The orthogonal projection approach (OPA) and multivariate curve resolution (MCR) are presented as a way to monitor batch processes using spectroscopic data. Curve resolution allows one to look within a batch and predict on-line real concentration profiles of the different species appearing during reactions. Taking into account the variations of the process by using an augmented matrix of complete batches, the procedure explained here calculates some prediction coefficients that can afterwards be applied for a new batch.
S. Gourvénec, C. Lamotte, P. Pestiaux, and D. L. Massart, "Use of the Orthogonal Projection Approach (OPA) to Monitor Batch Processes," Appl. Spectrosc. 57, 80-87 (2003)