Image Formation by Integrated Scanning

In conventional optical instruments, imaging implies that all the rays passing through the lenses and reflecting from the mirrors of the instrument converge in the image plane in such a manner that a magnified duplicate of the object plane is formed. However, this correspondence between the object and the image need not always be present in an optical instrument, in which case we say the instrument is non-imaging. We do not consider such an instrument in this report. We do wish to discuss, however, a loosely-defined class of optical systems called scanning systems. This class includes systems with multiple transmitters and receivers, complicated scanner motions, synthetic apertures, etc. We direct our attention, however, only to systems where the object is time-sequentially scanned by a spatially localized beam. Furthermore, the entire instantaneous image, or intermediate image, produced by the scanning system is integrated according to some summation law. The integrated signal constitutes the intensity of the image point corresponding to the object point being scanned at that instant. When all integrated image points are displayed on a map according to their corresponding object positions we have the integrated scan image, and hence we call this system integrated scanning.