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Linear filtering of images is usually performed in the spatial domain using the linear convolution operation. In the case of images stored in the block DCT space, the linear filtering is usually performed on the sub-image obtained by applying an inverse DCT to the block DCT data. However, this results in severe blocking artifacts caused by the boundary conditions of individual blocks as pixel values outside the boundaries of the blocks are assumed to be zeros. To get around this problem, we propose to use the symmetric convolution operation in such a way that the operation becomes equivalent to the linear convolution operation in the spatial domain. This is achieved by operating on larger block sizes in the transform domain. We demonstrate its applications in image sharpening and removal of blocking artifacts directly in the compressed domain.

In this work we propose a hierarchical state-based model for representing an echocardiogram video using objects present and their dynamic behavior. The modeling is done on the basis of the different types of views like short axis view, long axis view, apical view, etc. For view classification, an artificial neural network is trained with the histogram of a ‘region of interest' of each video frame. A state transition diagram is used to represent the states of objects in different views and corresponding transition from one state to another. States are detected with the help of synthetic M-mode images. In contrast to traditional single M-mode approach, we propose a new approach named as ‘Sweep M-mode' for the detection of states.

This paper presents a heuristic approach to reduce the computational power requirement of SAD cost function used in the motion estimation phase of video encoding. The proposed technique selects the best matched macroblock based on partial SAD sums. This results in lower power consumption with marginal loss in image quality. Different levels to trade-off image quality with computational power have also been proposed. The mathematical intuition in support of the heuristics is discussed. Our approach shows good performance, especially at low bitrates.

In this paper we propose a new adaptive block based compressed domain data hiding scheme which can embed relatively large number of secret bits without significant perceptual distortion in video domain. Macro blocks are selected for embedding on the basis of low inter frame velocity. From this subset, the blocks with high prediction error are selected for embedding. The embedding is done by modifying the quantized DCT AC coefficients in the compressed domain. The number of coefficients (both zero and non zero) used in embedding is adaptively determined using relative strength of the prediction error block. Experimental results show that this blind scheme can embed a relatively large number of bits without degrading significant video quality with respect to Human Visual System (HVS).

As the number of different video compression standards increase, there is a growing need for conversion between video formats coded in different standards. H.264/AVC is a newly emerging video coding standard which achieves better video quality at reduced bit rate than other standards. The standalone media players that are available in the market do not support H.264 video playback. In this paper, we present novel techniques that can achieve conversion of pre-coded video in H.264/AVC standard to MPEG-2 standard directly in the compressed domain. Experimental results show that the proposed approach can produce transcoded video with quality comparable to the pixel-domain approach at significantly reduced cost.

Digital video databases are widely available in compressed format. In many applications such as video browsing, picture in picture, video conferencing etc. data transfer at lower bit rate is required. This requires downscaling of the video before transmission. The conventional spatial domain approach for downscaling video is computationally very expensive. The computation can greatly be reduced if downscaling and inverse motion compensation (IMC) are performed in Discrete Cosine Transform (DCT) domain. There are many algorithms in the literature to perform IMC in the DCT domain. In this paper, we propose an efficient integrated technique to perform IMC and downscaling in DCT domain. This new approach results in significant improvement in computational complexity.

A new approach of color image compression using relative fractal coding has been presented in this paper. In relative fractal coding, given the fractal code of a reference image, one can generate a relative fractal code of any other image of same size. This method is found to be extremely useful for color image compression as the subsequent color components are highly correlated. It produces fractal code where the inter-component spectral changes are coded and the convergence is guaranteed for individual components. Several experimental results are also presented which are found to be comparable with other fractal color coding techniques.

Recent advancement in wireless technology and the emergence of powerful handheld devices have greatly extended the traditional communication technology in the healthcare environment. Healthcare environments are, by nature, mobile, where doctors and nurses do not have a fixed work space and have to move from one place to another. Regular and exceptional events are generated in the daily hospital routine, such as normal checkup of patients and attending emergency cases. For better and time effective management of such a situation, medical personnel always need to keep in touch with the patient's medical information. We have developed a system that has the potential to support mobile diagnosis and treatment within a hospital. The system allows doctors to get a patient's information on a handheld device using WLAN. The physical transmission of patient information to the mobile device is also supported to get them outside the range of WLAN connection. The system has been tested and experimented in laboratory conditions.

We present a circuit based LC oscillator phase noise model for flicker noise using non linear perturbation techniques. Closed form equations for obtaining phase and amplitude spectra have been developed which then lead to the final expression of voltage noise density across the oscillator terminal. Since flicker noise occurs at very low frequencies, we propose that any perturbation in oscillation due to this noise is equivalent to perturbation in the dc bias of the devices present in the oscillator and develop the closed form analytic expressions on the basis of this assumption. A trap level model of flicker noise is used for that analysis. Expressions are obtained for a single trap, which are then scaled up for all traps. Doing so enables us to work around the problem of "blow up" of flicker noise at low frequencies. The derivations take into account the correlation existing between amplitude and phase deviations due to noise which has previously not been documented and new parameters are introduced which account for this correlation. The noise spectrum shows a 1/f3 distribution as has been shown in other literature. The proposed model is applied on a practical differential oscillator for comparison. We introduce a novel method of analysis by splitting the noise contribution of the various transistors into modes. The modes that contribute the most to flicker noise are picked. Further the tail noise contribution is analyzed and shown to be mostly upconverted noise. The proposed model which is compared with simulation results and agreement of within 1.5 dB with simulation results was obtained

We present a circuit based model of LC oscillator phase noise due to white noise using non linear perturbation techniques. Differential equations establishing the relation between device noise and amplitude and phase deviations have been rigorously developed which lead to closed form equations for obtaining the phase and the amplitude spectra. These relations are then used to obtain the final expression for voltage noise density across the oscillator terminals. We introduce new parameters which take into account the correlations existing between amplitude and phase deviations due to noise and give better agreement with simulation results. Further, the buffer noise in oscillators is examined. We mathematically demonstrate that the noise floor of an oscillation spectrum arises due the buffer present in an oscillator circuit. The oscillator noise spectrum is shown to have a Lorentzian distribution initially, which then flattens out due to the noise floor. As a result, two distinct corner frequencies arise. The proposed model is compared with simulation results for both a practical differential oscillator as well as a Van Der Pol oscillator. For the Van Der Pol oscillator the proposed model matches perfectly with the simulation results and for the differential oscillator a close agreement of within 1.5 dB is obtained

This paper describes the use of the newly developed Cadence to ADS dynamic link in loadpull simulations for BiCMOS RFIC design in a University environment. The process described here helps a designer achieve an integrated design environment where both RF design and traditional VLSI design principles can be applied in an integrated manner.

A connectionist network is presented for segmenting gray level images. The network detects the local peaks in the inverted histogram which will correspond to the bottoms of the valleys in the actual histogram. The neural network implementation successfully uses circumstantial evidence and detects multiple winners over the entire range of gray values such that these winners correspond to multiple thresholds for segmenting the image. The dynamics of the network has been analyzed and the conditions for convergence have been established. Experimental results obtained by applying the network for segmenting two X-ray images are presented. >

A connectionist clustering strategy is presented for segmenting color images. First the local peaks in the 3-D red, green, blue histogram are located. Then using these as the prototypes other patterns are classified into one of them. The prototype selection method employs only neuronal dynamics and therefore is faster than existing clustering neural networks. The classification network takes into account the distribution of the data and hence is less prone to misclassifications. Experimental results obtained by applying the network for segmenting one color image are presented. >

In a single-chip digital color imaging sensor, a color filter array (CFA) is used to obtain sampled spectral components (red, green and blue) in an interleaved fashion. Color demosaicing is the process of interpolating these regularly spaced sampled values into a dense pixel map for each spectral component. We present two new color interpolation techniques with low buffer requirements for processing while developing color images with very good quality. We also present a comparative study with other interpolation techniques of similar buffer requirements.

In this work we propose a new approach to model video data. To interpret the video semantic, we propose to model the video on the basis of the underlying dynamics contained in the video. Thus, the video is seen as a measurement of properties of objects embedded in the video and of their behaviors over time. The objects' behaviors are described by states and state transitions using statechart diagram. Then, this diagram is used to partition the video into meaningful segments. For efficient retrieval of information, we propose to use indexes based on the states of objects. The proposed model thus helps to store information about similar types of video data in a single database schema and supports content-based querying from a repository of video data.

In this work we propose a state-based approach to model video data so that the semantics of the video is specified by the properties (static and dynamic) of the objects present in the video. The object dynamics is captured by the states and state transitions. The video database is then segmented and indexed based on these information. Finally, examples have been given to show how state-based queries can be used to retrieve information from the video database.

We have developed III-V-based high-efficiency laser power converters (LPCs), optimized specifically for converting monochromatic laser radiation at the eye-safe wavelength of 1.55 m into electrical power. The applications of these photovoltaic cells include high-efficiency space-based and terrestrial laser power transfer and subsequent conversion to electrical power. In addition, these cells also find use in fibre-optic power delivery, remote powering of subcutaneous equipment and several other optical power delivery applications. The LPC design is based on lattice-matched InGaAsP/InP and incorporates elements for photon-recycling and contact design for efficient carrier extraction. Here we compare results from electro-optical design simulations with experimental results from prototype devices studied both in the lab and in field tests. We analyse wavelength and temperature dependence of the LPC characteristics. An experimental conversion efficiency of 44.6% [±1%] is obtained from the prototype devices under monochromatic illumination at 1.55 m (illumination power density of 1 kW m) at room temperature. Further design optimization of our LPC is expected to scale the efficiency beyond 50% at 1 kW m. © 2013 IOP Publishing Ltd.

Image representation schemes are of importance in fields of computer vision, graphics, image processing, CAD/CAM, etc. Various representation schemes are presented in the literature for both 2D and 3D. In this paper, we present a scheme of representation using the concept of octagonal distances. They are called Medial circle representation (MCR) and Medial sphere representation (MSR) in 2-D and 3-D, respectively. Storage requirements, computational complexity, merits and demerits of the representation schemes are discussed.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Various colonic side-effects of herbal enema have been reported in literature ranging from mild abdominal discomfort to self-limiting haemorrhagic colitis. It rarely requires blood transfusion or subtotal colectomy. We report a 57-year-old male patient developing severe ileo-colitis with persistent massive rectal bleeding immediately after herbal enema administration for the treatment of chronic constipation and was resistant to conservative management. Patient was managed successfully with emergency total laparoscopic colectomy. Post-operative recovery of the patient was excellent.

In this article, a parallel metal-plated split U-shaped omnidirectional ultra wideband (UWB) antenna fed by a novel 1x3 microstrip line is proposed. Printed monopole antennas fabricated on a substrate offer impedance bandwidth which can cover UWB. However, radiation pattern varies significantly over the bandwidth. The cross polar component increases with frequency and the pattern degrades from the desired omnidirectional characteristics. Omnidirectional radiation bandwidth can be increased significantly by decreasing the substrate thickness and using substrate material of low dielectric constant. With the use of the proposed feeding arrangement, parallel metal-plated split U-shaped monopole antenna shows omnidirectional radiation pattern. The proposed metal-plated structure using foam as dielectric is designed, fabricated, and tested. The measured VSWR is < 2 over 3.1 to 10.6 GHz frequency band. The antenna offers high efficiency, stable gain, small group delay variation, and its radiation patterns indicate its suitability for UWB applications.

Diabetes mellitus is a well-studied metabolic disease related to insulin deficiency that leads to high risk of cardiovascular diseases. This paper presents a non-invasive, preventive approach to measure arterial parameters from photoplethysmograph (PPG) signals of diabetic subjects. A recently proposed Two Pulse Synthesis (TPS) model (Goswami, 2010) has been used to measure Pulse Wave Velocity (PWV) of one group of 25 diabetic subjects without hypertension and another group of 45 diabetic subjects with hypertension. Results, presented through tables and figures, indicate appreciable changes in several TPS model-derived parameters due to diabetes and increase in PWV compared to normal subjects.

Transcoding in the transform domain avoids inverse transform and re-transform computations. In this paper, discrete cosine transform, the authors propose a new technique for transcoding wavelet coefficients to block discrete cosine transform (DCT) coefficients in the transform domain. In the first step, wavelet coefficients are transformed into upsampled DCT blocks. Subsequently, these transformed blocks are synthesised by filtering in the block DCT space. To reduce the cost of transcoding, the authors perform upsampling and filtering operations in a single combined step. The proposed technique achieves the quality of reconstruction (except rounding errors in processing) as same as the spatial domain technique with reduced complexity for a given wavelet synthesis filter. The proposed technique is based on simple linear operations like matrix multiplication. This makes the algorithm more convenient for efficient hardware implementations. The technique can be used by the DCT-based services when the input data are available as wavelet coefficients.

Visual attention is an indispensable component of complex vision tasks. A multi-scale, complex network-based approach for determining visual saliency is described. It uses degree centrality (conceptually and computationally the simplest among all the centrality measures) over a network of image regions to form a saliency map. The regions used in the network are multiscale in nature with scale selected automatically. Experimental evaluation establishes the superiority of the method over existing saliency methods, even in noisy environments.

Thermal-induced destruction of pulpal material on account of prolonged exposure to laser irradiation frequently offers serious challenges for application of lasers in dentistry. Here, we develop a mathematical model of heat transfer within the dental profile due to laser irradiation and attempt to locate the probable paths of heat flow by identifying the pertinent thermal resistances. Corresponding to a maximum allowable rise of temperature, we obtain suitable ranges of laser power, so that a negligible heat flux prevails at tooth locations farthest from the spot of laser treatment, thereby obtaining safe operating parameter regimes and avoiding any undesirable pulpal damage.

A new approach of Motion-Compensated JPEG2000 (MCJ2K) video compression is proposed in this paper. It uses simplified MPEG-2 fundamentals along with JPEG2000 encoding for compression of the image frames. MCJ2K generates differential images using motion compensation algorithms and store the motion vectors in a customised header. The images are then compressed using JPEG2000 based scheme. MCJ2K have been studied on QCIF and CIF formated videos for various rate control mechanism. The proposed scheme produced encouraging results compared to standard MPEG-2 and MJPEG2000 schemes, especially at higher bit rates.

Using the spatial relationship of the block discrete cosine transform (DCT) coefficients and subband approximations, algorithms for image halving and doubling operations are presented. The computational steps identified in the process provide a general framework for image resizing operations. Some of the previously reported image halving and doubling algorithms are shown to be special cases. The proposed approach is general enough to accommodate resizing operations with arbitrary factors, namely with integral and rational factors. The application of these methods to the conversion in the compressed domain of images (video frames) from one format to another is demonstrated.

In this paper the Extended Safe Point Thinning Algorithm (ESPTA) is presented for thinning 3-D images. It is developed on a 2-D algorithm by Naccache & Shinghal (1984). It is shown that ESPTA preserves the 18-connectivity of the image. Some experimental results with ESPTA will also be discussed.

Supplemental Material. Figure S1. Participants included in the Biocohort in the IMMEDIATE Trial. Figure S2. Correlation between hs-CRP Levels and 30-day Infarct Size. Table S1. Baseline Demographic and Clinical Characteristics of Study Participants by Treatment Group Compared to the Participants from the IMMEDIATE Trial. Table S2. Results of Regression Analysis between Initial hs-CRP Levels and Baseline Demographic and Clinical Characteristics. Table S3. hs-CRP Levels per Treatment Arm. (DOCX 148 kb)

This paper proposes a new architecture for the Phase Frequency Detector (PFD) with improved gain and lower Blind Zone (BZ). The new architecture introduces a selective reset technique with trailing edge detection, which is less sensitive to process and voltage variations in achieving minimal BZ. The proposed PFD is designed and fabricated in 180 nm CMOS process. The circuit is tested for large variations in the supply voltage (1.3 V and 1.8 V), achieving the BZ of 17.5 ps, which is around three times less compared to earlier reported works. The effect of improvement in gain and BZ of the proposed PFD on the reduction of settling time of a phase-locked loop with which the proposed PFD has been integrated is shown with the post-layout simulation results.

In this paper a geometric approach is suggested to find the closest approximation to Euclidean metric based on geometric measures of the digital circles in 2D and the digital spheres in 3D for the generalized octagonal distances. First we show that the vertices of the digital circles (spheres) for octagonal distances can be suitably approximated as a function of the number of neighborhood types used in the sequence. Then we use these approximate vertex formulae to compute the geometric features in an approximate way. Finally we minimize the errors of these measurements with respect to respective Euclidean discs to identify the best distances. We have verified our results by experimenting with analytical error measures suggested earlier. We have also compared the performances of the good octagonal distances with good weighted distances. It has been found that the best octagonal distance in 2D ({1,1,2}) performs equally good with respect to the best one for the weighted distances (〈3,4〉). In fact in 3D, the octagonal distance {1,1,3} has an edge over the other good weighted distances.

Background Some benefits of glucose-insulin-potassium (GIK) in patients with acute coronary syndromes (ACS) may be from an anti-inflammatory effect. The primary aim of this study was to assess the impact of GIK administration early in the course of ACS on inflammatory marker C-reactive protein (CRP) levels. A secondary aim was to investigate the association between CRP and 30-day infarct size. Methods and Results Retrospective analysis of participants with ACS randomly assigned to GIK or placebo for at least 8 h in the IMMEDIATE Trial biological mechanism cohort (n = 143). High sensitivity CRP (hs-CRP) was measured at emergency department presentation, and 6 and 12 h into infusion. Logarithmically transformed hs-CRP values at 12-hours were lower with GIK vs. placebo (mean =0.65 mg/L in GIK, 0.84 mg/L in placebo), with a marginal trend toward significance (P = 0.053). Furthermore, using mixed models of hs-CRP, time, and study group, there was a significant increase in hs-CRP levels over time, but the rate of change did not differ between treatment arms (P = 0.3). Multivariable analysis showed that an elevation in hs-CRP, measured at 12 h, was an independent predictor of 30-day infarct size (β coefficient, 6.80; P = 0.04) using sestamibi SPECT imaging. Conclusions The results of this study show no significant effect of GIK on hs-CRP. In addition our results show that in patients with ACS, hs-CRP measured as early as 12 h can predict 30-day infarct size. Electronic supplementary material The online version of this article (doi:10.1186/s12872-015-0153-7) contains supplementary material, which is available to authorized users.

Representation schemes play an important role in the fields of Computer Vision, Graphics, Image Processing, CAD/CAM etc. Various representation schemes have been discussed in the literature for both 2D and 3D. In this paper, we are presenting a scheme of representation using the concept of octagonal distances. They are called Medial Circle Representation (MCR) and Medial Sphere Representation (MSR) in 2D and 3D, respectively. Storage requirement, computational complexity, merits and demerits of the representation schemes are discussed.

Supplemental Material. Figure S1. Participants included in the Biocohort in the IMMEDIATE Trial. Figure S2. Correlation between hs-CRP Levels and 30-day Infarct Size. Table S1. Baseline Demographic and Clinical Characteristics of Study Participants by Treatment Group Compared to the Participants from the IMMEDIATE Trial. Table S2. Results of Regression Analysis between Initial hs-CRP Levels and Baseline Demographic and Clinical Characteristics. Table S3. hs-CRP Levels per Treatment Arm. (DOCX 148 kb)

A YIELD value is noticeable in hydrogen bentonites at a concentration lower than that at which thixotropy first appears. This seems to happen generally with bentonites. Some natural calcium bentonites show coacervation1. Coacervation of fine sub-fractions of a natural bentonite has been reported2 at concentrations above the thixotropic range. Hydrogen bentonites, however, show coacervation over a wide range and even below the thixotropic range of concentrations. Near about the concentration at which yield value becomes noticeable a sharp ehange in several properties has been observed. The cataphoretic velocity rapidly increases and tends to a maximum. The conductivity, (Σ, per gram of colloid can be calculated from the relation Σ = 1000 (Σc; π Σu)/C, where Σc is the specific conductivity at a concentration of C grams per litre and Σu that of its ultra-filtrate; it passes through a minimum if plotted against C or C.