Comparison of Initialization Techniques for the Accurate Extraction of Muscle Synergies from Myoelectric Signals via Nonnegative Matrix Factorization

Figure 5

Relationship between the estimation quality QR and the approximation error of NNMF (i.e., Frobenius norm) with different initialization techniques. (a) Independent synergies . (b) Dependent synergies . In both cases, for RAND and NSVD initialization, higher synergy estimation accuracy QR is obtained with a higher approximation error via NNMF, while SPARSE initialization is not dependent on the NNMF convergence error.