Modified watershed approach for segmentation of complex optical coherence tomographic images

Watershed segmentation method has been used in various applications. But many a times, due to its over-segmentation attributes, it underperforms in several tasks where noise is a dominant source. In this study, Optical Coherence Tomography images have been acquired, and segmentation has been performed to analyse the different regions of fluid filled sacs in a lemon. A modified watershed algorithm has been proposed which gives promising results for segmentation of internal lemon structures

Why Sociology Has a Marginal Position in Civic Education in Bulgaria Nationally Specific and/or Universal Trends

The authors claim that, to an extent, the marginalization is a by-product of relationship among sociology, citizenship education and school education in general. This relationship is pretty complex and problematic because each of the three constituents undergoes a phase of fundamental crisis of axiological and institutional character. The developments in American sociology that exemplifies the state of affairs in the field are taken as point of departure while the Bulgarian case is used just as a magnifying glass to see clearer the triple crises which bring us to the roots of the civilizational transformation experienced today.The moral of the story is that sociology has been marginalized in last decades because its public and academic status won by the previous generation can not be taken for granted. It does not correspond to the pressing demands of the changing world for a different type of sociology. Thus sociology falls easy prey to the academic competitors who follow aggressive strategy and policy of public expansion even in civil education. The particular situation in other countries may be different but these are common general rules of construing sociology. At the end the paper offers some guidelines for transformation of the pattern in which contemporary sociology should be practiced in order to raise its public and civic relevance through refocusing it on sophisticated mediation of public policy and actions of citizens and through new forms of cultural communication

3D Capture and 3D Contents Generation for Holographic Imaging

The intrinsic properties of holograms make 3D holographic imaging the best candidate for a 3D display. The holographic display is an autostereoscopic display which provides highly realistic images with unique perspective for an arbitrary number of viewers, motion parallax both vertically and horizontally, and focusing at different depths. The 3D content generation for this display is carried out by means of digital holography. Digital holography implements the classic holographic principle as a two‐step process of wavefront capture in the form of a 2D interference pattern and wavefront reconstruction by applying numerically or optically a reference wave. The chapter follows the two main tendencies in forming the 3D holographic content—direct feeding of optically recorded digital holograms to a holographic display and computer generation of interference fringes from directional, depth and colour information about the 3D objects. The focus is set on important issues that comprise encoding of 3D information for holographic imaging starting from conversion of optically captured holographic data to the display data format, going through different approaches for forming the content for computer generation of holograms from coherently or incoherently captured 3D data and finishing with methods for the accelerated computing of these holograms

Digital Holography and 3D Imaging: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America A.

This feature issue is a continuation of a tradition, since 2007, to follow the conclusion of the OSA Topical Meeting on Digital Holography and 3D Imaging (DH+3D). It addresses current research topics in digital holography (DH) and 3D imaging that are also in line with the topics of Applied Optics (AO) and the Journal of the Optical Society of America A (JOSA A)

Projection moire measurement of glass specimens retrofitted with safety film

Protection of buildings and critical public infrastructure against blast load has been recently improved by retrofitting glass windows with a safety film. As the exact physical mechanisms of the interaction between glass and safety film are not quite well understood, intensive research is conducted on the properties of this assembly. The loadings on the glass/film assembly are typically dynamic (blast, wind pressure, impact), so the lab tests are done on a drop weight set-up, where a mass is falling on a retrofitted glass plate. In this work, the drop weight setup was combined with pattern projection (moire) technique to study the time history of the out-of-plane deformations of the glass/film assembly. The fringe pattern, projected on the back side of the specimen, was generated by means of a sinusoidal phase grating under divergent high intensity infrared illumination. The whole process was recorded with a high speed camera. Local routines based on fast Fourier transform were used to process the captured images, and to extract the phase. The exact out-of-plane displacements were calculated by means of calibration based on previous shape measurements of several different objects with known dimensions

Intensity-based dynamic speckle method for analysis of variable-rate dynamic events

We study efficiency of intensity-based dynamic speckle method for characterization of dynamic events which occur at variable rate in time within the temporal averaging interval. We checked ability of the method to describe the speed evolution by i) numerical simulation at variable speed, ii) processing of speckle patterns obtained from phase distributions fed to a SLM at controllable change of the temporal correlation radius of speckle intensity fluctuations and iii) conducting experiments with a polymer solution drying by using a hot-stage. The numerical and SLM simulation experiments allowed for modification of the used estimates in order to obtain relevant informatio

Opto-UNet: Optimized UNet for Segmentation of Varicose Veins in Optical Coherence Tomography

Human veins are important for carrying the blood from the body-parts to the heart. The improper functioning of the human veins may arise from several venous diseases. Varicose vein is one such disease wherein back flow of blood can occur, often resulting in increased venous pressure or restricted blood flow due to changes in the structure of vein. To examine the functional characteristics of the varicose vein, it is crucial to study the physical and bio mechanical properties of the vein. This work proposes a segmentation model Opto-UNet, for segmenting the venous wall structure. Optical Coherence Tomography system is used to acquire images of varicose vein. As the extracted vein is not uniform in shape, hence adequate method of segmentation is required to segment the venous wall. Opto-UNet model is based on the U-Net architecture wherein a new block is integrated into the architecture, employing atrous and separable convolution to extract spatially wide-range and separable features maps for attaining advanced performance. Furthermore, the depth wise separable convolution significantly reduces the complexity of the network by optimizing the number of parameters. The model achieves accuracy of 0.9830, sensitivity of 0.8425 and specificity of 0.9980 using 8.54 million number of parameters. These results indicate that model is highly adequate in segmenting the varicose vein wall without deteriorating the segmentation quality along with reduced complexity.acceptedVersionPeer reviewe

Measurement of differential cross sections for top quark pair production using the lepton plus jets final state in proton-proton collisions at 13 TeV

National Science Foundation (U.S.