Only the mixed nodes in a quad tree have children the

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Only the mixed nodes in a quad tree have children. The full nodes and empty nodes are leaf nodes. Larger number of levels are required to produce a reasonably smoothly curved boundary. Quad trees have been used to represent map regions in geographic information systems. Draw the quad tree represention of the region shown in Fig Qu. 2 below. Fig Qu. 2 2.5 Property tables. Property table is the representation of a region by its extracted properties rather than by its pixels. It is a table in the relational database sense that has a row for each region in the image and a column for each property of interest. Properties can represent the size, shape, intensity, color, or texture of the region. For example, in content based image retrieval system, regions might be described by area, ratio of minor-to-major axis of the best fitting ellipse, two main colors, and one or more texture measures. Simple geometric border representation. Boundary length – boundary length is an elementary region property, that is simply derived from the chain code representation. Vertical and horizontal steps have unit length, and the length of diagonal steps in 8-connectivity is √2. it can be shown that the boundary is longer in 4-connectivity, where a diagonal step consists of two rectangular steps with a total length of 2. a closed boundary length (perimeter) can also be easily evaluated from the run length or quadtree representations. Boundary length increases as the image raster resolution increases; on the other hand, region area is not affected by higher resolution and converges to some limit. Curvature- in the continuous case, curvature is defined as the rate of change of slope. In discrete space, the curvature description must be slightly modified to overcome difficulties resulting from violation of curve smoothness. The curvature scalar descriptor finds the ratio between the total number of boundary pixels and the number of boundary pixels where the boundary direction changes significan...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online