Browsing by Author "Bourn, William"

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    Automatic Generation of Labelled mmWave FMCW Radar Datasets Using Collocated Optical Sensors and Computer Vision
    (2026) Bourn, William; Paine, Stephen
    Advancements made in computational power, the development of complex AI algorithms, and an industry push to create self-driving cars and autonomous systems has resulted in a large amount of research into computer vision. The majority of computer vision research is performed with optical sensors because radar and lidar sensors suffer from a paucity of data that makes classification tasks difficult, and lack easily implemented open-source datasets for general applications. Future research into radar-based computer vision would benefit from a method of automating the process of annotating data, which can be implemented using sensor fusion and existing image recognition algorithms. We propose a processing chain that uses fused spatio-optical and radar data to automatically produce class and localisation ground truth labels in radar data using a YOLO image recognition model to label objects in a projection of 3D optical space. We developed a processing pipeline to perform automatic labelling of radar data and a prototype data capture rig. We analysed the performance of the pipeline by processing data captured by the rig into annotated radar range-azimuth-Doppler frames for human classification and training a CNN classification model on the data. Furthermore, we analysed the performance of the approach to calibration in the processing chain. The CNN classifier achieved strong human classification performance, though was affected by localisation errors that were produced by the processing pipeline. Despite this, the strong classification performance indicates that the pipeline was able to successfully perform automatic annotation of radar range-azimuth-Doppler data with human target information. The processing chain has potential use in radar-based computer vision going forward, and the automatic labelling approach detailed in this report merits further development.
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    An oral recombinant Salmonella enterica serovar Typhimurium mutant elicits systemic antigen-specific CD8+ T cell cytokine responses in mice
    (BioMed Central Ltd, 2009) Chin'ombe, Nyasha; Bourn, William; Williamson, Anna-Lise; Shephard, Enid
    BACKGROUND:The induction of antigen-specific CD8+ T cell cytokine responses against an attenuated, oral recombinant Salmonella enterica serovar Typhimurium vaccine expressing a green fluorescent protein (GFP) model antigen was investigated. A GFP expression plasmid was constructed in which the gfp gene was fused in-frame with the 5' domain of the Escherichia coli beta-galactosidase alpha-gene fragment with expression under the lac promoter. Groups of mice were orally immunized three times with the bacteria and systemic CD8+ T cell cytokine responses were evaluated. RESULTS: High level of the GFP model antigen was expressed by the recombinant Salmonella vaccine vector. Systemic GFP-specific CD8+ T cell cytokine (IFN-gamma and IL-4) immune responses were detected after mice were orally vaccinated with the bacteria. It was shown that 226 net IFN-gamma and 132 net IL-4 GFP-specific SFUs/10e6 splenocytes were formed in an ELISPOT assay. The level of IFN-gamma produced by GFP peptide-stimulated cells was 65.2-fold above background (p < 0.05). The level of IL-4 produced by the cells was 10.4-fold above background (p < 0.05). CONCLUSION: These results suggested that a high expressing recombinant Salmonella vaccine given orally to mice would elicit antigen-specific CD8+ T cell responses in the spleen. Salmonella bacteria may, therefore, be used as potential mucosal vaccine vectors.
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    Recombinant Salmonella enterica serovar Typhimurium vaccine vector expressing green fluorescent protein as a model antigen or human immunodeficiency virus type 1 subtype C Gag
    (2007) Chin'ombe, Nyasha; Williamson, Anna-Lise; Shephard, Enid G; Bourn, William
    Includes bibliographical references (leaves 172-200).