Algorithm 1 In pseudocode: Motion Artifact Algorithm for Walking.

1: Procedure Record PPG signal and accelerometer signal x,y,z for 8 s 2: Initialize HR_est = 78 3: Construct Hankel matrix Hppg for PPG 4: Construct Hankel matrix Hx for x 5: Construct Hankel matrix Hy for y 6: Construct Hankel matrix Hz for z 7: Find SVD of matrix obtained from step 3, 4, 5, 6 8: Construct a correlation matrix between the 3-axis accelerometer and PPG 9: Select eigenvalues 10: Reconstruct using inverse SVD 11: Find DFT of the reconstructed signal 12: Find HR 13: Heart rate estimation 14: End procedure