{"id":{"repo_id":"uhi-uk","oai_identifier":"oai:pure.atira.dk:studenttheses/7d159d9c-297b-4817-831e-673ddc4e5e67"},"canonical_url":"https://search.dev.ndltd.org/etd/uhi-uk/oai:pure.atira.dk:studenttheses/7d159d9c-297b-4817-831e-673ddc4e5e67","repository":{"repo_id":"uhi-uk","name":"University of the Highlands and Islands","base_url":"https://pureadmin.uhi.ac.uk/ws/oai"},"display":{"title":"Surveyance of the marine environment for beached plastic debris using a novel, hyperspectral shortwave infrared camera on an uncrewed aerial vehicle (UAV)","abstract":"Plastic waste has been rapidly accumulating in the natural environment for decades since<br/>the commercial introduction of plastic in the 1950s as a disposable material. Millions of<br/>tonnes of durable, persistent plastic waste now contaminate global ecosystems, including<br/>rivers, urban beaches, remote islands, the deep sea, soils, mountains, and very small<br/>pieces (microplastics) have even been detected in the air. Such pervasive plastic debris is<br/>a deadly and common threat to wildlife due to ingestion and entanglement. Large debris<br/>are particularly problematic not only because of these direct consequences, but because<br/>they break down into smaller pieces in the environment. These smaller pieces are more<br/>easily ingested by a greater diversity of species and are more difficult to remediate. It is<br/>therefore sensible to focus prevention, remediation, and monitoring efforts on large, more<br/>easily observable debris. In the past five years, monitoring efforts have increasingly<br/>included the investigation of automated plastic detection via remote sensing technologies<br/>and techniques. This approach has the potential to reduce observer bias (associated with<br/>manual, visual surveys), and realise regular and widespread plastic pollution monitoring,<br/>with the ultimate goal of achieving environmentally relevant reductions in plastic production<br/>and pollution. This thesis contributes to these aims by i) investigating the performance of<br/>novel remote sensing methods for plastic detection, ii) developing and implementing a new<br/>plastic detection algorithm, and iii) evaluating for the first time, the impact of operational and<br/>environmental variables on these specific plastic detection methods.<br/>A large proportion of plastic litter detection investigations have implemented inexpensive<br/>and common digital cameras that operate in the visible light spectrum. This approach is<br/>often limited in capability/reliability by inherent ambiguity, resulting from two-dimensional<br/>imagery of materials of unverifiable chemical composition. This thesis investigates the<br/>detection of shoreline plastic litter with the aerial deployment of a specialised, hyperspectral<br/>camera that is sensitive to shortwave infrared (SWIR) light and that measures signal from<br/>more than ten times as many wavelengths as a conventional digital camera. The rationale<br/>for pursuing this research is further detailed in Chapter 1, as well as thesis structure and<br/>objectives. The chosen SWIR sensing technology was selected from numerous other<br/>sensor technologies introduced in Chapter 2, for its specific relevance to detecting plastic<br/>based on chemical composition. Chapter 3 details the functional principles of this<br/>technology, which sees widespread use in commercial recycling facilities to successfully<br/>sort large volumes of different types of plastic. The criteria for selecting the specific SWIR<br/>camera (“OCI-F SWIR” from BaySpec, San Jose, CA, USA) implemented in this work, and an initial evaluation of its capabilities under a controlled lab environment are also presented<br/>in Chapter 3, prior to assessing field performance in Chapters 4 and 5.<br/>Chapter 4 presents the development of a customised, software-based plastic detection<br/>algorithm, informed by results from Chapter 3 and by methods implemented in the literature.<br/>Spectral Correlation Mapping (SCM) was selected for its computational efficiency and<br/>documented improvement over detection with the commonly applied Spectral Angle<br/>Mapping (upon which SCM is based). This method achieved successful classification of<br/>plastic and non-plastic pixels within imagery of individual items of polyethylene (PE) and<br/>polypropylene (PP) – the most common polymers produced globally – placed on a sandy<br/>shoreline. The images were collected with a distance of approximately one metre between<br/>the camera and the plastic items to measure a strong signal from the plastic and to inform<br/>algorithm parameter selection before increasing image complexity and introducing<br/>environmental variability in Chapter 5.<br/>Imagery analysed in Chapter 5 was collected on different days to evaluate the impacts on<br/>plastic detection performance of: plastic type, cloud cover, beach substrate, plastic’s<br/>exposure to the environment (harvested from domestic and environmental sources), and<br/>the altitude of the camera above the plastic. The camera was first deployed on a “highline”<br/>apparatus and manually conveyed across a fixed transect, at a height of five metres above<br/>a variety of plastic items arranged on the beach below. The purpose of this approach was<br/>to ensure the collection of data under steady, regular movement, which might not be as<br/>easily achieved with an uncrewed aerial vehicle (UAV). SCM was not able to consistently<br/>classify plastic pixels in each transect as PE nor PP when SCM was applied in the same<br/>way it had been in Chapter 4 (to images recorded at a one metre distance, of individual<br/>plastic items). The mathematical factors contributing to this discrepancy were investigated<br/>and modifications were subsequently implemented to the application of SCM, to compare<br/>segmented spectra. An additional, new algorithm called Reflectance Range Analysis (RRA)<br/>was also developed and evaluated. The development of RRA was based on differences<br/>observed in the spectral characteristics of plastic items and substrate measured in the aerial<br/>imagery, and on recommendations in the literature to develop/implement algorithms that<br/>detect the intensity of plastic’s characteristic absorption. Where SCM classifies every image<br/>pixel based on spectral similarity to a selected reference, RRA reveals spectral differences<br/>between image pixels without requiring similarity to a reference.<br/>Chapter 6 concludes this work by summarising the key findings and demonstrating the place<br/>of this research in the evolution of plastic detection with SWIR remote sensing.<br/>Recommendations are made here for augmenting plastic detection capabilities through<br/>further study and improvements to survey and equipment design, as well as leveraging the<br/>strengths of multiple remote sensing technologies. The diversity of current, newly available,<br/>and upcoming sensor technologies offers numerous opportunities to measure, monitor, and<br/>collectively address the problem of human-driven plastic pollution.","abstract_html":"Plastic waste has been rapidly accumulating in the natural environment for decades since&lt;br/&gt;the commercial introduction of plastic in the 1950s as a disposable material. Millions of&lt;br/&gt;tonnes of durable, persistent plastic waste now contaminate global ecosystems, including&lt;br/&gt;rivers, urban beaches, remote islands, the deep sea, soils, mountains, and very small&lt;br/&gt;pieces (microplastics) have even been detected in the air. Such pervasive plastic debris is&lt;br/&gt;a deadly and common threat to wildlife due to ingestion and entanglement. Large debris&lt;br/&gt;are particularly problematic not only because of these direct consequences, but because&lt;br/&gt;they break down into smaller pieces in the environment. These smaller pieces are more&lt;br/&gt;easily ingested by a greater diversity of species and are more difficult to remediate. It is&lt;br/&gt;therefore sensible to focus prevention, remediation, and monitoring efforts on large, more&lt;br/&gt;easily observable debris. In the past five years, monitoring efforts have increasingly&lt;br/&gt;included the investigation of automated plastic detection via remote sensing technologies&lt;br/&gt;and techniques. This approach has the potential to reduce observer bias (associated with&lt;br/&gt;manual, visual surveys), and realise regular and widespread plastic pollution monitoring,&lt;br/&gt;with the ultimate goal of achieving environmentally relevant reductions in plastic production&lt;br/&gt;and pollution. This thesis contributes to these aims by i) investigating the performance of&lt;br/&gt;novel remote sensing methods for plastic detection, ii) developing and implementing a new&lt;br/&gt;plastic detection algorithm, and iii) evaluating for the first time, the impact of operational and&lt;br/&gt;environmental variables on these specific plastic detection methods.&lt;br/&gt;A large proportion of plastic litter detection investigations have implemented inexpensive&lt;br/&gt;and common digital cameras that operate in the visible light spectrum. This approach is&lt;br/&gt;often limited in capability/reliability by inherent ambiguity, resulting from two-dimensional&lt;br/&gt;imagery of materials of unverifiable chemical composition. This thesis investigates the&lt;br/&gt;detection of shoreline plastic litter with the aerial deployment of a specialised, hyperspectral&lt;br/&gt;camera that is sensitive to shortwave infrared (SWIR) light and that measures signal from&lt;br/&gt;more than ten times as many wavelengths as a conventional digital camera. The rationale&lt;br/&gt;for pursuing this research is further detailed in Chapter 1, as well as thesis structure and&lt;br/&gt;objectives. The chosen SWIR sensing technology was selected from numerous other&lt;br/&gt;sensor technologies introduced in Chapter 2, for its specific relevance to detecting plastic&lt;br/&gt;based on chemical composition. Chapter 3 details the functional principles of this&lt;br/&gt;technology, which sees widespread use in commercial recycling facilities to successfully&lt;br/&gt;sort large volumes of different types of plastic. The criteria for selecting the specific SWIR&lt;br/&gt;camera (“OCI-F SWIR” from BaySpec, San Jose, CA, USA) implemented in this work, and an initial evaluation of its capabilities under a controlled lab environment are also presented&lt;br/&gt;in Chapter 3, prior to assessing field performance in Chapters 4 and 5.&lt;br/&gt;Chapter 4 presents the development of a customised, software-based plastic detection&lt;br/&gt;algorithm, informed by results from Chapter 3 and by methods implemented in the literature.&lt;br/&gt;Spectral Correlation Mapping (SCM) was selected for its computational efficiency and&lt;br/&gt;documented improvement over detection with the commonly applied Spectral Angle&lt;br/&gt;Mapping (upon which SCM is based). This method achieved successful classification of&lt;br/&gt;plastic and non-plastic pixels within imagery of individual items of polyethylene (PE) and&lt;br/&gt;polypropylene (PP) – the most common polymers produced globally – placed on a sandy&lt;br/&gt;shoreline. The images were collected with a distance of approximately one metre between&lt;br/&gt;the camera and the plastic items to measure a strong signal from the plastic and to inform&lt;br/&gt;algorithm parameter selection before increasing image complexity and introducing&lt;br/&gt;environmental variability in Chapter 5.&lt;br/&gt;Imagery analysed in Chapter 5 was collected on different days to evaluate the impacts on&lt;br/&gt;plastic detection performance of: plastic type, cloud cover, beach substrate, plastic’s&lt;br/&gt;exposure to the environment (harvested from domestic and environmental sources), and&lt;br/&gt;the altitude of the camera above the plastic. The camera was first deployed on a “highline”&lt;br/&gt;apparatus and manually conveyed across a fixed transect, at a height of five metres above&lt;br/&gt;a variety of plastic items arranged on the beach below. The purpose of this approach was&lt;br/&gt;to ensure the collection of data under steady, regular movement, which might not be as&lt;br/&gt;easily achieved with an uncrewed aerial vehicle (UAV). SCM was not able to consistently&lt;br/&gt;classify plastic pixels in each transect as PE nor PP when SCM was applied in the same&lt;br/&gt;way it had been in Chapter 4 (to images recorded at a one metre distance, of individual&lt;br/&gt;plastic items). The mathematical factors contributing to this discrepancy were investigated&lt;br/&gt;and modifications were subsequently implemented to the application of SCM, to compare&lt;br/&gt;segmented spectra. An additional, new algorithm called Reflectance Range Analysis (RRA)&lt;br/&gt;was also developed and evaluated. The development of RRA was based on differences&lt;br/&gt;observed in the spectral characteristics of plastic items and substrate measured in the aerial&lt;br/&gt;imagery, and on recommendations in the literature to develop/implement algorithms that&lt;br/&gt;detect the intensity of plastic’s characteristic absorption. Where SCM classifies every image&lt;br/&gt;pixel based on spectral similarity to a selected reference, RRA reveals spectral differences&lt;br/&gt;between image pixels without requiring similarity to a reference.&lt;br/&gt;Chapter 6 concludes this work by summarising the key findings and demonstrating the place&lt;br/&gt;of this research in the evolution of plastic detection with SWIR remote sensing.&lt;br/&gt;Recommendations are made here for augmenting plastic detection capabilities through&lt;br/&gt;further study and improvements to survey and equipment design, as well as leveraging the&lt;br/&gt;strengths of multiple remote sensing technologies. The diversity of current, newly available,&lt;br/&gt;and upcoming sensor technologies offers numerous opportunities to measure, monitor, and&lt;br/&gt;collectively address the problem of human-driven plastic pollution.","abstract_has_math":false,"creators":["Cocking, Jennifer Laura"],"institution":"University of the Highlands and Islands","degree_name":"Doctor of Philosophy (awarded by UHI)","degree_level":"Doctoral Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Narayanaswamy, Bhavani","Williamson, Benjamin"],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-5-9","date_published":"2023-5-9","updated_at":"2026-07-24T05:12:10Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.atira.dk:studenttheses/7d159d9c-297b-4817-831e-673ddc4e5e67"],"render_values":[{"text":"oai:pure.atira.dk:studenttheses/7d159d9c-297b-4817-831e-673ddc4e5e67","href":null,"code":true}]}]},"links":{"outbound_url":"https://pure.uhi.ac.uk/en/studentTheses/7d159d9c-297b-4817-831e-673ddc4e5e67","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Narayanaswamy, Bhavani","Williamson, Benjamin"]},{"key":"dc:contributor.sponsor","label":"Sponsor","values":["NERC"]},{"key":"dc:creator","label":"Author","values":["Cocking, Jennifer Laura"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2023-5-9"]},{"key":"dc:date.issued","label":"Date","values":["2023-5-9"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["The Scottish Association for Marine Science, Scottish Marine Institute"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of the Highlands and Islands"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://pure.uhi.ac.uk/en/studentTheses/7d159d9c-297b-4817-831e-673ddc4e5e67"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (awarded by UHI)"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.atira.dk:studenttheses/7d159d9c-297b-4817-831e-673ddc4e5e67","https://pure.uhi.ac.uk/en/studentTheses/7d159d9c-297b-4817-831e-673ddc4e5e67"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://pure.uhi.ac.uk/files/43318567/Jennifer_Cocking_thesis.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Plastic waste has been rapidly accumulating in the natural environment for decades since<br/>the commercial introduction of plastic in the 1950s as a disposable material. Millions of<br/>tonnes of durable, persistent plastic waste now contaminate global ecosystems, including<br/>rivers, urban beaches, remote islands, the deep sea, soils, mountains, and very small<br/>pieces (microplastics) have even been detected in the air. Such pervasive plastic debris is<br/>a deadly and common threat to wildlife due to ingestion and entanglement. Large debris<br/>are particularly problematic not only because of these direct consequences, but because<br/>they break down into smaller pieces in the environment. These smaller pieces are more<br/>easily ingested by a greater diversity of species and are more difficult to remediate. It is<br/>therefore sensible to focus prevention, remediation, and monitoring efforts on large, more<br/>easily observable debris. In the past five years, monitoring efforts have increasingly<br/>included the investigation of automated plastic detection via remote sensing technologies<br/>and techniques. This approach has the potential to reduce observer bias (associated with<br/>manual, visual surveys), and realise regular and widespread plastic pollution monitoring,<br/>with the ultimate goal of achieving environmentally relevant reductions in plastic production<br/>and pollution. This thesis contributes to these aims by i) investigating the performance of<br/>novel remote sensing methods for plastic detection, ii) developing and implementing a new<br/>plastic detection algorithm, and iii) evaluating for the first time, the impact of operational and<br/>environmental variables on these specific plastic detection methods.<br/>A large proportion of plastic litter detection investigations have implemented inexpensive<br/>and common digital cameras that operate in the visible light spectrum. This approach is<br/>often limited in capability/reliability by inherent ambiguity, resulting from two-dimensional<br/>imagery of materials of unverifiable chemical composition. This thesis investigates the<br/>detection of shoreline plastic litter with the aerial deployment of a specialised, hyperspectral<br/>camera that is sensitive to shortwave infrared (SWIR) light and that measures signal from<br/>more than ten times as many wavelengths as a conventional digital camera. The rationale<br/>for pursuing this research is further detailed in Chapter 1, as well as thesis structure and<br/>objectives. The chosen SWIR sensing technology was selected from numerous other<br/>sensor technologies introduced in Chapter 2, for its specific relevance to detecting plastic<br/>based on chemical composition. Chapter 3 details the functional principles of this<br/>technology, which sees widespread use in commercial recycling facilities to successfully<br/>sort large volumes of different types of plastic. The criteria for selecting the specific SWIR<br/>camera (“OCI-F SWIR” from BaySpec, San Jose, CA, USA) implemented in this work, and an initial evaluation of its capabilities under a controlled lab environment are also presented<br/>in Chapter 3, prior to assessing field performance in Chapters 4 and 5.<br/>Chapter 4 presents the development of a customised, software-based plastic detection<br/>algorithm, informed by results from Chapter 3 and by methods implemented in the literature.<br/>Spectral Correlation Mapping (SCM) was selected for its computational efficiency and<br/>documented improvement over detection with the commonly applied Spectral Angle<br/>Mapping (upon which SCM is based). This method achieved successful classification of<br/>plastic and non-plastic pixels within imagery of individual items of polyethylene (PE) and<br/>polypropylene (PP) – the most common polymers produced globally – placed on a sandy<br/>shoreline. The images were collected with a distance of approximately one metre between<br/>the camera and the plastic items to measure a strong signal from the plastic and to inform<br/>algorithm parameter selection before increasing image complexity and introducing<br/>environmental variability in Chapter 5.<br/>Imagery analysed in Chapter 5 was collected on different days to evaluate the impacts on<br/>plastic detection performance of: plastic type, cloud cover, beach substrate, plastic’s<br/>exposure to the environment (harvested from domestic and environmental sources), and<br/>the altitude of the camera above the plastic. The camera was first deployed on a “highline”<br/>apparatus and manually conveyed across a fixed transect, at a height of five metres above<br/>a variety of plastic items arranged on the beach below. The purpose of this approach was<br/>to ensure the collection of data under steady, regular movement, which might not be as<br/>easily achieved with an uncrewed aerial vehicle (UAV). SCM was not able to consistently<br/>classify plastic pixels in each transect as PE nor PP when SCM was applied in the same<br/>way it had been in Chapter 4 (to images recorded at a one metre distance, of individual<br/>plastic items). The mathematical factors contributing to this discrepancy were investigated<br/>and modifications were subsequently implemented to the application of SCM, to compare<br/>segmented spectra. An additional, new algorithm called Reflectance Range Analysis (RRA)<br/>was also developed and evaluated. The development of RRA was based on differences<br/>observed in the spectral characteristics of plastic items and substrate measured in the aerial<br/>imagery, and on recommendations in the literature to develop/implement algorithms that<br/>detect the intensity of plastic’s characteristic absorption. Where SCM classifies every image<br/>pixel based on spectral similarity to a selected reference, RRA reveals spectral differences<br/>between image pixels without requiring similarity to a reference.<br/>Chapter 6 concludes this work by summarising the key findings and demonstrating the place<br/>of this research in the evolution of plastic detection with SWIR remote sensing.<br/>Recommendations are made here for augmenting plastic detection capabilities through<br/>further study and improvements to survey and equipment design, as well as leveraging the<br/>strengths of multiple remote sensing technologies. The diversity of current, newly available,<br/>and upcoming sensor technologies offers numerous opportunities to measure, monitor, and<br/>collectively address the problem of human-driven plastic pollution."]},{"key":"dc:title","label":"Title","values":["Surveyance of the marine environment for beached plastic debris using a novel, hyperspectral shortwave infrared camera on an uncrewed aerial vehicle (UAV)"]}]}],"canonical_facts":{"dc:contributor.advisor":["Narayanaswamy, Bhavani","Williamson, Benjamin"],"dc:contributor.sponsor":["NERC"],"dc:creator":["Cocking, Jennifer Laura"],"dc:date":["2023-5-9"],"dc:date.issued":["2023-5-9"],"dc:description.abstract":["Plastic waste has been rapidly accumulating in the natural environment for decades since<br/>the commercial introduction of plastic in the 1950s as a disposable material. Millions of<br/>tonnes of durable, persistent plastic waste now contaminate global ecosystems, including<br/>rivers, urban beaches, remote islands, the deep sea, soils, mountains, and very small<br/>pieces (microplastics) have even been detected in the air. Such pervasive plastic debris is<br/>a deadly and common threat to wildlife due to ingestion and entanglement. Large debris<br/>are particularly problematic not only because of these direct consequences, but because<br/>they break down into smaller pieces in the environment. These smaller pieces are more<br/>easily ingested by a greater diversity of species and are more difficult to remediate. It is<br/>therefore sensible to focus prevention, remediation, and monitoring efforts on large, more<br/>easily observable debris. In the past five years, monitoring efforts have increasingly<br/>included the investigation of automated plastic detection via remote sensing technologies<br/>and techniques. This approach has the potential to reduce observer bias (associated with<br/>manual, visual surveys), and realise regular and widespread plastic pollution monitoring,<br/>with the ultimate goal of achieving environmentally relevant reductions in plastic production<br/>and pollution. This thesis contributes to these aims by i) investigating the performance of<br/>novel remote sensing methods for plastic detection, ii) developing and implementing a new<br/>plastic detection algorithm, and iii) evaluating for the first time, the impact of operational and<br/>environmental variables on these specific plastic detection methods.<br/>A large proportion of plastic litter detection investigations have implemented inexpensive<br/>and common digital cameras that operate in the visible light spectrum. This approach is<br/>often limited in capability/reliability by inherent ambiguity, resulting from two-dimensional<br/>imagery of materials of unverifiable chemical composition. This thesis investigates the<br/>detection of shoreline plastic litter with the aerial deployment of a specialised, hyperspectral<br/>camera that is sensitive to shortwave infrared (SWIR) light and that measures signal from<br/>more than ten times as many wavelengths as a conventional digital camera. The rationale<br/>for pursuing this research is further detailed in Chapter 1, as well as thesis structure and<br/>objectives. The chosen SWIR sensing technology was selected from numerous other<br/>sensor technologies introduced in Chapter 2, for its specific relevance to detecting plastic<br/>based on chemical composition. Chapter 3 details the functional principles of this<br/>technology, which sees widespread use in commercial recycling facilities to successfully<br/>sort large volumes of different types of plastic. The criteria for selecting the specific SWIR<br/>camera (“OCI-F SWIR” from BaySpec, San Jose, CA, USA) implemented in this work, and an initial evaluation of its capabilities under a controlled lab environment are also presented<br/>in Chapter 3, prior to assessing field performance in Chapters 4 and 5.<br/>Chapter 4 presents the development of a customised, software-based plastic detection<br/>algorithm, informed by results from Chapter 3 and by methods implemented in the literature.<br/>Spectral Correlation Mapping (SCM) was selected for its computational efficiency and<br/>documented improvement over detection with the commonly applied Spectral Angle<br/>Mapping (upon which SCM is based). This method achieved successful classification of<br/>plastic and non-plastic pixels within imagery of individual items of polyethylene (PE) and<br/>polypropylene (PP) – the most common polymers produced globally – placed on a sandy<br/>shoreline. The images were collected with a distance of approximately one metre between<br/>the camera and the plastic items to measure a strong signal from the plastic and to inform<br/>algorithm parameter selection before increasing image complexity and introducing<br/>environmental variability in Chapter 5.<br/>Imagery analysed in Chapter 5 was collected on different days to evaluate the impacts on<br/>plastic detection performance of: plastic type, cloud cover, beach substrate, plastic’s<br/>exposure to the environment (harvested from domestic and environmental sources), and<br/>the altitude of the camera above the plastic. The camera was first deployed on a “highline”<br/>apparatus and manually conveyed across a fixed transect, at a height of five metres above<br/>a variety of plastic items arranged on the beach below. The purpose of this approach was<br/>to ensure the collection of data under steady, regular movement, which might not be as<br/>easily achieved with an uncrewed aerial vehicle (UAV). SCM was not able to consistently<br/>classify plastic pixels in each transect as PE nor PP when SCM was applied in the same<br/>way it had been in Chapter 4 (to images recorded at a one metre distance, of individual<br/>plastic items). The mathematical factors contributing to this discrepancy were investigated<br/>and modifications were subsequently implemented to the application of SCM, to compare<br/>segmented spectra. An additional, new algorithm called Reflectance Range Analysis (RRA)<br/>was also developed and evaluated. The development of RRA was based on differences<br/>observed in the spectral characteristics of plastic items and substrate measured in the aerial<br/>imagery, and on recommendations in the literature to develop/implement algorithms that<br/>detect the intensity of plastic’s characteristic absorption. Where SCM classifies every image<br/>pixel based on spectral similarity to a selected reference, RRA reveals spectral differences<br/>between image pixels without requiring similarity to a reference.<br/>Chapter 6 concludes this work by summarising the key findings and demonstrating the place<br/>of this research in the evolution of plastic detection with SWIR remote sensing.<br/>Recommendations are made here for augmenting plastic detection capabilities through<br/>further study and improvements to survey and equipment design, as well as leveraging the<br/>strengths of multiple remote sensing technologies. The diversity of current, newly available,<br/>and upcoming sensor technologies offers numerous opportunities to measure, monitor, and<br/>collectively address the problem of human-driven plastic pollution."],"dc:identifier":["oai:pure.atira.dk:studenttheses/7d159d9c-297b-4817-831e-673ddc4e5e67","https://pure.uhi.ac.uk/en/studentTheses/7d159d9c-297b-4817-831e-673ddc4e5e67"],"dc:identifier.uri":["https://pure.uhi.ac.uk/files/43318567/Jennifer_Cocking_thesis.pdf"],"dc:language":["eng"],"dc:publisher.department":["The Scottish Association for Marine Science, Scottish Marine Institute"],"dc:publisher.institution":["University of the Highlands and Islands"],"dc:relation.isreferencedby":["https://pure.uhi.ac.uk/en/studentTheses/7d159d9c-297b-4817-831e-673ddc4e5e67"],"dc:title":["Surveyance of the marine environment for beached plastic debris using a novel, hyperspectral shortwave infrared camera on an uncrewed aerial vehicle (UAV)"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral Thesis"],"dc:type.qualificationname":["Doctor of Philosophy (awarded by UHI)"]},"updated_at":"2026-07-24T05:12:10Z"}