Object Analysis

Detect edges, circles and lines; trace boundaries; perform quadtree decomposition

In an image, an edge is a curve that follows a path of rapid change in image intensity. Edges are often associated with the boundaries of objects in a scene. Different algorithms are suited for detecting edges of straight lines, round objects, or arbitrarily shaped regions. Conversely, you can detect homogenous blocks that lack edges.

Functions

expand all

显示边界

`bwboundaries`	二进制图像中的痕量区域边界
`bwtraceboundary`	Trace object in binary image
`visboundaries`	Plot region boundaries

检测圆

`imfindcircles`	Find circles using circular Hough transform
`viscircles`	Create circle

Detect Edges and Gradients

`edge`	Find edges in grayscale image
`边缘3`	Find edges in 3-D intensity volume
`imgradient`	Find gradient magnitude and direction of 2-D image
`imgradientxy`	Find directional gradients of 2-D image
`imgradient3`	Find gradient magnitude and direction of 3-D image
`imgradientxyz`	Find directional gradients of 3-D image

Detect Lines

`hough`	霍夫变换
`houghlines`	Extract line segments based on Hough transform
`houghpeaks`	识别霍夫变换中的峰
`radon`	Radon transform
`iradon`	Inverse Radon transform

Detect Homogenous Blocks Using Quadtree Decomposition

`QTDECOMP`	Quadtree分解
`qtgetblk`	Block values in quadtree decomposition
`qtsetblk`	Set block values in quadtree decomposition

Topics

边缘检测

Edge detection is a technique for finding the boundaries of objects within an image.

图像中的边界跟踪

You can display the boundaries of a single object or of all objects in an image.

Hough Transform

The Hough transform detects lines in an image, including lines tilted at arbitrary angles from vertical and horizontal. The Hough transform tends to be quick, but can exhibit artifacts.

Detect Lines Using the Radon Transform

This example shows how to detect lines and identify the strongest lines in an image using the Radon transform.

Quadtree分解

Quadtree分解is useful as a first step in adaptive image compression. The decomposition involves subdividing an image into homogenous blocks.