Improving the accuracy of pedometer used by the elderly with the FFT algorithm
Improving the accuracy of pedometer used by the elderly with the FFT algorithm
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DOI：
10.1249/01.mss.0000227641.68360.c2
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发表时间：
2006-09-01
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影响因子：
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通讯作者：
Tamura, Toshiyo
中科院分区：
文献类型：
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作者：
Ichinoseki-Sekine, Noriko;Kuwae, Yutaka;Tamura, Toshiyo
目的：本研究的目的是调查和提高老年人使用的加速度计型计步器的准确性，步行速度慢，有或没有步态障碍，谁做或不使用拐杖。研究方法：18名受试者拄着拐杖行走（5例男性，13例女性;年龄：80.9 ± 7.7岁;身高：148.1 ± 7.7 cm;体重：51.8 ± 8.8 kg（平均值± SD）; 9例步态受损），31例受试者不使用拐杖行走（7例男性，24例女性;年龄：80.9 ± 7.7岁;身高：148.1 ± 7.7 cm;体重：51.8 ± 8.8 kg; 15例步态受损）。受试者以自己的速度行走约20 m（每个方向10 m，转弯弧线）。我们通过步数计（PM）、视觉计数实际步数（RM）和三轴加速度信号确定步数。通过快速傅里叶变换（FFT）计算的4s时间窗口的加速度计在每个方向上的功率谱与每个窗口的最大功率进行归一化。它是合成的，最大功率的频率被认为是节奏。通过对每个窗口中的所有估计步数求和来确定所采取的步数（FM）。结果：PM的误差为RM的53.2 ± 34.1%（P < 0.05）。FM与RM没有差异，FM的平均误差为RM的-0.7 +/- 7.9%（绝对值：5.8 +/- 5.3%）。结论：我们建议，我们的FFT方法是适合于估计的步数在步行过程中，在这个群体。
Purpose: The aim of this study was to investigate and improve the accuracy of accelerometer-type pedometers used by the elderly with slow walking speeds, with or without gait disorders, who do or do not use a cane. Methods: Eighteen subjects walked with a cane (5 males, 13 females; age, 80.9 +/- 7.7 yr; height, 148.1 +/- 7.7 cm; weight, 51.8 +/- 8.8 kg (mean +/- SD); nine had impaired gait), and 31 subjects walked without a cane (7 males, 24 females; age, 80.9 +/- 7.7 yr; height, 148.1 +/- 7.7 cm; weight, 51.8 +/- 8.8 kg; 15 had impaired gait). Subjects walked for approximately 20 m (10 m in each direction and a turning arc) at their own speed. We determined the number of steps by pedometer (PM), by visually counting the actual number of steps (RM), and by the triaxial acceleration signals. The power spectrum of the accelerometer in each direction calculated by fast Fourier transform (FFT) for a 4-s temporal window was normalized with the maximum power of each window. It was composited, and the frequency at maximum power was considered as the cadence. The number of steps taken (FM) was determined by summing all the estimated steps in each window. Results: PM was significantly less than the RM (P < 0.05), and the error of PM was 53.2 +/- 34.1% of RM. FM did not differ from the RM, and the average error of FM was -0.7 +/- 7.9% of RM (absolute value: 5.8 +/- 5.3%). Conclusion: We suggest that our FFT method is suitable for estimating the number of steps during walking in this population.