Color Reproduction Stabilization with Time-Sequential Sampling

Color reproduction stabilization is a control process to ensure that the printed output matches the desired color tones. In this paper we consider the stabilization of single color tone separation. The mapping of input-tone to output-color is characterized by the color tone reproduction curve(TRC). By compensating for any variations of the Xerographic printing process, the TRC stabilization controller aims to achieve identity TRC maps. This problem is critical to ensure high fidelity color printing. To make TRC stabilization viable in an actual Xerographic printing process, there are two major issues to address; 1) there exist only small number of actuators to stabilize a potentially infinite dimensional TRC; 2) only a small number of color sensor patches can be printed and measured at a time. We will look into TRC stabilization controller based on optimal controller. To address the second problem, we proposed the use of time-sequential sampling to fulfill the sparse spatio-temporal sampling requirement of sensing the TRC. We also proposed using Kalman filtering approach to reconstruct the time-sequential sampled signal. Two types of time-sequential sampling strategies lexicographical and bit reversed strategies are analyzed and their suitability for TRC stabilization discussed. The time-sequential sampling and Kalman filter forms a linear time invariant observer for the TRC stabilization controller. This gives a straightforward implementation of the TRC stabilization control with time-sequential sampling. Experimental and simulation results verified the adequacy of the approach taken in realizing a practical color reproduction stabilization control system.