Regional reconstruction of spatially distributed functions

Apparatus for estimating the value of spatially distributed functions in regions of interest in an object, comprising:

• a plurality of detectors, arranged at a plurality of loci distributed about the object in a spatial frame of reference to detect a signal along a plurality of lines through the object, said signal being related to the value of the function in the region of interest through which a line passes;
• a repository containing a spatial reference dataset suitable for defining regions of interest in articles such as the object;
• a man-machine interface which allows a person to input and receive information to and from the apparatus and
• a processor arranged to execute programmed applications which:
• specifies a set of regions of interest in the spatial reference dataset, to a spatial geometric sampling size that is smaller than the resolution that is attainable by reconstruction of an image from the set of projection values;
• map the spatial reference dataset on to the spatial frame of reference;
• project the regions of interest on to the loci of the detectors;
• and
• calculating a value, and an associated confidence measure, of the spatially distributed function for each region of interest.