title: 3D Shape Reconstruction from Multiple Range Image Views

authors: Ganapathi Annadurai, Kartick

subjects: shape reconstruction

abstract: Shape reconstruction of different three dimensional objects using multiple range images has evolved recently within the recent past. In this research shape reconstruction of a three dimensional object using multiple range image views is investigated.
Range images were captured using the Waikato Range Imager. This range images camera is novel in that it uses heterodyne imaging and is capable of acquiring range images with precision less than a millimeter simultaneously over a full field. Multiple views of small objects were taken and the FastRBF was explored as a mean of registration and surface rendering. For comparison to the real range data, simulated range data under noise free condition were also generated and reconstructed with the FastRBF tool box.
The registration and reconstruction of simple object was performed using different views with the FastRBF toolbox. Analysis of the registration process showed that the translation error produced due to distortion during registration of different views hinders the process of reconstructing a complete surface. While analyzing the shape reconstruction using the FastRBF tool it is also determined that a small change in accuracy values can affect the interpolation drastically. Results of reconstruction of a real 3D object from multiple views are shown.

text: 3D Shape Reconstruction from Multiple Range Image Views Shape reconstruction of different three dimensional objects using multiple range images has evolved recently within the recent past. In this research shape reconstruction of a three dimensional object using multiple range image views is investigated.
Range images were captured using the Waikato Range Imager. This range images camera is novel in that it uses heterodyne imaging and is capable of acquiring range images with precision less than a millimeter simultaneously over a full field. Multiple views of small objects were taken and the FastRBF was explored as a mean of registration and surface rendering. For comparison to the real range data, simulated range data under noise free condition were also generated and reconstructed with the FastRBF tool box.
The registration and reconstruction of simple object was performed using different views with the FastRBF toolbox. Analysis of the registration process showed that the translation error produced due to distortion during registration of different views hinders the process of reconstructing a complete surface. While analyzing the shape reconstruction using the FastRBF tool it is also determined that a small change in accuracy values can affect the interpolation drastically. Results of reconstruction of a real 3D object from multiple views are shown.

year: 2006

title: Improving the success of a translocation of black mudfish (Neochanna diversus)

authors: McDonald, Amy Elizabeth

subjects: black mudfish

abstract: All of New Zealand's five endemic species of mudfish (Neochanna) are threatened, and translocation has been recommended as an option for conservation.  This research undertakes a translocation of black mudfish (Neochanna diversus) into wetland margins of Lake Kaituna, in the Waikato region, and addresses research questions applicable to improving translocation success.  Results from this research are intended to aid possible future translocations of the more threatened Northland mudfish (Neochanna heleios) and other genetically distinct populations of black mudfish.

Captive rearing of juveniles collected from the wild is currently the most feasible option for sourcing translocation stock.  Mudfish juveniles (greater than 25 mm T.L.) had greater survival rates, compared to mudfish fry less than 25 mm T.L.  Mudfish growth was far greater when fed on a combined diet of brine shrimp (Artemia salina) and white worms (Enchytraeus albidus) than when fed exclusively on brine shrimp.  Temperature was found to have a small effect on mudfish growth, with a slightly greater growth in fish at 15 C than those at 10 C.

The introduced species Gambusia affinis has been the subject of concern for mudfish conservation and commonly found at wetland sites suitable for mudfish translocation.  Found to prey on mudfish fry and eggs in aquaria, it was important to determine the effects of Gambusia density prior to undertaking a translocation to a location where Gambusia were present.  Investigations were made into the effect of Gambusia density on black mudfish juveniles in 9 outdoor mesocosms.  Increasing Gambusia density was found to have an inhibitory effect on black mudfish growth.  This may be due to increased competition for food, a theory supported by analysis of zooplankton communities, where, in the presence of Gambusia, large zooplankton had been removed and smaller rotifers flourished.

Monitoring programmes are required to assess any impacts or improvements of mudfish populations, including those created by translocation.  A Gee minnow trapping programme in outdoor mesocosms was conducted to test the reliability of traps, finding that water depth, mudfish density, mudfish memory and trap shyness had no effect on the trapability of mudfish.  Trap position was found to have the most significant effect, with a greater number of mudfish caught when traps were set overnight at the surface than when set on the bottom of mesocosms.

Black mudfish adults and juveniles were translocated into 18 pools (~1 m diameter) on the wetland margins of Lake Kaituna in September 2006, followed by monthly monitoring.  Water quality monitoring and an assessment of hydrology and vegetation was undertaken.  Habitat characterisation was found to be a key factor, with correlations between water quality data and trapping results finding fewer fish remaining in pools with less suitable characteristics for mudfish (e.g. high turbidity and conductivity).  Other species were found to have a large impact, with predation by shortfinned eels (Anguilla australis) thought to have eliminated mudfish from some pools.  In addition fewer mudfish were caught in pools with Gambusia, possibly due to increased competition.

text: Improving the success of a translocation of black mudfish (Neochanna diversus) All of New Zealand's five endemic species of mudfish (Neochanna) are threatened, and translocation has been recommended as an option for conservation.  This research undertakes a translocation of black mudfish (Neochanna diversus) into wetland margins of Lake Kaituna, in the Waikato region, and addresses research questions applicable to improving translocation success.  Results from this research are intended to aid possible future translocations of the more threatened Northland mudfish (Neochanna heleios) and other genetically distinct populations of black mudfish.

Captive rearing of juveniles collected from the wild is currently the most feasible option for sourcing translocation stock.  Mudfish juveniles (greater than 25 mm T.L.) had greater survival rates, compared to mudfish fry less than 25 mm T.L.  Mudfish growth was far greater when fed on a combined diet of brine shrimp (Artemia salina) and white worms (Enchytraeus albidus) than when fed exclusively on brine shrimp.  Temperature was found to have a small effect on mudfish growth, with a slightly greater growth in fish at 15 C than those at 10 C.

The introduced species Gambusia affinis has been the subject of concern for mudfish conservation and commonly found at wetland sites suitable for mudfish translocation.  Found to prey on mudfish fry and eggs in aquaria, it was important to determine the effects of Gambusia density prior to undertaking a translocation to a location where Gambusia were present.  Investigations were made into the effect of Gambusia density on black mudfish juveniles in 9 outdoor mesocosms.  Increasing Gambusia density was found to have an inhibitory effect on black mudfish growth.  This may be due to increased competition for food, a theory supported by analysis of zooplankton communities, where, in the presence of Gambusia, large zooplankton had been removed and smaller rotifers flourished.

Monitoring programmes are required to assess any impacts or improvements of mudfish populations, including those created by translocation.  A Gee minnow trapping programme in outdoor mesocosms was conducted to test the reliability of traps, finding that water depth, mudfish density, mudfish memory and trap shyness had no effect on the trapability of mudfish.  Trap position was found to have the most significant effect, with a greater number of mudfish caught when traps were set overnight at the surface than when set on the bottom of mesocosms.

Black mudfish adults and juveniles were translocated into 18 pools (~1 m diameter) on the wetland margins of Lake Kaituna in September 2006, followed by monthly monitoring.  Water quality monitoring and an assessment of hydrology and vegetation was undertaken.  Habitat characterisation was found to be a key factor, with correlations between water quality data and trapping results finding fewer fish remaining in pools with less suitable characteristics for mudfish (e.g. high turbidity and conductivity).  Other species were found to have a large impact, with predation by shortfinned eels (Anguilla australis) thought to have eliminated mudfish from some pools.  In addition fewer mudfish were caught in pools with Gambusia, possibly due to increased competition.

year: 2007

title: Coastal communities, leisure and wellbeing: Advancing a trans-disciplinary agenda for understanding ocean-human relationships in Aotearoa New Zealand

authors: Wheaton, Belinda

subjects: Science & Technology

abstract: Commentators are advocating for research to better understand relationships between healthy coastal ecosystems and human wellbeing. Doing so requires inter- and transdisciplinary approaches across humanities, arts, social sciences, and science and technology disciplines. These approaches include culturally diverse knowledge systems, such as indigenous ones, that locate sustainable use of and relationships to marine ecosystems. This paper contributes to this agenda through a case-study of relationships between coastal ecosystems and human wellbeing in Aotearoa New Zealand. This article highlights interconnected cultural and wellbeing benefits of, and socio-ecological relationships between, these coastal ecosystems drawing on a case study of one ocean-based, ‘immersive’ leisure activity, surfing. Further, it examines how these relationships impact human physical, emotional and spiritual wellbeing, and the wellbeing of communities and ecosystems. The research illustrates that surfing creates strong bonds between practitioners and coastal places, linking the health of marine environments and people. We demonstrate the value of a transdisciplinary place-based approach that integrates research across the humanities and social sciences and engages with Indigenous knowledge (Mātauranga Māori). This argument for multicultural co-learning shows the value of Western and Māori vantage points for how we understand coastal blue spaces. Indigenous perspectives, we conclude, deepen appreciation, as well as equity considerations, of how we understand place, wellbeing, and long-term sustainable relationships with marine ecosystems.

text: Coastal communities, leisure and wellbeing: Advancing a trans-disciplinary agenda for understanding ocean-human relationships in Aotearoa New Zealand Commentators are advocating for research to better understand relationships between healthy coastal ecosystems and human wellbeing. Doing so requires inter- and transdisciplinary approaches across humanities, arts, social sciences, and science and technology disciplines. These approaches include culturally diverse knowledge systems, such as indigenous ones, that locate sustainable use of and relationships to marine ecosystems. This paper contributes to this agenda through a case-study of relationships between coastal ecosystems and human wellbeing in Aotearoa New Zealand. This article highlights interconnected cultural and wellbeing benefits of, and socio-ecological relationships between, these coastal ecosystems drawing on a case study of one ocean-based, ‘immersive’ leisure activity, surfing. Further, it examines how these relationships impact human physical, emotional and spiritual wellbeing, and the wellbeing of communities and ecosystems. The research illustrates that surfing creates strong bonds between practitioners and coastal places, linking the health of marine environments and people. We demonstrate the value of a transdisciplinary place-based approach that integrates research across the humanities and social sciences and engages with Indigenous knowledge (Mātauranga Māori). This argument for multicultural co-learning shows the value of Western and Māori vantage points for how we understand coastal blue spaces. Indigenous perspectives, we conclude, deepen appreciation, as well as equity considerations, of how we understand place, wellbeing, and long-term sustainable relationships with marine ecosystems.

year: 2021