Objective optical system and endoscope device including the same

An endoscope device comprising:

• an objective optical system,
• an image pickup element, and
• an image processing device,
• wherein the objective optical system includes:
• a lens group configured to form an image of an object;
• and
• an optical path splitting element disposed on an image side of the lens group,
• wherein:
• the optical path splitting element is disposed on an optical path of the lens group,
• the optical path splitting element includes an optical path splitting surface configured to form a first optical path and a second optical path,
• the first optical path is formed on a line extended from the optical path of the lens group,
• the second optical path is formed to cross the first optical path,
• an optical path length in the first optical path is different from an optical path length in the second optical path,
• a sum total of a number of transmissions of light and a number of reflections of light in the second optical path is larger than a sum total of a number of transmissions of light and a number of reflections of light in the first optical path,
• a first optical image formed in the first optical path and a second optical image formed in the second optical path are imaged with the image pickup element,
• the image processing device includes:
• an image correction processor configured to correct two images acquired by imaging such that differences of the two images other than focus are corrected to be substantially equal to each other;
• and
• an image composition processor configured to generate a composite image from the two images corrected by the image correction processor, and
• the image correction processor includes a tone correction unit configured to make relative luminance and saturation of the two images to substantially agree in at least one desired specific wavelength region.