1. An automated object dimensioning system comprising: (1) a Polar-coordinate based laser detecting and ranging (LADAR) scanning subsystem, including (i) a polygonal-type laser scanning mechanism, employing a rotating polygon mirror, for repeatedly scanning a substantially linear amplitude modulated laser beam across the width of a conveyor belt structure along which objects are transported, and without the use of curved mirror structure; (ii) an optical bench, disposed within said Polar-coordinate based LADAR scanning subsystem; (iii) a light collecting mechanism for collecting laser light from said amplitude modulated laser beam reflected off said scanned objects and focusing said reflected laser light onto a photodetector detecting said focused laser light and producing an electrical signal corresponding to the detected focused laser light, and (iv) signal processing circuitry for processing said produced electrical signal and, during each scan of said amplitude modulated laser beam across said scanned object, generating a row of raw digital range data representative of the distance from said rotating polygon to sampled points along said scanned object, and referenced with respect to a Polar-type coordinate reference system symbolically-embedded within said Polar-coordinate based LADAR-based scanning subsystem; said signal processing circuitry including and (v) a preprocessing data buffer for buffering rows of raw digital range data produced by said signal processing circuitry; and (2) a programmed digital image processor including: a first data processing stage for automatically processing said rows of raw digital range data in said preprocessing data buffer, so as to produce said two-dimensional range data map representative of the space above said conveyor belt structure; and a second data processing stage for automatically tracing contours within said buffered range data map, wherein said traced contours are represented by a first set of indices (m,n) indicative of objects being transported along said conveyor belt structure; a third data processing stage for automatically processing said first set of indices (m,n) associated with said traced contours so as to detect vertices associated with polygonal-shaped objects extracted from said range data map, said detected vertices being represented by a second set of indices (m,n) and indicative of polygonal-shaped objects corresponding to objects being transported along said conveyor belt structure; and a fourth data processing stage for automatically processing said second set of indices (m,n) associated with said detected vertices so as to detect a set of candidate corner points associated with the corners of a particular object being transported along said conveyor belt structure, said candidate corner points being represented by a third set of indices (m,n) and indicative of the corners of a particular object being transported along said conveyor belt structure.