Camera movement artefact correction

While simulator based maritime training is widely implemented under international maritime organization (IMO) convention and model courses, troublesome issues such as objective evaluation of training effectiveness remain unsolved. Physiological computing system (PhyCS) refers to an innovative bidirectional human computer interaction which is achieved by monitoring, analysing, and responding to operators’ psychophysiological activities in real-time. With the development of wearable devices, it becomes promising to apply PhyCS, which was considered as a laboratory technology, in real-world scenarios. In our experience utilizing view tracker, portable heart beat sensor, electroencephalogram device, and web-cameras in simulator based maritime training, PhyCS shows potential for advanced applications in operator performance assessment, usability tests, and adaptive training. However, ambulatory working environment, body movement artefact, and model verification are intricate obstacles that constrain its applications in the real world. By examining the advantages and obstacles, this paper aims to develop guidelines to apply PhyCS in the real-world.

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Effect of micro-computed tomography reconstruction protocols on bone fractal dimension analysis

Dentomaxillofacial Radiology ◽

10.1259/dmfr.20190235 ◽

2019 ◽

Vol 48 (8) ◽

pp. 20190235

Author(s):

Hugo Gaêta-Araujo ◽

Nicolly Oliveira-Santos ◽

Danieli Moura Brasil ◽

Eduarda Helena Leandro do Nascimento ◽

Daniela Verardi Madlum ◽

...

Keyword(s):

Fractal Dimension ◽

Trabecular Bone ◽

Micro Ct ◽

Ct Reconstruction ◽

Micro Computed Tomography ◽

Beam Hardening ◽

Scan Time ◽

Beam Hardening Correction ◽

Box Counting Method ◽

Artefact Correction

Objectives: To evaluate the influence of the level of three micro-CT reconstruction tools: beam-hardening correction (BHC), smoothing filter (SF), and ring artefact correction (RAC) on the fractal dimension (FD) analysis of trabecular bone. Methods: Five Wistar rats’ maxillae were individually scanned in a SkyScan 1174 micro-CT device, under the following settings: 50 kV, 800 µA, 10.2 µm voxel size, 0.5 mm Al filter, rotation step 0.5°, two frames average, 180° rotation and scan time of 35 min. The raw images were reconstructed under the standard protocol (SP) recommended by the manufacturer, a protocol without any artefact correction tools (P0) and 35 additional protocols with different combinations of SF, RAC and BHC levels. The same volume of interest was established in all reconstructions for each maxilla and the FD was calculated using the Kolmogorov (box counting) method. One-way ANOVA with Dunnet’s post-hoc test was used to compare the FD of each reconstruction protocol (P0–P35) with the SP (α = 5%). Multiple linear regression verified the dependency of reconstruction tools in FD. Results: Overall, FD values are not dependent on RAC (p = 0.965), but increased significantly when the level of BHC and SF increased (p < 0.001). FD values from protocols with BHC at 45% combined with SF of 2, and BHC at 30% combined with SF of 4 or 6 had no statistical difference compared to SP. Conclusions: BHC and SF tools affect the FD values of micro-CT images of the trabecular bone. Therefore, these reconstruction parameters should be standardized when the FD is analyzed.

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The clinical potential of ultra-high-speed echo-planar imaging

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1990.0178 ◽

1990 ◽

Vol 333 (1632) ◽

pp. 507-514 ◽

Cited By ~ 7

Keyword(s):

Real Time ◽

High Speed ◽

Echo Planar Imaging ◽

Lesion Detection ◽

Whole Body ◽

Planar Imaging ◽

Cardiac Events ◽

Ultra High Speed ◽

Movement Artefact ◽

Echo Planar

Ultra-high-speed echo-planar imaging (EP1) allows acquisition of a complete twodimensional image in 64 to 128 ms devoid of movement artefact and without sacrifice of contrast due to relaxation time effects. In conventional whole-body MRI, however, obtrusive movement artefact and extended imaging time, resulting from the need to apply multiple sequences to facilitate lesion detection and pathological characterization, remain limitations. Reduced total examination time increases patient tolerance and throughput • furthermore optimization of contrast to achieve maximal conspicuity of particular features in liver or brain pathology is achieved simply and interactively by real time adjustment of the imaging parameters. The method provides the opportunity to study in real time dynamic events such as flow phenomena in the vascular and cerebrospinal fluid compartments of the brain as well as the kinetics of administered contrast agents, EPI is the only means of capturing the irregular motion of aperiodic cardiac events and bowel peristalsis.

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