A method for calibrating a camera and a display monitor is provided. The method includes identifying a parameter for optimization, assigning to a test color a target color relevant to the parameter, repeatedly performing, two or more times, a set of steps, determining a direction and timing of color divergence for the target color from obtained images, and adjusting the parameter based on the direction and rate of color divergence for the target color. The set of steps includes instructing the display monitor to display the test color on a portion of the display monitor, obtaining an image captured by the camera while the display is executing the instruction, and reassigning, to the test color, a color obtained from a portion of the image in which the portion of the display monitor was captured. The obtained image includes the portion of the display monitor.