title: Multiple range imaging camera operation with minimal performance impact

authors: Whyte, Refael Z.

subjects: time of flight

abstract: Time-of-flight range imaging cameras operate by illuminating a scene with amplitude modulated light and measuring the phase shift of the modulation envelope between the emitted and reflected light. Object distance can then be calculated from this phase measurement. This approach does not work in multiple camera environments as the measured phase is corrupted by the illumination from other cameras. To minimize inaccuracies in multiple camera environments, replacing the traditional cyclic modulation with pseudo-noise amplitude modulation has been previously demonstrated. However, this technique effectively reduced the modulation frequency, therefore decreasing the distance measurement precision (which has a proportional relationship with the modulation frequency). A new modulation scheme using maximum length pseudo-random sequences binary phase encoded onto the existing cyclic amplitude modulation, is presented. The effective modulation frequency therefore remains unchanged, providing range measurements with high precision. The effectiveness of the new modulation scheme was verified using a custom time-of-flight camera based on the PMD19-K2 range imaging sensor. The new pseudo-noise modulation has no significant performance decrease in a single camera environment. In a two camera environment, the precision is only reduced by the increased photon shot noise from the second illumination source.

text: Multiple range imaging camera operation with minimal performance impact Time-of-flight range imaging cameras operate by illuminating a scene with amplitude modulated light and measuring the phase shift of the modulation envelope between the emitted and reflected light. Object distance can then be calculated from this phase measurement. This approach does not work in multiple camera environments as the measured phase is corrupted by the illumination from other cameras. To minimize inaccuracies in multiple camera environments, replacing the traditional cyclic modulation with pseudo-noise amplitude modulation has been previously demonstrated. However, this technique effectively reduced the modulation frequency, therefore decreasing the distance measurement precision (which has a proportional relationship with the modulation frequency). A new modulation scheme using maximum length pseudo-random sequences binary phase encoded onto the existing cyclic amplitude modulation, is presented. The effective modulation frequency therefore remains unchanged, providing range measurements with high precision. The effectiveness of the new modulation scheme was verified using a custom time-of-flight camera based on the PMD19-K2 range imaging sensor. The new pseudo-noise modulation has no significant performance decrease in a single camera environment. In a two camera environment, the precision is only reduced by the increased photon shot noise from the second illumination source.

year: 2010

title: Effect of an overhead goal on landing error scoring system and jump height measures

authors: Hébert-Losier, Kim

subjects: anterior cruciate ligament

abstract: Objectives: Compare overall Landing Error Scoring System (LESS) scores, risk categorisation, specific LESS errors, and double-leg jump-landing jump heights between overhead goal and no goal conditions. 

Design: Randomised cross-over. 

Setting: Laboratory. 

Participants: 76 (51% male). 

Main outcome measures: Participants landed from a 30-cm box to 50% of their body height and immediately jumped vertically for maximum height. Participants completed three trials under two random-ordered conditions: with and without overhead goal. Group-level mean LESS scores, risk categorisation (5-error threshold), specific landing errors, and jump heights were compared between conditions. 

Results: Mean LESS scores were greater (0.3 errors, p < 0.001) with the overhead goal, but this small difference was not clinically meaningful. Similarly, although the number of high-risk participants was greater with the overhead goal (p = 0.039), the 9.2% difference was trivial. Participants jumped 2.7 cm higher with the overhead goal (p < 0.001) without affecting the occurrence of any specific LESS errors. 

Discussion: Performing the LESS with an overhead goal enhances sport specificity and elicits greater vertical jump performances with minimal change in landing errors and injury-risk categorisation. Adding an overhead goal to LESS might enhance its suitability for injury risk screening, although the predictive value of LESS with an overhead goal needs confirmation.

text: Effect of an overhead goal on landing error scoring system and jump height measures Objectives: Compare overall Landing Error Scoring System (LESS) scores, risk categorisation, specific LESS errors, and double-leg jump-landing jump heights between overhead goal and no goal conditions. 

Design: Randomised cross-over. 

Setting: Laboratory. 

Participants: 76 (51% male). 

Main outcome measures: Participants landed from a 30-cm box to 50% of their body height and immediately jumped vertically for maximum height. Participants completed three trials under two random-ordered conditions: with and without overhead goal. Group-level mean LESS scores, risk categorisation (5-error threshold), specific landing errors, and jump heights were compared between conditions. 

Results: Mean LESS scores were greater (0.3 errors, p < 0.001) with the overhead goal, but this small difference was not clinically meaningful. Similarly, although the number of high-risk participants was greater with the overhead goal (p = 0.039), the 9.2% difference was trivial. Participants jumped 2.7 cm higher with the overhead goal (p < 0.001) without affecting the occurrence of any specific LESS errors. 

Discussion: Performing the LESS with an overhead goal enhances sport specificity and elicits greater vertical jump performances with minimal change in landing errors and injury-risk categorisation. Adding an overhead goal to LESS might enhance its suitability for injury risk screening, although the predictive value of LESS with an overhead goal needs confirmation.

year: 2023

title: Using inclusive research with participants with learning (intellectual) disability to better inform adult literacy policies in Aotearoa New Zealand

authors: Newcombe, Nicolina

abstract: Western ideas about disability and literacy were developed in tandem during the Industrial Revolution and subsequently brought to Aotearoa New Zealand via colonisation. These ideas inform and reinforce educator attitudes, which are the leading factor impeding adults with learning [intellectual] disability from their educational pathways of choice. People without learning disability need to hear the voices of people with learning disability to counteract these attitudes and move towards transformational equality.

There is a paucity of information about the access to and accessibility of adult literacy education for people with learning disability in Aotearoa New Zealand. However, anecdotal evidence reports their exclusion, even from foundational adult learning. There was a gap in knowledge where collaborative research that conveys the experiences of adults with learning disability was needed to gain greater insight to these issues in our bicultural context. My original contribution to knowledge is to present the voices of adults with learning disability as they discuss and demonstrate their literacy practices, and to use their perspectives to make recommendations for adult literacy policies in Aotearoa New Zealand.

I undertook a thematic analysis of current adult literacy policies in Aotearoa New Zealand and found that they target “most” adult learners, while positioning disabled people as needing specialised, and by inference optional to provide, education and resources. These policies also prescribe a linear and progressive andragogy that may not meet the needs of all adults with learning disability, while measuring literacy skills in a way that does not foreground their strengths or value their purposes for engagement.

Then, I conducted Inclusive Participatory Action Research with five adults with learning disability to gather information about their literacy practices and perspectives. Participants in this research decided to call themselves the Passioners. We met for 10 research meetings, preceded by at least two home visits, and interspersed by reflective meetings with individual participants. All research information was presented in easy read and key information was distributed audiovisually.

The Passioners added value to this research by providing unique opportunities that are only available through doing inclusive research with them, prompting research improvements, innovation, and my efforts towards acculturation in their worlds. I evaluated my inclusive approach in this research to learn more about how people with learning disability do research as people with learning disability, and what dispositions, resources, and skills people without learning disability need to do research with them.

Using reflexive thematic analysis, I constructed six themes from our research meetings data: learning disability cultural literacies, Māori (Indigenous peoples of Aotearoa New Zealand) cultural literacies, Pākehā (New Zealanders of European descent) cultural literacies, encoding, decoding, and social media, which extends the narrow definition of literacy in our adult literacy policies. These findings, and those from my policy analysis, were used to inform policy recommendations. Policy recommendations in this research may support implementation of the United Nations Convention on the Rights of Persons with Disabilities, particularly access to lifelong learning on an equal basis with others.

text: Using inclusive research with participants with learning (intellectual) disability to better inform adult literacy policies in Aotearoa New Zealand Western ideas about disability and literacy were developed in tandem during the Industrial Revolution and subsequently brought to Aotearoa New Zealand via colonisation. These ideas inform and reinforce educator attitudes, which are the leading factor impeding adults with learning [intellectual] disability from their educational pathways of choice. People without learning disability need to hear the voices of people with learning disability to counteract these attitudes and move towards transformational equality.

There is a paucity of information about the access to and accessibility of adult literacy education for people with learning disability in Aotearoa New Zealand. However, anecdotal evidence reports their exclusion, even from foundational adult learning. There was a gap in knowledge where collaborative research that conveys the experiences of adults with learning disability was needed to gain greater insight to these issues in our bicultural context. My original contribution to knowledge is to present the voices of adults with learning disability as they discuss and demonstrate their literacy practices, and to use their perspectives to make recommendations for adult literacy policies in Aotearoa New Zealand.

I undertook a thematic analysis of current adult literacy policies in Aotearoa New Zealand and found that they target “most” adult learners, while positioning disabled people as needing specialised, and by inference optional to provide, education and resources. These policies also prescribe a linear and progressive andragogy that may not meet the needs of all adults with learning disability, while measuring literacy skills in a way that does not foreground their strengths or value their purposes for engagement.

Then, I conducted Inclusive Participatory Action Research with five adults with learning disability to gather information about their literacy practices and perspectives. Participants in this research decided to call themselves the Passioners. We met for 10 research meetings, preceded by at least two home visits, and interspersed by reflective meetings with individual participants. All research information was presented in easy read and key information was distributed audiovisually.

The Passioners added value to this research by providing unique opportunities that are only available through doing inclusive research with them, prompting research improvements, innovation, and my efforts towards acculturation in their worlds. I evaluated my inclusive approach in this research to learn more about how people with learning disability do research as people with learning disability, and what dispositions, resources, and skills people without learning disability need to do research with them.

Using reflexive thematic analysis, I constructed six themes from our research meetings data: learning disability cultural literacies, Māori (Indigenous peoples of Aotearoa New Zealand) cultural literacies, Pākehā (New Zealanders of European descent) cultural literacies, encoding, decoding, and social media, which extends the narrow definition of literacy in our adult literacy policies. These findings, and those from my policy analysis, were used to inform policy recommendations. Policy recommendations in this research may support implementation of the United Nations Convention on the Rights of Persons with Disabilities, particularly access to lifelong learning on an equal basis with others.

year: 2024-09