An Instrument Combining Computerized 3D Plant Photogrammetry With Automated Physiological Monitoring

测量植物的光合作用过程和水分关系有着广泛的历史。然而，一个主要的障碍是在生理实验期间无法实际确定特定植物整个表面上的光分布；植物几何太复杂了。尽管如此，虽然获得了许多有用的信息，但其他重要的问题也被搁置了。这类信息将有助于理解(1)生物量在植物成分之间的分配及其与光合作用的关系；(2)考察物种和亚种之间细微的形态差异；(3)光生物学对形态和物候的影响(如伸长、向日性)；(4)植物对化学和环境因素(如水分胁迫、温度和二氧化碳)的形态反应；以及许多其他因素。该项目旨在开发一种实验室仪器，能够测量植物的瞬时光合作用和蒸腾速率，同时确定其树冠的完整三维结构。该仪器将结合机器视觉和立体摄影测量的元素，与传统的气体交换监测和在线树液流量测量方法相结合。基本设计将包括一个气密、透明的腔体，其中包含与CO2/H2O气体分析仪相连的实验装置。SAP流量传感器将安装在工厂上。所有输出都将由微型计算机监控。照明将被控制，植物将通过机器人操作的相机以不同的角度拍摄。机器视觉技术将被用来将植物从背景中分离出来，然后将其分割成叶子、茎等。多幅图像将通过立体摄影测量进行组合，以获得植物的立体3D计算机模型。然后，可以使用标准的光能传递成像软件来计算植物表面的光照分布。考虑到在实验室测量光合作用和蒸腾作用的植物科学家的数量，这种设备有很大的潜在受众。我们也有充分的理由相信，这一努力将取得成功。One PI已经开发了一种立体摄影测量系统，可以从手动数字化的照片中计算3D植物模型并为其成像。该团队还包括机器视觉专业知识和文献中存在的分割数字植物图像的例子。生理学技术已经确立，三个PI精通它们的使用。团队成员还具有数据采集系统设计和一般工程方面的经验。最后，在公共领域中可以获得适当的光能传递代码。

There is an extensive history of measuring plant photosynthetic processes and water relations. However, a major impediment has been the impossibility of actually determining the light distribution over the entire surface of a particular plant during a physiological experiment; plant geometry is just too complex. While much useful information has been obtained in spite of this, other, important questions have gone begging. Information of this type would contribute to the understanding of (1) the partitioning of biomass among plant components and its relationship to photosynthesis; (2) examination of subtle morphological differences between species and subspecies; (3) influence of photobiology on morphology and phenology (e.g., elongation, heliotropism); (4) plant morphological responses to chemical and environmental factors (e.g., water stress, temperature, and CO2); and many others. This project seeks to develop a laboratory instrument capable of measuring transient photosynthetic and transpiration rates of a plant while simultaneously determining the complete 3D structure of its canopy. The instrument will combine elements of machine vision and stereophotogrammetry with traditional methods of gas exchange monitoring and online sap flow measurement. The basic design will involve a gas tight, transparent chamber containing the experimental plant with connections to CO2/H2O gas analyzers. Sap flow sensors will be attached to the plant. All outputs will be monitored by microcomputer. Illumination will be controlled and the plants will be photographed at various angles by a robotically operated camera. Machine vision techniques will be used to separate the plant from the background and then segment it into leaves, stems, etc. Multiple images will be combined through stereophotogrammetry to obtain a solid, 3D computer model of the plant. The plant surface illumination distribution can then be calculated using standard radiosity imaging software. Given the num ber of plant scientists who make laboratory measurements of photosynthesis and transpiration, there is a large potential audience for this device. There is also good reason for confidence that the effort will be successful. One PI has already developed a stereophotogrammetry system which computes and images 3D plant models from manually digitized photos. The team also includes machine vision expertise and examples of segmenting digital plant images exists in the literature. The physiological techniques are well established and three PI's are versed in their use. Team members also have experience with data acquisition system design and general engineering. Finally, appropriate radiosity codes are available in the public domain.