Analytical formula for two-dimensional ring artefact suppression

Titarenko, Valeriy

doi:10.1107/s160057751601479x

Cited by 15 publications

(11 citation statements)

References 33 publications

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“…1B,C). Projection images were flat-and dark-field corrected prior to reconstruction into 3D volumes using a filtered back projection algorithm (Basham et al 2015, Titarenko 2016. Figure 1: Tomographic images of bee heads and eyes.…”

Section: X-ray Microtomographymentioning

confidence: 99%

Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity

Taylor

Tichit

Schmidt

et al. 2018

Preprint

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The quality of visual information that is available to an animal is limited by the size of its eyes. Differences in eye size can be observed even between closely related individuals but we understand little about how this affects visual quality. Insects are good models for exploring the effects of size on visual systems because many species exhibit size polymorphism, which modifies both the size and shape of their eyes. Previous work in this area has been limited, however, due to the challenge of determining the 3D structure of eyes. To address this, we have developed a novel method based on x-ray tomography to measure the 3D structure of insect eyes and calculate their visual capabilities. We investigated visual allometry in the bumblebee Bombus terrestris and found that size affects specific aspects of visual quality including binocular overlap, optical sensitivity across the field of view, and visual resolution in the dorsofrontal visual field. This holistic study on eye allometry reveals that differential scaling between different eye areas provides substantial flexibility for larger bumblebees to have improved visual capabilities. List of abbreviations:az. -Azimuth CC -Crystalline cone el. -Elevation EV -Eye volume FOV -Field of view ITW -Inter-tegula width IO -Inter-ommatidial microCT -micro-computed tomography NV -Normal vector

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Section: X-ray Microtomographymentioning

confidence: 99%

Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity

Taylor

Tichit

Schmidt

et al. 2018

Preprint

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“…All images were first corrected for zingers - bright pixels resulting from the interaction of stray X-rays and cosmic rays with the sCMOS sensor 37 . Sample projections were then subject to flat- and dark-field correction, followed by a separate correction for radial distortion 61 , and another to suppress ring artefacts 32 . For the latter, distortion coefficients were calculated from visible light images of a Thorlabs Multi-Frequency Grid Distortion Target (Thorlabs Inc., USA).…”

Section: Methodsmentioning

confidence: 99%

“…A final aspect of enhancing image quality and data accuracy, is signal processing to correct for image acquisition artefacts. This includes zinger artefact reduction, dark- and flat-field correction, lens radial distortion correction 31 and ring artefact suppression 32 . We demonstrate the use of such filtering following an evaluation of multiple sample mounting methods and sample contrast enhancing techniques.…”

Section: Introductionmentioning

confidence: 99%

Optimising complementary soft tissue synchrotron X-ray microtomography for reversibly-stained central nervous system samples

Strotton

Bodey

Wanelik

et al. 2018

Sci Rep

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Synchrotron radiation microtomography (SRμCT) is a nominally non-destructive 3D imaging technique which can visualise the internal structures of whole soft tissues. As a multi-stage technique, the cumulative benefits of optimising sample preparation, scanning parameters and signal processing can improve SRμCT imaging efficiency, image quality, accuracy and ultimately, data utility. By evaluating different sample preparations (embedding media, tissue stains), imaging (projection number, propagation distance) and reconstruction (artefact correction, phase retrieval) parameters, a novel methodology (combining reversible iodine stain, wax embedding and inline phase contrast) was optimised for fast (~12 minutes), high-resolution (3.2–4.8 μm diameter capillaries resolved) imaging of the full diameter of a 3.5 mm length of rat spinal cord. White-grey matter macro-features and micro-features such as motoneurons and capillary-level vasculature could then be completely segmented from the imaged volume for analysis through the shallow machine learning SuRVoS Workbench. Imaged spinal cord tissue was preserved for subsequent histology, establishing a complementary SRμCT methodology that can be applied to study spinal cord pathologies or other nervous system tissues such as ganglia, nerves and brain. Further, our ‘single-scan iterative downsampling’ approach and side-by-side comparisons of mounting options, sample stains and phase contrast parameters should inform efficient, effective future soft tissue SRμCT experiment design.

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“…These scans were conducted with a 1.25× objective providing 2.5× total magnification (2.6 μm voxel size). The radiographic projections acquired from the synchrotron scans were reconstructed, using a filtered back projection algorithm, into 3D volumes using DAWN v1.7 (Basham et al 2015;Titarenko, 2016).…”

Section: X-ray Micro Computed-tomographymentioning

confidence: 99%

Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli

Wilby

Aarts

Tichit

et al. 2018

Preprint

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Many insects have triplets of camera type eyes, called ocelli, whose function remains unclear for most species. Here, we investigate the ocelli of the bumblebee, Bombus terrestris , using reconstructed 3D data from X-ray micro computed-tomography scans combined with computational ray-tracing simulations. This method enables us, not only to predict the visual fields of the ocelli, but to explore for the first time the effect that hair has on them as well as the difference between worker female and male ocelli.We find that bumblebee ocellar fields of view are directed forward and dorsally, incorporating the horizon as well as the sky. There is substantial binocular overlap between the median and lateral ocelli, but no overlap between the two lateral ocelli. Hairs in both workers and males occlude the ocellar field of view, mostly laterally in the worker median ocellus and dorsally in the lateral ocelli. There is little to no sexual dimorphism in the ocellar visual field, suggesting that in B. terrestris they confer no advantage to mating strategies.We compare our results with published observations for the visual fields of compound eyes in the same species as well as with the ocellar vision of other bee and insect species.

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Analytical formula for two-dimensional ring artefact suppression

Cited by 15 publications

References 33 publications

Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity

Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity

Optimising complementary soft tissue synchrotron X-ray microtomography for reversibly-stained central nervous system samples

Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli

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