Smutz W P, Drexler M, Berglund L J, Growney E, An K N
Orthopedic Biomechanics Laboratory, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA.
J Biomech. 1996 Jun;29(6):813-7. doi: 10.1016/0021-9290(95)00131-x.
The purpose of this study was to determine the accuracy of a video system which our laboratory has been using to measure soft tissue strain. Both static and dynamic error analyses were performed to assess the accuracy of our video system. Static error was defined as the amount of movement reported by the video system for markers that were stationary. Dynamic error was defined as the difference between the motion of the markers as reported by the video system and their actual motion. Two sets of fluorescent markers were attached to a servo-hydraulic materials test machine. One marker set was attached to the hydraulic actuator (moving markers) and the other set was attached to the base of the machine (stationary markers). Five different marker sizes, five camera distances, and seven different loading rates were studied. Results indicated that the static error was independent of marker size, and that the dynamic error was independent of the loading rate and marker size for loading rates of 50% of the camera field of view (CFV) per second or slower. For loading rates greater than 50 percent of CFV per second, the marker size did have an affect on the dynamic error. The mean static error was found to be 0.026 percent of CFV and the mean dynamic error was found to be 0.062 percent of CFV.
本研究的目的是确定我们实验室一直在使用的用于测量软组织应变的视频系统的准确性。进行了静态和动态误差分析，以评估我们视频系统的准确性。静态误差定义为视频系统报告的固定标记的移动量。动态误差定义为视频系统报告的标记运动与其实际运动之间的差异。两组荧光标记附着在一台伺服液压材料试验机上。一组标记附着在液压致动器上（移动标记），另一组附着在机器底座上（固定标记）。研究了五种不同的标记尺寸、五个相机距离和七种不同的加载速率。结果表明，静态误差与标记尺寸无关，对于每秒50%相机视野（CFV）或更低的加载速率，动态误差与加载速率和标记尺寸无关。对于每秒大于50%CFV的加载速率，标记尺寸确实会对动态误差产生影响。发现平均静态误差为CFV的0.026%，平均动态误差为CFV的0.062%。
