Measurement and control technology can simplify the operation of process equipment, improve product quality and asset productivity, and minimize waste by increasing first-pass yield. Thus, there are real economic incentives for improving the control of these processes. In the past, the feedback used for industrial control systems was based on scalar quantities such as temperature and pressure, which were measured at single points in the process. Due to the increasingly stringent demands on the quality of products produced by increasingly complex systems, more sophisticated measurements are needed to control manufacturing processes. Two-dimensional (2D) and sometimes three-dimensional (3D) information is needed to optimize processes such as casting of polymer film and mixing chemical components. Process imaging techniques provide this higher dimensionality.