title: Extracting the MESA SR4000 Calibrations

authors: Charleston, Sean A.

subjects: Science & Technology

abstract: Time-of-flight range imaging cameras are capable of acquiring depth images of a scene. Some algorithms require these cameras to be run in `raw mode', where any calibrations from the off-the-shelf manufacturers are lost. The calibration of the MESA SR4000 is herein investigated, with an attempt to reconstruct the full calibration. Possession of the factory calibration enables calibrated data to be acquired and manipulated even in “raw mode.” This work is motivated by the problem of motion correction, in which the calibration must be separated into component parts to be applied at different stages in the algorithm. There are also other applications, in which multiple frequencies are required, such as multipath interference correction. The other frequencies can be calibrated in a similar way, using the factory calibration as a base. A novel technique for capturing the calibration data is described; a retro-reflector is used on a moving platform, which acts as a point source at a distance, resulting in planar waves on the sensor. A number of calibrations are retrieved from the camera, and are then modelled and compared to the factory calibration. When comparing the factory calibration to both the “raw mode” data, and the calibration described herein, a root mean squared error improvement of 51:3mm was seen, with a standard deviation improvement of 34:9mm. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

text: Extracting the MESA SR4000 Calibrations Time-of-flight range imaging cameras are capable of acquiring depth images of a scene. Some algorithms require these cameras to be run in `raw mode', where any calibrations from the off-the-shelf manufacturers are lost. The calibration of the MESA SR4000 is herein investigated, with an attempt to reconstruct the full calibration. Possession of the factory calibration enables calibrated data to be acquired and manipulated even in “raw mode.” This work is motivated by the problem of motion correction, in which the calibration must be separated into component parts to be applied at different stages in the algorithm. There are also other applications, in which multiple frequencies are required, such as multipath interference correction. The other frequencies can be calibrated in a similar way, using the factory calibration as a base. A novel technique for capturing the calibration data is described; a retro-reflector is used on a moving platform, which acts as a point source at a distance, resulting in planar waves on the sensor. A number of calibrations are retrieved from the camera, and are then modelled and compared to the factory calibration. When comparing the factory calibration to both the “raw mode” data, and the calibration described herein, a root mean squared error improvement of 51:3mm was seen, with a standard deviation improvement of 34:9mm. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

year: 2015

title: Estimating the abundance of banded kokopu (galaxias fasciatus gray) in small streams by nocturnal counts under spotlight illumination

authors: Hicks, Brendan J.

subjects: biology

abstract: The abundance of banded kokopu (Galaxias fasciatus Gray) in small streams has usually been determined by the labour intensive and invasive method of electric fishing. Recently, nocturnal counts under spotlight illumination have been used to determine presence or absence and relative abundance of banded kokopu, but the proportion of the population seen was unknown. We compared 20 spotlight counts of banded kokopu in approximately 20 m reaches in streams in the North Island, New Zealand, to population estimates determined by removal electric
fishing in the same reaches. Spotlight counts were related to population estimates
over a range of densities, and on average, spotlight counts were 64% of the population estimates. Though we tried to separate age-0 fish from older fish visually in the spotlight counts, the size frequency distribution of the fish caught by electric fishing showed that the visual separation was not reliable. In addition, visual counts were generally inefficient for age-0 fish (40-70 mm total length), as only about 40% were observed. Banded kokopu were also recorded in streams using time-lapse video recordings with a camera sensitive to low light levels. Diel activity showed two major peaks, one in the early morning from 0400 h to 0900 h, and the other in the afternoon
and evening from 1300 h to 1900 h. Fish were less disturbed by the observer.s approach after dark than during the day, so we suggest that from dusk to about 2200 h is the best time for visual counts of banded kokopu by spotlight in summer months.

text: Estimating the abundance of banded kokopu (galaxias fasciatus gray) in small streams by nocturnal counts under spotlight illumination The abundance of banded kokopu (Galaxias fasciatus Gray) in small streams has usually been determined by the labour intensive and invasive method of electric fishing. Recently, nocturnal counts under spotlight illumination have been used to determine presence or absence and relative abundance of banded kokopu, but the proportion of the population seen was unknown. We compared 20 spotlight counts of banded kokopu in approximately 20 m reaches in streams in the North Island, New Zealand, to population estimates determined by removal electric
fishing in the same reaches. Spotlight counts were related to population estimates
over a range of densities, and on average, spotlight counts were 64% of the population estimates. Though we tried to separate age-0 fish from older fish visually in the spotlight counts, the size frequency distribution of the fish caught by electric fishing showed that the visual separation was not reliable. In addition, visual counts were generally inefficient for age-0 fish (40-70 mm total length), as only about 40% were observed. Banded kokopu were also recorded in streams using time-lapse video recordings with a camera sensitive to low light levels. Diel activity showed two major peaks, one in the early morning from 0400 h to 0900 h, and the other in the afternoon
and evening from 1300 h to 1900 h. Fish were less disturbed by the observer.s approach after dark than during the day, so we suggest that from dusk to about 2200 h is the best time for visual counts of banded kokopu by spotlight in summer months.

year: 2002

title: Te mana o ngā toa: Māori experiences of Ngāti Tūmatauenga, the New Zealand Army

authors: Kohere, Cheyenne Atairehia Mere

subjects: Kaupapa Māori

abstract: Diverse realities impact Māori people and their capacity to flourish. It is well- established that Māori are significant contributors to the New Zealand Defence Force (NZDF), and especially the New Zealand Army. Noteworthy participation in major conflicts, especially WWI and WWII create a whakapapa of military tradition which contributed to institutional change within the Army in the 1990s. The inclusion of Māori cultural training in the New Zealand Army can contribute to morale and the effectiveness of the organisation (Hohaia, 2016). This master’s thesis aims to deepen understandings of the experiences of Māori personnel in the Army by exploring the role of the New Zealand Army in the health and wellbeing of Māori soldiers, as well as how the Army can be a career pathway for Māori and their whānau to flourish.
This research employs the use qualitative methods such as Kaupapa Māori theory, phenomenology, and pūrākau as a form of narrative analysis. Semi-structured interviews with five participants (three retired personnel and two currently serving) explores these factors that contribute to the flourishing of Māori soldiers in the New Zealand Army. Each pūrākau developed from interview data is an acknowledgment of the personal journeys of the five participants and contains philosophical thought, epistemological constructs, cultural codes, and worldviews (Lee, 2009).
The findings of the research highlight the complexities that arise when considering the health and wellbeing of Māori soldiers. A range of interconnected factors conceptualised within five themes contributes to participants’ ability to flourish. These five themes include hauora (health), whanaungatanga (relationships), manaakitanga (support), whanonga pono (values) and whakapāwera (hardships). These results suggest that flourishing for Māori personnel is complex, and there is not a simple route to enable Māori to flourish. There are many ‘trade-offs’ for Māori and their experiences. However, Māori service provides opportunities and obstacles for an individual, as well as their whānau, hapū and iwi.

text: Te mana o ngā toa: Māori experiences of Ngāti Tūmatauenga, the New Zealand Army Diverse realities impact Māori people and their capacity to flourish. It is well- established that Māori are significant contributors to the New Zealand Defence Force (NZDF), and especially the New Zealand Army. Noteworthy participation in major conflicts, especially WWI and WWII create a whakapapa of military tradition which contributed to institutional change within the Army in the 1990s. The inclusion of Māori cultural training in the New Zealand Army can contribute to morale and the effectiveness of the organisation (Hohaia, 2016). This master’s thesis aims to deepen understandings of the experiences of Māori personnel in the Army by exploring the role of the New Zealand Army in the health and wellbeing of Māori soldiers, as well as how the Army can be a career pathway for Māori and their whānau to flourish.
This research employs the use qualitative methods such as Kaupapa Māori theory, phenomenology, and pūrākau as a form of narrative analysis. Semi-structured interviews with five participants (three retired personnel and two currently serving) explores these factors that contribute to the flourishing of Māori soldiers in the New Zealand Army. Each pūrākau developed from interview data is an acknowledgment of the personal journeys of the five participants and contains philosophical thought, epistemological constructs, cultural codes, and worldviews (Lee, 2009).
The findings of the research highlight the complexities that arise when considering the health and wellbeing of Māori soldiers. A range of interconnected factors conceptualised within five themes contributes to participants’ ability to flourish. These five themes include hauora (health), whanaungatanga (relationships), manaakitanga (support), whanonga pono (values) and whakapāwera (hardships). These results suggest that flourishing for Māori personnel is complex, and there is not a simple route to enable Māori to flourish. There are many ‘trade-offs’ for Māori and their experiences. However, Māori service provides opportunities and obstacles for an individual, as well as their whānau, hapū and iwi.

year: 2022