3 research outputs found
Automation of the Registration of Range Plant Images Using Geomagic Studio
As plant science advances, the quantitative measurement of 3D plant growth has become an essential tool to evaluate the growth performance of genetically modified seeds or plants. In the past, “wet volumes” had been used to quantitatively measure plant growth which result in the destruction of the plants. Other traditional methods like interferometry methods or mechanical methods are also inefficient because they are either invasive or unable to provide sufficient growth information of the plant body. On the other hand, computer vision methods, especially optical and range flow techniques, are non-contact, more accurate, and relatively less expensive. But they require a fixed light source for the experimental environment and also, higher acquisition rate for the data.
In this thesis, unlike optical or range flow methods, we generate a number of 3D range scans of the Arabidopsis thaliana plant from different viewpoints to reconstruct 3D polygonal meshes of it. We use ShapeGrabber range sensor to acquire the scanned data and Geomagic Studio 12 CAD software to register these scans to produce 3D polygonal meshes. Then, the canopy surface area and 3D stem volume of the plant are computed from these meshes to determine its growth over a time cycle. To perform the registration process in Geomagic, 6 ping pong balls are used as reference spheres.However, because the laser scanner can only see the parts of an object that are visible from its viewpoint, the balls are imaged as semi-spheres in the original range images.But, Geomagic is unable to register multiple images with incomplete semi-sphere data and requires full spheres as target objects. Zhao (MSc UWO 2010) and Yang (MSc UWO 2009) manually replaced these semi-spheres with artificially generated spheres using Geomagic which is both tedious and error prone. Moreover, they manually rotated the images to find out the pair of spheres that matches in adjacent range scans and aligned them manually before performing the registration. Because of the manual nature of this processing, automation of the registration process is very desirable. Among the major contributions of this research are not only to automatically generate synthetic sphere data but also detect and localize the semi-spheres in the original range images using parameter estimation techniques and parametric equation of spheres. Additionally, we reconstruct the original range images by replacing the incomplete semi-sphere data with “perfect” full sphere data to aid Geomagic during the automatic detection of target objects. After this pre-processing, the modified images are automatically registered using Geomagic macros so that the 3D polygonal meshes found from the registration process can be used to measure plant growth quantitatively. We believe that the automation of the registration process is a good first step towards a fully automated system of 3D plant growth measurement
Transition overtime in household latrine use in rural Bangladesh: a longitudinal cohort study
An experimental look into efficient quaternary Bi5O7I/Bi(IO3)3/Bi2(IO4) (IO3)3/BiOIO3 photocatalytic composite
The prototypical toxic dye rhodamine B (RhB) is perhaps one of the most abundant pollutants in industrial wastewater. Its efficient photocatalytic degradation through composite photocatalysts is crucial for environmental remediation. Here, we synthesized quaternary Bi5O7I/Bi(IO3)3/Bi2(IO4)(IO3)3/BiOIO3 bismuth iodate composites through facile hydrothermal and solvothermal methods. The coexistence of multiple bismuth iodate phases was confirmed by x-ray diffraction analysis, room temperature Raman, and Fourier-transform infrared spectroscopy. The desired chemical states of Bi, I, and O inside the composites were confirmed by x-ray photoelectron spectroscopy. Field emission electron microscopy revealed flower-shaped nanosheet morphology for the composite synthesized at 120 °C, whereas randomly shaped nanoparticles with an average size of 80 nm were formed in the composite calcined at 400 °C. High-resolution transmission electron microscopy further corroborated the existence of multiple phases in the composites. The diffuse reflectance spectroscopy confirmed the optical absorption edges of the composites to be located within the visible range of 1.68–3.16 eV. The flower-shaped quaternary bismuth iodate composite demonstrated 100% degradation of RhB dye within 40 min of optical exposure. This quaternary bismuth iodate composite is suitable for solar harvesting-driven toxic dye remediation