blob detection in matlab

34 views (last 30 days)
mW
mW on 9 Feb 2015
Commented: Image Analyst on 6 Jun 2018
I am new to Matlab. My Gray scale image has Blobs and Lines. How to detect blobs?. Using 8-connctivity rules. Need to log the sizes of each blob followed by x,y of pixel?. I read about bwlabel. Is it possible to detect Blobs and lines separately?.
  1 Comment
Erik S.
Erik S. on 9 Feb 2015
can you provide an example image?

Sign in to comment.

Answers (1)

Alexey Gordienko
Alexey Gordienko on 17 Aug 2017
Edited: Alexey Gordienko on 17 Aug 2017
Hello! Here is my example of processing a binary image for highlighting license plates of cars using blob analysis
function [BBOX_OUT, NUM_BLOBS, LABEL] = CCA(Image)
BBOX_OUT = [];
NUM_BLOBS = [];
LABEL = [];
%%connected component analisys
hblob = vision.BlobAnalysis;
hblob.CentroidOutputPort = false;
hblob.MaximumCount = 3500;
hblob.Connectivity = 4;
hblob.MaximumBlobArea = 6500;
hblob.MinimumBlobArea = 200;
hblob.LabelMatrixOutputPort = true;
hblob.OrientationOutputPort = true;
hblob.MajorAxisLengthOutputPort = true;
hblob.MinorAxisLengthOutputPort = true;
hblob.EccentricityOutputPort = true;
hblob.ExtentOutputPort = true;
hblob.BoundingBoxOutputPort = true;
[AREA,BBOX,MAJOR,MINOR,ORIENT,ECCEN,EXTENT,LABEL] = step(hblob,Image);
imshow(LABEL*2^16)
numberOfBlobs = length(AREA);
allowableAxis = (((MAJOR./MINOR) > 3.8) & (AREA > 200) & (abs(rad2deg(ORIENT))<10) & (EXTENT> 0.6));
idx = find(allowableAxis);
keeperBlobsImage = ismember(LABEL, idx);
imshow(keeperBlobsImage)
LABEL = bwlabel(keeperBlobsImage, 4);
for i =1:length(idx)
BBOX_OUT((i),1:4) = BBOX(idx(i),1:4);
end
NUM_BLOBS = length(idx);
end
  3 Comments
Stephen23
Stephen23 on 6 Jun 2018
Edited: Stephen23 on 6 Jun 2018
@Yosef Asseaf: the function CCA requires one input argument: did you call it with one input argument?

Sign in to comment.

Categories

Find more on Image Processing Toolbox in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!