findTracks

Find matched points across multiple views

Syntax

tracks = findTracks(vSet)

tracks = findTracks(vSet,viewIds)

tracks = findTracks(___,'MinTrackLength',trackLength)

Description

tracks = findTracks(vSet) finds and returns point tracks across multiple views in the view set, vSet. Each track contains 2-D projections of the same 3-D world point.

tracks = findTracks(vSet,viewIds) finds point tracks across a subset of views specified by viewIds.

tracks = findTracks(___,'MinTrackLength',trackLength) specifies the minimum length of the tracks.

Examples

Find Point Tracks Across Sequence of Images

Load images in the workspace.

imageDir = fullfile(toolboxdir('vision'),'visiondata','structureFromMotion');
images = imageDatastore(imageDir);

Compute features for the first image.

I = im2gray(readimage(images,1));
pointsPrev = detectSURFFeatures(I);
[featuresPrev,pointsPrev] = extractFeatures(I,pointsPrev);

Create an image view set and add one view to the set.

vSet = imageviewset;
vSet = addView(vSet,1,'Features',featuresPrev,'Points',pointsPrev);

Compute features and matches for the rest of the images.

for i = 2:numel(images.Files)
  I = im2gray(readimage(images, i));
  points = detectSURFFeatures(I);
  [features, points] = extractFeatures(I,points);
  vSet = addView(vSet,i,'Features',features,'Points',points);
  pairsIdx = matchFeatures(featuresPrev,features);
  vSet = addConnection(vSet,i-1,i,'Matches',pairsIdx);
  featuresPrev = features;
end

Find point tracks across views in the image view set.

tracks = findTracks(vSet);

Input Arguments

vSet — Image view set

imageviewset object

Image view set, specified as an imageviewset object.

viewIds — View identifiers

vector of integers

View identifiers, specified as a vector of positive integers. View identifiers are unique to a specific view.

trackLength — Minimum length of the tracks

positive integer equal to or greater than 2

Minimum length of the tracks, specified as a positive integer equal to or greater than 2.

Output Arguments

tracks — Point tracks

pointTrack object

Point tracks across multiple views, returned as a pointTrack object.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2020a