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Papers by Ravichandran CG

Content Delivery Networks (CDNs) is anticipated to provide better performance delivery of content... more Content Delivery Networks (CDNs) is anticipated to provide better performance delivery of content in internet through worldwide coverage, which would be a fence for new content delivery network providers. The appearance of Web as a omnipresent media for sharing content and services has led to the rapid growth of the Internet. At the same time, the number of users accessing Web-based content and services are growing exponentially. This has placed a heavy demand on Internet bandwidth and Web systems hosting content and application services. As a result, many Web sites are unable to manage this demand and offer their services in a timely manner. Content Delivery Networks (CDNs) have emerged to overcome these limitations by offering infrastructure and mechanisms to deliver content and services in a scalable manner, and enhancing users’ Web experience. The planned research provides a framework designed to enhance QoS of Web service processes for real time servicing. QoS parameters of various domains can be combined to provide differentiated services, and allocating dynamically available resources in the midst of customers while delivering high-quality real time multimedia content. While accessing the service by a customer, it is possible to adapt real time streams to vastly changeable network conditions to give suitable quality in spite of factors upsetting Quality of service. To reach these intentions, adaptive web service processes to supply more information for determining the quality and size of the delivered object. The framework includes a section for QoS monitoring and adaptation and QoS faults prediction possibility and convalesce actions in case of failure. The aim of this research is to encourage research about quality of composite services in service-oriented architectures with security measures.

Automatic detection of blood vessel in retinal fundus image is an important task in the computer ... more Automatic detection of blood vessel in retinal fundus image is an important task in the computer aided diagnosis
of ophthalmology. This paper presents a fully automatic enhancement/thresholding based vessel extraction
method. The input image is enhanced by histogram matching and Contrast Limited Adaptive Histogram Equalization
(CLAHE) techniques. Following CLAHE, Wiener filtering is carried in order to remove the background
noise. A local entropy based thresholding technique is then used to extract blood vessel from the 2 dimensional
Gabor filter response of CLAHE’d image. The performance of the proposed method was evaluated on
two publicly available DRIVE and STARE databases and compared with the methods reported recently. The
proposed method extracts blood vessels in a DRIVE image within 1.47 seconds(s) with (accuracy, sensitivity,
specificity) = 9574%7259%9799%, and (9526%7693%9672%) for the DRIVE and STARE databases,
respectively. The average predictive value on both the databases were also higher (73.56%) compared to the
recent methods

Quality of Service (QoS) is a key factor in many research areas like multimedia real time systems... more Quality of Service (QoS) is a key factor in many research areas like multimedia real time systems, Web
services, distributed systems, Business networking and runtime monitoring. QoS is multi-faceted, fuzzy
and dynamic. Current researches focus on implementation level performance assurance, ignoring domain
specific or application level metrics which are also very important to service users. In multimedia real time
transmissions are distributed and it met various hurdles across the networks. Many real time protocols
having difficulties to handle real time multimedia streaming content through the networks. The proposed
system provides the multimedia streams to the end users in the high quality in terms reliability, scalability,
and uptime with enlarge the communication bandwidth to transfer the compressed multimedia streams
using Switched Ethernet Protocol(SEP) at the gateway of each network. Video compressors generate
highly variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by real-time
protocols severely reducing the efficiency of network utilization. This model views on a framework with
the bandwidth and the parameters which is related to the compression. The objective of the model is to
provide best possible Quality of Service to each and every user across the networks that access the
multimedia real time transmission.

This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense mul... more This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

Fuzzy logic-based histogram equalization (FHE) is proposed for image contrast enhancement. The FH... more Fuzzy logic-based histogram equalization (FHE) is proposed for image contrast enhancement. The FHE consists of two stages. First, fuzzy histogram is computed based on fuzzy set theory to handle the inexactness of gray level values in a better way compared to classical crisp histograms. In the second stage, the fuzzy histogram is divided into two subhistograms based on the median value of the original image and then equalizes them independently to preserve image brightness. The qualitative and quantitative analyses of proposed FHE algorithm are evaluated using two well-known parameters like average information contents (AIC) and natural image quality evaluator (NIQE) index for various images. From the qualitative and quantitative measures, it is interesting to see that this proposed method provides optimum results by giving better contrast enhancement and preserving the local information of the original image. Experimental result shows that the proposed method can effectively and significantly eliminate washed-out appearance and adverse artifacts induced by several existing methods. The proposed method has been tested using several images and gives better visual quality as compared to the conventional methods.

In this paper a new intelligent segmentation of functional magnetic resonance imaging (fMRI) has ... more In this paper a new intelligent segmentation of functional magnetic resonance imaging (fMRI) has been implemented using echo state neural network (ESNN). fMRI is a non-invasive method which can be used to indirectly localize neuronal activations in the human brain. The term segmentation includes not only the detection and localization, but also the delineation of activation region in the brain. Perfect segmentation is important especially for the detection and position of brain tumor. In spite of the existing segmentation methods, we have proposed a novel estimation method for accurate segmentation irrespective of noise level. The Recurrent ESNN is an estimation method able to produce an accurate segmentation when compared to the contextual clustering segmentation method. In order to show the accuracy of segmentation, the existing Contextual clustering (CC) segmentation method has been considered. Peak Signal to Noise Ratio (PSNR) of the segmented image of ESNN is 6 and found to be higher than PSNR of CC 57. The segmented images can be used in Medical Imaging application like 3D Reconstruction.

Quality of Service (QoS) is a key factor in many research areas like multimedia real time systems... more Quality of Service (QoS) is a key factor in many research areas like multimedia real time systems, Web services, distributed systems, Business networking and runtime monitoring. QoS is multi-faceted, fuzzy and dynamic. Current researches focus on implementation level performance assurance, ignoring domain specific or application level metrics which are also very important to service users. In multimedia real time transmissions are distributed and it met various hurdles across the networks. Many real time protocols having difficulties to handle real time multimedia streaming content through the networks. The proposed system provides the multimedia streams to the end users in the high quality in terms reliability, scalability, and uptime with enlarge the communication bandwidth to transfer the compressed multimedia streams using Switched Ethernet Protocol(SEP) at the gateway of each network. Video compressors generate highly variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by real-time protocols severely reducing the efficiency of network utilization. This model views on a framework with the bandwidth and the parameters which is related to the compression. The objective of the model is to provide best possible Quality of Service to each and every user across the networks that access the multimedia real time transmission.

Power efficient is an important availability for various image processing subsystems and portable... more Power efficient is an important availability for various image processing subsystems and portable devices applications. The design of proposed probabilistic multiplier is to trade a lesser amount of accuracy with reduced power consumption. In this paper, the probabilistic multiplier is eliminating the some part of the partial product generating path in least significant bit to reduce the power consumption and transistor count. The power consumption and probabilistic error behaviour of the proposed multiplier is verified and compared with other multipliers.

Problem statement: Image enhancement improves an image appearance by increasing dominance of some... more Problem statement: Image enhancement improves an image appearance by increasing dominance of some features or by decreasing ambiguity between different regions of the image. Histogram based image enhancement technique is mainly based on equalizing the histogram of the image and increasing the dynamic range corresponding to the image. Approach: Histogram Equalization is widely used in different ways to perform contrast enhancement in images. As a result, such image creates side-effects such as washed out appearance and false contouring due to the significant change in brightness. In order to overcome these problems, mean brightness preserving Histogram Equalization based techniques have been proposed. Generally, these methods partition the histogram of the original image into sub histograms and then independently equalize each sub histogram with Histogram Equalization. Results: The comparison of recent histogram based techniques is presented for contrast enhancement in low illumination environment and the experiment results are collected using low light environment images. Conclusion: The histogram modification algorithm is simple and computationally effective that makes it easy to implement and use in real time systems.

Diabetic macular edema is one of the retinal abnormalities which affects the central vision of th... more Diabetic macular edema is one of the retinal abnormalities which affects the central vision of the person and causes total blindness in severe cases. Fovea (center of macula) localization is an important step in retinal image analysis especially for grading diabetic macular edema. This paper describes a method to automatically localize the fovea center in retinal fundus images. The method is mainly based on mathematical morphology along with the information of other anatomic structures such as blood vessel and optic disc. Initially, the vascular structure and optic disc center are extracted, and then the morphological operations are employed on the gray scale image of green channel for fovea candidates' selection. The candidates' satisfying area, density and distance criteria are considered for the final stage. In the final stage, the candidate having lesser vessel pixels was considered as fovea region. The proposed method was evaluated on the two publicly available DRIVE and STARE databases. The method was able to obtain 100% of fovea localization accuracy on DRIVE database with 2.88 seconds average computation time.

Lung cancer is becoming a threat to mankind. Applying machine learning algorithms for detection a... more Lung cancer is becoming a threat to mankind. Applying machine learning algorithms for detection and segmentation of irregular shaped lung nodules remains a remarkable milestone in CT scan image analysis research. In this paper, we apply ACO algorithm for lung nodule detection. We have compared the performance against three other algorithms, namely, Otsu algorithm, watershed algorithm, and global region based segmentation. In addition, we suggest a novel approach which involves variations of ACO, namely, refined ACO, logical ACO, and variant ACO. Variant ACO shows better reduction in false positives. In addition we propose black circular neighborhood approach to detect nodule centers from the edge detected image. Genetic algorithm based clustering is performed to cluster the nodules based on intensity, shape, and size. The performance of the overall approach is compared with hierarchical clustering to establish the improvisation in the proposed approach.

Quality of Service (QoS) is a key factor in many research areas like multimedia real time systems... more Quality of Service (QoS) is a key factor in many research areas like multimedia real time systems, Web services, distributed systems, Business networking and runtime monitoring. QoS is multi-faceted, fuzzy and dynamic. Current researches focus on implementation level performance assurance, ignoring domain specific or application level metrics which are also very important to service users. In multimedia real time transmissions are distributed and it met various hurdles across the networks. Many real time protocols having difficulties to handle real time multimedia streaming content through the networks. The proposed system provides the multimedia streams to the end users in the high quality in terms reliability, scalability, and uptime with enlarge the communication bandwidth to transfer the compressed multimedia streams using Switched Ethernet Protocol(SEP) at the gateway of each network. Video compressors generate highly variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by real-time protocols severely reducing the efficiency of network utilization. This model views on a framework with the bandwidth and the parameters which is related to the compression. The objective of the model is to provide best possible Quality of Service to each and every user across the networks that access the multimedia real time transmission.