An image processing apparatus receives an input of an image signal obtained by imaging an object, and performs signal conversion on the image signal to output the image signal to a display apparatus. The image processing apparatus includes a calculation unit configured to calculate an absolute luminance value of the object from a luminance value of the object acquired from the image signal and an exposure parameter in the imaging, a determination unit configured to determine a predetermined absolute luminance code for the luminance value of the object according to input-output characteristics of the display apparatus so that the object is displayed at the absolute luminance value on the display apparatus, and a conversion unit configured to perform signal conversion for converting the image signal based on a relationship between the luminance value of the object and the absolute luminance code.