MATLAB File Help: cv.SimpleBlobDetector Index
cv.SimpleBlobDetector

Class for extracting blobs from an image.

The class implements a simple algorithm for extracting blobs from an image:

  1. Convert the source image to binary images by applying thresholding with several thresholds from MinThreshold (inclusive) to MaxThreshold (exclusive) with distance ThresholdStep between neighboring thresholds.
  2. Extract connected components from every binary image by cv.findContours and calculate their centers.
  3. Group centers from several binary images by their coordinates. Close centers form one group that corresponds to one blob, which is controlled by the MinDistBetweenBlobs parameter.
  4. From the groups, estimate final centers of blobs and their radiuses and return as locations and sizes of keypoints.

This class performs several filtrations of returned blobs. You should set FilterBy* to true/false to turn on/off corresponding filtration. Available filtrations:

Default values of parameters are tuned to extract dark circular blobs.

See also
Class Details
Superclasses handle
Sealed false
Construct on load false
Constructor Summary
SimpleBlobDetector Constructor 
Property Summary
id Object ID 
Method Summary
  addlistener Add listener for event. 
  clear Clears the algorithm state 
  delete Destructor 
  detect Detects keypoints in an image or image set. 
  empty Checks if detector object is empty. 
  eq == (EQ) Test handle equality. 
  findobj Find objects matching specified conditions. 
  findprop Find property of MATLAB handle object. 
  ge >= (GE) Greater than or equal relation for handles. 
  getDefaultName Returns the algorithm string identifier 
  gt > (GT) Greater than relation for handles. 
Sealed   isvalid Test handle validity. 
  le <= (LE) Less than or equal relation for handles. 
  load Loads algorithm from a file or a string 
  lt < (LT) Less than relation for handles. 
  ne ~= (NE) Not equal relation for handles. 
  notify Notify listeners of event. 
  save Saves the algorithm parameters to a file 
  typeid Name of the C++ type (RTTI)