Documentation for Video/3DShapeSpectrum

Technique 3D Shape Spectrum Descriptor
Document MPEG-7 Visual (ISO/IEC 15938-3)
Name Titus Zaharia, Institut National des Telecommunications
EMail titus.zaharia@int-evry.fr
Type Application
External Libraries NONE
Related Ds/DSs 2D Shape Descriptors, Multiview Descriptor
Used Ds/DSs NONE
Input 3D Meshes in VRML2.0 format
Extraction Yes
Client Appl Search & Retrieval
Summary The 3D Shape Spectrum Descriptor provides a compact shape description of 3D data represented as 3D meshes.
The 3D Shape Spectrum Descriptor is the histogram (distribution) of the shape index over the entire mesh.
The shape index is defined as the angular coordinate of a polar representation of the pricipal curvature vector.
The descriptor includes two additional components quantifying the amount of singular components (e.g. borders)
and planar components (for which the shape index is not defined).
Strong Points Compactness
Limitations None
Known Problems None
Parameters NoOfBins : represents the number of bins used for the histogram representation.
NoOfBins may take any positive integer value. Usual values range in the [10, 100] interval.
NoOfBits : represents the number of bits that uniformly quantize the 3D Shape Spectrum values.
Usual values: 8, 9, 10, 11, 12, 13, 14.
Metric : specifies the metric used for similarity retrieval.
The possible values and their associated metrics are listed here below:
0 - L1-based distance, without the singular and planar surface components
1 - L2-based distance, without the singular and planar surface components
2 - pseudo-weighted similarity measure, without the singular and planar surface components
3 - L1-based distance, without the singular surface components
4 - L2-based distance, without the singular surface components
5 - pseudo-weighted similarity measure, without the singularr surface components
6 - L1-based distance, with all components
7 - L2-based distance, with all the components
8 - pseudo-weighted similarity measure, with all components
Example: NoOfBins 100
NoOfBits 12
Metric 0