title: Video-rate or high-precision: A flexible range imaging camera

authors: Dorrington, Adrian A.

subjects: range image

abstract: A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications.
Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system’s frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution. 
In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.

text: Video-rate or high-precision: A flexible range imaging camera A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications.
Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system’s frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution. 
In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.

year: 2008

title: Foraging on café sugar packets by the house sparrow (Passer domesticus): Learning mechanisms, distribution, and human perception

authors: Davy, Michael Ambrose

subjects: urban ecology

abstract: People in cities interact with house sparrows (Passer domesticus) on a daily basis. Sparrows have previously been observed foraging on sugar packets at a single café in Hamilton City, New Zealand. The aim of this thesis was to explore aspects of this novel foraging innovation by sparrows and to investigate people’s perceptions of sparrows being present at cafés. 

Sparrows’ preferences for different grain sizes of raw sugar and artificial sweetener were assessed at a single café, which demonstrated that sparrows have a strong preference for raw sugar over artificial sweetener, but no clear preference between granulated raw sugar and powdered raw sugar. Sparrows’ responses to novel sugar packet colours were also investigated at the same café. The sparrows did not start foraging on the novel-coloured sugar packets within 10 experimental sessions, but did interact with the novel sugar packets, which demonstrated neophilia in the sparrows and is an important step in the process of learning.

The distribution of sugar packet foraging by sparrows across 174 cafés in Hamilton City was determined, and staff from 15 cafés had observed sparrows taking sugar packets. A short survey was also used to assess the attitudes of café staff members towards the presence of sparrows at their cafés, which showed that café staff had mixed views on the local sparrows. A different survey was used to investigate the attitudes of 249 members of the general public towards sparrows being at cafés. These participants tended to like sparrows being present as part of their café experience. 

This thesis demonstrates the value of sparrows being present in the urban environment, and is the first study to comprehensively describe sugar packet foraging in sparrows: a fascinating behavioural innovation.

text: Foraging on café sugar packets by the house sparrow (Passer domesticus): Learning mechanisms, distribution, and human perception People in cities interact with house sparrows (Passer domesticus) on a daily basis. Sparrows have previously been observed foraging on sugar packets at a single café in Hamilton City, New Zealand. The aim of this thesis was to explore aspects of this novel foraging innovation by sparrows and to investigate people’s perceptions of sparrows being present at cafés. 

Sparrows’ preferences for different grain sizes of raw sugar and artificial sweetener were assessed at a single café, which demonstrated that sparrows have a strong preference for raw sugar over artificial sweetener, but no clear preference between granulated raw sugar and powdered raw sugar. Sparrows’ responses to novel sugar packet colours were also investigated at the same café. The sparrows did not start foraging on the novel-coloured sugar packets within 10 experimental sessions, but did interact with the novel sugar packets, which demonstrated neophilia in the sparrows and is an important step in the process of learning.

The distribution of sugar packet foraging by sparrows across 174 cafés in Hamilton City was determined, and staff from 15 cafés had observed sparrows taking sugar packets. A short survey was also used to assess the attitudes of café staff members towards the presence of sparrows at their cafés, which showed that café staff had mixed views on the local sparrows. A different survey was used to investigate the attitudes of 249 members of the general public towards sparrows being at cafés. These participants tended to like sparrows being present as part of their café experience. 

This thesis demonstrates the value of sparrows being present in the urban environment, and is the first study to comprehensively describe sugar packet foraging in sparrows: a fascinating behavioural innovation.

year: 2019

title: Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan Canada: A comparative study

authors: Green, Jane Alison

subjects: Indigenous

abstract: For more than two decades, components of Māori knowledges in the form of Māori words and concepts have been part of health policy in Aotearoa New Zealand. Health policy that engages Māori words and concepts resonates with Māori community values and aspirations and is thought to contribute to the revitalisation of Māori knowledges. Absent from the literature is an examination of this phenomenon; specifically, the socio-political factors that facilitate and limit the engagement of Māori knowledges with health policy. Of the four settler states, only in Aotearoa New Zealand are the knowledges of the Indigenous peoples engaged with health policy. In Saskatchewan, Canada, the First Nations and Métis peoples have engaged their knowledges with federal and provincially funded health programmes and services but not health policy. This study adopts a two-country comparative policy framework to investigate and theorise the historical and contemporary socio-political factors associated with the engagement of Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan, Canada. An adaption is made to the Kaupapa Māori approach so that the complexities of a two-country case study approach are addressed and engagement in health policy as a strategy for knowledge revitalisation is theorised. The study also takes a path less travelled which is to investigate the impact that engagement with health policy has upon the intangible or the ontological aspects of Māori knowledges. Māori describe their knowledges as comprised of tangible and intangible elements, both of which are important. Another adaption is made to the Kaupapa Māori theoretical approach which is to add speculative inquiry. The study argues that speculative inquiry in the form of contemplative, analytical, relational and viscerally aware practices are commonplace in Māori communities. Adding speculative inquiry to an already rich theoretical body that is Kaupapa Māori research provides an opening for other Kaupapa Māori researchers to expand non-empirical inquiry. The study concludes that government policies have had a decimating effect upon Māori, First Nations and Métis knowledges. Moreover, recent reports from commissions and inquiries indicate these knowledges and associated languages continue to decline for a number of reasons, including the impact of contemporary government policies. Health policy, this study asserts, is an uncertain site from which to revitalise Māori, First Nations and Métis knowledges.

text: Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan Canada: A comparative study For more than two decades, components of Māori knowledges in the form of Māori words and concepts have been part of health policy in Aotearoa New Zealand. Health policy that engages Māori words and concepts resonates with Māori community values and aspirations and is thought to contribute to the revitalisation of Māori knowledges. Absent from the literature is an examination of this phenomenon; specifically, the socio-political factors that facilitate and limit the engagement of Māori knowledges with health policy. Of the four settler states, only in Aotearoa New Zealand are the knowledges of the Indigenous peoples engaged with health policy. In Saskatchewan, Canada, the First Nations and Métis peoples have engaged their knowledges with federal and provincially funded health programmes and services but not health policy. This study adopts a two-country comparative policy framework to investigate and theorise the historical and contemporary socio-political factors associated with the engagement of Indigenous knowledges in health policy in Aotearoa New Zealand and Saskatchewan, Canada. An adaption is made to the Kaupapa Māori approach so that the complexities of a two-country case study approach are addressed and engagement in health policy as a strategy for knowledge revitalisation is theorised. The study also takes a path less travelled which is to investigate the impact that engagement with health policy has upon the intangible or the ontological aspects of Māori knowledges. Māori describe their knowledges as comprised of tangible and intangible elements, both of which are important. Another adaption is made to the Kaupapa Māori theoretical approach which is to add speculative inquiry. The study argues that speculative inquiry in the form of contemplative, analytical, relational and viscerally aware practices are commonplace in Māori communities. Adding speculative inquiry to an already rich theoretical body that is Kaupapa Māori research provides an opening for other Kaupapa Māori researchers to expand non-empirical inquiry. The study concludes that government policies have had a decimating effect upon Māori, First Nations and Métis knowledges. Moreover, recent reports from commissions and inquiries indicate these knowledges and associated languages continue to decline for a number of reasons, including the impact of contemporary government policies. Health policy, this study asserts, is an uncertain site from which to revitalise Māori, First Nations and Métis knowledges.

year: 2018