Head Contour Research Articles

Multi-Person Tracking Based on Video Information Fusion

In order to solve the problem that human objects in complex environments would be affected by illumination, deformation, moving, etc, a multi-feature information fusion based video tracking approach was proposed. In a particle filter framework, both the face color information and the head contour cue were fused effectively.This method overcomed the instability brought by using a single measurement source, and improved the tracking accuracy and reliability. Experiments on real video sequences demonstrate that in the same case our approach has more reliable performance than trackers utilizing only color or contour information with particle filter.

Bayesian data fusion for water table interpolation: Incorporating a hydrogeological conceptual model in kriging

The creation of a contour map of the water table in an unconfined aquifer based on head measurements is often the first step in any hydrogeological study. Geostatistical interpolation methods (e.g., kriging) may provide exact interpolated groundwater levels at the measurement locations but often fail to represent the hydrogeological flow system. A physically based, numerical groundwater model with spatially variable parameters and inputs is more adequate in representing a flow system. Because of the difficulty in parameterization and solving the inverse problem, however, a considerable difference between calculated and observed heads will often remain. In this study the water‐table interpolation methodology presented by Fasbender et al. (2008), in which the results of a kriging interpolation are combined with information from a drainage network and a digital elevation model (DEM), using the Bayesian data fusion framework, is extended to incorporate information from a tuned analytic element groundwater model. The resulting interpolation is exact at the measurement locations whereas the shape of the head contours is in accordance with the conceptual information incorporated in the groundwater‐flow model. The Bayesian data fusion methodology is applied to a regional, unconfined aquifer in central Belgium. A cross‐validation procedure shows that the predictive capability of the interpolation at unmeasured locations benefits from the Bayesian data fusion of the three data sources (kriging, DEM, and groundwater model), compared to the individual data sources or any combination of two data sources.

The role of external head contours in face processing in the human occipitotemporal cortex

The role of external head contours in face processing in the human occipitotemporal cortex

Numerical modeling of the groundwater flow system of the Gumera sub‐basin in Lake Tana basin, Ethiopia

AbstractThe groundwater flow contribution into Lake Tana was simulated using Gumera River sub‐basin as a case study. Draining into Lake Tana, the Gumera sub‐basin boundary was delineated from a 90‐m Shuttle Radar Terrain Mapping (SRTM) digital elevation model (DEM) using ArcHydro tools. The sub‐basin boundary served as the divide line of the groundwater flow while stream networks were used as internal drainage lines. Input parameters such as transmissivity and hydraulic conductivity were obtained from past studies and experts' knowledge. Based on the geological information of the sub‐basin, unconfined subsurface flow condition was considered and simulated using MODular 3D finite difference ground‐water FLOW model (MODFLOW). Analytical solutions were also used for comparison purposes. The result indicates that head contours are aligned to the streams showing their relationship as a subdued form of the surface water flow, which are dictated by the morphology of the basin. This suggested the need to account groundwater contribution of the sub‐basins to Lake Tana as baseflow, and to estimate groundwater inflow from the floodplain separately. The contribution from the floodplain was estimated using a finite differences method which showed an inflow of 0·15 billion cubic meter (BCM) from rivers into the floodplain out of which 0·09 BCM is flowing out to the Lake Tana and 0·06 BCM stored in the aquifers of the floodplain. The stored quantity could meet irrigation demands as well as contribute to the preservation of the ecological structure and function of the area. The study suggests further research on validation of parameters through inverse modeling approaches and optimization of water allocations. Copyright © 2009 John Wiley & Sons, Ltd.

An unconfined groundwater model of the Death Valley Regional Flow System and a comparison to its confined predecessor

Summary The MODFLOW version of the United States Geological Survey (USGS) Death Valley Regional Flow System (DVRFS) in California and Nevada is conceptually inaccurate in that it models an unconfined aquifer as a confined system and does not accurately simulate unconfined drawdown in transient pumping simulations. The transfer of geologic and hydrologic information from the confined MODFLOW DVRFS model to an unconfined MODFLOW–SURFACT (SURFACT) version was accomplished by maintaining cell structure between models and computing effective cell properties to translate the HUF2 package used in MODFLOW to the BCF4 package used by SURFACT. The confined version of the DVRFS was compared to the unconfined SURFACT version by examining head contour maps and the ability of the SURFACT model to match the 4900 observations of hydraulic head/drawdown, 49 observations of groundwater discharge, and 15 estimates of groundwater fluxes into/out of the model domain. Resultant weighted root mean squared error (ωRMSE) for the unconfined SURFACT model was lower than the USGS confined model. Despite a lower ωRMSE, unconfined conditions simulated with SURFACT did produce greater heads in mountainous regions compared to the confined MODFLOW with differences most pronounced in regions where cell thickness is large, horizontal conductivity small and recharge large. Difference in computed heads reflects computation schemes employed by both models to estimate interblock conductance. Specifically, interblock conductance for the unconfined SURFACT model is dependent on the relative saturation of a modeled cell while MODFLOW’s confined system is not. Despite head differences, SURFACT simulates comparable flux estimates to MODFLOW (e.g. observed ET, groundwater spring flow, and groundwater flux across model boundaries), while significantly improving transient well drawdown estimates. SURFACT is also capable of producing more realistic estimates of water availability from proposed groundwater development and resultant potential impacts to the region.

Evaluation of appearance transfer and persistence in central face transplantation: A computer simulation analysis

Partial facial allotransplantation is an emerging option in reconstruction of central facial defects, providing function and aesthetic appearance. Ethical debate partly stems from uncertainty surrounding identity aspects of the procedure. There is no objective evidence regarding the effect of donors' transplanted facial structures on appearance change of the recipients and its influence on facial recognition of donors and recipients. Full-face frontal view color photographs of 100 volunteers were taken at a distance of 150 cm with a digital camera (Nikon/DX80). Photographs were taken in front of a blue background, and with a neutral facial expression. Using image-editing software (Adobe-Photoshop-CS3), central facial transplantation was performed between participants. Twenty observers performed a familiar 'facial recognition task', to identify 40 post-transplant composite faces presented individually on the screen at a viewing distance of 60 cm, with an exposure time of 5s. Each composite face comprised of a familiar and an unfamiliar face to the observers. Trials were done with and without external facial features (head contour, hair and ears). Two variables were defined: 'Appearance Transfer' refers to transfer of donor's appearance to the recipient. 'Appearance Persistence' deals with the extent of recipient's appearance change post-transplantation. A t-test was run to determine if the rates of Appearance Transfer differed from Appearance Persistence. Average Appearance Transfer rate (2.6%) was significantly lower than Appearance Persistence rate (66%) (P<0.001), indicating that donor's appearance transfer to the recipient is negligible, whereas recipients will be identified the majority of the time. External facial features were important in facial recognition of recipients, evidenced by a significant rise in Appearance Persistence from 19% in the absence of external features to 66% when those features were present (P<0.01). This study may be helpful in the informed consent process of prospective recipients. It is beneficial for education of donors families and is expected to positively affect their decision to consent for facial tissue donation.

Real-time elliptical head contour detection under arbitrary pose and wide distance range

In this paper, we propose a real time elliptical head contour detection method based on quadrant arcs, which is efficient and robust to arbitrary head pose and wide distance range. First, the moving object area is detected according to background model which is built on three color channels. Then, all the valid elliptical arcs are extracted out from connected edges, and classified into four kinds of quadrant arc sets according to their gradient information. Finally, the arcs lying in different sets are combined to fit out the elliptical head contour based on the least square method. Experimental results confirm the robustness and the accuracy of this method under arbitrary head pose and wider distance range, as well as the real time property, strong robustness to long or short hair and with or without hat.

The Effect of Face Eccentricity on the Perception of Gaze Direction

The perception of a looker's gaze direction depends not only on iris eccentricity (the position of the looker's irises within the sclera) but also on the orientation of the lookers' head. One among several potential cues of head orientation is face eccentricity, the position of the inner features of the face (eyes, nose, mouth) within the head contour, as viewed by the observer. For natural faces this cue is confounded with many other head-orientation cues, but in schematic faces it can be studied in isolation. Salient novel illustrations of the effectiveness of face eccentricity are 'Necker faces', which involve equal iris eccentricities but multiple perceived gaze directions. In four experiments, iris and face eccentricity in schematic faces were manipulated, revealing strong and consistent effects of face eccentricity on perceived gaze direction, with different types of tasks. An additional experiment confirmed the 'Mona Lisa' effect with this type of stimuli. Face eccentricity most likely acted as a simple but robust cue of head turn. A simple computational account of combined effects of cues of eye and head turn on perceived gaze direction is presented, including a formal condition for the perception of direct gaze. An account of the 'Mona Lisa' effect is presented.

Application of Ganz Surgical Hip Dislocation Approach in Pediatric Hip Diseases

BackgroundGanz surgical hip dislocation is useful in the management of severe hip diseases, providing an unobstructed view of the femoral head and acetabulum. We present our early experience with this approach in pediatric hip diseases.MethodsTwenty-three hips of 21 patients with pediatric hip diseases treated using the Ganz surgical hip dislocation approach were the subjects of this study. The average age at the time of surgery was 15.7 years. There were 15 male and 6 female patients who were followed for an average of 15.1 months (range, 6 to 29 months). Diagnoses included hereditary multiple exostoses in 9 hips, slipped capital femoral epiphysis in 7, Legg-Calvé-Perthes disease in 4, osteoid osteoma in 1, pigmented villonodular synovitis in 1, and neonatal septic hip sequelae in 1. Medical records were reviewed to record diagnoses, principal surgical procedures, operative time, blood loss, postoperative rehabilitation, changes in the range of hip joint motion, and complications.ResultsFemoral head-neck osteochondroplasty was performed in 17 patients, proximal femoral realignment osteotomy in 6, open reduction and subcapital osteotomy for slipped capital femoral epiphysis (SCFE) in 2, core decompression and bone grafting in 2, hip distraction arthroplasty in 2, and synovectomy in 2. Operative time averaged 168.6 minutes when only osteochondroplasty and/or synovectomy were performed. Hip flexion range improved from a preoperative mean of 84.7° to a mean of 115.0° at the latest follow-up visit. Early continuous passive motion and ambulation were stressed in rehabilitation. No avascular necrosis of the femoral head was noted up to the time of the latest follow-up visit, except for in one SCFE patient whose surgical intervention was delayed for medical reasons.ConclusionsGanz surgical hip dislocation provides wide exposure of the femoral head and neck, which enables complete and precise evaluation of the femoral head and neck contour. Hence, the extensive impinging bump can be excised meticulously, and the circulation of the femoral head can be monitored during surgery. The Ganz procedure was useful in severe pediatric hip diseases and allowed for quick rehabilitation with fewer complications.

Towards Pain Recognition in Post-Operative Phases Using 3D-based Features From Video and Support Vector Machines

In this article first results are presented of our new method for vision based recognition of pain from facial expressions. Incorporating a series of image processing, low level computer vision and pattern recognition techniques the proposed method not only detects facial expressions of pain but also ones related to emotion or neutrally speaking subjects. In order to extract the facial features through image processing our approach uses color and gradient information along with a head contour model. In the 3D related part a camera model is included along with an initial registration step, in which we use method that automatically builds a person specific face model from stereo. By using this model information 3D geometric feature measures are determined and normalized through the application of photogrammetric techniques. A support vector machine based classifier is trained and applied to these features. The presented approach leads to minimal mixing between different expression classes. Also, our framework achieves robust and clear classification results while reaching high performance.

Buried Deep Inferior Epigastric Perforator Flaps for Complex Head and Neck Contour Defects

The deep inferior epigastric perforator (DIEP) flap is presented as a potential source of tissue for head and neck reconstruction. It has been sparingly reported for pharyngeal reconstruction and to provide a large bulk of skin but not previously described for buried contour defects. We present a retrospective study of a consecutive series of six buried DIEP flaps performed between 2005 and 2007 with a review of their indications, results, and complications. Three patient defects had previous radiation. All flaps were used in the delay setting as secondary reconstructions. Soft tissue defects addressed in this study were the result of a variety of different pathologies, including temporal fossa meningioma, fibrous dysplasia of the skull and orbit, nasopharyngeal carcinoma, neck scar repair, sinus cancer, and osteomyelitis. We report a 100% success rate with primary flap survival, secondary contouring, minimal donor site, provision of moldable bulk soft tissue fill, and ability to fillet and redistribute. Patient-reported satisfaction at 6 months and 1 year was good to excellent in all cases. We concluded that in select cases, the functional and aesthetic advantages of the DIEP flap for head and neck reconstruction of soft tissue defects are superior to implants, fillers, and nonvascularized fat grafts. During revisions, these flaps are amendable to liposuction as a contouring tool with portions that can be redistributed on pedicles. The subcutaneous fat of the DIEP flap has resilience that tends to last and retain its shape with maintenance of residual volume over muscle flaps.

63 EXPERIMENTALLY INDUCED EARLY DEGENERATION OF THE HIP JOINT IN A SHEEP MODEL

Purpose: A non-spherical femoral head is a known risk factor for early osteoarthritis of the hip joint. Recently, a new pathomechanism termed femoro-acetabular impingement has been postulated as an underlying cause. This mechanism is postulated to represent an abutment conflict between the non-spherical portion of the head/neck junction and the acetabular rim during extreme flexion and internal rotation. It is thought to lead to repetitive trauma resulting in subsequent lesions of the labrum and adjacent cartilage at the acetabular rim or femoral head. The aim of this research study is to confirm in an animal model, that a non-spherical head contour leads to primary lesions at the acetabulum and at the nonspherical portion of the femoral head similar to the findings in human hip joints. Methods: Sheep have been chosen as animal model since the acetabular anatomy is close to that in humans including the presence of a labrum and the femoral head has a distinct non-spherical extension of the cartilage in its superior portion. By performing an intertrochanteric adduction osteotomy of the proximal femur the non-spherical portion was rotated toward the weight bearing zone and created similar impingement conditions during the end range of flexion as postulated in young adult human beings. In a pilot study with 6 sheep localized peripheral hip joint lesions could be produced at the acetabular rim and the non-spherical portion of the head similar to the finding in humans. For this study a total of 16 sheep was chosen. The sheep were divided into 4 groups, each group with 4 sheep that were sacrificed after 14, 22, 30, 38-weeks after surgery. After sacrifice the joint cartilage was evaluated for visible alterations macroscopically according to grading by Beck et al. Thereafter samples were harvested of standardized segments on both, the operated and non-operated (control) sides for histological work-up using conventional staining methods with Toluidin-blue O to evaluate proteoglycan depletion and grading of cartilage alterations according to Mankin. Results: Localized labral lesions as also typically seen in humans were present in 14 out of 16 hips on the operated side versus 2 lesions on the unoperated side. Cartilage lesions including flaps, tears or superficial fraying were seen in all 16 operated hips in the caudodorsal segment of the acetabulum versus alterations in 3 out of 16 hips on the unoperated side (different stages of alteration showed in Figure). Histochemical staining confirmed the macroscopic findings and showed statistically significant higher degenerative changes according to the Mankin staging in the caudodorsal segment on the operated side versus the non-operated side. Conclusions: With the presented animal model a cam impingementmechanism and localized, peripheral intraarticular lesions of the hip similar those seen in humans could be reproduced. Therefore a model of development of early osteoarthritis in the hip with different stages of the disease could be defined. This allows to develop and to evaluate new invasive and non-invasive treatment methods for this pathomechanism. It will be also used to further clarify the sequential steps of the osteoarthritic process and help to define the ideal time point for surgical interventions.

OP23.08: The effects of intrapartum continuous epidural analgesia on uterine artery flow velocity waveforms

Objectives: To evaluate the usefulness of a novel software to assess on three-dimensional (3D) ultrasound volumes the progression of the fetal head in the second stage of labour. Methods: a software (L&D) was developed as an application of the program 4D view (GE Healthcare, Zipf, Austria) with the purpose to help the evaluation of fetal head progression by serial ultrasound volumes obtained with a translabial approach throughout the second stage of labour. Volumes can be aligned by usign the pubic bone as reference. In the longitudinal plane of the pelvis, the head contour can be traced and the angle formed by the head and the antero-posterior diameter (head direction) can be measured. In the transverse plane of the pelvis, the angle formed by the midline with the anteroposterior axis of the posterior (head rotation) can also be measured. Subsequent volumes can be superimposed to demonstrate visually the progression of the head contour, modification of the head direction and head rotation. Between november 2007 and january 2008 serial ultrasound volumes were obtained in labouring patients, stored and subsequently evaluated with the L&D software Results: A total of 15 volumes from 9 patients were analyzed. Superimposition of serial volumes allowed to visualize the progression of the fetal head. With increasing station, the parietal line angle increased and the midline angle decreased. Conclusions: Using 3D ultasound and a novel software the progression of the second stage of labour can be directly visualized. Measurement of angles (head direction and rotation) could also prove useful, as they provide a quantitative estimate of the progression. These tools may support and facilitate the clinical diagnosis of normal and abnormal labour.

Course of Avascular Necrosis of Femoral Head Without Collapse of Femoral Head at First Examination: Minimum 8-Year Follow-up

Disruption of the femoral head contour by collapse of necrotic segments is considered to be an important turning point in the history of avascular necrosis of the femoral head, and in many cases, surgical treatment is required soon after the onset of symptoms. However, in a few cases, conservative treatment is sufficiently effective to avoid surgical procedures for long periods. For patients with early-stage avascular necrosis, it is important to accurately predict its natural course. This article documents the characteristics of patients who can be treated without surgery for long periods. Seventeen hips in 13 patients with avascular necrosis of the femoral head without collapse of the femoral head at first examination were followed for at least 8 years of conservative treatment. Long-term outcomes of hips with avascular necrosis were divided into 3 groups: (1) hips without collapse, (2) hips with progression but cessation of collapse, and (3) hips with progression of collapse. In groups 1 and 2, good clinical results are expected. Hips with femoral head collapse .3 mm at 3 years from the onset of hip pain progressed to osteoarthritis. Our analysis indicated that collapse of the femoral head does not necessarily indicate a poor prognosis, and even after collapse occurs, subsequent cessation of collapse can be expected in a certain percentage of hips.

Facial expression recognition – A real time approach

Face localization, feature extraction, and modeling are the major issues in automatic facial expression recognition. In this paper, a method for facial expression recognition is proposed. A face is located by extracting the head contour points using the motion information. A rectangular bounding box is fitted for the face region using those extracted contour points. Among the facial features, eyes are the most prominent features used for determining the size of a face. Hence eyes are located and the visual features of a face are extracted based on the locations of eyes. The visual features are modeled using support vector machine (SVM) for facial expression recognition. The SVM finds an optimal hyperplane to distinguish different facial expressions with an accuracy of 98.5%.

Idiopathic chondrolysis of the hip

Idiopathic chondrolysis of the hip is a rare disease in which gradual necrosis of the hyaline cartilage covering the femoral head and acetabulum leads to joint space narrowing and motion restriction. Pain, motion range limitation, and radiographic joint space narrowing are the main manifestations. We report 2 cases in 15-year-old girls, one black and the other Caucasian. Unexplained pain and motion restriction in the left hip were the presenting manifestations. Narrowing of the hip joint space was noted on standard radiographs. Magnetic resonance imaging showed a joint effusion in 1 patient and unevenness of the femoral head contour in the other. Laboratory tests including microbiological studies were normal or negative. Nonspecific synovitis was found in biopsy specimens. Immobilization and traction were the main components of the treatment strategy.

Eye detection based on head contour geometry and wavelet subband projection

We propose a novel two-step approach for eyes detection in complex scenes including both indoor and outdoor environments. This approach adopts face localization to eye extraction strategy. First, we use energy analysis to remove most noise-like regions to enhance face localization performance, and then use the head contour detection (HCD) approach to search for the best combinations of facial sides and head contours with an anthropometric measure, and thereafter the face-of-interest (FOI) region is located. In the meantime, via the deedging preprocessing for facial sides, a wavelet subband interorientation projection method is adopted to select eye-like candidates. Along with the geometric discrimination among the facial components, such as the eyes, nose, and mouth, this eye verification rule verifies the selected eyes candidates. The eye positions are then marked and refined by the bounding box of FOI region as the ellipse being the best fit of the facial oval shape. The experimental results demonstrate that the performance of our proposed method has significant improvement compared to others on three head-and-shoulder databases.

Serious metallosis of a metal head due to fragmented ceramic screws in a cemented THA

We reported a rare revision case necessitated by massive metallosis of a metal head due to a fragmented ceramic screw which had been extraarticularily used in the primary THA here and reviewed previous literature about metallosis of metal heads associated with ceramic materials. The ceramic screw had been used for the fixation of a bone graft and reattachment of the greater trochanter in the primary THA. Scanning electron microscope analysis revealed large alumina ceramic particles embedded on the bearing surface of the polyethylene. It has previously been pointed out that metallosis of an inner head occurred in bipolar case due to a fracture of the ceramic screws in contact with a proximally migrated outer head. However, this case showed that if a ceramic screw fragmented even though it was used outside of the hip joint, the fragments could migrate into bearing surface and cause serious metallosis of the metal head. Thus, we recommend that surgeons should pay special attention to the radiographic signs of ceramic failure or metallosis such as a change of the metal head contour, if an aseptic loosening or severe osteolysis is observed in a THA in which ceramic materials were used near the hip joint. And, when a surgical revision is planned, the surgeon should be prepared to exchange with a new ceramic head.

Durability studies of metal evaporated tapes in a linear tape drive: Role of head contour and tape tension

Magnetic performance of metal evaporated (ME) tape makes it a prominent storage media candidate for future data recording systems. However, the durability of ME tapes, limited by a number of tribological issues, is a major concern. A preliminary investigation on durability of ME tapes in a linear tape drive has been carried out. The effect of head contour and tape tension on the durability of the head-tape interface has been studied. An optical microscopy based technique has been used to measure the quality of factory-slit tape edges and after use in a liner tape drive. Debris distribution over the head surface at the end of the testing has been monitored. The ME tapes are found to be sensitive to both head contour and tape tension. Some desirable attributes of ME tapes required to improve durability are discussed.

Eine quantitative Studie zur MRT-basierten Bestrahlungsplanung der perkutanen Therapie von Hirntumoren

This study examined to which extent treatment plans for brain tumors can be constructed with a commercial treatment planning system (TPS) based on MRI data only. CadPlan®6.4.7 was used as TPS. In particular, differences between MRT-based and conventional CT-based plans were examined systematically. The quantification of the retrospective evaluation was carried out by the point-wise dose difference and the γ-distribution. In this study the γ-distribution did not appear advantageous over the dose difference for the tolerance range (point-wise dose difference <3%, distance criterion LLL5 mm). The calculated dose distribution showed large differences (up to 103%) at the boundary of the treatment fields, in the regions of the head contour, and in areas with air inclusions and significant bone structures. The inner parts of the fields, and therefore the actual target volume, revealed only small deviations in the range of 2% in the homogeneous distribution.