Fig. 4
The flow chart of the KR algorithm data analysis. Normalization was based on the average value of the data from the right knee key point remaining still for 10 s, and it reseted the data for the KR algorithm. Data noise was attenuated using an FIR filter with a 3 Hz cutoff frequency. Selecting an appropriate window function and time-frequency resolution is essential for STFT to depict the data characteristics accurately. The Hanning function was selected as the window function for the calculation parameters, and the window length was 0.8. TIMU and TKR represent the transition time points derived from IMU and KR