LCD-projector-based 3D color PTV
LCD-projector-based 3D color PTV
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DOI：
10.1016/j.expthermflusci.2012.12.019
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发表时间：
2013-05
影响因子：
3.2
通讯作者：
T. Watamura;Y. Tasaka;Y. Murai
中科院分区：
文献类型：
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作者：
T. Watamura;Y. Tasaka;Y. Murai
基于颜色的三维粒子跟踪测速技术（3D Particle Tracking Velocimetry，PTV）采用单摄像机和液晶投影仪，可以根据粒子的颜色信息测量出离面速度分量，在保持平面二维PTV光学结构简单性的基础上，改进了PTV的光学结构，使其在3D测速中得到了实际应用。为了最大限度地减少识别粒子的代表性颜色的不确定性，我们提出了新的颜色识别算法，平均色调在极坐标，而不是线性坐标。所提出的算法，饱和度加权平均色调在极坐标，产生比传统算法更小的标准偏差：1.4%的色调和2.0%的位置检测。使用多色彩循环渐变光来对流体层进行体积照明还提高了深度方向上的位置和速度测量的分辨率。所提出的测量技术可以显示流的轴对称旋转流从瞬时3D-3C速度矢量场，以及涡结构的非定常流表示为等值面的拟能密度。
Color-based three-dimensional (3D) Particle Tracking Velocimetry (PTV) using a single camera and an liquid crystal display (LCD) projector, which can measure the out-of-plane velocity component from particle color information, is improved for practical use in 3D velocimetry without losing the original simplicity on the optical configuration of planner 2D PTV. To minimize the uncertainties in identifying the representative color of particles, we propose new color identifying algorithms that average hue in polar rather than linear coordinates. The proposed algorithm, a saturation-weighted-averaged hue in polar coordinates, yields smaller standard deviations than conventional algorithms: 1.4% in hue and 2.0% in position detection. Use of a multiple color-cycle gradation light for volumetric illumination of the fluid layers also improves the resolution of the position and velocity measurements in the depth direction. The proposed measurement technique can display the flow patterns of an axisymmetric rotating flow from instantaneous 3D–3C velocity vector fields, as well as the vortex structure of an unsteady flow represented as iso-surfaces of enstrophy density.