This paper introduces a "Diminished Reality" technique for removing an object or collection of objects and replacing it with an appropriate background image. Diminished Reality can be considered an important part of many Mixed and Augmented Reality applications. Our target application is the use of Augmented Reality (AR) to revamp procedures in industrial plants. An object or a region of interest is delineated on a single reference image. A paraperspective projection model is used to generate the correct background from multiple calibrated views of the scene. We propose methods to deal with approximately planar backgrounds with different orientations. We also propose a multi-resolution approach to deal with non-planar backgrounds. Different sets of experimental results demonstrate the success and limits of the algorithms. Results on real data from water treatment and power plants show the usefulness of this method for industrial applications.