Building Computer Vision Projects with OpenCV 4 and C++

Eigenvalues, Eigenfaces, and Fisherfaces

Let's view the actual component values in the Eigenvalues (as text), shown as follows:

    Mat eigenvalues = model->get<Mat>("eigenvalues");     printMat(eigenvalues, "eigenvalues");

For Eigenfaces, there is one Eigenvalue for each face, so if we have three people with four faces each, we get a column vector with 12 Eigenvalues sorted from best to worst as follows:

    eigenvalues: 1w18h 1ch 64bpp, range[4.52e+04,2.02836e+06]     2.03e+06      1.09e+06     5.23e+05     4.04e+05     2.66e+05     2.31e+05     1.85e+05     1.23e+05     9.18e+04     7.61e+04      6.91e+04     4.52e+04

For Fisherfaces, there is just one eigenvalue for each extra person, so if there are three people with four faces each, we just get a row vector with two Eigenvalues ...