Figure 2From: Unsupervised machine-learning method for improving the performance of ambulatory fall-detection systems The application of the Haar Discrete Wavelet Transform. Convolutions between the original signal A[n] and low pass filters G0, G1, and G2 produces down sampled signal A↓[n]. ↓2 block denotes down-sampling, which increase the sample time by two, effectively reducing the number of samples.Back to article page