8202 hits

Holographic particle image velocimetry is a promising technique to probe and characterize complex flow dynamics since it is a truly three-dimensional (3D) three-component measurement technique. The technique simply records the coherent light scattered by small seeding particles that are assumed to faithfully follow the flow and uses it to reconstruct the event afterward. Re-construction of the event is usually performed using a digital video micro-scope mounted on a 3D translation stage. The microscope records the inten-sity only which consequently results in loss of phase information. The objec-tive of this paper is to develop and apply digital holographic microscopy with the aim to recover the phase information. Digital holographic microscopy has immense potentials in microscale solid and fluid measurements as it offers the possibility of digital wavefront processing by manipulating amplitude and phase of the recorded holograms. In this paper, we have developed an off-axis digital ho.....

1123 hits

Particle image velocimetry (PIV) technique in its original form is limited to in-plane two-dimensional two-component (2D-2C) displacement and velocity measurements. Although it is possible to extract the out-of-plane component through stereoscopic viewing, the useful measurement volume remains limited to a light sheet of several millimeters thick. On the other hand, integration of holographic recording in PIV (HPIV) has finally realised whole-field, three-dimensional three-component (3D-3C) displacement and velocity measurements. In comparison to in-line particle holography, off-axis particle holography offers a relatively higher signal-to-noise ratio (SNR) although it demands long coherence and high laser energy for flow diagnostics. In-line particle holography relaxes the requirements of such a system but at the expense of image (signal) degradation due to superposition of virtual image waves, the directly transmitted reconstruction wave and the real image. On this basis, off-axis se.....

1003 hits

Digital holographic microscopy (DHM) is a promising tool for a three-dimensional imaging of microscopic particles. It offers the possibility of wavefront processing by manipulating amplitude and phase of the recorded digital holograms. With a view to compensate for aberration in the reconstructed particle images, this paper discusses a new approach of aberration compensation based on complex amplitude correlation and the use of a priori information. The approach is applied to holograms of microscopic particles flowing inside a cylindrical micro-channel recorded using an off-axis digital holographic microscope. The approach results in improvements in the image and signal qualities...

1877 hits

Computer-assisted technology plays an important role in helping to reduce risk during pregnancy, particularly serious risks associated with intra-uterine growth restriction (IUGR). Fetal gestational age estimation and fetal weight estimation are two crucial factors in evaluating fetal growth and detecting any abnormality of growth, in order to identify IUGR risk to the fetus. The estimation is made through serial measurement of fetal anatomy comprising the length, diameter and circumference of multiple segments in the fetus scanned through an ultrasound machine. The computing method helps to overcome human subjectivity in assessment that is prone to variability in measurement. Automatic measurement methods carried out by the computer can help in producing fast, accurate and reproducible measurement and assessment of the fetal anatomy. This study presents an analysis of techniques attempted by researchers in conducting automated fetal biometric anatomy measurements using ultrasound imag.....

1055 hits

Human ear is an intriguing individual anatomical part of a passive, physiological biometrics systems based on the image acquired from digital cameras. The human ear has many singular features that permit the finding of particular individuals. It could be implemented as effective biometrics systems, for example, in crowd surveillance and identifying terrorist at public places such as airports, as well as controlling access to government offices. Challenges and issues faced in the field of human identification using ear detection and recognition includes problem of occlusion, varieties in illumination, and real-time implementation in accessing information from an integrated database system with higher accuracy. Research on ear detection and recognition systems have been developing in a steady rate and mostly are constrained to controlled indoor environment. Notwithstanding, other research issues incorporate; ear print criminology; ear symmetry; and ear uniqueness. This paper presents a r.....

1064 hits

Automatic classification of cell types and biological products are considered crucial in the field of hematology especially for early detection of diseases when the quantity that needs to be examined is considerably large. In a previous study, a cylindrical micro-channel was employed to mimic actual blood flow in the arteriole but it was found to cause astigmatism in the reconstructed holographic particle images. Additionally, correction of the images is important to avoid false disease detection. In this paper, we describe a new application of feed-forward backpropagation neural network for classifying images of astigmatic and non-astigmatic synthetic platelets that were obtained by digital holographic microscopy. Image cropping was performed to suppress noise, followed by image normalization to reduce variation in contrast/brightness. Using MATLABTM, a two-layer neural network with two class classifier was trained with these images to compute the weights of each layer and the perform.....

748 hits

This research aims to build a general framework for choosing the most appropriate set of criteria for recruiting student as a research assistant in a university research project. University researchers could benefit from such a framework because it could optimize the costs of research while also enhancing students research skills. In the same time, it is also essential that the quality of research ought to measure up to the grants provided by the university. Nevertheless, it is a challenging problem for many research supervisors in the selection of qualified research assistants. In this paper, we attempted to resolve this problem by building a general framework for selecting the appropriate criteria in the evaluation of student performance. We explored earlier studies on the proposed evaluation criteria of the research assistant and identified 47 most impactful criteria criteria. We obtained experts in engineering and information technology fields from two universities to answer questi.....

876 hits

Purpose: Medical images are important in diagnosing disease and treatment planning. Computer algorithms that describe anatomical structures that highlight regions of interest and remove unnecessary information are collectively known as medical image segmentation algorithms. The quality of these algorithms will directly affect the performance of the following processing steps. There are many studies about the algorithms of medical image segmentation and their applications, but none involved a bibliometric of medical image segmentation. Methods: This bibliometric work investigated the academic publication trends in medical image segmentation technology. These data were collected from the Web of Science (WoS) Core Collection and the Scopus. In the quantitative analysis stage, important visual maps were produced to show publication trends from five different perspectives including annual publications, countries, top authors, publication sources, and keywords. In the qualitative analysis st.....

1351 hits

Purpose: The paper aims to explore the role and the involvement of local community within the context of Malaysian early childhood centers (nursery and kindergarten). Design/methodology/approach: The research used a mixed method with a questionnaire survey in the first phase and qualitative interviews in the second phase. Quantitative data were obtained from a survey completed by 3,519 staffs from nursery and kindergarten all over Malaysia. Qualitative data were collected from individual and focus group semistructured interviews conducted with 140 participants of the Malaysian public and private internal and external stakeholders ranging from the relevant personnel of the early childhood care and education (ECCE) centers (administrators, teachers and practitioners), academic experts, regulatory agencies and parents. Findings: Survey results indicate that the parents and community involvement with ECCE centers from the perspective of the management and practitioners is in the medium cat.....

419 hits