An RGB video signal is generated by illuminating an object with light from a first monitor and capturing an image of the object with a camera. The second monitor holds a profile representing the correspondence relationship between R, G, andB values generated by displaying an image including values of R, G, and B on a reference monitor and capturing an image of the displayed image with the camera and X, Y, and Z values which are measurements of tristimulus values of the displayed image in the XYZ color space. The second monitor converts the first R, G, and B values of the video signal to first X, Y, and Z values based on the profile, and converts the first X, Y, and Z values to second R, G, and B values appropriate for the second monitor to display an image of the object on a display unit.