Image binarization is the process of separation of pixel values into two groups, white as backgro... more Image binarization is the process of separation of pixel values into two groups, white as background and black as foreground. Thresholding plays a major in binarization of images. Thresholding can be categorized into global thresholding and local thresholding. In images with uniform contrast distribution of background and foreground like document images, global thresholding is more appropriate. In degraded document images, where considerable background noise or variation in contrast and illumination exists, there exists many pixels that cannot be easily classified as foreground or background. In such cases, binarization with local thresholding is more appropriate. This paper describes a locally adaptive thresholding technique that removes background by using local mean and mean deviation. Normally the local mean computational time depends on the window size. Our technique uses integral sum image as a prior processing to calculate local mean. It does not involve calculations of stand...
is a process of separation of pixel values of an input image into two pixel values like white as ... more is a process of separation of pixel values of an input image into two pixel values like white as background and black as foreground. It is an important part in image processing and it is the first step in many document analysis and OCR processes. Most of the binarization techniques associate a certain intensity value called threshold which separate the pixel values of the concerned input grayscale image into two classes like background and foreground. Each and every pixel should be compared with the threshold and transformed to its respective class according to the threshold value. Thus threshold takes a major role in binarization. Hence determination of proper threshold value in binarization is a major factor of being a good binarised image and it can be approached in two categories like global thresholding and local thresholding techniques. In uniform contrast distribution of background and foreground documents, global thesholding is more suitable than that of local thresholding o...
Normally the quality of an image is improved by enhancing contrast and sharpness. The enhancement... more Normally the quality of an image is improved by enhancing contrast and sharpness. The enhancement of contrast and sharpening of an image with a single function is a complex task. In real-time imaging, many complex scenes require local contrast improvements that should bring details to the best possible visibility of the image. However, local enhancement methods mainly suffer from ringing artefacts and noise over-enhancement. In this paper, we present a new adaptive spatial domain contrast and sharpness enhancement method, in which modified powerlaw transformations function is applied. Our algorithm controls perceived sharpness/smoothness, ringing artefacts (contrast) and noise, resulting in a good balance between visibility of details and non-disturbance of artefacts by controlled parameters. Its advantage over the standard power-law transformations is to enhance sharpness /smoothness and contrast with a single function by appropriate choice of control parameters. Sharpness control parameter can be also used to smoothen the image by taking the negative value of sharpness parameter. This method can be applied both to grey scale and colour images like Gamma Correction (GC). In the case of colour images, it is applied to each channel R, G and B separately.
The technology of computer graphics and digital cameras are prevalent. High-resolution display an... more The technology of computer graphics and digital cameras are prevalent. High-resolution display and printer are available. High-resolution images are needed in order to produce high quality display images and high quality prints for use in desktop publishing, large artistic printing, mobile phone etc. However, since high-resolution images are not usually provided, there is a need to magnify the original images. This paper proposes an algorithm for image magnification by linear interpolation, which is better than some of the prevalent methods such as pixel replication, bilinear interpolation and bicubic interpolation. The proposed algorithm uses linear interpolation method to magnify pixels that lie in the perimeter, whereas it uses directed bilinear interpolation method to magnify the interior region inside the magnified blocks. Determination of the right direction for interpolation is the key for achieving better performance of the proposed algorithm.
2014 IEEE International Advance Computing Conference (IACC), 2014
VoIP applications are becoming popular these days. A lot of Internet traffic are being generated ... more VoIP applications are becoming popular these days. A lot of Internet traffic are being generated by them. Detection of VoIP traffic is becoming important because of QoS issues and security concerns. A VoIP client typically opens a number of network connection between VoIP client and VoIP client, VoIP client and VoIP server. In the case of peer to peer VoIP applications like Skype network, connections may be between client to client, client to Super Node, client to login server, Super Node to Super Node. Typically, VoIP media traffic are carried by UDP unless firewalls blocks UDP, in which case media and signalling traffic are carried by TCP. Many VoIP applications uses RTP to carry media traffic. Notable examples includes GTalk, Google+ Hangouts, Asterisk based VoIP and Apple's FaceTime. On the other hand, Skype uses a proprietary protocol based on P2P architecture. It uses encryption for end to end communications and adopts obfuscation and anti reverse engineering techniques to prevent reverse engineering of the Skype protocol. This makes the detection of Skype flows a challenging task. Although Skype encrypts all communications, still a portion of Skype payload header known as Start of Message (SoM) is left unecrypted. In this paper, we develop a method for detection of VoIP flows in UDP media streams. Our detection method relies on signalling traffic generated by VoIP applications and heuristics based on the information contained in Skype SoM and RTP/RTCP headers.
International Journal of Computer Applications, 2012
Binarization is a process of separation of pixel values of an input image into two pixel values l... more Binarization is a process of separation of pixel values of an input image into two pixel values like white as background and black as foreground. It is an important part in image processing and it is the first step in many document analysis and OCR processes. Most of the binarization techniques associate a certain intensity value called threshold which separate the pixel values of the concerned input grayscale image into two classes like background and foreground. Each and every pixel should be compared with the threshold and transformed to its respective class according to the threshold value. Thus threshold takes a major role in binarization. Hence determination of proper threshold value in binarization is a major factor of being a good binarised image and it can be approached in two categories like global thresholding and local thresholding techniques. In uniform contrast distribution of background and foreground documents, global thesholding is more suitable than that of local thresholding one. In degraded documents, where considerable background noise or variation in contrast and illumination exists, local technique is more suitable than that of global one. In this paper a local thresholding technique using local contrast and mean is described. Local adaptation is carried out with the local contrast and mean.
International Journal of Computer Applications, 2012
For a detailed visibility of an image, since only the global enhancement is not sufficient, local... more For a detailed visibility of an image, since only the global enhancement is not sufficient, local contrast enhancement plays a great role. One of the successful locally adaptive image contrast enhancement methods is by using Local Standard Deviation (LSD). The contrast enhancement using LSD is successfully used in many applications like in medical images, real time images, surveillance applications and many others. These types of applications employ a contrast factor which is divided by LSD. For such type of methods, limitation occurs when the LSD becomes zero. This limitation due to divide by zero can be overcome by adjusting the LSD to a modified value.
2013 IEEE International Conference on Advanced Networks and Telecommunications Systems (ANTS), 2013
As the use and popularity of VoIP applications grows, more and more Internet traffic are being ge... more As the use and popularity of VoIP applications grows, more and more Internet traffic are being generated by them. Many VoIP applications uses RTP to carry media traffic. Notable examples includes Gtalk, Google+ Hangouts, Asterisk based VoIP and Apple's FaceTime. On the other hand, Skype uses a proprietary protocol based on P2P architecture. It uses encryption for end to end communications and adopts obfuscation and anti reverse engineering techniques to prevent reverse engineering of the Skype protocol. This makes the detection of Skype flows a challenging task. Although Skype encrypts all communications, still a portion of Skype payload header known as Start of Message (SoM) is left unencrypted. In this paper, we develop an efficient technique for detection of Skype flows in UDP media streams. Our detection techniques relies on heuristics based on the information contained in Skype SoM and RTP headers.
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Papers by Tejmani sinam