Technique | Region shape descriptor |
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Document | MPEG-7 Visual (ISO/IEC 15938-3) |
Name | Whoi-Yul Kim (Hanyang University) |
wykim@email.hanyang.ac.kr | |
Contact | wykim@email.hanyang.ac.kr |
Type | Application |
External Libraries | none |
Related Ds/DSs | Still region DS |
Used Ds/DSs | none |
Input | Binary/Gray shape masks |
Extraction | Yes |
Client Appl | Search & Retrieval |
Summary | Shape of an object may consist of either single region or a set of regions as well as some holes in the object in a frame. The region-based shape descriptor describes shape features of the object as long as it can be defined by a shape mask. The mask may be binary to contain holes or multiple disjoint regions within. The mask may also be in gray shade to distinguish different regions within the object. The descriptor consists of a set of 35 quantized coefficients of Angular-Radial Transform of an object. |
Strong Points | The descriptor is rotational, scale and position invariant. It can deal with objects with multiple regions including holes in the object. It is robust to noise along the contour of the object that is common during the segmentation process of an image, or to shape deformations due to affine transform. The descriptor is also characterized by its small size, fast extraction time and matching. The data size for this representation is fixed to 17.5byte. The feature extraction and matching processes is straightforward to have low order of computational complexities, and is suitable for tracking shapes in the video data processing. |
Limitations | None |
Known Problems | None |
Parameters | Uses the general XM-SW parameters. |