1. A method of correcting PICA image data, comprising: a. Acquiring optical image data of a target having identifiable optical-image features, b. Acquiring PICA image data of the target having identifiable PICA-image features corresponding to the optical-image features, c. Matching PICA-image features with corresponding optical-image features, and d. Calculating from matched PICA-image features and optical-image features a set of coefficients defining relationships between observed positions of PICA-image features and optical-image features.