title: Visual Perception of a Motion Aftereffect in Domestic Chickens (Gallus gallus): A Behavioural Analytic Approach

authors: Wan, Jennifer

subjects: motion aftereffect

abstract: The motion aftereffect (MAE) is an illusory motion in the opposite direction after the sudden halt of a prolonged moving visual stimulus. The human experience of the motion aftereffect has been extensively researched utilising many different experimental approaches. The ability of the avian species to perceive this motion illusion has not been so well researched and such a phenomenon has never been investigated in domestic chickens. The aim of the experiment reported in this thesis was to test whether domestic chickens can perceive a motion aftereffect. Xiao and Gunturkun (2008) carried out a study to investigate whether pigeons could perceive the motion aftereffect. After initially failing to obtain evidence for the effect they modified their procedure and found results that were better but still not strongly suggestive of a robust motion aftereffect. Their methodology was further refined for this thesis to see if evidence for the motion aftereffect could be found in chickens. The chickens received initial discrimination training to differentiate between static, upward and downward moving grating patterns. Once they reached the criterion for this task reliably, each subject underwent test trials where they were exposed to a static pattern after prolonged presentation of a moving grating stimulus. Results from the choice behaviour of the chickens indicated they did not experience a motion aftereffect. This thesis and the previous study would suggest there is not a reliable motion aftereffect for birds. Whether this reflects limitations of the research design or the nature of the avian visual system is still to be determined.

text: Visual Perception of a Motion Aftereffect in Domestic Chickens (Gallus gallus): A Behavioural Analytic Approach The motion aftereffect (MAE) is an illusory motion in the opposite direction after the sudden halt of a prolonged moving visual stimulus. The human experience of the motion aftereffect has been extensively researched utilising many different experimental approaches. The ability of the avian species to perceive this motion illusion has not been so well researched and such a phenomenon has never been investigated in domestic chickens. The aim of the experiment reported in this thesis was to test whether domestic chickens can perceive a motion aftereffect. Xiao and Gunturkun (2008) carried out a study to investigate whether pigeons could perceive the motion aftereffect. After initially failing to obtain evidence for the effect they modified their procedure and found results that were better but still not strongly suggestive of a robust motion aftereffect. Their methodology was further refined for this thesis to see if evidence for the motion aftereffect could be found in chickens. The chickens received initial discrimination training to differentiate between static, upward and downward moving grating patterns. Once they reached the criterion for this task reliably, each subject underwent test trials where they were exposed to a static pattern after prolonged presentation of a moving grating stimulus. Results from the choice behaviour of the chickens indicated they did not experience a motion aftereffect. This thesis and the previous study would suggest there is not a reliable motion aftereffect for birds. Whether this reflects limitations of the research design or the nature of the avian visual system is still to be determined.

year: 2016

title: Identification and manipulation of lily bulbs for an automated lily bulb planting system

authors: Venter, Gerhard Meyer

subjects: Agriculture Automation

abstract: Automation in agriculture is growing year by year. The goal of automating processes is to provide inexpensive and more effective solutions for everyday problems present in the industry. Automation in agriculture adds value to the product and in turn, to the farmer's infrastructure. This automation also aims to provide higher skill labour for workers that the automation processes substitute.  Using machine vision as a means of automating processes is very common in factory environments and is being adapted for the external agriculture environments (i.e. automated detection for produce harvesting).

Machine vision and manipulation techniques for a lily bulb plantation were presented. The techniques were investigated to determine the feasibility of using an autonomous, machine vision based approach to manipulate and plant lily bulbs from a provided source, to pre-augered holes produced by a pre-defined autonomous platform.

The machine vision approach involved taking a top down image of the bulbs and identifying the head positions and what orientation they were facing relative to their root structures. This was achieved using various standard machine vision techniques like segmenting using global thresholding and identification of heads using the Hough circular transform. The investigated manipulation method involved applying the above mentioned vision system to a standard ABB IRB-120 universal manipulator with a three bellow suction gripper to pick up the detected bulbs and manipulate the bulbs in the orientation perceived by the vision system.

It was found that the machine vision algorithm provided a 75 per cent success rate when providing an optimal region of interest within the bulbs head. The success rate is a considerably successful result as the detection algorithm not only needed to detect the location of the bulbs, but the centroid of its head and also determine the approximate orientation relative to each samples individual root structure. The manipulation results showed that the engagement of the suction gripper was a significant component of failure during testing. The observed success rate was at 41 per cent. This high failure rate means that further improvements should be made before a successful end effector and manipulation pair would be achieved. Improving suction rate or developing a specialized gripper for the specific amorphous bulbs would have to be investigated further before there is confirmation of a satisfactory solution for the Automated Lily Planter. Further work could be done to improve the algorithm and fine-tune the output provided. Improvements could be made to optimise the detection algorithm like improved lighting and better contrast between the bulbs colour gradient and that of the platform's background. Further development on the manipulators approach should also be conducted for validation.

text: Identification and manipulation of lily bulbs for an automated lily bulb planting system Automation in agriculture is growing year by year. The goal of automating processes is to provide inexpensive and more effective solutions for everyday problems present in the industry. Automation in agriculture adds value to the product and in turn, to the farmer's infrastructure. This automation also aims to provide higher skill labour for workers that the automation processes substitute.  Using machine vision as a means of automating processes is very common in factory environments and is being adapted for the external agriculture environments (i.e. automated detection for produce harvesting).

Machine vision and manipulation techniques for a lily bulb plantation were presented. The techniques were investigated to determine the feasibility of using an autonomous, machine vision based approach to manipulate and plant lily bulbs from a provided source, to pre-augered holes produced by a pre-defined autonomous platform.

The machine vision approach involved taking a top down image of the bulbs and identifying the head positions and what orientation they were facing relative to their root structures. This was achieved using various standard machine vision techniques like segmenting using global thresholding and identification of heads using the Hough circular transform. The investigated manipulation method involved applying the above mentioned vision system to a standard ABB IRB-120 universal manipulator with a three bellow suction gripper to pick up the detected bulbs and manipulate the bulbs in the orientation perceived by the vision system.

It was found that the machine vision algorithm provided a 75 per cent success rate when providing an optimal region of interest within the bulbs head. The success rate is a considerably successful result as the detection algorithm not only needed to detect the location of the bulbs, but the centroid of its head and also determine the approximate orientation relative to each samples individual root structure. The manipulation results showed that the engagement of the suction gripper was a significant component of failure during testing. The observed success rate was at 41 per cent. This high failure rate means that further improvements should be made before a successful end effector and manipulation pair would be achieved. Improving suction rate or developing a specialized gripper for the specific amorphous bulbs would have to be investigated further before there is confirmation of a satisfactory solution for the Automated Lily Planter. Further work could be done to improve the algorithm and fine-tune the output provided. Improvements could be made to optimise the detection algorithm like improved lighting and better contrast between the bulbs colour gradient and that of the platform's background. Further development on the manipulators approach should also be conducted for validation.

year: 2019

title: Reflections on the renewal of music: a polemic

authors: Lodge, Martin

abstract: Pluralism has been accepted as the best broad working definition of the current cultural and artistic situation in the West for some time now. In New Zealand, the debate over 'biculturalism' versus 'multiculturalism' drones on. Commercially this is reflected in both 'market segmentation' and its opposite-attempts at 'cross-over'. Artistically, it has made 'bicultural' works fashionable, as creative
attempts are made to fuse various traditions together, especially the Maori and Western, and nowhere more so than in music. The key to making successful 'fusion' pieces seems to lie in first grasping the essential differences between the musics, then trying to resolve the clashes or accommodate friendly juxtapositions.

text: Reflections on the renewal of music: a polemic Pluralism has been accepted as the best broad working definition of the current cultural and artistic situation in the West for some time now. In New Zealand, the debate over 'biculturalism' versus 'multiculturalism' drones on. Commercially this is reflected in both 'market segmentation' and its opposite-attempts at 'cross-over'. Artistically, it has made 'bicultural' works fashionable, as creative
attempts are made to fuse various traditions together, especially the Maori and Western, and nowhere more so than in music. The key to making successful 'fusion' pieces seems to lie in first grasping the essential differences between the musics, then trying to resolve the clashes or accommodate friendly juxtapositions.

year: 1998