurality of the input image data and derive a gray-scale conversion characteristic from the reference image data;
• and
• an image synthesis processing unit configured to derive a new pixel value for each pixel using a pixel value of one or more input image data selected from a plurality of the input image data based on the gray-scale conversion characteristic to create synthesized image data.