Research Center for Agricultural Robotics, NARO

Development of 3D technology for measuring plant body surface temperature

- Visualize 3D temperature distribution of the whole plant, for the first time -

National Agriculture and Food Research Organization (NARO) has developed a technology that visualizes the temperature distribution on the surface of a plant in 3D with high accuracy. It is now possible to create a three-dimensional image that integrates the complex shape, color, and surface temperature of a plant by means of superimposing the 3D image of the temperature distribution and the 3D image of the visible image. This will contribute to the establishment of a technology for precisely quantifying physiological responses of plants, such as those associated with temperature changes. In the future, it is also expected that this technology will be applied as a basic technology to the early detection technology of environmental stress and disease of agricultural products.


The data of plant surface temperature is often used as an indicator of growth status and the detection of physiological disorders to develop cultivation techniques for agricultural crops.

In order to accurately identify the surface temperature distribution of the plant body and the part showing that temperature, generally it is necessary to take a thermal image and an RGB image from the same angle of view and superimpose two types of images so that the object overlaps. With conventional technology, however, superimposition is possible only with 2D images, and physiological disorders in hidden areas can be overlooked. Additionally, in order to extract data from different angles, such as the front side and back side of a leaf, it took time and effort to superimpose the images taken from each angle every time.

Meanwhile, NARO has developed a technology for acquiring highly accurate 3D data that integrates the complex 3D shape, color, and surface temperature distribution of plants. With a single shot, it is possible to observe and record the appearance of plants from all angles, and to detect temperature changes on the surface without overlooking them. This technology creates a 3D image from each of the thermal image and the RGB image and integrates them with an accuracy of a few millimeters. This makes it possible to acquire the data of surface temperature after measuring the area and volume of specified parts such as leaves, stems, and fruits with high precision.

In the future, we will apply this technology as a basic technology for precise measurement of physiological responses and build a technology to detect environmental stress and disease in plants at an early stage and a system to predict the risk of poor growth and yield reduction. This technology is expected to contribute to the improvement of the precision of cultivation technology.
【Video】Three-dimensional measurement of plant body surface temperature(Japanese only)
This video explains how the surface temperature of a plant with a complex shape is measured in 3D.

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