Patent ID: 7295215

Claim:
A method for calculating rendering error of a rendering device in a color space of the rendering device, the rendering device color space having N dimensions, the rendering error being calculated from measurements in a sensor color space of a sensor of the rendering device having no more than N−1 dimensions, wherein N is an integer having a value of 2 or greater, the rendering error being applicable to monitoring, diagnostics and/or control of the rendering device, the method comprising: predetermining a mapping from coordinates in the N dimensional rendering device color space to coordinates in the sensor color space having no more than N−1 dimensions; receiving a color description in one of the rendering device color space coordinates and the sensor device color space coordinates; converting the color description to rendering device color space coordinates, if the color description is received in sensor color space coordinates, based on the predetermined mapping, thereby generating a converted color description; rendering an image based on the received color description or the converted color description; measuring a color of the rendered image with the sensor, thereby generating a measurement in sensor color space coordinates; establishing an underdetermined system of equations relating errors expressed in sensor color space coordinates to errors expressed in rendering device color space coordinates based on the predetermined mapping; applying an appropriate constraint to the underdetermined system of equations, thereby generating a determined set of equations; and calculating a rendering error in rendering device color space coordinates based on the predetermined mapping, the measurement and at least one of the received color description and the converted color description using the determined set of equations.