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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

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bwboundaries 二进制图像中的痕量区域边界
bwtraceboundary Trace object in binary image
visboundaries Plot region boundaries
imfindcircles Find circles using circular Hough transform
viscircles Create circle
edge Find edges in 2-D grayscale image
edge3 Find edges in 3-D grayscale 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
hough 霍夫变换
houghlines Extract line segments based on Hough transform
houghpeaks Identify peaks in Hough transform
radon Radon transform
iradon Inverse Radon transform
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.

  • Boundary Tracing in Images

    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 Decomposition

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