A Camera-Projector System for Robot Positioning by Visual Servoing

Positioning a robot with respect to objects by using data provided by a camera is a well known technique called visual servoing. In order to perform a task, the object must exhibit visual features which can be extracted from different points of view. Then, visual servoing is object-dependent as it depends on the object appearance. Therefore, performing the positioning task is not possible in presence of nontextured objets or objets for which extracting visual features is too complex or too costly. This paper proposes a solution to tackle this limitation inherent to the current visual servoing techniques. Our proposal is based on the coded structured light approach as a reliable and fast way to solve the correspondence problem. In this case, a coded light pattern is projected providing robust visual features independently of the object appearance

An approach to visual servoing based on coded light

Positioning a robot with respect to objects by using data provided by a camera is a well known technique called visual servoing. In order to perform a task, the object must exhibit visual features which can be extracted from different points of view. Then, visual servoing is object-dependent as it depends on the object appearance. Therefore, performing the positioning task is not possible in presence of non-textured objects or objects for which extracting visual features is too complex or too costly. This paper proposes a solution to tackle this limitation inherent to the current visual servoing techniques. Our proposal is based on the coded structured light approach as a reliable and fast way to solve the correspondence problem. In this case, a coded light pattern is projected providing robust visual features independently of the object appearance

Robust decoupled visual servoing based on structured light

This paper focuses on the problem of realizing a plane-to-plane virtual link between a camera attached to the end-effector of a robot and a planar object. In order to do the system independent to the object surface appearance, a structured light emitter is linked to the camera so that 4 laser pointers are projected onto the object. In a previous paper we showed that such a system has good performance and nice characteristics like partial decoupling near the desired state and robustness against misalignment of the emitter and the camera (J. Pages et al., 2004). However, no analytical results concerning the global asymptotic stability of the system were obtained due to the high complexity of the visual features utilized. In this work we present a better set of visual features which improves the properties of the features in (J. Pages et al., 2004) and for which it is possible to prove the global asymptotic stability

Plane-to-plane positioning from image-based visual servoing and structured light

In this paper we face the problem of positioning a camera attached to the end-effector of a robotic manipulator so that it gets parallel to a planar object. Such problem has been treated for a long time in visual servoing. Our approach is based on linking to the camera several laser pointers so that its configuration is aimed to produce a suitable set of visual features. The aim of using structured light is not only for easing the image processing and to allow low-textured objects to be treated, but also for producing a control scheme with nice properties like decoupling, stability, well conditioning and good camera trajectory

Comparison of visual preservation after transplantation of BDNF or GDNF secreting mesenchymal stem cells in glaucomatous rat eyes

Purpose:To functionally and morphologically characterize the retina and optic nerve after transplantation of Brain-derived neurotrophic factor (BDNF) and Glial-derived neurotrophic factor (GDNF) secreting mesenchymal stem cells (MSCs) into glaucomatous rat eyes. Methods:Chronic ocular hypertension (COH) was induced in Brown Norway rats. Lentiviral constructs were used to transduce rat MSCs to produce BDNF, GDNF, or green fluorescent protein (GFP). The fellow eyes served as internal controls. Two days following COH induction, eyes received intravitreal injections of transduced MSCs. Electroretinography was performed to assess retinal function. Tonometry was performed throughout the experiment to monitor IOP. 42 days after MSC transplantation, rats were euthanized and the eyes and optic nerves were prepared for analysis. Results:Increased expression and secretion of BDNF and GDNF from lentiviral-transduced MSCs was verified using ELISA, and a bioactivity assay. Ratio metric analysis (COH eye/ Internal control eye response) of the Max combined response A-Wave showed animals with BDNF-MSCs (23.35 ± 5.15%, p=0.021) and GDNF-MSCs (28.73 ± 3.61%, p=0.025) preserved significantly more visual function than GFP-MSC treated eyes MSCs (18.05 ± 5.51%). Animals receiving BDNF-MSCs also had significantly better B-wave (33.80 ± 7.19%) and flicker ERG responses (28.52 ± 10.43%) than GFP-MSC treated animals (14.06 ± 12.67%; 3.52 ± 0.07%, respectively). Animals receiving GDNF-MSC transplants tended to have better function than animals with GFP-MSC transplants, but were not statistically significant (p=0.057 and p=0.0639). Conclusions:Mesenchymal stem cells are an excellent source of cells for autologous transplantation for the treatment of neurodegenerative diseases. We have demonstrated that lentiviral- transduced MSCs can survive following transplantation and preserve visual function in glaucomatous eyes. These results suggest that MSCs may be an ideal cellular vehicle for delivery of specific neurotrophic factors to the retina.

La igualdad de género y la autonomía personal, objetivos del I plan de acción integral para las mujeres con discapacidad en Andalucía

Boletín semanal para profesionales sanitarios de la Secretaría General de Salud Pública y Participación Social de la Consejería de Salud

La atención a la dependencia, la discapacidad y la inmigración en clave de género, a debate en el X Congreso Mundos de Mujeres 08

Boletín semanal para profesionales sanitarios de la Secretaría General de Salud Pública y Participación Social de la Consejería de Salud

El diagnostico precoz de la hipoacusia en recién nacidos, clave en la prevención de la discapacidad infantil

Boletín semanal para profesionales sanitarios de la Secretaría General de Salud Pública y Participación Social de la Consejería de Salud

Guía de buenas prácticas sobre personas con discapacidad para profesionales de la comunicación. Manual de estilo

Publicado en la página web de la Consejería de Salud y Bienestar Social: www.juntadeandalucia.es/salud (Consejería de Salud y Bienestar Social / Información General - Guía de buenas prácticas sobre personas con discapacidad para profesionales de la comunicación

Efectos de la deficiencia de yodo sobre variables intelectuales en una población infantil.

An association between severe iodine deficiency and poor mental development has been found in many studies. We examined the relationship between moderate or mild iodine deficiency and intellectual capacity in order to determine whether problems common to severe iodine deficiency (including mental retardation) also emerge in a more subtle form. We also wished to know whether the classic methodology (comparing iodine-deficient zones with nondeficient zones) is the most adequate, and propose to combine this grouping by zones with urinary iodine presented by individuals in each zone. We measured IQ, manipulative and verbal capacity, attention, visual motor ability and disruptive behaviour, variables that have barely been studied in this kind of investigations. The sample comprised 760 schoolchildren from the province of Jaén (southern Spain). Our results show that children with low levels of iodine intake and with urinary iodine concentration lower than 100 microg/litre had a lower IQ and displayed more disruptive behaviour than children with high levels of the criteria. The other variables were not associated with iodine deficiency.

Characteristics of eyes with secondary loss of visual acuity receiving variable dosing ranibizumab for neovascular age-related macular degeneration.

PURPOSE: The aim of this work is to investigate the characteristics of eyes failing to maintain visual acuity (VA) receiving variable dosing ranibizumab for neovascular age-related macular degeneration (nAMD) after three initial loading doses. METHODS: A consecutive series of patients with nAMD, who, after three loading doses of intravitreal ranibizumab (0.5 mg each), were re-treated for fluid seen on optical coherence tomography. After exclusion of eyes with previous treatment, follow-up less than 12 months, or missed visits, 99 patients were included in the analysis. The influence of baseline characteristics, initial VA response, and central retinal thickness (CRT) fluctuations on the VA stability from month 3 to month 24 were analyzed using subgroups and multiple regression analyses. RESULTS: Mean follow-up duration was 21.3 months (range 12-40 months, 32 patients followed-up for ≥24 months). Secondary loss of VA (loss of five letters or more) after month 3 was seen in 30 patients (mean VA improvement from baseline +5.8 letters at month 3, mean loss from baseline -5.3 letters at month 12 and -9.7 at final visit up to month 24), while 69 patients maintained vision (mean gain +8.9 letters at month 3, +10.4 letters at month 12, and +12.8 letters at final visit up to month 24). Secondary loss of VA was associated with the presence of pigment epithelial detachment (PED) at baseline (p 0.01), but not with baseline fibrosis/atrophy/hemorrhage, CRT fluctuations, or initial VA response. Chart analysis revealed additional individual explanations for the secondary loss of VA, including retinal pigment epithelial tears, progressive fibrosis, and atrophy. CONCLUSIONS: Tissue damage due to degeneration of PED, retinal pigment epithelial tears, progressive fibrosis, progressive atrophy, or massive hemorrhage, appears to be relevant in causing secondary loss of VA despite vascular endothelial growth factor suppression. PED at baseline may represent a risk factor.

Selective integration of auditory-visual looming cues by humans.

An object's motion relative to an observer can confer ethologically meaningful information. Approaching or looming stimuli can signal threats/collisions to be avoided or prey to be confronted, whereas receding stimuli can signal successful escape or failed pursuit. Using movement detection and subjective ratings, we investigated the multisensory integration of looming and receding auditory and visual information by humans. While prior research has demonstrated a perceptual bias for unisensory and more recently multisensory looming stimuli, none has investigated whether there is integration of looming signals between modalities. Our findings reveal selective integration of multisensory looming stimuli. Performance was significantly enhanced for looming stimuli over all other multisensory conditions. Contrasts with static multisensory conditions indicate that only multisensory looming stimuli resulted in facilitation beyond that induced by the sheer presence of auditory-visual stimuli. Controlling for variation in physical energy replicated the advantage for multisensory looming stimuli. Finally, only looming stimuli exhibited a negative linear relationship between enhancement indices for detection speed and for subjective ratings. Maximal detection speed was attained when motion perception was already robust under unisensory conditions. The preferential integration of multisensory looming stimuli highlights that complex ethologically salient stimuli likely require synergistic cooperation between existing principles of multisensory integration. A new conceptualization of the neurophysiologic mechanisms mediating real-world multisensory perceptions and action is therefore supported.

Bilateral sequential nonarteritic anterior ischemic optic neuropathy: a comparison of visual outcomes in fellow eyes using quantitative analysis of goldmann visual fields.

OBJECTIVE To better define the concordance of visual loss in patients with nonarteritic anterior ischemic optic neuropathy (NAION). METHODS The medical records of 86 patients with bilateral sequential NAION were reviewed retrospectively, and visual function was assessed using visual acuity, Goldmann visual fields, color vision, and relative afferent papillary defect. A quantitative total visual field score and score per quadrant were analyzed for each eye using the numerical Goldmann visual field scoring method. RESULTS Outcome measures were visual acuity, visual field, color vision, and relative afferent papillary defect. A statistically significant correlation was found between fellow eyes for multiple parameters, including logMAR visual acuity (P = .01), global visual field (P < .001), superior visual field (P < .001), and inferior visual field (P < .001). The mean deviation of total (P < .001) and pattern (P < .001) deviation analyses was significantly less between fellow eyes than between first and second eyes of different patients. CONCLUSIONS Visual function between fellow eyes showed a fair to moderate correlation that was statistically significant. The pattern of vision loss was also more similar in fellow eyes than between eyes of different patients. These results may help allow better prediction of visual outcome for the second eye in patients with NAION.

Décrire et convaincre: rhétoriques visuelles de la cinématographie en médecine [Describe and convince: visual rhetoric of cinematography in medicine]

The tools of visualisation occupy a central place in medicine. Far from being simple accessories of glance, they literally constitute objects of medicine. Such empirical acknowledgement and epistemological position open a vast field of investigation: visual technologies of medical knowledge. This article studies the development and transformation of medical objects which have permitted to assess the role of temporality in the epistemology of medicine. It firstly examines the general problem of the relationships between cinema, animated image and medicine and secondly, the contribution of the German doctor Martin Weiser to medical cinematography as a method. Finally, a typology is sketched out organising the variety of the visual technology of movement under the perspective of the development of specific visual techniques in medicine.

Intraocular Straylight And Contrast Sensitivity Two Months After Lasik: Intraocular Straylight Measurement As A New Parameter In Visual Quality Assessment

PROPÒSIT: Estudiar l'efecte de la cirurgia LASIK en la llum dispersa i la sensibilitat al contrast. MÈTODES: Vint-i-vuit pacients van ser tractats amb LASIK. La qualitat visual es va avaluar abans de l'operació i dos mesos després. RESULTATS: La mitjana de llum dispersa i la sensibilitat al contrast abans de l'operació no va canviar en dos mesos després. Només un ull tenia un marcat augment en la llum dispersa. Nou ulls van presentar una lleugera disminució en la sensibilitat al contrast. S'han trobat dues complicacions. CONCLUSIÓ: Després de LASIK la majoria dels pacients (80%) no van tenir complicacions i van mantenir la seva qualitat visual. Uns pocs pacients (16%) van tenir una mica de qualitat visual disminuïda. Molt pocs (4%) van tenir complicacions clíniques amb disminució en la qualitat visual.