Screening neonatal jaundice based on the sclera color of the eye using digital photography

A new screening technique for neonatal jaundice is proposed exploiting the yellow discoloration in the sclera. It involves taking digital photographs of newborn infants' eyes (n = 110) and processing the pixel colour values of the sclera to predict the total serum bilirubin (TSB) levels. This technique has linear and rank correlation coefficients of 0.75 and 0.72 (both p<0.01) with the measured TSB. The mean difference ( ± SD) is 0.00 ± 41.60 µmol/l. The receiver operating characteristic curve shows that this technique can identify subjects with TSB above 205 µmol/l with sensitivity of 1.00 and specificity of 0.50, showing its potential as a screening device

Feasibility of smartphone colorimetry of the face as an anaemia screening tool for infants and young children in Ghana

Background Anaemia affects approximately a quarter of the global population. When anaemia occurs during childhood, it can increase susceptibility to infectious diseases and impair cognitive development. This research uses smartphone-based colorimetry to develop a non-invasive technique for screening for anaemia in a previously understudied population of infants and young children in Ghana. Methods We propose a colorimetric algorithm for screening for anaemia which uses a novel combination of three regions of interest: the lower eyelid (palpebral conjunctiva), the sclera, and the mucosal membrane adjacent to the lower lip. These regions are chosen to have minimal skin pigmentation occluding the blood chromaticity. As part of the algorithm development, different methods were compared for (1) accounting for varying ambient lighting, and (2) choosing a chromaticity metric for each region of interest. In comparison to some prior work, no specialist hardware (such as a colour reference card) is required for image acquisition. Results Sixty-two patients under 4 years of age were recruited as a convenience clinical sample in Korle Bu Teaching Hospital, Ghana. Forty-three of these had quality images for all regions of interest. Using a naïve Bayes classifier, this method was capable of screening for anaemia (<11.0g/dL haemoglobin concentration) vs healthy blood haemoglobin concentration (≥11.0g/dL) with a sensitivity of 92.9% (95% CI 66.1% to 99.8%), a specificity of 89.7% (72.7% to 97.8%) when acting on unseen data, using only an affordable smartphone and no additional hardware. Conclusion These results add to the body of evidence suggesting that smartphone colorimetry is likely to be a useful tool for making anaemia screening more widely available. However, there remains no consensus on the optimal method for image preprocessing or feature extraction, especially across diverse patient populations

Developing a home monitoring system for patients with chronic liver disease using a smartphone

Liver disease is a growing problem in the UK, and one of the major causes of working-age premature death. Patients with advanced liver disease are typically admitted to hospital on multiple occasions, where they are stabilised before discharge. At home, there is little or no monitoring of their condition available, making it difficult to time additional treatment. Here, a system for non-invasive assessment of serum bilirubin level is proposed, based on imaging the white of the eye (sclera) using a smartphone. Elevated bilirubin level manifests as jaundice, and is a key indicator of overall liver function. Smartphone imaging makes the system low cost, portable and non-contact. An ambient subtraction technique based on subtracting data from flash/ no-flash image pairs is leveraged to account for variations in ambient light. The subtracted signal to noise ratio (SSNR) metric has been developed to ensure good image quality. Values falling below the experimentally-determined threshold of 3.4 trigger a warning to re-capture. To produce device-independent results, mapping approaches based on image metadata and colour chart images were compared. It was found that introducing a one-time calibration step of imaging a colour chart for each device leads to the best compatibility of results from different phones. In a clinical study at the Royal Free Hospital, London, over 100 sets of patient scleral images were captured with two different smartphones and paired clinical information was recorded. A filtering algorithm was developed to tackle the high density of blood vessels and specular reflection observed in the images, yielding a 94% success rate. Strong cross-sectional and longitudinal correlations of scleral yellowness and serum bilirubin level were found of 0.89 and 0.72 respectively (both p<0.001). When the proposed processing was applied, results from the two phones were demonstrated to be compatible. These results demonstrate the strong potential for the system as a monitoring tool

Screening for Neonatal Jaundice by Smartphone Sclera Imaging

Jaundice is observed in over 60% of neonates and must be carefully monitored. Ifsevere cases go unnoticed, death or permanent disability can result. Neonatal jaun-dice causes 100,000 deaths yearly, with low-income countries in Africa and SouthAsia particularly affected. There is an unmet need for an accessible and objectivescreening method. This thesis proposes a smartphone camera-based method forscreening based on quantification of yellow discolouration in the sclera.The primary aim is to develop and test an app to screen for neonatal jaundicethat requires only the smartphone itself. To this end, a novel ambient subtractionmethod is proposed and validated, with less dependence on external hardware orcolour cards than previous app-based methods. Another aim is to investigate thebenefits of screening via the sclera. An existing dataset of newborn sclera images(n=87) is used to show that sclera chromaticity can predict jaundice severity.The neoSCB app is developed to predict total serum bilirubin (TSB) fromambient-subtracted sclera chromaticity via a flash/ no-flash image pair. A studyis conducted in Accra, Ghana to evaluate the app. With 847 capture sessions, thisis the largest study on image-based jaundice detection to date. A model trained onsclera chromaticity is found to be more accurate than one based on skin. The modelis validated on an independent dataset collected at UCLH (n=38).The neoSCB app has a sensitivity of 100% and a specificity of 76% in iden-tifying neonates with TSB≥250μmol/L (n=179). This is equivalent to the TcB(JM-105) data collected concurrently, and as good as the best-performing app in theliterature (BiliCam). Following a one-time calibration, neoSCB works without spe-cialist equipment, which could help widen access to effective jaundice screening

Improved facial feature fitting for model based coding and animation

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Eye Tracking in User Interfaces

Tato diplomová práce byla vytvořena během studijního pobytu na Uviversity of Estern Finland, Joensuu, Finsko. Tato diplomová práce se zabývá využitím technologie sledování pohledu neboli také sledování pohybu očí (Eye-Tracking) pro interakci člověk-počítač (Human-Computer Interaction (HCI)). Navržený a realizovaný systém mapuje pozici bodu pohledu/zájmu (the point of gaze), která odpovídá souřadnicím v souřadnicovém systému kamery scény do souřadnicového systému displeje. Zároveň tento systém kompenzuje pohyby uživatele a tím odstraňuje jeden z hlavních problémů využití sledování pohledu v HCI. Toho je dosaženo díky stanovení transformace mezi projektivním prostorem scény a projektivním prostorem displeje. Za použití význačných bodů (interesting points), které jsou nalezeny a popsány pomocí metody SURF, vyhledání a spárování korespondujících bodů a vypočítání homografie. Systém byl testován s využitím testovacích bodů, které byly rozložené po celé ploše displeje.This MSc Thesis was performed during a study stay at the University of Eastern Finland, Joensuu, Finland. This thesis presents the utilization of Eye-Tracking technology in Human-Computer Interaction (HCI). The proposed and implemented system is able to map co-ordinates in the plane of a scene camera, which correspond with co-ordinates of the point of gaze, into co-ordinates in the plane of a display device. In addition, the system compensates user's motions and thus removes one of main problems of use of Eye-Tracking in HCI. This is achieved by determination of a transformation between the projective space of scene and the projective space of display. Method is based on detection and description of interesting points by using SURF, matching of corresponding points and calculating of homography. The system has been tested by using testing points, which are spread over the display area.

Within- and among-individual variation in metabolic rate in juvenile Atlantic salmon, Salmo salar

Animals may adopt a range of energy strategies to persist and perhaps prosper under various prevailing environmental conditions. For example, they may achieve similar growth by investing heavily in maintaining a high capacity food capture and processing system or by using a lower capacity system that is cheap to run but which is less effective at accruing further resources. The way that individuals within species allocate energy resources is an intriguing issue that has implications for understanding competition, population structuring and the response of populations to environmental change. Energy budgets account quantitatively for the pathways by which food energy results in variation in somatic resources and constitute an important basis for evaluating links between behaviour and aspects of performance. Atlantic salmon have been an important model for exploring relationships between growth performance, metabolic strategies and individual behaviour. Juvenile salmonid fish have been a particularly useful subject for exploring individual variation in metabolism because it has been possible to relate standard metabolic rate (SMR) to behavioural traits and lifestyle within a species. SMR correlates with dominance status, which is reflected in the ability of fish to access high value food patches and may promote faster growth under some conditions. This thesis focuses on the within- and among-individual variation in SMR and looks at how a fish’s external environment and social interactions can influence its SMR, and whether this variation in SMR can affect other aspects of metabolism such as feeding. Experiments were carried out to determine: (A) whether the presence of a shelter reduces SMR; this may provide an additional reason for the extent to which these fish will compete aggressively for shelters when these are limiting (Chapter 2); (B) the extent of intraspecific variation in SDA (i.e. differences in the measured parameters that are used to define SDA), and to test whether the SDA for a given meal varies as a function of individual traits such as SMR. If SMR is directly related to scope for growth, then the speed and size of the SDA response should also correlate with SMR (Chapter 3); (C) whether ventilation rate is sufficiently accurately related to metabolic rate (MR) at a range of temperatures and activities so as to allow energy expenditure to be predicted outside a respirometer (Chapter 4); and (D) how visual isolation and the presence of a conspecific can affect SMR, using the method developed in the previous chapter (Chapter 5). Access to shelter was shown to have a significant impact on SMR, producing on average a 30% increase in metabolic costs in the absence of shelter. Therefore, the presence of appropriate shelter not only reduces the risk of predation but also provides a metabolic benefit to fish that is likely to have implications for growth performance and activity budgets. Variation in SMR was shown to affect the profile of energy consumption during digestion of a meal. The peak in post-prandial oxygen consumption, the duration of elevated metabolism and the overall magnitude of SDA all increased with the size of meal consumed. However, for a given meal size, fish with a higher SMR also had a higher peak and greater magnitude of SDA, yet experienced a shorter duration over which metabolism was elevated following the meal. Intraspecific variation in SMR is thus linked to variation in digestive strategies, although the costs and benefits of a given SMR are likely to vary with resource availability and predictability. Ventilation frequency was shown to be a good correlate of MR, since MR was found to correlate strongly with VR in all fish tested, at all temperatures and the relationship was independent of causal factor. The relationship was linear, and both the slope and corresponding intercept of the regression equation were strongly dependent on the fish’s body weight and the test temperature. Visual measurements of VR may therefore provide a highly accurate, cheap and non-invasive method of measuring the energy consumption of fish engaged in natural behaviours. Comparing SMR of individual fish when alone with response to presence and absence of physical shelters showed that all fish exhibited a reduction in SMR when provided with an appropriate shelter. However, when grouped, there were both positive and negative group effects on SMR depending on the relative size of fish. The consequences are that, although the group effect on SMR may be small on average, at the population level it is large, of variable sign and profoundly important in terms of the overall energy budget at the individual level. This thesis therefore shows that metabolic rates can vary extensively within as well as between individuals, depending on the context, and this variation will have profound effects on overall energy budgets

Contextual and own-age effects in age perception

Our judgement of certain facial characteristics such as emotion, attractiveness or age, is affected by context. Faces that are flanked by younger faces, for example, are perceived as being younger, whereas faces flanked by older faces are perceived as being older. Here, we investigated whether contextual effects in age perception are moderated by own age effects. On each trial, a target face was presented on the screen, which was flanked by two faces. Flanker faces were either identical to the target face, were 10 years younger or 10 years older than the target face. We asked 40 older (64–69 years) and 43 younger adults (24–29) to estimate the age of the target face. Our results replicated previous studies and showed that context affects age estimation of faces flanked by target faces of different ages. These context effects were more pronounced for younger compared to older flankers but present across both tested age groups. An own-age advantage was observed for older adults for unflanked faces who had larger estimation errors for younger faces compared to older faces and younger adults. Flanker effects, however, were not moderated by own-age effects. It is likely that the increased effect of younger flankers is due to mechanisms related to perceptual averaging

Contextual and own-age effects in age perception

Our judgement of certain facial characteristics such as emotion, attractiveness or age, is affected by context. Faces that are flanked by younger faces, for example, are perceived as being younger, whereas faces flanked by older faces are perceived as being older. Here, we investigated whether contextual effects in age perception are moderated by own age effects. On each trial, a target face was presented on the screen, which was flanked by two faces. Flanker faces were either identical to the target face, were 10 years younger or 10 years older than the target face. We asked 40 older (64–69 years) and 43 younger adults (24–29) to estimate the age of the target face. Our results replicated previous studies and showed that context affects age estimation of faces flanked by target faces of different ages. These context effects were more pronounced for younger compared to older flankers but present across both tested age groups. An own-age advantage was observed for older adults for unflanked faces who had larger estimation errors for younger faces compared to older faces and younger adults. Flanker effects, however, were not moderated by own-age effects. It is likely that the increased effect of younger flankers is due to mechanisms related to perceptual averaging