imregionalmax() - Image Processing
BW = imregionalmax(I) returns
the binary image BW that identifies the regional
maxima in I. Regional maxima are connected components
of pixels with a constant intensity value, t, whose
external boundary pixels all have a value less than t.
In BW, pixels that are set to 1 identify
regional maxima; all other pixels are set to 0.BW = imregionalmax(I,conn) computes
the regional maxima, where conn specifies the connectivity.
By default, imregionalmax uses 8-connected neighborhoods
for 2-D images and 26-connected neighborhoods for 3-D images.gpuarrayBW = imregionalmax(gpuarrayI,___) performs
the operation on a GPU. The input image must be a gpuArray.
The function returns a gpuArray. This syntax requires Parallel Computing Toolbox™.Code Generation support:
Yes.MATLAB Function Block support:
Yes.
Syntax
<![CDATA[BW = imregionalmax(I) exampleBW = imregionalmax(I,conn)gpuarrayBW = imregionalmax(gpuarrayI,___)]]>
Example
<![CDATA[Find Regional Maxima in Simple Sample ImageOpen This Example
Create a simple sample image with several regional maxima.A = 10*ones(10,10);
A(2:4,2:4) = 22;
A(6:8,6:8) = 33;
A(2,7) = 44;
A(3,8) = 45;
A(4,9) = 44
A =
10 10 10 10 10 10 10 10 10 10
10 22 22 22 10 10 44 10 10 10
10 22 22 22 10 10 10 45 10 10
10 22 22 22 10 10 10 10 44 10
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 33 33 33 10 10
10 10 10 10 10 33 33 33 10 10
10 10 10 10 10 33 33 33 10 10
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 10 10 10 10 10
Find the regional maxima. Note that the result includes the regional maxima at (3,8).regmax = imregionalmax(A)
regmax =
0 0 0 0 0 0 0 0 0 0
0 1 1 1 0 0 0 0 0 0
0 1 1 1 0 0 0 1 0 0
0 1 1 1 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
Find Regional Maxima in Simple Sample Image on a GPUCreate a 10-by-10 pixel sample image that contains two
regional maxima.A = 10*gpuArray.ones(10,10);
A(2:4,2:4) = 22; % maxima 12 higher than surrounding pixels
A(6:8,6:8) = 33; % maxima 23 higher than surrounding pixels
A(2,7) = 44;
A(3,8) = 45; % maxima 1 higher than surrounding pixels
A(4,9) = 44
A =
10 10 10 10 10 10 10 10 10 10
10 22 22 22 10 10 44 10 10 10
10 22 22 22 10 10 10 45 10 10
10 22 22 22 10 10 10 10 44 10
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 33 33 33 10 10
10 10 10 10 10 33 33 33 10 10
10 10 10 10 10 33 33 33 10 10
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 10 10 10 10 10Pass the sample image A to imregionalmax.
The function returns a binary image, the same size as A,
in which pixels with the value 1 represent the
regional maxima in A. imregionalmax sets
all other pixels in to 0.regmax = imregionalmax(A)regmax =
0 0 0 0 0 0 0 0 0 0
0 1 1 1 0 0 0 0 0 0
0 1 1 1 0 0 0 1 0 0
0 1 1 1 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0]]>
Output / Return Value
Limitations
Alternatives / See Also
Reference