Remote measurement of citrus fruit volume based on fluorescence Scheimpflug-LiDAR system

Three-dimensional (3D) shape information is crucial for evaluating fruit quality. Grading fruits is one of the key postharvest task performed by fruit processing industries. While the internal quality of fruit is important, the external quality significantly influences consumers and market prices. This study focuses on developing a high-flux, non-destructive measurement method for citrus fruit phenotype were using a fluorescence Scheimpflug-LiDAR system. The system uses a 405nm photodiode as the excitation light source to generate light plates and a CMOS camera to collect the reflected signals and fluorescence signals of the measured vegetation. The three-dimensional information of vegetation can be obtained through the point cloud information recorded by the blue channel pixels of the CMOS camera, and the fluorescence spectrum information of vegetation can be obtained through the red and green channel pixel information of the camera. Combined with the vegetation fluorescence spectrum information obtained by the red and green channels of the CMOS sensor, citrus fruit can be well separated from the background environment. By comparing the measured citrus fruit point cloud volume with the real fruit volume, the accuracy of this system applied to fruit volume measurement is verified, and it can be further applied to future agricultural harvesting robots in the future.