Some properties of image-processing operations on projection sets obtained from digital pictures

This paper examines some of the properties of projection sets when they are operated upon by image-processing operations. It is shown that operators such as additions, averaging, and simple difference on two or more pictures have analogous operators on their projection sets. Others, such as smoothing, distance measure, and testing of symmetry and antisymmetry features must be modified to be directly applicable to projection sets. These results are useful in that they can be used to determine what is and is not allowable when dealing with projection sets directly without having to reconstruct their associated pictures.