Department of Podiatry, Faculty of Nursing, Physiotherapy and Podiatry, Universidad de Sevilla, C/Avice-na s/n, 41009 Seville, Spain.
Department of Nursing, Faculty of Nursing, Physiotherapy and Podiatry, Universidad de Sevilla, C/Avenzoar nº6, 41009 Seville, Spain.
Sensors (Basel). 2021 Apr 7;21(8):2585. doi: 10.3390/s21082585.
The study of the foot is relevant in kinematic analyses of gait. Images captured through a lens can be subjected to various aberrations or distortions that affect the measurements. An in vitro study was performed with a rearfoot simulator to compare the apparent degrees (photographed) with the real ones (placed in the simulator) in the plane of the rearfoot's orientation, according to variations in the capture angle in other planes of space (the sagittal plane and transverse plane-the latter determined by the foot progression angle). The following regression formula was calculated to correct the distortion of the image: real frontal plane = 0.045 + (1.014 × apparent frontal plane) - (0.018 × sagittal plane × foot progression angle). Considering the results of this study, and already knowing its angle in the transverse and sagittal planes, it is possible to determine the angle of a simulated calcaneus with respect to the ground in the frontal plane, in spite of distortions caused by perspective and the lack of perpendicularity, by applying the above regression formula. The results show that the angular measurements of a body segment made on frames can produce erroneous data due to the variation in the perspective from which the image is taken. This distortion must be considered when determining the real values of the measurements.
足部研究与步态运动学分析相关。通过镜头捕捉到的图像可能会受到各种像差或失真的影响，从而影响测量结果。本体外研究使用后足模拟器，根据其他空间平面（矢状面和横断面-由足前进角决定的后者）中捕获角度的变化，比较了后足方位平面上的实际角度（置于模拟器中）与拍摄角度（拍摄）的明显角度。计算出以下回归公式来校正图像的失真：真实额状面=0.045+（1.014×明显额状面）-（0.018×矢状面×足前进角）。考虑到这项研究的结果，并且已经知道其在横断面和矢状面的角度，那么就可以通过应用上述回归公式，确定模拟跟骨相对于额状面的地面角度，尽管存在透视失真和不垂直的情况。研究结果表明，由于图像拍摄的视角不同，框架上的体节角度测量可能会产生错误数据。在确定测量的实际值时，必须考虑这种失真。
