Three-Dimensional Coordinates of an Animal Body Ror Analysis of Heat and Mass Transfer at the Body Surface

利用光学测距法和数字图像处理技术，研制了一套测量动物体三维坐标的仪器系统和计算机程序。该系统由电视摄像机、录像机、监视电视机、图像处理单元、电子微机单元和激光光源单元组成，在激光光源照射下，用电视摄像机拍摄了3只活体猪（27、65和88 kg）的图像。将采集到的图像传输到计算机，并通过图像处理方法进行分析。根据摄影测量原理，从图像数据中提取猪体表各点的三维坐标。以27 kg猪为例，用13224个小三角形面片对猪体进行三维重建，并利用计算机图形学中的透视投影变换方法，将猪体表面立体显示为多面体。利用边缘搜索技术，可以很容易地检测出多面体清管器的轮廓线，通过立体角投影法将轮廓线内的面积转化为清管器辐射换热的辐射器配置因子。太阳直接辐射在猪体上的分布与猪体的表面积有关，猪体的表面积经平行投影变换后，得到猪体表面的三维坐标，为猪体表面的传热传质分析提供了依据。在此之后，本程序将应用于其他动物。

An instrument system and computer programs were developed in order to measure the three-dimensional coordinates of an animal body by using the optical range sensing method and digital image processing techniques. The system was composed of a television camera, a video tape recorder, a monitor television, an image processing unit, an electronic micro-computer unit and a laser-light unit.Images of three stuffed pigs (27,65 and 88 kg in live-weight) were taken with the TV camera under projecting rays of laser-light on them. The images were transmitted to the computer and were analyzed by the image processing method. Three-dimensional coordinates of points at the pig body surface wereescalated based on the principle of photogrammetry from the image data. The accuracy of these coordinates was satisfactory.A pig body was reconstructed by small triangular patches, for example 27 kg pig surface was made of 13224 patches and then was stereo-graphically displayed as polyhedron with the perspective-projection transformation, the one of computer graphics methods. A contour line of a polyhedric pig was easily detected with the edge-search technique.A pig's configuration factor for radiant for radiant heat exchange is related to the area within the contour line that is transformed with the solid-angle projection method. Direct solar radiation incident on a pig body is dependent on the surface area of a polyhedric pig that is transformed with the parallel projection.The three-dimensional coordinates obtained by this study are useful for the analysis heat and mass transfer at the pig body surface. The present procedures will be applied to other animals after this.