Comparison of Artificial Light for Plant Factory by 3D Image Measurement

Abstract

In this study, we proposed a system to quantify the plant height from a three-dimensional point cloud of a plant using the INTEL REALSENSE DEPTH CAMERA D415. This system was used to compare and evaluate plant growth under LEP, LED, and fluorescent lighting. In the experiment, four basil plants were hydroponically cultivated as measurement targets. The highest point from the three-dimensional point cloud of each plant reconstructed by D415 was calculated as the plant height, and the change for about one month was recorded. As a result of the experiment, it was confirmed that the plants grow faster in the order of LEP, LED, and fluorescent lamp. Regarding the illuminance, LEP, fluorescent lamp, and LED were the highest in this order. LEP is advantageous for plant growth because it can emit light with a wide band spectrum with high efficiency. Cultivation using LED tended to grow faster than fluorescent lamps. Since the LED emits only light in the wavelength band related to plant growth, it was considered that efficient plant growth was realized. It was confirmed that the proposed measurement system not only enables easy quantification of plant height, but also enables visualization of growth by presenting a three-dimensional point cloud. Under artificial light illumination, it became clear that the accuracy of 3D reconstruction differs between when artificial light is on and when it is off. Under artificial light lighting, the reconstruction accuracy tends to be lower, and improvement is a future task.