CODEWITHSUNDEEP
opencvface-recognition
theroom101
theroom101

Reputation: 609

FaceRec tutorial explanation

I try to do this face recognition example, with Eigenfaces. And cannot understand what these functions subspaceProject() and subspaceReconstruct() actually do. I tried to search on http://docs.opencv.org/ but there was not any link to description.

Could you explain me what this part of the code actually do? 

Mat evs = Mat(W, Range::all(), Range(0, num_components));
Mat projection = subspaceProject(evs, mean, images[0].reshape(1,1));
Mat reconstruction = subspaceReconstruct(evs, mean, projection);
    // Normalize the result:
reconstruction = norm_0_255(reconstruction.reshape(1, images[0].rows));

I mean what these functions do, what kind of cv::Mat they return ?

Upvotes: 1

Views: 1036

Answers (1)

Bull
Bull

Reputation: 11941

subspaceProject() will basically give you a dimensionality reduction.

projection = (images[0] - mean) * evs

Subtracting the mean ensures that the images approximate a subspace. Presumably evs is the truncated right singular vectors.

and for subspaceReconstruct()

reconstruction = projection * transpose(evs) + mean

The reconstruction is just the reverse of the projection, except since evs is truncated, it can not be perfect.

See PCA

Upvotes: 1

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