Vasudevan Lakshminarayanan

University of Waterloo | UWaterloo

To factor an integer N into a product of two other numbers N1 and N2, Shor’s algorithm uses the Quantum Fourier Transform on n qubits, denoted QFTn, to determine the period r of a Modular Exponentiation Function (MEF), which is later used to compute a factor of N. In this work, we present Shor’s algorithm for factoring an integer of n qubits and il...

The enduring challenge of facilitating profound knowledge acquisition and meaningful learning of mathematical concepts has been a constant throughout contemporary and historical educational contexts. This issue is particularly pronounced at higher education levels, where many students struggle to connect theoretical mathematical concepts with pract...

Mobile health apps are widely used for breast cancer detection using artificial intelligence algorithms, providing radiologists with second opinions and reducing false diagnoses. This study aims to develop an open-source mobile app named “BraNet” for 2D breast imaging segmentation and classification using deep learning algorithms. During the phase...

The tessellation of the retina is of clinical importance, especially in the study of myopia. This paper presents an automated grading algorithm for tessellation based on the calculation of three Tessellated Fundus Indices (TFIs). Our new algorithm utilizes the red (R), green (G), and blue (B) color components of the region of interest (ROI) surroun...

INTRODUCTION: Ultrasound in conjunction with mammography imaging, plays a vital role in the early detection and diagnosis of breast cancer. However, speckle noise affects medical ultrasound images and degrades visual radiological interpretation. Speckle carries information about the interactions of the ultrasound pulse with the tissue microstructur...

There has been considerable progress in implicit neural representation to upscale an image to any arbitrary resolution. However, existing methods are based on defining a function to predict the Red, Green and Blue (RGB) value from just four specific loci. Relying on just four loci is insufficient as it leads to losing fine details from the neighbor...

We present results on the design of an optical image forming system. The design will enable us to study small apertures effect in image formation of the eye. The system is designed to operate with various laser sources and to obtain the Modulation transfer function (MTF) dependence with wavelength. It is then extended to characterize the monochroma...

There has been considerable progress in implicit neural representation to upscale an image to any arbitrary resolution. However, existing methods are based on defining a function to predict the RGB value from just four specific loci. Relying on just four loci is insufficient as it leads to losing fine details from the neighboring region(s). We show...

Purpose: The fractal dimension (Df) serves as a quantitative measure for the branching pattern of blood vessels. Retinal Df has been recognized as a sensitive indicator for early vascular changes in various vascular diseases. However, there is currently no built-in method for measuring Df using commercially available retinal imaging devices. This s...

Purpose: To identify optical coherence tomography angiography (OCTA) biomarkers in patients who were treated for diabetic macular oedema (DME) with intravitreal anti-vascular endothelial growth factor (VEGF) injections and compare the OCTA parameters between responders and non-responders. Methods: A retrospective cohort study of 61 eyes with DME...

Pupil reflex to variations in illumination and associated dynamics are of importance in neurology and ophthalmology. This is typically measured using a near Infrared (IR) pupillometer to avoid Purkinje reflections that appear when strong Visible Light (VL) illumination is present. Previously we demonstrated the use of deep learning techniques to ac...

(1) Background: Cancer is one of the leading causes of death worldwide, and trends in cancer incidence and mortality are increasing over last years in Loja-Ecuador. Cancer treatment is expensive because of social and economic issues which force the patients to look for other alternatives. One such alternative treatment is ivermectin-based antiparas...

Visual impairment is considered as a primary global challenge in the present era [...]

Osteoarthritis (OA) affects nearly 240 million people worldwide. Knee OA is the most common type of arthritis, especially in older adults. Physicians measure the severity of knee OA according to the Kellgren and Lawrence (KL) scale through visual inspection of X-ray or MR images. We propose a semi-automatic CADx model based on Deep Siamese convolut...

Quantum machine learning by superposition and entanglement, for disease categorization utilizing OCT images will be discussed in this paper. To the best of our knowledge, this is the first application of the quantum computing element in a neural network model for classifying ophthalmological disease. The model was built and tested with PennyLane (P...

Osteoarthritis (OA) is the most common chronic and progressive musculoskeletal disorder. These chronic disorders are not diagnosed early nor is the treatment adequate, resulting in challenges for health care systems. Radiography is the most widely used imaging method for OA diagnosis since it allows a two-dimensional evaluation, whose main advantag...

Optics concepts are fundamental to optometry. Currently, there is no published data on the status of conceptual optics among Indian optometrists. The results indicate the need for optics continuing education throughout their career

We propose a Controlled–Controlled-phase gate (CCZ) using three atoms trapped in separate optical cavities and connected by two optical fibers considered in the short fiber limit. The gate is realized within the null, single and double-excitation subspaces. The Hamiltonian of the atom-cavity-fiber system is presented, and we give Hamiltonian matrix...

One of the leading causes of irreversible vision loss is Diabetic Retinopathy (DR). The International Clinical Diabetic Retinopathy scale (ICDRS) provides grading criteria for DR. Deep Convolutional Neural Networks (DCNNs) have high performance in DR grading in terms of classification evaluation metrics; however, these metrics are not sufficient fo...

Fractals dimension (Df) is the quantification measure of blood vessels branching pattern. The retinal Df is reported to be a sensitive indicator in early vascular changes in various ocular vascular diseases like diabetic retinopathy. To the best of our knowledge, there is no inbuilt method to measure the Df by the commercially available retinal ima...

Optic disc tilt (ODT), increased ovality, peripapillary atrophy, and abnormally large or small optic discs are the earliest known reported changes in myopic eyes. Studies of these early changes may lead to a better understanding of the pathophysiology of myopia progression. The study aims to investigate if there is a relationship between the ODT an...

The foveal avascular zone (FAZ), as visualized by optical coherence tomography angiography (OCTA), has distinct parametric characteristics. These metrics can help us understand FAZ variations in various ophthalmic conditions such as diabetic retina, retinopathy of prematurity, glaucoma, and pathological myopia. One of the several factors that influ...

Background: Posterior vitreous detachment (PVD) can result in serious pathologic events at the vitreoretinal interface. This study aims to assess the relationship between PVD, macular thickness (MT), and the foveal avascular zone (FAZ) in myopic eyes. Methods: This retrospective study evaluated 63 myopic subjects' data who were examined between...

Optical coherence tomography (OCT) images are widely used for clinical examination of the retina. Automatic deep learning-based methods have been developed to classify normal and pathological OCT images. However, lack of the big enough training data reduces the performance of these models. A synthesis of data using generative adversarial networks (...

Introduction Various ocular diseases and high myopia influence the anatomical reference point Foveal Avascular Zone (FAZ) dimensions. Therefore, it is important to segment and quantify the FAZs dimensions accurately. To the best of our knowledge, there is no automated tool or algorithms available to segment the FAZ’s deep retinal layer. The paper d...

In photoreceptors of a dark adapted eye, the inward flux of sodium and calcium ions in the outer segment is balanced by the outward flux of potassium ions. But in the presence of light the creation of cyclic guanosine monophosphate in the outer segment decreases. Due to low concentration of cG (cyclic GMP) the channels in the outer segment open rel...

Various ocular diseases and high myopia influence the anatomical reference point Foveal Avascular Zone (FAZ) dimensions. Therefore, it is important to segment and quantify the FAZs dimensions accurately. To the best of our knowledge, there is no automated tool or algorithms available to segment the FAZ's deep retinal layer. The paper describes a ne...

Introduction Optic disc tilt (ODT) or tilted optic disc is a common finding in the general population. It is due to anomalous development caused by the malclosure of the embryonic optic fissure. ODT is commonly associated with high myopia as well as other conditions. In recent days, the common method to image the optic disc (OD) is by optical coher...

Breast cancer screening is an efficient method to detect breast lesions early. The common screening techniques are tomosynthesis and mammography images. However, the traditional manual diagnosis requires an intense workload for pathologists, and hence is prone to diagnostic errors. Thus, the aim of this study was to build a deep convolutional neura...

Optics concepts are fundamental to optometry. Currently, there is no published data on the status of conceptual optics among Indian optometrists. The results indicate the need for optics continuing education throughout their career.

Diabetic Retinopathy (DR) is a leading cause of vision loss in the world. In the past few years, artificial intelligence (AI) based approaches have been used to detect and grade DR. Early detection enables appropriate treatment and thus prevents vision loss. For this purpose, both fun-dus and optical coherence tomography (OCT) images are used to im...

The Pupillary Light Reflex (PLR) refers to the change in pupil size due to changes in illumination. The PLR is used by clinicians for the non-invasive assessment of the pupillary pathway. Typically, Infrared (IR) illumination-based pupillometers are used to measure the PLR. Researchers have explored the problem of robust pupil detection and reconst...

Diabetic Retinopathy (DR) is a leading cause of vision loss in the world,. In the past few Diabetic Retinopathy (DR) is a leading cause of vision loss in the world. In the past few years, Artificial Intelligence (AI) based approaches have been used to detect and grade DR. Early detection enables appropriate treatment and thus prevents vision loss,...

Background The lack of explanations for the decisions made by deep learning algorithms has hampered their acceptance by the clinical community despite highly accurate results on multiple problems. Attribution methods explaining deep learning models have been tested on medical imaging problems. The performance of various attribution methods has been...

We investigate the counterparts of random walks in universal quantum computing and their implementation using standard quantum circuits. Quantum walks have been recently well investigated for traversing graphs with certain oracles. We focus our study on traversing a 1D graph, namely a circle, and show how to implement a discrete-time quantum walk i...

We propose a new method for training convolutional neural networks (CNNs) and use it to classify glaucoma from fundus images. This method integrates reinforcement learning along with supervised learning and uses it for transfer learning. The training method uses hill climbing techniques via two different climber types, namely, “random movement” and...

Due to the fractal nature of retinal blood vessels, the retinal fractal dimension is a natural parameter for researchers to explore and has garnered interest as a potential diagnostic tool. This review aims to summarize the current scientific evidence regarding the relationship between fractal dimension and retinal pathology and thus assess the cli...

Background: The posterior vitreous detachment (PVD) is a separation of the posterior vitreous cortex from the internal limiting membrane of the retina. The PVD induces several potentially serious pathologic events at the vitreoretinal interface. The aim of the study is to determine if relationships exist between PVD, macular thickness (MT) and the...

Featured Application: This review provides a critical review of deep/machine learning algorithms used in the identification of ischemic stroke and demyelinating brain diseases. It evaluates their strengths and weaknesses when applied to real world clinical data. Abstract: Medical brain image analysis is a necessary step in computer-assisted/compute...

We propose a new method for training convolutional neural networks which integrates reinforcement learning along with supervised learning and use it for transfer learning for classification of glaucoma from colored fundus images. The training method uses hill climbing techniques via two different climber types viz. "random movement" and "random det...

Deep learning methods for ophthalmic diagnosis have shown considerable success in tasks like segmentation and classification. However, their widespread application is limited due to the models being opaque and vulnerable to making a wrong decision in complicated cases. Explainability methods show the features that a system used to make prediction w...

Breast cancer is the most common invasive cancer in women, and the second main cause of death. Breast cancer screening is an efficient method to detect indeterminate breast lesions early. The common approaches of screening for women are tomosynthesis and mammography images. However, the traditional manual diagnosis requires an intense workload by p...

Due to the fractal nature of retinal blood vessels, the retinal fractal dimension is a natural parameter for researchers to explore and has garnered interest as a potential diagnostic tool. This review aims to summarize the current scientific evidence regarding the relationship between fractal dimension and retinal pathology and thus assess the cli...

Medical brain image analysis is a necessary step in the Computers Assisted /Aided Diagnosis (CAD) systems. Advancements in both hardware and software in the past few years have led to improved segmentation and classification of various diseases. In the present work, we review the published literature on systems and algorithms that allow for classif...

The majority of recent deep learning research has been the reapplication of established image-processing techniques to retinal images. Another prominent and substantially richer imaging modality used by ophthalmic professionals is optical coherence tomography (OCT), which provides the same topological information as retinal images, as well as 3D ti...

The ETOP meeting is the oldest international conference devoted solely to optics/photonics education. Looking back at the history of the conference can help gain insight into past successes and plan for challenges of the future.

Purpose: The aim of this study was to measure blur thresholds before and after refractive surgery. Methods: In this prospective cohort study conducted in a tertiary eye hospital in South India. Blur thresholds were measured for 30 young adult myopic patients 1 month prior to and after refractive surgery. Patients were asked to report three stage...