Image processing device, electronic camera, image processing method, and image processing program

An image processing method, comprising:

• an image inputting step for acquiring a plurality of low-resolution images obtained by shooting the same subject under a plurality of exposure conditions with an imaging unit shooting images of the subject with a plurality of different resolutions and a high-resolution image obtained by shooting the subject under a correct exposure condition with the imaging unit;
• and
• a synthesizing step for synthesizing at least one of the low-resolution images chosen from the plurality of low-resolution images and the high-resolution image, and generating a synthesized image having a resolution equivalent to the high-resolution image, wherein
• the synthesizing step comprises:
• an adjusting step for adjusting a tone level of a corresponding pixel of the synthesized image by reflecting a tone level of each pixel included in at least one of the low-resolution images chosen and a tone level of corresponding pixel of the high-resolution image;
• and
• a controlling step for controlling adjusting processing of the tone level of each pixel of the synthesized image in the adjusting step based on at least one of the followings, a histogram of a tone level obtained for each of the plurality of low-resolution images, a histogram of a tone level obtained for the high-resolution image, and the number of the low-resolution images acquired in the image inputting step.