title: 3D Shape Measurement of Moving Objects for Industrial Applications

authors: Charleston, Sean Andrew

subjects: Time-of-flight

abstract: Three dimensional (3D) cameras provide distance measurements to objects, allowing computers and instruments to interact with their environment. The applications are wide-ranging, from human gesture control to industrial processing. Time-offlight cameras measure the distance to the scene by measuring the flight time of a modulated light source. Sequential captures are required to produce the depth map, hence time-of-flight cameras are vulnerable to depth errors from motion blur in dynamic scenes. This is a major hindrance for industrial applications, where accurate results are required when reconstructing objects. The fruit grading industry is of particular interest for this work, where significant advancements can be made using 3D cameras. The produce moves at a constant velocity, providing an ideal case for initial work into industrial motion correction.

The SR4000 from Mesa Imaging is an industrial grade time-of-flight camera with a high quality factory calibration, and is used throughout this work. When applying custom algorithms (such as motion correction), the camera is run in ‘raw mode’ where the sequential captures can be individually manipulated, however the factory calibration set is lost. The first part of this work investigates calibrations in time-of-flight cameras, where the factory calibration set in the SR4000 is extracted from the camera to be used on the ‘raw mode’ data in custom algorithms. The factory calibrated data is compared to both the ‘raw mode’ data, as well as data acquired using the extracted calibration set. The key results show a root mean squared error (RMSE) of 62.4 mm for ‘raw mode’ data, while using the extracted calibrations shows an RMSE of 6.1 mm.

The effects of motion blur on time-of-flight cameras are then investigated. The technique from Hussmann et al. (2011) provides a good first attempt at motion correction, however fails to implement a number of calibrations. The improvements presented in this thesis on the motion correction technique manipulates the demodulation of time-of-flight cameras so that these additional calibrations are incorporated, resulting in a more robust motion correction algorithm. To test these improvements, a controlled experiment is setup to image a moving spherical object, and a stationary reference image of the same object is captured for comparison. Without motion correction the RMSE is 75.9 mm. Using the naive correction technique from Hussmann et al. (2011) gives an RMSE of 58.7 mm, and finally applying the suggested improvements reduces the RMSE to 4.3 mm.

text: 3D Shape Measurement of Moving Objects for Industrial Applications Three dimensional (3D) cameras provide distance measurements to objects, allowing computers and instruments to interact with their environment. The applications are wide-ranging, from human gesture control to industrial processing. Time-offlight cameras measure the distance to the scene by measuring the flight time of a modulated light source. Sequential captures are required to produce the depth map, hence time-of-flight cameras are vulnerable to depth errors from motion blur in dynamic scenes. This is a major hindrance for industrial applications, where accurate results are required when reconstructing objects. The fruit grading industry is of particular interest for this work, where significant advancements can be made using 3D cameras. The produce moves at a constant velocity, providing an ideal case for initial work into industrial motion correction.

The SR4000 from Mesa Imaging is an industrial grade time-of-flight camera with a high quality factory calibration, and is used throughout this work. When applying custom algorithms (such as motion correction), the camera is run in ‘raw mode’ where the sequential captures can be individually manipulated, however the factory calibration set is lost. The first part of this work investigates calibrations in time-of-flight cameras, where the factory calibration set in the SR4000 is extracted from the camera to be used on the ‘raw mode’ data in custom algorithms. The factory calibrated data is compared to both the ‘raw mode’ data, as well as data acquired using the extracted calibration set. The key results show a root mean squared error (RMSE) of 62.4 mm for ‘raw mode’ data, while using the extracted calibrations shows an RMSE of 6.1 mm.

The effects of motion blur on time-of-flight cameras are then investigated. The technique from Hussmann et al. (2011) provides a good first attempt at motion correction, however fails to implement a number of calibrations. The improvements presented in this thesis on the motion correction technique manipulates the demodulation of time-of-flight cameras so that these additional calibrations are incorporated, resulting in a more robust motion correction algorithm. To test these improvements, a controlled experiment is setup to image a moving spherical object, and a stationary reference image of the same object is captured for comparison. Without motion correction the RMSE is 75.9 mm. Using the naive correction technique from Hussmann et al. (2011) gives an RMSE of 58.7 mm, and finally applying the suggested improvements reduces the RMSE to 4.3 mm.

year: 2015

title: A landscape genetics approach reveals species-specific connectivity patterns for stream insects in fragmented habitats

authors: de Araujo Barbosa, Vanessa

subjects: aquatic insects

abstract: Dispersal is a critical process in ecology and evolution, shaping global biodiversity patterns. In stream habitats, which often exist within diverse and fragmented landscapes, dispersal ensures population connectivity and survival. For aquatic insects in particular, landscape features may significantly influence the degree of genetic connectivity among populations. Thus, understanding connectivity drivers in such populations is essential for the conservation and management of streams. We conducted a landscape genetic study using mitochondrial DNA (mtDNA) and genome-wide single nucleotide polymorphism (SNP) markers to assess the functional connectivity of stream insects in a fragmented pasture-dominated landscape. We focused on three species with terrestrial winged adults: the mayfly Coloburiscus humeralis, the stonefly Zelandobius confusus, and the caddisfly Hydropsyche fimbriata. We observed significant spatial genetic structure at larger geographical distances (populations separated by ~30 and 170 km). However, the effects of landscape factors, which were assessed at fine spatial scales, varied among species: for C. humeralis SNP data, genetic differentiation was weakly correlated with land cover, suggesting greater population connectivity within stream channels protected by forested riparian zones compared to fragmented streams; for Z. confusus, widespread gene flow indicated high dispersal potential across forested and pasture land; while overland dispersal was reduced for H. fimbriata (potentially due to local habitat features), this did not seem to hinder broader population connectivity. Our results emphasise the importance of assessing landscape features when evaluating population connectivity in stream riparian zones, which can greatly benefit stream management efforts through an enhanced understanding of connectivity dynamics.

text: A landscape genetics approach reveals species-specific connectivity patterns for stream insects in fragmented habitats Dispersal is a critical process in ecology and evolution, shaping global biodiversity patterns. In stream habitats, which often exist within diverse and fragmented landscapes, dispersal ensures population connectivity and survival. For aquatic insects in particular, landscape features may significantly influence the degree of genetic connectivity among populations. Thus, understanding connectivity drivers in such populations is essential for the conservation and management of streams. We conducted a landscape genetic study using mitochondrial DNA (mtDNA) and genome-wide single nucleotide polymorphism (SNP) markers to assess the functional connectivity of stream insects in a fragmented pasture-dominated landscape. We focused on three species with terrestrial winged adults: the mayfly Coloburiscus humeralis, the stonefly Zelandobius confusus, and the caddisfly Hydropsyche fimbriata. We observed significant spatial genetic structure at larger geographical distances (populations separated by ~30 and 170 km). However, the effects of landscape factors, which were assessed at fine spatial scales, varied among species: for C. humeralis SNP data, genetic differentiation was weakly correlated with land cover, suggesting greater population connectivity within stream channels protected by forested riparian zones compared to fragmented streams; for Z. confusus, widespread gene flow indicated high dispersal potential across forested and pasture land; while overland dispersal was reduced for H. fimbriata (potentially due to local habitat features), this did not seem to hinder broader population connectivity. Our results emphasise the importance of assessing landscape features when evaluating population connectivity in stream riparian zones, which can greatly benefit stream management efforts through an enhanced understanding of connectivity dynamics.

year: 2025

title: The Treaty of Waitangi and Asian Immigrants in Aotearoa: A Reflective Journey

authors: Omura, Saburo

subjects: Te Tiriti o Waitangi

abstract: The Treaty of Waitangi was signed in 1840 between the British Crown and Māori, the indigenous people of New Zealand being represented at the signing by chiefs from various tribes. The Treaty promised to ensure legitimate control on European settlers, while guaranteeing Māori their sovereignty, undisturbed possession of natural and cultural resources, and citizenship. However, these commitments were reneged upon and were largely discarded over the next century, including devastating confiscations of land and other natural resources, undignified treatment of Māori culture and language, and the loss of indigenous sovereignty following large-scale European migration to Aotearoa/New Zealand in the late 19th century. 
The New Zealand government maintained a ‘white’ New Zealand immigration policy until the late 1980s. An orientation towards white British in New Zealand was so deeply entrenched that the idea of monocultural assimilation remained the norm and went unchallenged until the 1960s. A reflection of this is in the fact that even today the Treaty of Waitangi is not formally recognised in the country’s immigration policies. 
Since the 1990s, there has been a major upsurge in the number of Asian migrants arriving in Aotearoa/New Zealand, so that today people of Chinese, Indian, and similar origin constitute about 11% of the national total population. 
However, settlement support programmes and academic research relating to them have focused on superficial coping and adaptation issues. Integration of these migrants has been frequently discussed but without specific cultural references. Māori culture and the Treaty have never been an integral part of the research scope in the study of acculturation of such migrants in Aotearoa/New Zealand. Government. Politicians, and academics have consequently isolated migrants from indigenous issues, because indigenous people were regarded as irrelevant in this field. 
Nevertheless, some ethnic community groups and individuals have taken initiatives to learn about the Treaty in recent times. I interviewed 17 key informants and conducted six focus groups, with seven people on average participating in each session. Employing a free-association approach in these interviews enabled me to explore significant psychological changes after my informants had learned about the Treaty. 
As a result, many of the participants went through a process of redefining their identity in a new country, rather than just adjusting to or coping with a different environment. Essentially, learning about the Treaty facilitated psychological integration after migrating to New Zealand. 
The future implications of such findings, especially the significant effect of repositioning Māori culture and history in cross-cultural research in New Zealand, is also discussed in this thesis.

text: The Treaty of Waitangi and Asian Immigrants in Aotearoa: A Reflective Journey The Treaty of Waitangi was signed in 1840 between the British Crown and Māori, the indigenous people of New Zealand being represented at the signing by chiefs from various tribes. The Treaty promised to ensure legitimate control on European settlers, while guaranteeing Māori their sovereignty, undisturbed possession of natural and cultural resources, and citizenship. However, these commitments were reneged upon and were largely discarded over the next century, including devastating confiscations of land and other natural resources, undignified treatment of Māori culture and language, and the loss of indigenous sovereignty following large-scale European migration to Aotearoa/New Zealand in the late 19th century. 
The New Zealand government maintained a ‘white’ New Zealand immigration policy until the late 1980s. An orientation towards white British in New Zealand was so deeply entrenched that the idea of monocultural assimilation remained the norm and went unchallenged until the 1960s. A reflection of this is in the fact that even today the Treaty of Waitangi is not formally recognised in the country’s immigration policies. 
Since the 1990s, there has been a major upsurge in the number of Asian migrants arriving in Aotearoa/New Zealand, so that today people of Chinese, Indian, and similar origin constitute about 11% of the national total population. 
However, settlement support programmes and academic research relating to them have focused on superficial coping and adaptation issues. Integration of these migrants has been frequently discussed but without specific cultural references. Māori culture and the Treaty have never been an integral part of the research scope in the study of acculturation of such migrants in Aotearoa/New Zealand. Government. Politicians, and academics have consequently isolated migrants from indigenous issues, because indigenous people were regarded as irrelevant in this field. 
Nevertheless, some ethnic community groups and individuals have taken initiatives to learn about the Treaty in recent times. I interviewed 17 key informants and conducted six focus groups, with seven people on average participating in each session. Employing a free-association approach in these interviews enabled me to explore significant psychological changes after my informants had learned about the Treaty. 
As a result, many of the participants went through a process of redefining their identity in a new country, rather than just adjusting to or coping with a different environment. Essentially, learning about the Treaty facilitated psychological integration after migrating to New Zealand. 
The future implications of such findings, especially the significant effect of repositioning Māori culture and history in cross-cultural research in New Zealand, is also discussed in this thesis.

year: 2014