Enhanced 3D Point Cloud from a Light Field Image

The importance of three-dimensional (3D) point cloud technologies in the field of agriculture environmental research has increased in recent years. Obtaining dense and accurate 3D reconstructions of plants and urban areas provide useful information for remote sensing. In this paper, we propose a novel strategy for the enhancement of 3D point clouds from a single 4D light field (LF) image. Using a light field camera in this way creates an easy way for obtaining 3D point clouds from one snapshot and enabling diversity in monitoring and modelling applications for remote sensing. Considering an LF image and associated depth map as an input, we first apply histogram equalization and histogram stretching to enhance the separation between depth planes. We then apply multi-modal edge detection by using feature matching and fuzzy logic from the central sub-aperture LF image and the depth map. These two steps of depth map enhancement are significant parts of our novelty for this work. After combing the two previous steps and transforming the point–plane correspondence, we can obtain the 3D point cloud. We tested our method with synthetic and real world image databases. To verify the accuracy of our method, we compared our results with two different state-of-the-art algorithms. The results showed that our method can reliably mitigate noise and had the highest level of detail compared to other existing methods

Experimental demonstration of the relationship between the second- and third-order polarizabilities of conjugated donor-acceptor molecules

The dependence of the second- and third-order polarizabilities ((beta) and (gamma) ) on ground-state polarization was measured for a series of donor-acceptor polyenes using electric field induced second harmonic generation and third harmonic generation, respectively. The changes in ground-state polarization, associated with the donor/acceptor strength or solvent polarity, were probed by x-ray crystallography, 1H-NMR, electronic absorption, and Raman spectroscopies. The observed behavior of (beta) and (gamma) as a function of ground- state polarization agrees well with theoretical predictions. In particular, positive and negative peaks, as well as sign changes, were observed for both (beta) and (gamma) . The dependences for (beta) and (gamma) are consistent with a derivative relationship between them. In addition, the third-order polarizability of a series of molecules possessing zero bond length alternation was found to be negative, in agreement with predictions based on the relationship between the polarizabilities and ground-state geometry

Growing a Software Language for Hardware Design

The Liquid Metal project at IBM Research aimed to design and implement a new programming language called Lime to address some of the challenges posed by heterogeneous systems. Lime is a Java-compatible programming language with features designed to facilitate high level synthesis to hardware (FPGAs). This article reviews the language design from the outset, and highlights some of the earliest design decisions. We also describe how these decisions were revised recently to accommodate important requirements that arise in networking and cryptography

Noise-Resilient Depth Estimation for Light Field Images Using Focal Stack and FFT Analysis

Depth estimation for light field images is essential for applications such as light field image compression, reconstructing perspective views and 3D reconstruction. Previous depth map estimation approaches do not capture sharp transitions around object boundaries due to occlusions, making many of the current approaches unreliable at depth discontinuities. This is especially the case for light field images because the pixels do not exhibit photo-consistency in the presence of occlusions. In this paper, we propose an algorithm to estimate the depth map for light field images using depth from defocus. Our approach uses a small patch size of pixels in each focal stack image for comparing defocus cues, allowing the algorithm to generate sharper depth boundaries. Then, in contrast to existing approaches that use defocus cues for depth estimation, we use frequency domain analysis image similarity checking to generate the depth map. Processing in the frequency domain reduces the individual pixel errors that occur while directly comparing RGB images, making the algorithm more resilient to noise. The algorithm has been evaluated on both a synthetic image dataset and real-world images in the JPEG dataset. Experimental results demonstrate that our proposed algorithm outperforms state-of-the-art depth estimation techniques for light field images, particularly in case of noisy images.</jats:p

A garbage collection design and bakeoff in JMTk: An efficient extensible Java memory management toolkit

In this paper, we describe the design, implementation, and evaluation of a new garbage collection framework called the Java Memory Management Toolkit (JMTk). The goals of JMTk are to provide an efficient, composable, extensible, and portable toolkit for quickly building and evaluating new and existing garbage collection algorithms. Our design clearly demarcates the external interface between the collector and the compiler for portability. For extensibility, JMTk provides a selection of allocators, garbage identification, collection, pointer tracking, and other mechanisms that are efficient and that a wide variety garbage collection algorithms can compose and share. For instance, our mark-sweep and reference counting collectors share the free list implementation. We perform a comprehensive and detailed study of collectors including copying, mark-sweep, reference counting, copying generational, and hybrid generational collectors using JMTk in Jikes RVM on a uniprocessor. We find that the performance of collectors in JMTk is comparable to the highly tuned original Jikes collectors. In a study of full heap and generational collectors, we confirm the significant benefits of generational collectors on a wide variety of heap sizes, and reveal that on very small heaps, collection time is enormous. These experiments add other new insights, such as firmly establishing that for a variety of generational collectors, a variable-size nursery which is allowed to grow to fill all the space not in use by the older generation performs better than a fixed-size nursery. We thus show the utility of extensive collector comparisons and establish the benefits of our design

Australian medical students’ and junior doctors' perceptions of gender discrepancies in obstetrics and gynaecology

Background: There is currently a gender imbalance 85:15 female/male in the intake into specialist training for the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). Aims: To determine the views and perceptions of Australian medical students, and junior doctors in the first five years of practice, toward obstetrics and gynaecology (O&G) as a career, including whether there are any perceived barriers to the pursuit of such a career. Materials and Methods: A semi-structured questionnaire was developed with members of the RANZCOG Gender Equity and Diversity Working Group There were two separate studies: the first involved telephone interviews of medical students across three campuses of a medical school in North Queensland. The second study surveyed junior doctors in Queensland who are members of the Australian Medical Association. Responses were analysed and compared using quantitative and qualitative methods. Results: Both studies found that experiences with O&G as a medical student influenced the decision to pursue O&G as a career. Exclusion from clinical scenarios and difficulty establishing good relationship with midwives within busy birthing suites were some reasons deterring male students from O&G. In addition, students felt poorly informed about the specialty in their preclinical years, affecting their early decisions in choice of specialty. Post-rotation, more female than male students reported positive experiences and were considering O&G as a career. Conclusions: Both groups see medical student experience as critical in attitudes toward the specialty as a possible career. This experience plays a significant role in encouraging female students toward a career in O&G and discouraging male students. More exposure to the specialty in the preclinical years, and attention to improving clinical rotations for all students, is required

Immunohistochemical characteristics of Renomedullary interstitial cell tumor: a study of 41 tumors with emphasis on differential diagnosis of mesenchymal neoplasms

Renomedullary interstitial cell tumors (RMICT) are almost always incidentally identified either at autopsy or resection of the kidney for other reasons. However, rare cases have been reported which are large, resulting in a clinical mass. The immunohistochemical phenotype of usual, incidental RMICT using modern soft tissue tumor markers in is largely unknown, however, providing little information to aid in classification of larger or atypical tumors. We retrieved 41 RMICTs from 36 patients, and studied pathologic characteristics including morphology, immunohistochemistry (S100, keratin AE1/AE3, smooth muscle actin, desmin, estrogen and progesterone receptors, calponin, CD34, CD35), and histochemical staining. Data collected included age, gender, tumor size, laterality, and indication for kidney examination. RMICTs (n = 41) were identified in 23 men and 13 women, with mean age 57 years (range 24–83), tumor sizes ranged from <1 to 13 mm (median 4 mm). Kidneys were resected for 32 tumors, 1 chronic pyelonephritis, 1 trauma, and 2 autopsies. All (41, 100%) had entrapped renal tubules, 5 (12%) of which included cystic or dilated tubules. Most (35, 85%) had collagenous fibers, all of which were negative for Congo red. RMICT demonstrates a largely negative immunohistochemical phenotype with weak to moderate labeling for smooth muscle actin and calponin that is substantially less than myofibroblastic lesions. Positive staining for estrogen and progesterone receptor is common (61%), which could overlap with mixed epithelial and stromal tumor and other entities; however, staining is typically weak. CD34 is usually negative, with occasional weak labeling, in contrast to solitary fibrous tumor

Reaching the nonlinear regime of Raman amplification of ultrashort laser pulses

The intensity of a subpicosecond laser pulse was amplified by a factor of up to 1000 using the Raman backscatter interaction in a 2 mm long gas jet plasma. The process of Raman amplification reached the nonlinear regime, with the intensity of the amplified pulse exceeding that of the pump pulse by more than an order of magnitude. Features unique to the nonlinear regime such as gain saturation, bandwidth broadening, and pulse shortening were observed. Simulation and theory are in qualitative agreement with the measurements.open695