A Reversible Data Hiding Scheme for Efficient Management of Tele-Ophthalmological Data

Advancements in medical sciences and induction of advanced technologies have led to increased role of medical images in tele-diagnosis. This paper proposes a technique for easy, efficient and accurate management of distributed medical databases and alleviates the risk of any distortion in images during transmission. It also provides remedy of issues like tampering, accidentally or intentionally, authentication and reliability without affecting the perceptual properties of the image. The technique is blind and completely reversible. Values of PSNR and BER imply that the changes made to original images are imperceptible to the Human Visual System. Performance of the technique has been evaluated for fundus images and the results are extremely encouraging. The technique is lossless and conforms to the firm necessities of medical data management by maintaining perceptual quality and diagnostic significance of the images, therefore is very practical to be used in health care centers.

Visual Perception from Object Scanning as Revealed by Electrooculography

We the human beings are blessed by the nature to become well competent for performing highly precise and copious visual processes with how ever a restricted field of view. Howbeit, this process of visual perception is, to a great extent, controlled by the saccades or more commonly the eye movements. The positioning and accommodation of eyes allows an image to be placed (or fixed) in the fovea centralis of the eyes but although we do so to fix our gaze at a particular object, our eyes continuously move. Even though these fixational eye movements includes magnitude that should make them visible to us yet we remain oblivious to them. Microsacades, drifts and tremors that occurs frequently during fixational eye movements, contribute largely to the visual perception. We use saccades several times per second to move the fovea between points of interest and build an understanding of our visual environment.

Case Study

In the developing countries, incidence of systemic tuberculosis is very high, with over 8 million new cases each year. The incidence of tuberculous uveitis is also rising correspondingly. It is difficult to diagnose ocular tuberculosis because of the lack of specific ocular findings and specific confirmatory laboratory tests. However, in a developing country like India, where the prevalence of latent tuberculosis is high, uveitis of unexplained cause not fitting into known uveitis entities, in presence of Monteux positivity, is more likely to be tubercular in origin. Hence, early diagnosis and prompt treatment with antitubercular treatment may result in dramatic drop in recurrence and improve individual patient outcomes.

Significant Enhancement of Segmentation Efficiency of Retinal Images Using Texture-Based Gabor Filter Approach Followed by Optimization Algorithm

Considering Retinal image as textured image, its texture based segmentation is required to identify the presence of retinal diseases. This pre-processing is important in automatic detection system for recognizing the abnormality present in the retinal images. Likewise, the proposed system mainly focused on diabetic retinopathy disease caused into eye –retina, generally leads to eye-blindness. Inspired from robust human's texture based segmentation capability, a mathematical model of the eye was formulated. A texture based Gabor filter was applied to get the output feature helping in detecting the abnormality and deriving statistical properties, further used in segmentation and classification. This work deals with the better separation of various clusters of Gabor filter output features, in order to get better segmentation efficiency. This was also followed by formalizing an objective function to tune filter parameters with Gradient descent and further Genetic Algorithm. This paper showed both qualitative and quantitative segmentation results with improved efficiency.

Principles of Binocular Stereoscopic Imaging

The relation between visual perception and the recorded image is discussed in this chapter, emphasising the historical growth of the understanding of depth perception and its visual cues. The stereoscopic principle is explained in detail, and figures are given for comfortable viewing of stereoscopic images.

Nanotechnology for Omics-Based Ocular Drug Delivery

Millions of people suffer from ocular diseases that impair vision and can lead to blindness. Advances in genomics and proteomics have revealed a number of different molecular markers specific for different ocular diseases, thereby optimizing the processes of drug development and discovery. Nanotechnology can increase the throughput of data obtained in omics-based studies and allows for more sensitive diagnostic techniques as more efficient drug delivery systems. Biocompatible and biodegradable nanomaterials developed through omics-based research are able to target reported molecular markers for different ocular diseases and offer novel alternatives to conventional drug therapy. In this chapter, the authors review the pathophysiology, current genomic and proteomic information, and current nanomaterial-based therapies of four ocular diseases: glaucoma, uveal melanoma, age-related macular degeneration, and diabetic retinopathy. Omics-based research can be used to elucidate specific genes and proteins and develop novel nanomedicine formulations to prevent, halt, or cure ocular diseases at the transcriptional or translational level.

An Approach for Automatic Detection and Grading of Macular Edema

Prolonged Diabetes causes massive destruction to the retina, known as Diabetic Retinopathy (DR) leading to blindness. The blindness due to DR may consequence from several factors such as Blood vessel (BV) leakage, new BV formation on retina. The effects become more threatening when abnormalities involves the macular region. Here automatic analysis of fundus images becomes important. This system checks for any abnormality and help ophthalmologists in decision making and to analyze more number of cases. The main objective of this chapter is to explore image processing tools for automatic detection and grading macular edema in fundus images.

Case Study

Epidemic dropsy is a multi-system disease involving the cardiovascular, hepatic, renal, ocular and other systems. Onset is usually subacute or insidious with watery diarrhea and vomiting. This lasts from a few days to more than a week. Bilaterally symmetrical pitting edema of the lower limbs extending from the ankles up to the scrotum and abdominal wall is a constant feature. It is a toxic disease caused by the unintentional ingestion of Argemone mexicana (prickly yellow poppy) seeds as an adulterant of wheat flour, or more commonly, of cooking oil such as mustard oil. Sanguinarine and dehydrosanguinarine are two major toxic alkaloids of Argemone oil. It is a rare phenomenon for practicing ophthalmologists to observe cases of epidemic dropsy, and the possibility of glaucoma should be kept in mind in cases of epidemic dropsy, when members of same family or village report with raised IOP, pedal edema and history of use of mustard oil for cooking or massage. Glaucoma is hypersecretory in nature; prostaglandin and histamine release may have significant roles in its pathogenesis. The disease has self limiting course but needs good control of intraocular pressure (IOP) medically till it returns to normal and visual field changes have stabilized. Its early diagnosis is very important to prevent grievous complications; hence, all cases should be followed up regularly for IOP measurement and visual field analysis up to 8-12 weeks, because, if ignored, optic atrophy may develop.

An Efficient and Lossless Cryptosystem for Security in Tele-Ophthalmology Applications Using Chaotic Theory

Tele-ophthalmology has gained a lot of popularity as it involves retinal fundus images which can be analyzed for identification of severe diseases like diabetic retinopathy and glaucoma. With this increasing popularity, requirement for medical data confidentiality and privacy has also increased during transmission or storage. To meet this challenge, this paper propose an efficient and lossless cryptosystem based upon chaotic theory for encryption of medical fundus images. In the proposed encryption scheme a strategic combination of scrambling and substitution architecture is proposed which complements each other. The proposed scheme of encryption for fundus images is challenging as these images are 3-D color image and cannot be compressed as compression may not be able to retain all relevant medical information. For performance analysis, the proposed algorithm has been evaluated for perceptual and cryptographic security. The experimental results indicate that the proposed method is lossless and resistant against attacks making the proposed scheme suitable for real time applications.

Analogizing the Thinning Algorithm and Elicitation of Vascular Landmark in Retinal Images

The retinal tissue is composed of network of blood vessels forming a unique biometric pattern. Feature extraction in retinal blood vessel is becoming an emerging trend in the field of personal identification. Because of its unique identity and less vulnerability to noise and distortion it has become one of the most secured biometric identities. The paper highlights the segmentation of blood vessel and the extraction of feature points such as termination and bifurcation points using Zhang Suen's thinning algorithm in retinal images. A comparison has been made and results are analyzed and tabulated between Zhang Suen and Morphological thinning. The count has been taken for both termination and bifurcation markings as spurious and non- spurious minutiae. The spurious minutiae are removed by using the crossing number method. The results clearly depict that the Zhang Suen's thinning algorithm gives better result when compared to morphological thinning.