title: Resolving depth measurement ambiguity with commercially available range imaging cameras

authors: McClure, Shane H.

subjects: range imaging

abstract: Time-of-flight range imaging is typically performed with the amplitude modulated continuous wave method. This involves illuminating a scene with amplitude modulated light. Reflected light from the scene is received by the sensor with the range to the scene encoded as a phase delay of the modulation envelope. Due to the cyclic nature of phase, an ambiguity in the measured range occurs every half wavelength in distance, thereby limiting the maximum useable range of the camera.
This paper proposes a procedure to resolve depth ambiguity using software post processing. First, the range data is processed to segment the scene into separate objects. The average intensity of each object can then be used to determine which pixels are beyond the non-ambiguous range. The results demonstrate that depth ambiguity can be resolved for various scenes using only the available depth and intensity information. This proposed method reduces the sensitivity to objects with very high and very low reflectance, normally a key problem with basic threshold approaches.
This approach is very flexible as it can be used with any range imaging camera. Furthermore, capture time is not extended, keeping the artifacts caused by moving objects at a minimum. This makes it suitable for applications such as robot vision where the camera may be moving during captures.
The key limitation of the method is its inability to distinguish between two overlapping objects that are separated by a distance of exactly one non-ambiguous range. Overall the reliability of this method is higher than the basic threshold approach, but not as high as the multiple frequency method of resolving ambiguity.

text: Resolving depth measurement ambiguity with commercially available range imaging cameras Time-of-flight range imaging is typically performed with the amplitude modulated continuous wave method. This involves illuminating a scene with amplitude modulated light. Reflected light from the scene is received by the sensor with the range to the scene encoded as a phase delay of the modulation envelope. Due to the cyclic nature of phase, an ambiguity in the measured range occurs every half wavelength in distance, thereby limiting the maximum useable range of the camera.
This paper proposes a procedure to resolve depth ambiguity using software post processing. First, the range data is processed to segment the scene into separate objects. The average intensity of each object can then be used to determine which pixels are beyond the non-ambiguous range. The results demonstrate that depth ambiguity can be resolved for various scenes using only the available depth and intensity information. This proposed method reduces the sensitivity to objects with very high and very low reflectance, normally a key problem with basic threshold approaches.
This approach is very flexible as it can be used with any range imaging camera. Furthermore, capture time is not extended, keeping the artifacts caused by moving objects at a minimum. This makes it suitable for applications such as robot vision where the camera may be moving during captures.
The key limitation of the method is its inability to distinguish between two overlapping objects that are separated by a distance of exactly one non-ambiguous range. Overall the reliability of this method is higher than the basic threshold approach, but not as high as the multiple frequency method of resolving ambiguity.

year: 2010

title: EPM effects on workplace well-being: The role of personality

authors: Robinson, Christopher

abstract: Within the workplace, electronic performance monitoring (EPM) is an electronically integrated system used to assess employee behaviours and ultimately performance. Previous research indicates EPM is associated with various negative psychosocial effects due to job roles being inherently changed with the use of these systems. However, research has yet to explore whether an individual's characteristics can also be attributable for influencing these outcomes. Therefore, the aim of this research was to investigate whether personality factors could moderate or mediate the negative effects of electronic performance monitoring.

Using a quantitative survey methodology this project acquired 112 participants to assess the relationship between the amount of EPM they were exposed to and the levels of trust in senior management, affective commitment and self-perceived stress. The participants also completed the Conscientiousness and Emotional Stability scales from the Five Factor of Personality and a shortened version of Rotter’s Locus of Control. Regressional, Moderation, mediation and MANCOVA analysis were conducted to assess whether the personality factors held moderating or mediating attributes.

The findings indicated that greater amounts of EPM did not predict lower levels of trust, commitment or an increase in stress. Furthermore, the Conscientiousness personality factor held no bearing on the negative effects of EPM, whereas Emotional Stability moderated the effects of trust and modestly meditated commitment and stress. The Locus of Control was also found to have influenced employees’ levels of trust.

The current findings suggest the use of electronic performance monitoring does not radically change the job design to a degree where employees experience a decline in well being at work. However, whether the organisation's intention to use EPM is for supportive or punitive purposes is likely to have been a pivotal factor in how the systems are perceived. This highlights the need for policies and clear communication detailing why the information will be collected and how it will be used. In addition, some personality factors were found to modest factors contributing negative effects of EPM. In practice, this finding suggests occupations requiring intensive monitoring may be more appropriate for those with greater levels of emotional stability and who possess an internal Locus of Control.

text: EPM effects on workplace well-being: The role of personality Within the workplace, electronic performance monitoring (EPM) is an electronically integrated system used to assess employee behaviours and ultimately performance. Previous research indicates EPM is associated with various negative psychosocial effects due to job roles being inherently changed with the use of these systems. However, research has yet to explore whether an individual's characteristics can also be attributable for influencing these outcomes. Therefore, the aim of this research was to investigate whether personality factors could moderate or mediate the negative effects of electronic performance monitoring.

Using a quantitative survey methodology this project acquired 112 participants to assess the relationship between the amount of EPM they were exposed to and the levels of trust in senior management, affective commitment and self-perceived stress. The participants also completed the Conscientiousness and Emotional Stability scales from the Five Factor of Personality and a shortened version of Rotter’s Locus of Control. Regressional, Moderation, mediation and MANCOVA analysis were conducted to assess whether the personality factors held moderating or mediating attributes.

The findings indicated that greater amounts of EPM did not predict lower levels of trust, commitment or an increase in stress. Furthermore, the Conscientiousness personality factor held no bearing on the negative effects of EPM, whereas Emotional Stability moderated the effects of trust and modestly meditated commitment and stress. The Locus of Control was also found to have influenced employees’ levels of trust.

The current findings suggest the use of electronic performance monitoring does not radically change the job design to a degree where employees experience a decline in well being at work. However, whether the organisation's intention to use EPM is for supportive or punitive purposes is likely to have been a pivotal factor in how the systems are perceived. This highlights the need for policies and clear communication detailing why the information will be collected and how it will be used. In addition, some personality factors were found to modest factors contributing negative effects of EPM. In practice, this finding suggests occupations requiring intensive monitoring may be more appropriate for those with greater levels of emotional stability and who possess an internal Locus of Control.

year: 2020

title: Culture is our business: Issues and challenges for forensic and correctional psychologists

authors: Tamatea, Armon J.

subjects: Science & Technology

abstract: Psychology has made significant advances in the development of more empirical, standardized, and consistent approaches to the prediction, assessment, and treatment of offending behaviour. However, crime occurs in a cultural context. Similarly, forensic and correctional psychology derive from a cultural basis that privileges certain types of knowledge and promotes certain forms of practice that are incommensurate with the outlook and realities of some offenders and their communities. While there is an emerging literature on ethnicity and race in criminal justice psychology, very little research that addresses culture is published. The reasons for this knowledge gap are complex, not least because the worldviews of indigenous and diverse communities do not superimpose neatly onto current best-practice models of risk assessment or offender rehabilitation. Given Australia and New Zealand’s commitment to the involvement and wellbeing of indigenous peoples as well as the shared experience of progressively more pluralistic societies, it is argued that there is a critical need to bring the somewhat disparate domains of forensic psychology and culture into conversation with a view to informing policy and practice. The example of risk assessment is used to illustrate some of the complexities of working with cultural difference. Central to this article is a call for a culturally-engaged and proactive philosophy of practice that embraces the needs of diverse offenders, victims and communities.

text: Culture is our business: Issues and challenges for forensic and correctional psychologists Psychology has made significant advances in the development of more empirical, standardized, and consistent approaches to the prediction, assessment, and treatment of offending behaviour. However, crime occurs in a cultural context. Similarly, forensic and correctional psychology derive from a cultural basis that privileges certain types of knowledge and promotes certain forms of practice that are incommensurate with the outlook and realities of some offenders and their communities. While there is an emerging literature on ethnicity and race in criminal justice psychology, very little research that addresses culture is published. The reasons for this knowledge gap are complex, not least because the worldviews of indigenous and diverse communities do not superimpose neatly onto current best-practice models of risk assessment or offender rehabilitation. Given Australia and New Zealand’s commitment to the involvement and wellbeing of indigenous peoples as well as the shared experience of progressively more pluralistic societies, it is argued that there is a critical need to bring the somewhat disparate domains of forensic psychology and culture into conversation with a view to informing policy and practice. The example of risk assessment is used to illustrate some of the complexities of working with cultural difference. Central to this article is a call for a culturally-engaged and proactive philosophy of practice that embraces the needs of diverse offenders, victims and communities.

year: 2017