title: Ground Plane Segmentation of Time-of-Flight Images for Asparagus Harvesting

authors: Peebles, Matthew Christopher Scott

subjects: Science & Technology

abstract: A key task in processing time-of-flight images for the detection of asparagus spears is the identification and segmentation of the ground plane. In this paper, we aim to compare the performance of RANSAC with a modified version of an existing deterministic method, namely Hyun’s method. Each method is tested on scenes with varying amounts of field clutter. Additionally, a variety of camera angles are investigated. We find that both RANSAC and the proposed method produce ground plane predictions with a root mean square error of less than 0.05m and execute at a rate of approximately 0.056s per frame. However, RANSAC was shown to be much less reliable in high clutter scenes. The camera mounting angle is found to significantly affect the density and noise of points in time-of-flight images. These factors translate to significantly worse performance for both methods at low camera angles.

text: Ground Plane Segmentation of Time-of-Flight Images for Asparagus Harvesting A key task in processing time-of-flight images for the detection of asparagus spears is the identification and segmentation of the ground plane. In this paper, we aim to compare the performance of RANSAC with a modified version of an existing deterministic method, namely Hyun’s method. Each method is tested on scenes with varying amounts of field clutter. Additionally, a variety of camera angles are investigated. We find that both RANSAC and the proposed method produce ground plane predictions with a root mean square error of less than 0.05m and execute at a rate of approximately 0.056s per frame. However, RANSAC was shown to be much less reliable in high clutter scenes. The camera mounting angle is found to significantly affect the density and noise of points in time-of-flight images. These factors translate to significantly worse performance for both methods at low camera angles.

year: 2018

title: No significant links between somatognosia, stereognosia, and hypermobility: sensory processing unlikely to drive common complaints in hypermobile population

authors: Hanzlíková, Ivana

subjects: Asymptomatic hypermobility

abstract: Background: Previous research has demonstrated impaired proprioception and poorer responses to tactile deep pressure, visual-tactile integration, and vestibular stimuli in individuals with generalized hypermobility, potentially leading to sensory processing issues. Therefore, we aimed to explore the influence of hypermobility on somatognosia and stereognosia. Methods: Forty-six participants were assessed using the Beighton score and categorized into three groups: non-hypermobile (n = 20), symptomatic hypermobile (n = 13), and asymptomatic hypermobile (n = 13). Somatognosia was evaluated using the shoulder width test in the vertical plane and pelvic width test in the vertical and horizontal planes. Stereognosia was assessed with Petrie’s test. Spearman’s rank correlation coefficient was examined the relationship between the Beighton score and measures of somatognosia and stereognosia. An unpaired t-test was used to compare variables between hypermobile (both symptomatic and asymptomatic) and non-hypermobile individuals, while a one-way ANOVA was used to compare data between the three groups. Results: No significant relationship was observed between Beighton scores and measures of somatognosia and stereognosia. The t-test revealed no statistically significant differences between hypermobile and non-hypermobile groups in the shoulder width, two pelvic widths, and Petrie’s tests (all p ≥ 0.105). Similarly, one-way ANOVA showed no statistically significant differences between the three groups across these tests (all p ≥ 0.177). Conclusions: The results indicate that somatognosia and stereognosia are not significantly related to the Beighton score and do not significantly differ between the groups studied. These sensory processing functions are unlikely to contribute to the common complaints reported by hypermobile individuals. Clinical trial number: Not applicable.

text: No significant links between somatognosia, stereognosia, and hypermobility: sensory processing unlikely to drive common complaints in hypermobile population Background: Previous research has demonstrated impaired proprioception and poorer responses to tactile deep pressure, visual-tactile integration, and vestibular stimuli in individuals with generalized hypermobility, potentially leading to sensory processing issues. Therefore, we aimed to explore the influence of hypermobility on somatognosia and stereognosia. Methods: Forty-six participants were assessed using the Beighton score and categorized into three groups: non-hypermobile (n = 20), symptomatic hypermobile (n = 13), and asymptomatic hypermobile (n = 13). Somatognosia was evaluated using the shoulder width test in the vertical plane and pelvic width test in the vertical and horizontal planes. Stereognosia was assessed with Petrie’s test. Spearman’s rank correlation coefficient was examined the relationship between the Beighton score and measures of somatognosia and stereognosia. An unpaired t-test was used to compare variables between hypermobile (both symptomatic and asymptomatic) and non-hypermobile individuals, while a one-way ANOVA was used to compare data between the three groups. Results: No significant relationship was observed between Beighton scores and measures of somatognosia and stereognosia. The t-test revealed no statistically significant differences between hypermobile and non-hypermobile groups in the shoulder width, two pelvic widths, and Petrie’s tests (all p ≥ 0.105). Similarly, one-way ANOVA showed no statistically significant differences between the three groups across these tests (all p ≥ 0.177). Conclusions: The results indicate that somatognosia and stereognosia are not significantly related to the Beighton score and do not significantly differ between the groups studied. These sensory processing functions are unlikely to contribute to the common complaints reported by hypermobile individuals. Clinical trial number: Not applicable.

year: 2025

title: A wiggle-match date for Polynesian settlement of New Zealand

authors: Hogg, Alan G.

subjects: East Polynesia

abstract: Dating initial colonisation and environmental impacts by Polynesians in New Zealand is controversial. A key horizon is provided by the Kaharoa Tephra, deposited from an eruption of Mt Tarawera, because just underneath this layer are the first signs of forest clearance which imply human settlement. The authors used a log of celery pine from within Kaharoa deposits to derive a new precise date for the eruption via "wiggle-matching" – matching the radiocarbon dates of a sequence of samples from the log with the Southern Hemisphere calibration curve. The date obtained was 1314 ± 12 AD (2σ error), and the first environmental impacts and human occupation are argued to have occurred in the previous 50 years, i.e. in the late 13th – early 14th centuries AD. This date is contemporary with earliest settlement dates determined from archaeological sites in the New Zealand archipelago.

text: A wiggle-match date for Polynesian settlement of New Zealand Dating initial colonisation and environmental impacts by Polynesians in New Zealand is controversial. A key horizon is provided by the Kaharoa Tephra, deposited from an eruption of Mt Tarawera, because just underneath this layer are the first signs of forest clearance which imply human settlement. The authors used a log of celery pine from within Kaharoa deposits to derive a new precise date for the eruption via "wiggle-matching" – matching the radiocarbon dates of a sequence of samples from the log with the Southern Hemisphere calibration curve. The date obtained was 1314 ± 12 AD (2σ error), and the first environmental impacts and human occupation are argued to have occurred in the previous 50 years, i.e. in the late 13th – early 14th centuries AD. This date is contemporary with earliest settlement dates determined from archaeological sites in the New Zealand archipelago.

year: 2002