On-line piecewise homeomorphism model prediction, control and calibration system for a dynamically varying color marking device

A color printer comprising:

• an image reproduction system for generating an output image in response to an input signal;
• a sensor for detecting a sensor signal representative of the output image;
• and,
• a processor comprising:
• a piecewise homeomorphic (PH) model of the image reproduction system for estimating the input signal into a model output;
• a real-time parameter adjustment algorithm;
• and
• a comparator for comparing an output signal of the system with the model output, wherein based upon an output from the comparator, the real-time parameter adjustment algorithm computes an updated set of parameters for the PH model and the PH model is updated in accordance with the updated parameters, for transforming a subsequent input signal with the updated model until the comparator output is less than a predetermined error value.

A method of calibrating a color printer comprising updating a set of parameters for a piecewise homeomorphic (PH) model representing color space transformations by the printer of an input signal to an output signal, wherein the printer includes a sensor for detecting a signal representative of printer color output, the method comprising steps of:

• producing an image with the printer in response to the input signal;
• sensing with the sensor the signal representative of the printer color output;
• generating an output from the PH model responsive to the input signal and comparable to the sensed color signal;
• determining a difference between the sensed signal and the parametric model output;
• adjusting the PH model if the difference exceeds a predetermined value;
• generating an inverse of the updated PH model;
• and,
• transforming a subsequent input signal with the inverse of the updated PH model whereby subsequent images produced by the printer are made in accordance with the inverse of the updated PH model.