Video normals from colored lights

We present an algorithm and the associated single-view capture methodology to acquire the detailed 3D shape, bends, and wrinkles of deforming surfaces. Moving 3D data has been difficult to obtain by methods that rely on known surface features, structured light, or silhouettes. Multispectral photometric stereo is an attractive alternative because it can recover a dense normal field from an untextured surface. We show how to capture such data, which in turn allows us to demonstrate the strengths and limitations of our simple frame-to-frame registration over time. Experiments were performed on monocular video sequences of untextured cloth and faces with and without white makeup. Subjects were filmed under spatially separated red, green, and blue lights. Our first finding is that the color photometric stereo setup is able to produce smoothly varying per-frame reconstructions with high detail. Second, when these 3D reconstructions are augmented with 2D tracking results, one can register both the surfaces and relax the homogenous-color restriction of the single-hue subject. Quantitative and qualitative experiments explore both the practicality and limitations of this simple multispectral capture system.

Traffic lights management using belief propagation

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Visual modes of governmentality:traffic lights in a housing association

This study focuses on the use of traffic lights by a Registered Social Landlord (RSL) as a visual representation of self conduct that reflects a way of thinking, acting and constituting a 'well governed, well managed and viable' housing association. We show that the visible representation of traffic lights introduced by the regulator as indicators of performance has been used widely by the RSL to reflect two self-imposed principles of continuous improvement and self assessment. In this context the different accounts of governmentality within the RSLs board reports are studied and some significant insights suggested. © 2010 Elsevier Ltd.

Effect of age related macular degeneration on the Eger macular stressometer photostress recovery time

Aim: To assess the repeatability of Eger macular stressometer (EMS) measures of photostress recovery and determine their association with other measures of visual function. Methods: EMS photostress recovery time was measured in 90 patients with bilateral exudative age related macular degeneration (AMD), 19 with bilateral atrophic AMD and 47 with both forms of the condition (mean age 79 (SD 13) years). Measurements were made on two occasions separated by 1 year. Intrasession repeatability was assessed by repeating the measures after a 10 minute recovery period at the first visit. Distance visual acuity was measured with a logMAR chart, near visual acuity with a MNRead chart at 25 cm, contrast sensitivity with a Pelli-Robson chart, and the presence of central visual disturbance assessed with an Amsler grid. A questionnaire was used to assess self reported difficulties with glare recovery. Results: The average EMS recovery time was 11.0 (SD 8.9) seconds, decreasing by 1.6 (5.2) seconds on repeated measurement (p<0.05). EMS photostress recovery was not correlated with visual function measures or subjective difficulties with lights (p>0.05). EMS photostress recovery time did not predict those whose vision decreased over the following year compared with those among whom it remained stable. Conclusions: The EMS test is not a useful tool in determining the severity or progression of AMD.

End-to-end versus hop-by-hop soft state refresh for multi-hop signalling systems

To ensure state synchronization of signalling operations, many signaling protocol designs choose to establish “soft” state that expires if it is not refreshed. The approaches of refreshing state in multi-hop signaling system can be classified as either end-to-end (E2E) or hop-by-hop (HbH). Although both state refresh approaches have been widely used in practical signaling protocols, the design tradeoffs between state synchronization and signaling cost have not yet been fully investigated. In this paper, we investigate this issue from the perspectives of state refresh and state removal. We propose simple but effective Markov chain models for both approaches and obtain closed-form solutions which depict the state refresh performance in terms of state consistency and refresh message rate, as well as the state removal performance in terms of state removal delay. Simulations verify the analytical models. It is observed that the HbH approach yields much better state synchronization at the cost of higher signaling cost than the E2E approach. While the state refresh performance can be improved by increasing the values of state refresh and timeout timers, the state removal delay increases largely for both E2E and HbH approaches. The analysis here shed lights on the design of signaling protocols and the configuration of the timers to adapt to changing network conditions.

Self-calibrated, multi-spectral photometric stereo for 3D face capture

This paper addresses the problem of obtaining 3d detailed reconstructions of human faces in real-time and with inexpensive hardware. We present an algorithm based on a monocular multi-spectral photometric-stereo setup. This system is known to capture high-detailed deforming 3d surfaces at high frame rates and without having to use any expensive hardware or synchronized light stage. However, the main challenge of such a setup is the calibration stage, which depends on the lights setup and how they interact with the specific material being captured, in this case, human faces. For this purpose we develop a self-calibration technique where the person being captured is asked to perform a rigid motion in front of the camera, maintaining a neutral expression. Rigidity constrains are then used to compute the head's motion with a structure-from-motion algorithm. Once the motion is obtained, a multi-view stereo algorithm reconstructs a coarse 3d model of the face. This coarse model is then used to estimate the lighting parameters with a stratified approach: In the first step we use a RANSAC search to identify purely diffuse points on the face and to simultaneously estimate this diffuse reflectance model. In the second step we apply non-linear optimization to fit a non-Lambertian reflectance model to the outliers of the previous step. The calibration procedure is validated with synthetic and real data.

Visual hallucinations in the Parkinsonian syndromes

Differential clinical diagnosis of the parkinsonian syndromes,viz., Parkinson's disease (PD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and corticobasal degeneration (CBD) can be difficult. Visual hallucinations, however, are a chronic complication of some parkinsonian disorders and their presence may be a useful aid to diagnosis. The visual hallucinations in parkinsonism are often recurrent, well-formed, and detailed and occur in a significant proportion of cases of DLB and PD but are less common in PSP, MSA, and CBD. Hallucinations in PD often occur later in the disease and are complex, with flickering lights, and illusionary misconceptions often preceding the most common manifestation, viz., stereotypical colourful images. Hallucinations in DLB, however, are often present earlier in the disease and are similar to those in the 'misidentification syndromes', 'visual agnosias', and in 'delerium' but differ from those produced by hallucinogenic drugs such as LSD. Most typically in DLB, the hallucinations involve people or animals invading the patient's home but may also include inanimate objects and the appearance of writing on walls or ceilings. Visual hallucinations may involve a number of brain mechanisms including a change in the balance of neurotransmitter activity between the cholinergic and monoaminergic systems and may be a specific consequence of Lewy body (LB) pathology in brain stem nuclei. Ocular and retinal pathology may also contribute to hallucinations by reducing occipital stimulation. Hence, in patients with unclassifiable or with indeterminate parkinsonian symptoms, the presence of visual hallucinations should be regarded as a 'red flag' symptom indicating underlying Lewy body pathology and therefore, supporting a diagnosis of PD or DLB rather than PSP, MSA, or CBD. The presence of early visual hallucinations would support a diagnosis of DLB rather than PD. © 2013 Nova Science Publishers, Inc. All rights reserved.

Migration und Utopie im deutschen Gegenwartskino am Beispiel von Achim von Borries’ "England!" und Hans-Christian Schmids "Lichter"

Achim von Borries’ England! and Hans-Christian Schmid’s Distant Lights [Lichter] are two key examples of how the current issue of (economic) migration from eastern to western Europe is explored in contemporary German cinema. Set in two locations that act as places of transit for migrants from the east - the capital Berlin and the economically depressed border region along the river Oder - the films show their characters’ utopian strive for a better future. Even though they deal with it in very different ways, both films emphasise the heightened role of the imagination in a globalised world and highlight its problematic consequences.

Orthogonally polarized bright–dark pulse pair generation in mode-locked fiber laser with a large-angle tilted fiber grating

We report on the generation of orthogonally polarized bright–dark pulse pair in a passively mode-locked fiber laser with a large-angle tilted fiber grating (LA-TFG). The unique polarization properties of the LA-TFG, i.e., polarization-dependent loss and polarization-mode splitting, enable dual-wavelength mode-locking operation. Besides dual-wavelength bright pulses with uniform polarization at two different wavelengths, the bright–dark pulse pair has also been achieved. It is found that the bright–dark pulse pair is formed due to the nonlinear couplings between lights with two orthogonal polarizations and two different wavelengths. Furthermore, harmonic mode-locking of bright–dark pulse pair has been observed. The obtained bright–dark pulse pair could find potential use in secure communication system. It also paves the way to manipulate the generation of dark pulse in terms of wavelength and polarization, using specially designed fiber grating for mode-locking.