Search for: All records

In recent years, robotic technologies, e.g. drones or autonomous cars have been applied to the agricultural sectors to improve the efficiency of typical agricultural operations. Some agricultural tasks that are ideal for robotic automation are yield estimation and robotic harvesting. For these applications, an accurate and reliable image-based detection system is critically important. In this work, we present a low-cost strawberry detection system based on convolutional neural networks. Ablation studies are presented to validate the choice of hyper- parameters, framework, and network structure. Additional modifications to both the training data and network structure that improve precision and execution speed, e.g., input compression, image tiling, color masking, and network compression, are discussed. Finally, we present a final network implementation on a Raspberry Pi 3B that demonstrates a detection speed of 1.63 frames per second and an average precision of 0.842. 

Low-cost 3D scanners and automatic photogrammetry software have brought digitization of objects into 3D models to the level of the consumer. However, the digitization techniques are either tedious, disruptive to the scanned object, or expensive. We create a novel 3D scanning system using consumer grade hardware that revolves a camera around the object of interest. Our approach does not disturb the object during capture and allows us to scan delicate objects that can deform under motion, such as potted plants. Our system consists of a Raspberry Pi camera and computer, stepper motor, 3D printed camera track, and control software. Our 3D scanner allows the user to gather image sets for 3D model reconstruction using photogrammetry software with minimal effort. We scale 3D scanning to objects of varying sizes by designing our scanner using programmatic modeling, and allowing the user to change the physical dimensions of the scanner without redrawing each part. 

We present a microenvironment of multiple cameras to capture multi-viewpoint time-lapse videos of objects showing spatiotemporal phenomena such as aging. Our microenvironment consists of four synchronized Raspberry Pi v2 cameras triggered by four corresponding Raspberry Pi v3 computers that are controlled by a central computer. We provide a graphical user interface for users to trigger captures and visualize multiple viewpoint videos. We show multiple viewpoint captures for objects such as fruit that depict shape changes due to water volume loss and appearance changes due to enzymatic browning. 

We provide an approach to reconstruct spatiotemporal 3D models of aging objects such as fruit containing time-varying shape and appearance using multi-view time-lapse videos captured by a microenvironment of Raspberry Pi cameras. Our approach represents the 3D structure of the object prior to aging using a static 3D mesh reconstructed from multiple photographs of the object captured using a rotating camera track. We manually align the 3D mesh to the images at the first time instant. Our approach automatically deforms the aligned 3D mesh to match the object across the multi-viewpoint time-lapse videos. We texture map the deformed 3D meshes with intensities from the frames at each time instant to create the spatiotemporal 3D model of the object. Our results reveal the time dependence of volume loss due to transpiration and color transformation due to enzymatic browning on banana peels and in exposed parts of bitten fruit.