초록 ▼

An automated package dimensioning subsystem comprising a Laser Detecting and Ranging (LADAR-based) scanning apparatus for capturing two-dimensional range data maps of the space above a conveyor structure, along which packages are transported, and an image contour tracing apparatus for extracting pac

An automated package dimensioning subsystem comprising a Laser Detecting and Ranging (LADAR-based) scanning apparatus for capturing two-dimensional range data maps of the space above a conveyor structure, along which packages are transported, and an image contour tracing apparatus for extracting package dimension data from the two-dimensional range data maps.

대표청구항 ▼

The invention claimed is: 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

The invention claimed is: 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. 2. The automated object dimensioning system of claim 1, wherein said programmed digital image processor comprises: a fifth data processing stage for automatically processing said third set of indices (m,n) associated with detected corner point candidates so as to reduce said set of candidate corner points down to a set of corner points most likely to correspond to the corner points of a regular-shaped polygonal object, said most likely set of candidate corner points being represented by a fourth set of indices (m,n) and indicative of the corners of a regular-shaped polygonal object which most likely corresponds to the particular object being transported along said conveyor belt structure; and a sixth data processing stage for automatically processing said fourth set of indices (m,n) associated with the corner points of a regular-shaped polygonal object so as to compute said dimension-related parameters of the object represented by said image contours traced within said buffered two-dimensional range data map. 3. The automated object dimensioning system of claim 2, wherein said sixth data processing stage further comprises: a first data processing substage for automatically processing said fourth set of indices (m,n) associated with the corner points of a regular-shaped polygonal object so as to compute the surface area of the object represented by said traced contours within said buffered two-dimensional range data map; and a second data processing substage for automatically processing said fourth set of indices (m,n) associated with the corner points of said regular-shaped polygonal object so as to compute the average height of the object represented by said traced contours in said buffered two-dimensional range data map, referenced relative to a global Cartesian-type coordinate reference system symbolically embedded within said system housing. 4. The automated object dimensioning system of claim 3, wherein said sixth data processing stage further comprises: a third data processing substage for automatically processing said fourth set of indices (m,n) associated with the corner points of said regular-shaped polygonal object so as to compute the x, y, z coordinates corresponding to the corners of the object represented by said traced contours in said buffered two-dimensional range data map, referenced relative to said global Cartesian-type coordinate reference system. 5. The automated object dimensioning system of claim 1, wherein said first data processing stage employs window-type convolution kernals that smooth and edge-detect the raw range data and thus improve its quality for subsequent dimension data extraction operations. 6. The automated object dimensioning system of claim 1, wherein said first data processing stage includes means for subtracting detected background information (including noise) from the continuously updated two-dimensional range data map as to accommodate for changing background lighting conditions. 7. The automated object dimensioning system of 1, wherein said laser scanning mechanism comprises a holographic-type laser scanning mechanism for scanning said amplitude modulated laser beam across the width of said conveyor belt structure. 8. The automated object dimensioning system of claim 1, wherein said photodetector comprises an avalanche-type photodetector mounted on said optical bench. 9. The automated object dimensioning system of claim 1, wherein said object is a package. 10. The automated object dimensioning system of claim 1, wherein a velocity of each said object is computed by using a pair of amplitude modulated laser beams projected from said automated object dimensioning subsystem at different angular projections over said conveyor belt structure along which said object is transported. 11. The automated object dimensioning system of claim 10, wherein said amplitude modulated laser beams have multiple wavelengths to sense objects having a wide range of reflectivity characteristics.