"Go" matlab function _ Connected Area

Reprinted from the Einyboy of the Bowen Regionprops in MATLAB

1, matlab function bwareaopen── Delete Small area object
Format: BW2 = Bwareaopen (bw,p,conn)
Function: Delete the binary image bw object with an area less than p, by default using 8 neighbors.
Algorithm:
(1) Determine the connected components.
L = Bwlabeln (BW, conn);
(2) Compute the area of each component.
S = Regionprops (L, ' area ');
(3) Remove small objects.
BW2 = IsMember (L, find ([S.area] >= P));

2. Matlab function bwarea── Calculating Object Area
Format: total = Bwarea (BW)
Effect: estimates the area of an object in a binary image.
Note: This area and two value images do not necessarily have equal number of pixels in the object.

3. Matlab function imclearborder── Boundary Object Suppression
Format: IM2 = Imclearborder (im,conn)
Action: Suppresses light objects that are connected to the image boundary. If IM is a two-value graph, Imclearborder will delete objects connected to the image boundary. The default is conn=8.
Note: For grayscale images, Imclearborder tends to reduce the overall intensity level in addition to suppressing border struct Ures.
Algorithm:
(1) Mask image is the input image.
(2) Marker image is zero everywhere except along the border, where it equals the mask image.

4. Matlab function bwboundaries── Get object outline
Format: B = Bwboundaries (bw,conn) (basic format)
Function: Gets the contour of the object in the binary graph, similar to the function of the cvfindcontours function in OpenCV. B is a Px1 cell array, p is the number of objects, each cell is a matrix of Qx2, corresponding to the coordinates of the object's contour pixel.

5, Matlab function imregionalmin── get the minimum area
Format: BW = Imregionalmin (i,conn)
Function: Find the minimum area of image I (regional maxima), conn=8 by default.
Regional minima is connected components of pixels with a constant intensity value, and whose external boundary pixels all has a higher value.


6, Matlab function bwulterode── The maximum value of the distance transformation
Format: BW2 = Bwulterode (bw,method,conn)
Effect: Ultimate corrosion. Find the region maxima of the distance transform graph of the binary image bw (regional maxima). The distance used for distance transformation defaults to Euclidean, and connectivity is 8 neighbors.

7, Regionprops statistics The area of the marked area distribution, showing the total number of regions.
The regionprops syntax rule for the function is: STATS = Regionprops (l,properties)
This function is used to measure a series of attributes for each label area in the label Matrix L.
The different positive integer elements in L correspond to different regions, for example: the element corresponding to the integer 1 in L is the corresponding region of the element in the 1;l equal to the integer 2 in the region 2;

The return value stats is a structure array of length Max (L (:)), and the corresponding fields of the structure array define the measures under the corresponding properties of each zone.

Properties can be a comma-delimited list of strings, an array of cells containing strings, a single string of ' all ', or ' basic '. If properties equals the string ' All ', the metric data in Table 4.1 will be computed, and if properties equals the string ' Basic ', then the attribute: ' area ', ' centroid ' and ' BoundingBox ' will be computed. Table 1 is all the valid property strings.

Table 1 List of property strings----Measures the properties or functions of an image area
' Area 'Total number of pixels in each area of the image
' BoundingBox ' contains the smallest rectangle of the corresponding area
' centroid ' centroid of each region (center of gravity)
' Majoraxislength ' The long axis length of the ellipse with the same standard second-order center moment as the region (in pixel sense)
' Minoraxislength ' the short axis length of the ellipse with the same standard second-order center moment as the region (in pixel sense)
' Eccentricity ' the eccentricity of the ellipse with the same standard second-order center moment as the region (can be used as a feature)
' Orientation ' the intersection of the long axis and the x-axis of the ellipse with the same standard second-order center moment as the region (degrees)
' Image ' has a logical matrix of the same size as an area
' Filledimage ' has the same size fill logical matrix as an area
The number of on pixels in the ' filledarea ' filled area image
' Convexhull ' contains the smallest convex polygon of an area
' Conveximage ' draws the smallest convex polygon in the area above
The number of on pixels in a convex polygon image of ' convexarea ' populated area
A topological invariants in the ' Eulernumber ' geometric topology--Euler number
' Extrema ' eight-directional region extremum Point
' Equivdiameter ' diameter of the circle with the same area as the area
The pixel ratio of ' solidity ' at the same time in the region and its smallest convex polygon
The pixel scale of ' Extent ' at the same time in the region and its minimum bounding rectangle
Index subscript for the ' pixelidxlist ' storage area pixels
' Pixellist ' stores the pixel coordinates of the above index

"Go" matlab function _ Connected Area