模型飛行機材と航空写真技術を用いた積雪観測法の開発

由于很难通过爬上屋顶来测量雪荷载的强度和分布，因此没有足够的结构设计所需的屋顶雪荷载数据。本研究提出了一种高效、准确的利用航空摄影测量屋顶雪荷载的方法。在之前的研究中，作者明确了以飞机为主的航空摄影测量屋顶积雪的测量精度，并给出了该方法用于积雪测量的概率。然而，航空测量的包机费用非常昂贵，而且用户不能自己操作飞机和相机，这很不方便。为了解决这些问题，笔者发展了以风筝气球为载体的航空摄影测量技术。在研究中，比较了以飞机为载体的风筝气球系统和无人遥控直升机系统的性能，并对其测量精度进行了讨论，因为气球上悬挂的摄像机与飞机上悬挂的摄像机质量不同。结果表明：1)对飞机、风筝气球和模型直升机航拍的特点进行比较，发现三种航拍方式的优点可以相互弥补缺点。因此，用户应综合考虑场地的地理条件、物体的周围环境、观测的总数或持续时间、测量费用等因素，合理选择最佳系统。2)风筝气球航拍系统测量精度在允许范围内，且在三种系统中性价比最好，适合实际应用。3)在实际使用中，使用偏立得滤镜作为防光晕的方法表现出最好的性能，因为这种方法几乎可以避免在任何阳光条件下发生光晕，并且在有限的时间内不限制拍摄。4)利用se系统研究了大型建筑物屋顶积雪深度的分布，并讨论了平均风向的影响。少

Sufficient data on roof snow loads for structural design are not available because there is difficulty in measuring the intensity and distribution of snow load by climbing onto roofs. This research develoiped an efficient and accurate method for surveying roof snow loads by adopting an aerial photogramtry. In the previous study, the authors had clarified the measurement accuracy of aerial photogramtry using mainly airplane for surveying roof snow and had shown the probability of this merthod for snow survey. A chartered flight for aerial survey, however, is very expensive and it is inconvenient that users can not operate the airplane nor camera by themselves. Therefore the authors developed the aerial photogramtry using a kite balloon as a carrier of camera in order to solve these problems.In the study, the performances of the kite balloon system and unmanned-radio control helicopter system were compared with the case using airplane as the carrier, and the measurement accuracy of the n … More ew systems was discussed because the quality of the camera hanged on the balloon was different from that on airplane. The results are as follows :1) The results of comparison among the features of aerial photography usig airplane, kite balloon and model helicopter, showed that the advantages of three different aircrafts made up disadvantages of each other. Therefore, users should properly select the best system in consideration of geographical conditions of a site, surroundings of a object, total number or duration of observations, expenses for measurements and so on.2) The kite balloon aerial photography system is enough for practical use to survey roof snow depths because the measurement accuracy is allowable and the cost performance was the best among the three systems.3) The way of using a polaroid filter as the counterplan against halation shows the best performance in practical use because this way can avoid occurring halation for almost any sunlight conditions and does not restrict the photographing within limited time.4) The distributions of snow depths on roofs of large buildings were investigated by the se systems and were discussed on effect of average wind direction. Less