cv.LSDDetector - MATLAB File Help Go to online doc for cv.LSDDetector
cv.LSDDetector

Line Segment Detector

Lines extraction methodology

The lines extraction methodology described in the following is mainly based on [EDL]. The extraction starts with a Gaussian pyramid generated from an original image, downsampled N-1 times, blurred N times, to obtain N layers (one for each octave), with layer 0 corresponding to input image. Then, from each layer (octave) in the pyramid, lines are extracted using LSD algorithm.

Differently from EDLine lines extractor used in original article, LSD furnishes information only about lines extremes; thus, additional information regarding slope and equation of line are computed via analytic methods. The number of pixels is obtained using cv.LineIterator. Extracted lines are returned in the form of KeyLine objects, but since extraction is based on a method different from the one used in cv.BinaryDescriptor class, data associated to a line's extremes in original image and in octave it was extracted from, coincide. KeyLine's field class_id is used as an index to indicate the order of extraction of a line inside a single octave.

References

[EDL]:

R Grompone Von Gioi, Jeremie Jakubowicz, Jean-Michel Morel, and Gregory Randall. "LSD: A fast line segment detector with a false detection control. IEEE Transactions on Pattern Analysis and Machine Intelligence, 32(4):722-732, 2010.

See also
cv.BinaryDescriptor, cv.drawKeylines, cv.LineSegmentDetector, cv.LineIterator
Class Details
Superclasses handle
Sealed false
Construct on load false
Constructor Summary
LSDDetector Creates an LSDDetector object 
Property Summary
id Object ID 
Method Summary
  addlistener Add listener for event. 
  clear Clears the algorithm state 
  delete Destructor 
  detect Detect lines inside 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. 
  listener Add listener for event without binding the listener to the source object. 
  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 
Event Summary
ObjectBeingDestroyed Notifies listeners that a particular object has been destroyed.