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    Nanobiomaterials for bionic eye: vision of the future

    , Article Engineering of Nanobiomaterials: Applications of Nanobiomaterials ; 2016 , Pages 257-285 ; 9780323417341 (ISBN); 9780323415323 (ISBN) Ghaffari, M ; Moztarzadeh, S ; Rahmanian, F ; Yazdanpanah, A ; Ramedani, A ; Mills, D. K ; Mozafari, M ; Sharif University of Technology
    Elsevier Inc 
    With the aid of nanotechnology and understanding of visual and retinal neuroscience, tremendous advances have been achieved in the treatment of people who have lost their vision. Among vision restoration techniques, stem cells or gene therapy remain in their early phases of development, while visual prosthesis (bionic eye) attains some approaches in vision restoration. There are several ongoing projects around the world on visual prosthesis, including Argus II (received FDA approval), Boston Retinal Implant Project, Epi-Ret 3, Intelligent Medical Implants and Alpha-IMS (Retina Implant AG). One of the most crucial traits of implants is vision resolution that theoretically correlates with... 

    Investigation on Using Fresnel Lens in Human Eye

    , M.Sc. Thesis Sharif University of Technology Eskandari, Mohammad Amin (Author) ; Seyyed Reihani, Nader (Supervisor)
    Human eye is one of the most important organs of the human body. Performance of the eye may be decreased by some anomalies such as myopia, hyperopia, astigmatism, cataract, glaucoma, etc. There are variety of techniques to treat eye anomalies including surgery, using optical elements and training methods.The easiest way of treating refractive errors of the eye, is to use optical elements such as contact lenses, intraocular lenses and glasses. In the case of cataract, Crystalline lens loses its opacity and should be replaced by artificial lens. The best choice is Fresnel lens which has lower weight and thickness than refractive lenses.Fresnel lens is a diffractive optical element which uses... 

    Eye detection and tracking in video streams

    , Article IEEE International Symposium on Communications and Information Technologies: Smart Info-Media Systems, ISCIT 2004, Sapporo, 26 October 2004 through 29 October 2004 ; Volume 2 , 2004 , Pages 1258-1261 ; 0780385934 (ISBN) Fathi, A ; Manzuri, M. T ; Sharif University of Technology
    This paper presents a new method for eye detection in a sequence of video pictures. We first find the face region using the features of skin's color, then the location of eye is determined by applying three cues on the detected face region. The first cue is the eye intensity and color, because the intensity of each eye region is relatively low and its color differs from the color of surrounding skin. The second cue is based on the position and size of eyes. The third cue is based on the convolution of proposed-eye-variance-filter with the eye-window candidates. After finding the precise location of eye, it will be tracked in a finite search window. We have evaluated and tested the presented... 

    Biomechanical Modeling of Human Eye in Blunt Impact: A Finite Element Study

    , M.Sc. Thesis Sharif University of Technology Rahmannia, Saeed (Author) ; Ahmadian, Mohammad taghi (Supervisor) ; Fallah Rajabzadeh, Famida (Co-Advisor)
    Nowadays, Eye injuries caused by blunt impacts are considered among the major causes of blindness and vision problems; therefore, studying the existence of possible damages can be quite useful and effective. One of the quickest and most suitable methods in identifying damage parameters is finite-element modeling of the human eye. In this regard, in the current study, first a geometrical design was created by incorporating CT-Scan images of the eye into Mimics and later Solid works software. Afterwards, the most suitable mechanical properties for the constituents of the eye were extracted from the literature. The mechanical properties of vitreous and Sclera were obtained by experimental... 

    Eye diagram parameter extraction of nano scale VLSI interconnects

    , Article 2012 IEEE 21st Conference on Electrical Performance of Electronic Packaging and Systems, EPEPS 2012 ; 2012 , Pages 327-330 ; 9781467325394 (ISBN) Mehri, M ; Sarvari, R ; Seydolhosseini, A ; Sharif University of Technology
    In this paper, jitter due to both capacitive and inductive coupling is studied. Maximum frequency of driving signal on a wire is limited by its input rise time, fall time, pulse width, and the coupling effect from its neighbors. The analytical expressions to estimate the deterministic jitter time due to these effects are presented. The estimation is based on the fastest and slowest approximation of the signal waveform components. Also, we have extracted the eye opening parameters of the eye diagram. The inductance effects significance is shown on eye opening and jitter time. The 45nm technology is used for estimating the horizontal and vertical eye opening and jitter time. The presented... 

    Biomechanical simulation of eye-airbag impacts during vehicle accidents

    , Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 232, Issue 7 , 2018 , Pages 699-707 ; 09544119 (ISSN) Shirzadi, H ; Zohoor, H ; Naserkhaki, S ; Sharif University of Technology
    SAGE Publications Ltd  2018
    Airbags are safety devices in vehicles effectively suppressing passengers’ injuries during accidents. Although there are still many cases of eye injuries reported due to eye-airbag impacts in recent years. Biomechanical approaches are now feasible and can considerably help experts to investigate the issue without ethical concerns. The eye-airbag impact–induced stresses/strains in various components of the eye were found to investigate the risk of injury in different conditions (impact velocity and airbag pressure). Three-dimensional geometry of the eyeball, fat and bony socket as well as the airbag were developed and meshed to develop a finite element model. Nonlinear material properties of... 

    Biomechanical Modeling of Human Eye in Car Airbag Blunt Impacts During Accident: an Empirical Test and Finite Element Study

    , M.Sc. Thesis Sharif University of Technology Shirzadi, Hooman (Author) ; Zohour, Hassan (Supervisor)
    Eye and vision are the most important tools and the perceptual sense of human. This important vital member is one of the most vulnerable organs of human body. For example in the United States 1.9 million eye surgery are being done yearly which include 9 thousand globe rupture and 30 thousand blindness due to impacts on the eye. Eye traumas could have occurred as mechanical, radiation, thermal, chemical, etc. among these, the damages related to the airbag impact which is subset of mechanical damages, take a significant percentage. Presenting a model of human eye in car airbag blunt impacts during accident could be effective for receiving helpful information from damage of the internal parts... 

    Low-cost, Non-infrared, MRI-compatible Eye Tracker for Research

    , M.Sc. Thesis Sharif University of Technology Cherakhloo, Mahdi (Author) ; Ghazizadeh, Ali (Supervisor)
    Looking for eye paths is widely used in various research and even commercial areas, Eye trackers that are used commercially today do this by using infrared transmitters and receivers. As the speed and performance of the processors advanced, many efforts have been made to create an eye-tracking device using visible light without any movement restrictions for the subject, and efforts to increase the accuracy and speed of sampling are still ongoing; The initial methods proposed in this area are feature-based, but newer papers and researches have used Deep learning methods to do this. The commonly used methods for eye tracking in visible light are three main steps: 1. Fetching frames from the... 

    Proposing an Empirical Motion-Time Ppattern for Hhuman Gaze Behavior in Bifferent Social Situations and Implementing the Pattern on RASA Social

    , M.Sc. Thesis Sharif University of Technology Mashaghi, Mohammad Hossein (Author) ; Taheri, Alireza (Supervisor) ; Behzadipour, Saeed (Supervisor)
    Social robots that are designed to interact with people in order to fulfill purposes like education, healthcare, etc. have to behave interactively like human. One of the human’s interactive behaviors is eye gaze. Studying the literature, we found out that in previous researches conducted to control the social robots’ gaze behavior, human gaze behavior was investigated in some limited situations such as two- or three-way conversation in order to extract the pattern of this behavior. Therefore, increasing the variety of studied social situations is a way to fill this gap. In this research we intend to propose an empirical motion-time pattern for human gaze behavior in some different social... 

    Freshness assessment of gilthead sea bream (Sparus aurata) by machine vision based on gill and eye color changes

    , Article Journal of Food Engineering ; Volume 119, Issue 2 , 2013 , Pages 277-287 ; 02608774 (ISSN) Dowlati, M ; Mohtasebi, S. S ; Omid, M ; Razavi, S. H ; Jamzad, M ; De La Guardia, M ; Sharif University of Technology
    The fish freshness was evaluated using machine vision technique through color changes of eyes and gills of farmed and wild gilthead sea bream (Sparus aurata), being employed lightness (L*), redness (a *), yellowness (b*), chroma (c *), and total color difference (ΔE) parameters during fish ice storage. A digital color imaging system, calibrated to provide accurate CIELAB color measurements, was employed to record the visual characteristics of eyes and gills. The region of interest was automatically selected using a computer program developed in MATLAB software. L*, b *, and ΔE of eyes increased with storage time, while c* decreased. The a* parameter of fish eyes did not show clear a trend... 

    Design of a ratiometric fluorescent probe for naked eye detection of dopamine

    , Article Analytical Methods ; Volume 9, Issue 23 , 2017 , Pages 3505-3512 ; 17599660 (ISSN) Farahmand Nejad, M. A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    A simple and effective ratiometric fluorescence sensor for selective detection of dopamine (DA) in alkaline media has been developed by simply mixing thioglycolic acid (TGA) functionalized orange fluorescent cadmium telluride (CdTe) quantum dots (QDs) with amino-functionalized blue fluorescent carbon nanodots (CDs). Under a single excitation wavelength of 365 nm, the sensor exhibits dual-emissions centered at 445 and 603 nm. The fluorescence of CdTe QDs is selectively quenched by DA, whereas the fluorescence of CDs is insensitive to the analyte. In the presence of different amounts of DA, the variations in the dual emission intensity ratios exhibit a continuous color change from pink to... 

    Task-specific modulation of PFC activity for matching-rule governed decision-making

    , Article Brain Structure and Function ; Volume 226, Issue 2 , 2021 , Pages 443-455 ; 18632653 (ISSN) Parto Dezfouli, M ; Zarei, M ; Constantinidis, C ; Daliri, M. R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Storing information from incoming stimuli in working memory (WM) is essential for decision-making. The prefrontal cortex (PFC) plays a key role to support this process. Previous studies have characterized different neuronal populations in the PFC for working memory judgements based on whether an originally presented stimulus matches a subsequently presented one (matching-rule decision-making). However, much remains to be understood about this mechanism at the population level of PFC neurons. Here, we hypothesized differences in processing of feature vs. spatial WM within the PFC during a matching-rule decision-making task. To test this hypothesis, the modulation of neural activity within the... 

    Towards energy optimization of transparent watermarks using entropy masking

    , Article IASTED International Conference on Internet and Multimedia Systems and Applications, EuroIMSA 2005, Grindelwald, 21 February 2005 through 23 February 2005 ; 2005 , Pages 259-264 ; 0889864861 (ISBN) Haghighi, M. S ; Ghaemmaghami, S ; Hamza M. H ; Sharif University of Technology
    An invisible image watermarking scheme tends to insert the mark in a transparent manner, with the highest possible energy. Several watermarking algorithms use human visual models as perceptual masks to maximize the power of watermark. We take advantage of inhibitory and excitatory characteristics of eye receptors which yield an extra capacity, for amplifying watermark power, while still satisfying imperceptibility constraint. Spatial-domain image entropy is used as a measure of strength of inhibitory effect. The principle of our idea is based on the decomposition of mark sequence into two parts, corresponding to two complementary sets of pixels in spatial-domain. These sets are determined... 

    Modeling, Analysis and Possible Solution for Excessive Intraocular Pressure in Glaucoma Patients

    , M.Sc. Thesis Sharif University of Technology Singh, Dara (Author) ; Firouzbakhsh, Keykhosrow (Supervisor)
    With the advent of new computer technologies, computational analysis on the human organs has become tremendously popular in the field of medical science. Every year thousands of people suffer irreversible eye damages pertaining to lack of adequate medications. In this regards, enormous amount of money is spent annually but mostly in vain due to the irreversibility and silent nature of eye diseases like glaucoma. Yet more precise studies on the topic are requisite. In this thesis, a validated half 3D finite volume model of human eye considering the fluid flow in collaboration with heat transfer in the steady state utilizing the well known discretized bio-heat transfer equation coupled with... 

    Simulation and Optimization of Drug Delivery Methods to Eye

    , M.Sc. Thesis Sharif University of Technology Jooybar, Elaheh (Author) ; Abdekhodaie, Mohammad Jafar (Supervisor) ; Farhadi, Fatollah (Supervisor)
    In this study a mathematical model for intravitreal injection and depositing controlled release systems in the eye to treat posterior segment deseases is developed. The effects of important parameters that play a critical role in drug distribution are also studied.
    Geometrical model is constructed using COMSOL software and governing equations for a 3-D model of drug distribution are solved by finite element method. The geometry is based on the exact dimensions of human eye and retina, choroid and sclera are considered separately. Choroidal losses to the circulatory system and active transport by the retinal pigment epithelium are incorporated as well. Moreover, two types of implant... 

    Pupil Detection and Eye Tracking

    , M.Sc. Thesis Sharif University of Technology Sobhani, Elahe (Author) ; Babaie Zadeh, Massoud (Supervisor)
    About a century, “Eye Tracking” has been studied, and it has two definitions: • The process of measuring the point of gaze (where one is looking). • The process of measuring the motion of an eye relative to the head. Eye tracking technology has been used in many fields such as psychology. However, applications of this technology has been recently considered in marketing, computer interfacing, entertainment, training and so forth. Since pupil is a distinc area in eye images, pupil detection is one of the effective solutions of eye tracking. In most of the pupil detection approaches, the edge points of the pupil contour are detected firstly, and then the optimal ellipse is fitted to them.... 

    Design of a Colorimetric Sensor Array Based on Aggregation of Gold Nanoparticles for Identification and Discrimination of Pesticides

    , M.Sc. Thesis Sharif University of Technology Mirghafouri, Mohammad Reza (Author) ; Hormozinezhad, Mohammad Reza (Supervisor) ; Ghasemi, Forough (Supervisor)
    There is great attention in developing rapid and straightforward methods for the identification of various pesticides that are usually used simultaneously in agricultural products. It is due to the extensive use of a diverse class of pesticides in agricultural products and their high toxicity which causes serious diseases in the human body. In the current study, a non-enzymatic sensor array has been developed for the identification and discrimination of five different pesticides belong to diverse classes including organophosphate, carbamate, and bipyridylium. For this aim, gold nanoparticles with two different capping agents consisting of citrate and borohydride were used as sensing... 

    Simple and efficient method to measure vessel tortuosity

    , Article Proceedings of the 3rd International Conference on Computer and Knowledge Engineering, ICCKE 2013, Mashhad: Iran ; 2013 , Pages 219-222 ; 9781479920921 (ISBN) Pourreza, H. R ; Pourreza, M ; Banaee, T ; Sharif University of Technology
    Retinal vessels tortuosity is one of the important signs of cardiovascular diseases such as diabetic retinopathy and hypertension. In this paper we present a simple and efficient algorithm to measure the grade of tortuosity in retinal images. This algorithm consists of four main steps,vessel detection, extracting vascular skeleton via thinning, detection of vessel crossovers and bifurcations and finally calculating local and global tortuosity. The last stage is based on a circular mask that is put on every skeleton point of retinal vessels. While the skeleton of vessel splits the circle in each position, the local tortuosity is considered to be the bigger to smaller area ratio. The proposed... 

    Optimization of head CT protocol to reduce the absorbed dose in eye lenses and thyroid: A phantom study

    , Article Iranian Journal of Medical Physics ; Volume 16, Issue 1 , 2019 , Pages 64-74 ; 1735160X (ISSN) Kalhor, P ; Changizi, V ; Hosseini, A ; Jazayeri, E ; Sharif University of Technology
    Mashhad University of Medical Sciences  2019
    Introduction: Utilization of computed tomography (CT) scans is increasing annually. This study aimed to reduce the absorbed dose of sensitive organs in the head (eye lenses and thyroid) and to assess changes in resultant images quality in head scans when the radiation dose is decreased. Material and Methods: An anthropomorphic phantom was examined with head protocols in both helical and sectional modes using two 16-slice CT scanners. The entrance surface dose of eye lenses and thyroid was measured with standard protocols and after reducing the mAS and kilo-voltage using thermo-luminescence dosimeters (TLDs). Results: In sectional mode with standard protocol, the highest surface dose was 2.3... 

    A method for eye detection based on SVD transforms

    , Article International Journal of Imaging Systems and Technology ; Volume 16, Issue 5 , 2006 , Pages 222-229 ; 08999457 (ISSN) Danafar, S ; Taghavi Sheikh, L ; Tavakoli Targhi, A. R ; Sharif University of Technology
    A set of transforms (SVD transforms) were introduced in (Shahshahani and Tavakoli Targhi) for understanding images. These transforms have been applied to some problems in computer vision including segmentation, detection of objects in a texture environment, classification of textures, detection of cracks or other imperfections, etc. This technique is shown to be applicable to determination of the location of eyes in a facial image. This method makes no use of color cues, prior geometric knowledge or other assumptions and does not require training. It is also insensitive to local perturbations in lighting, change of orientation and pose, scaling, and complexity of the background including...