Coarse Head Research Articles

Computational errors of the induced electric field in voxelized and tetrahedral anatomical head models exposed to spatially uniform and localized magnetic fields

At low and intermediate frequencies, the strength of the induced electric field is used as dosimetric quantity for human protection in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. To compute the induced electric field, numerical methods based on anatomically realistic voxel models are commonly used. However, grid-based models introduce staircase approximation errors when curved surfaces are discretized with voxels, particularly in correspondence of boundaries with large differences in electrical conductivity. By contrast, those kind of artefacts are absent in tetrahedral meshes. Here, we investigate the computational errors that affect voxelized and tetrahedral head models when exposed to uniform magnetic fields at 50 Hz, and localized exposure due to transcranial magnetic stimulation. Five subjects were considered, and for each of them four voxel grids and four tetrahedral meshes were reconstructed with different resolutions. The differences in the results were characterized by comparing the induced electric fields computed using those meshes/grids. The results showed modest discrepancies in the overall electric field distributions between the various grids and meshes. However, the peak electric field strengths were erroneous for both tetrahedral and voxel models. Therefore, post-processing techniques are needed to suppress those numerical artefacts. For this purpose, the 99.99th, or lower, percentile of the electric field strength was found to remove the numerical errors. In addition, we found that spatially averaging the electric fields over 2 mm cubical volumes, as described by the ICNIRP, was effective in removing most of the spuriously large electric fields. When spatial averaging was used, relative coarse head models consisting of approximately 1 mm voxels or tetrahedral meshes with 2 mm average side length were sufficient to mitigate the artefacts. Nonetheless, the additional percentile filtering might still be needed to suppress the erroneous values completely.

Exploring the Sphinx and the Great Pyramid Through the Logos Heuristics

After detecting a primary triangulation through the crossing of two 18-mile (diameter) identical circles around a shared 14-mile baseline in ancient Egypt, the author hypothesizes that, in the 26th century before the Common Era, Pharaoh Khufu replaced with hope the general fear for the catlike goddess that preceded Giza’s Sphinx. Khufu changed the monstrous head of a monumental lioness on Giza’s plateau into the coarse head of the respected Horus-Pharaoh that guarded the southern lily plant and the northern papyrus. The Sphinx’s new symbolic head, or classical conservation in the finite first attention, joined flexible quantum computing in the ambiguous creativity of its body and the infinite second attention. The changed Sphinx and the Great Pyramid that followed its transfiguration point silently at the union of classical and quantum computing in the Third Attention that recreates natural systems, dreams, and social progress.

Audio head pose estimation using the direct to reverberant speech ratio

Head pose is an important cue in many applications such as, speech recognition and face recognition. Most approaches to head pose estimation to date have focussed on the use of visual information of a subject’s head. These visual approaches have a number of limitations such as, an inability to cope with occlusions, changes in the appearance of the head, and low resolution images. We present here a novel method for determining coarse head pose orientation purely from audio information, exploiting the direct to reverberant speech energy ratio (DRR) within a reverberant room environment. Our hypothesis is that a speaker facing towards a microphone will have a higher DRR and a speaker facing away from the microphone will have a lower DRR. This method has the advantage of actually exploiting the reverberations within a room rather than trying to suppress them. This also has the practical advantage that most enclosed living spaces, such as meeting rooms or offices are highly reverberant environments. In order to test this hypothesis we also present a new data set featuring 56 subjects recorded in three different rooms, with different acoustic properties, adopting 8 different head poses in 4 different room positions captured with a 16 element microphone array. As far as the authors are aware this data set is unique and will make a significant contribution to further work in the area of audio head pose estimation. Using this data set we demonstrate that our proposed method of using the DRR for audio head pose estimation provides a significant improvement over previous methods.

A Hierarchical Regression Approach for Unconstrained Face Analysis

Head pose and facial feature detection are important for face analysis. However, many studies reported good results in constrained environment, the performance could be decreased due to the high variations in facial appearance, poses, illumination, occlusion, expression and make-up. In this paper, we propose a hierarchical regression approach, Dirichlet-tree enhanced random forests (D-RF) for face analysis in unconstrained environment. D-RF introduces Dirichlet-tree probabilistic model into regression RF framework in the hierarchical way to achieve the efficiency and robustness. To eliminate noise influence of unconstrained environment, facial patches extracted from face area are classified as positive or negative facial patches, only positive facial patches are used for face analysis. The proposed hierarchical D-RF works in two iterative procedures. First, coarse head pose is estimated to constrain the facial features detection, then the head pose is updated based on the estimated facial features. Second, the facial feature localization is refined based on the updated head pose. In order to further improve the efficiency and robustness, multiple probabilitic models are learned in leaves of the D-RF, i.e. the patch’s classification, the head pose probabilities, the locations of facial points and face deformation models (FDM). Moreover, our algorithm takes a composite weight voting method, where each patch extracted from the image can directly cast a vote for the head pose or each of the facial features. Extensive experiments have been done with different publicly available databases. The experimental results demonstrate that the proposed approach is robust and efficient for head pose and facial feature detection.

Head pose estimation using image abstraction and local directional quaternary patterns for multiclass classification

This study treats the problem of coarse head pose estimation from a facial image as a multiclass classification problem. Head pose estimation continues to be a challenge for computer vision systems because extraneous characteristics and factors that lack pose information can change the pixel values in facial images. Thus, to ensure robustness against variations in identity, illumination conditions, and facial expressions, we propose an image abstraction method and a new representation method (local directional quaternary patterns, LDQP), which can remove unnecessary information and highlight important information during facial pose classification. We verified the efficacy of the proposed methods in experiments, which demonstrated its effectiveness and robustness against different types of variation in the input images.

Coarse head pose estimation of construction equipment operators to formulate dynamic blind spots

Several hundred workers die in construction in the United States every year because equipment operators are unable to see their fellow workers during operation of their vehicle. In this paper we propose a step towards improving this situation by providing an automated method based on range imaging for estimating the coarse head orientation of a construction equipment operator. This research utilizes commercially-available low resolution range cameras to measure the continuously changing field-of-view (FOV) of an equipment operator in outdoor construction. This paper presents a methodology to measure so-called dynamic blind spot maps. The dynamic blind spot map is then projected on a known static equipment blind spot map that already exists to each construction vehicle. A robust computational coarse head pose estimation algorithm and results to three different pieces of construction equipment and multiple operators are presented. The developed method has the potential in automatically determining the spaces around vehicles that are currently not in the field-of-view of the vehicle operator thus providing eventually additional means and technology for improving safety in construction.

Anti-Thy-1 immunotoxin, OX7-saporin, destroys cerebellar purkinje cells after intraventricular injection in rats

Thy-1 is an abundant surface glycoprotein of rat neurons. OX7 is a monoclonal antibody with high affinity for Thy-1. This study sought to determine if intraventricularly administered OX7 could serve as a carrier to deliver cytotoxin to neurons, thus destroying those neurons. Saporin (Sap), a ribosome-inactivating protein was disulfide-coupled to OX7 (OX7-Sap). OX7-Sap, OX7, saporin alone, pooled non-immune mouse IgG, and an irrelevant immunotoxin, RFT-1-Sap, were injected into the lateral ventricles of anesthetized adult rats. Animals were observed for 1–8 days. OX7-Sap-injected animals developed coarse head tremor and gait/truncal ataxia in a dose-dependent manner beginning 24 h or more after injection. All control animals remained healthy. After OX7 or OX7-Sap injection, immunoperoxidase staining for mouse IgG was most intense and specific in the molecular and Purkinje cell layers of the cerebellar cortex. Cresyl violet staining demonstrated destruction of the Purkinje cell layer in the OX7-Sap-treated animals but not in controls. These results indicate that intraventricular injections of OX7 can be used to deliver biologically active moieties to the Purkinje cells. This approach may prove useful in analysis of Purkinje cell function and as a model of cerebellar degeneration.

Prediction of Lifetime Relative Net Income from First Lactation Production and Individual Type Traits in Holstein Cows ,

Official type classification data and Dairy Herd Improvement Registry production records of Holstein cows calving between January 1, 1967, and June 1, 1976, were used to estimate contributions of individual descriptive type traits evaluated in first lactation to lifetime profitability as measured by a profit function, relative net income. Relative net income estimated total profit from variables available through Dairy Herd Improvement. Contributions of individual type components to profitability were estimated from least squares constants adjusted for all descriptive type traits and for linear and quadratic effects of final score, first lactation production, age at first calving, herdlife opportunity, stage of lactation, and age when classified.For the model to predict total profit, regressions were most significant for udder traits. Significant positive regressions were for plain or coarse head; firmly attached high and wide rear udder; and desirable teat size and placement. Significant negative regressions were for narrow and pinched, loose or broken rear udder; lack of defined udder support; and winged shoulders.Differences in total profit for body, feet, and hind legs were relatively unimportant as compared with alternative codes for udder traits. Codes considered conformationally most desirable for rear udder, udder support, and teats were also most desirable for total profit.

EXPERIMENTAL VESTIBULAR TREMORS, WITH ANALOGOUS CLINICAL CASES

Since the memorable work of Flourens in 1824, experiments on pigeons have contributed greatly to our knowledge of the anatomy and physiology of the static labyrinth. During the epidemic of 1918 and 1919, I treated a number of cases of epidemic cerebrospinal meningitis, in some of which postmeningitic symptoms were noted. Since my observations did not seem to be explained by the generally accepted views concerning the physiology of the membranous labyrinth, I have approached the problem experimentally during the past year and a half. In this work I have noted, not only the coarse head and eye nystagmus found by so many investigators, but also a fine tremor which I have designated vestibular tremor. It will suffice for the scope of this paper if I call attention to the anatomic landmarks of the apparatus, the saccule, the utricle, and the three semicircular canals, the tubulated enlargements