Image Region Analyzer
Browse and filter connected components in image
Description
The Image Region Analyzer app measures a set of properties for each connected component (also called an object or region) in a binary image and displays this information in a table. You can also use this app to create other binary images by filtering the image on region properties.
Image Region Analyzer can calculate these properties.
| Property Name | Description |
|---|---|
"Area" | Number of pixels in the region. |
"Centroid" | Coordinates of the centroid of the region. |
"Circularity" | Roundness of object. The circularity value is computed as:
The maximum circularity value is 1. |
"ConvexArea" | Number of pixels in the convex hull. The convex hull is the smallest convex polygon that can contain the region. For more information about classifying pixels on the boundary of the hull, see Classify Pixels That Are Partially Enclosed by ROI. |
"Eccentricity" | Eccentricity of the ellipse that has the same second-moments as the region. The eccentricity is the ratio of the distance between the foci of the ellipse and its major axis length. The value is between 0 and 1. (0 and 1 are degenerate cases. An ellipse whose eccentricity is 0 is actually a circle, while an ellipse whose eccentricity is 1 is a line segment.) |
"EquivDiameter" | Diameter (in pixels) of a circle with the
same area as the region, calculated as
sqrt(4*Area/pi). |
"EulerNumber" | Euler number (also known as the Euler characteristic), calculated as 1 minus the number of holes in the region. |
"Extent" | Ratio of pixels in the region to pixels in
the total bounding box, calculated as
Area divided by the area of the
bounding box. |
"FilledArea" | Number of pixels in the region after filling all holes in the region. |
"MajorAxisLength" | Length (in pixels) of the major axis of the ellipse that has the same normalized second central moments as the region. |
"MinorAxisLength" | Length (in pixels) of the minor axis of the ellipse that has the same normalized second central moments as the region. |
"Orientation" | Angle (in degrees) between the x-axis and the major axis of the ellipse that has the same second-moments as the region. The value is in the range (–90, 90]. This figure illustrates the axes and orientation of the ellipse. The left side of the figure shows an image region and its corresponding ellipse. The right side shows the same ellipse with the solid blue lines representing the axes. The red dots are the foci. The orientation is the angle between the horizontal dotted line and the major axis.
|
"Perimeter" | Distance (in pixels) around the boundary of the region, calculated by adding the distance between each adjoining pair of pixels around the border of the region. This figure illustrates the pixels included in the perimeter calculation for a sample region.
|
"Solidity" | Proportion of the pixels in the convex hull
that are also in the region, calculated as
Area/ConvexArea. |
Open the Image Region Analyzer App
MATLAB® Toolstrip: On the Apps tab, under Image Processing and Computer Vision, click the Image Region Analyzer app icon.
MATLAB command prompt: Enter
imageRegionAnalyzer.
Examples
Programmatic Use
Tips
Image Region Analyzer uses the
regionpropsfunction to identify regions in the image and calculate properties of those regions. Note that theregionpropsoffers additional capabilities for calculating region properties:Measure properties of images with discontiguous regions
Measure additional properties such as the maximum and minimum Feret diameter and angle
Measure pixel value properties of grayscale images
Measure a subset of properties for N-D images
Perform measurements on a GPU and generate code
Image Region Analyzer uses the
bwpropfiltandbwareafiltfunctions to filter binary images.
