Monika Jain

Continuous Adaptation Enhancement in Linear Regression Algorithm for Clock Recovery in IPTV Environment

This paper presents a new technique for Clock Recovery in MPEG-2 Transport Streams in DVB-IPTV environment. The amount of jitter in this environment is very high compared to DVB-S or DVB-T. Use of linear regression algorithm for clock synchronization over packet switched networks is suggested by researchers in the similar field. However, the stability of such a filter in real time set top box application posed a problem. The continuous adaptive feedback loop used with the linear regression algorithm provides accurate clock synchronization even when subjected to jitter of half a second. This robustness is needed for IP environment because of the increasing network traffic. The algorithm was simulated and found to require low computation time, high jitter attenuation and fast response as needed for the IP network. It is auto-adaptive for both low and high jitter environments by analysing the jitter present in the stream. The algorithm was implemented for real time application in IPTV set top box and tested to be stable in the RTOS environment.

A sparse regression based approach for cuff-less blood pressure measurement

This paper proposes a sparse regression based approach for accurate continuous Blood Pressure (BP) monitoring. ECG and Finger PPG signals serve as the input; from which 32 parameters are extracted. Not all parameters are indicative of BP; to automatically trim the redundant parameters a sparse regression based approach is proposed. To build the BP predicting model the necessary parameters and their corresponding weights are learned using data from 99 subjects. The learned model is applied on 10 test subjects. The ground truth BP is measured using a clinically proven, professional automatic digital BP monitor OMRON HBP1300., The BP prediction results show that the SBP/DBP mean absolute error and error standard deviation, with OMRON monitor as a reference, is 4.43/2.46 and 4.90/3.31 mmHg respectively, which falls under the standard allowable error mentioned by Association for the Advancement of Medical Instrumentation for estimation of BP. We have compared our work with other BP prediction techniques (Linear Regression and Feed Forward Neural Network) and have seen that our proposed method yields considerably better results, especially for diastolic BP.

Face video based touchless blood pressure and heart rate estimation

Hypertension (high blood pressure) is the leading cause for increasing number of premature deaths due to cardiovascular diseases. Continuous hypertension screening seems to be a promising approach in order to take appropriate steps to alleviate hypertension-related diseases. Many studies have shown that physiological signal like Photoplethysmogram (PPG) can be reliably used for predicting the Blood Pressure (BP) and Heart Rate (HR). However, the existing approaches use a transmission or reflective type wearable sensor to collect the PPG signal. These sensors are bulky and mostly require an assistance of a trained medical practitioner; which preclude these approaches from continuous BP monitoring outside the medical centers. In this paper, we propose a novel touchless approach that predicts BP and HR using the face video based PPG. Since the facial video can easily be captured using a consumer grade camera, this approach is a convenient way for continuous hypertension monitoring outside the medical centers. The approach is validated using the face video data collected in our lab, with the ground truth BP and HR measured using a clinically approved BP monitor OMRON HBP1300. Accuracy of the method is measured in terms of normalized mean square error, mean absolute error and error standard deviation; which complies with the standards mentioned by Association for the Advancement of Medical Instrumentation. Two-tailed dependent sample t-test is also conducted to verify that there is no statistically significant difference between the BP and HR predicted using the proposed approach and the BP and HR measured using OMRON.

Enhanced FIR filter based module for clock synchronization in MPEG2 transport stream

Existing Set-Top Boxes experiences very large jitter in terrestrial environment due to multi path reflections. Existing algorithms for achieving clock recovery for DVB-T relies on very complex calculations which are not suitable for real time data processing. In digital Set-top box most of the CPU bandwidth is consumed in audio & video data decoding so clock synchronization algorithms get very less CPU time to execute. This paper presents Low cost weighing filter approach to solve the color loss problem in Digital Set-top Box. This algorithm has been tested in practical satellite and terrestrial environment. Its performance has been compared with Linear Regression based algorithm and shows distinct advantages.

Anti-forensic technique for median filtering using L 1 -L 2 TV model

Median filtering is one of the most popular image anti-forensic technique. Due to its nonlinearity, median filtering effectively hides traces of different types of image manipulation and therefore is integrated into several Anti-Forensic algorithms. As a result, the detection of median filtering has become of great significance for forensic analysis. To this end, several median filtering detectors have been proposed. In order to counter this, various anti-forensic techniques have also been suggested. In this paper we propose an effective anti-forensic technique that performs the median filtering operation on the image while ensuring minimal change in its spatial characteristics. The anti-forensic attack is formulated as an optimization problem and is constrained by a difference of Anisotropic and Isotropic Total Variation regularization. We demonstrate the effectiveness of the proposed technique by performing various experiments on popular median filtering detectors and observing the degradation of their performance on the anti-forensically generated images.

An affordable cuff-less blood pressure estimation solution

This paper presents a cuff-less hypertension pre-screening device that non-invasively monitors the Blood Pressure (BP) and Heart Rate (HR) continuously. The proposed device simultaneously records two clinically significant and highly correlated biomedical signals, viz., Electrocardiogram (ECG) and Photoplethysmogram (PPG). The device provides a common data acquisition platform that can interface with PC/laptop, Smart phone/tablet and Raspberry-pi etc. The hardware stores and processes the recorded ECG and PPG in order to extract the real-time BP and HR using kernel regression approach. The BP and HR estimation error is measured in terms of normalized mean square error, Error Standard Deviation (ESD) and Mean Absolute Error (MAE), with respect to a clinically proven digital BP monitor (OMRON HBP1300). The computed error falls under the maximum standard allowable error mentioned by Association for the Advancement of Medical Instrumentation; MAE <; 5 mmHg and ESD <; 8mmHg. The results are validated using two-tailed dependent sample t-test also. The proposed device is a portable low-cost home and clinic bases solution for continuous health monitoring.

A multi-signal acquisition system for preventive cardiology with cuff-less BP measurement capability

Remarkable technological developments in recent years have opened up new possibilities of improving public health care system. Developments in computing, signal processing and communication technologies have resulted in new diagnostic instruments with better precision and connectivity with computing machines, communication gadgets and databases. However, many of these technical marvels are young by age and not yet available to all potential users at affordable cost. Among the various vital biomedical signals that can be collected non-invasively, ECG, PPG, SpO2 and PCG collected simultaneously, can help in examining electrical (ECG) and mechanical (PCG) functioning of heart, efficiency of lungs (SpO2) and condition of arteries (PPG). This promises to give a composite overview of the whole cardiovascular system non-invasively. We propose to develop a portable multi-parameter, non-invasive biomedical signal acquisition system (which can monitor, store and communicate the above mentioned four biomedical signals) for regular telemonitoring of patients especially with cardiovascular complaints. The device will be easy to use and can be operated by a paramedical staff with minimal training. It will be low-cost, so that a large population can be covered using multiple portable units. The gathered physiological data can be sent to the monitoring station and depending on the condition of the patient, further instructions can be issued from there. We also propose to analyze the different signals gathered and find correlation present in them which can lead to a better understanding of the whole cardiovascular system and assist doctors in early diagnosis of crucial symptoms. As an initial step towards that, Blood pressure (BP) and Heart rate (HR) is monitored using the gathered ECG and PPG signals from the device. The reliability of the device for BP and HR monitoring is estimated by comparing it with a clinically proven professional automatic digital BP monitor (OMRON HBP1300).

Performance evaluation of enhanced FIR filter based module for clock synchronization in MPEG2 transport stream

Existing Set-Top Boxes experiences very large jitter in terrestrial environment due to multi path reflections. Existing algorithms for achieving clock recovery for DVB-T relies on very complex calculations which are not suitable for real time data processing. In digital Set-top box most of the CPU bandwidth is consumed in audio & video data decoding so clock synchronization algorithms get very less CPU time to execute. This paper presents Low cost weighing filter approach to solve the color loss problem in Digital Set-top Box. This algorithm has been tested in practical satellite and terrestrial environment. Its performance has been compared with Linear Regression based algorithm and shows distinct advantages.

Corrections to “Continuous Adaptation Enhancement in Linear Regression Algorithm for Clock Recovery in IPTV Environment” [Jun 09 485-490]

In the above titled paper (ibid., vol. 55, no. 2, pt. 2, pp. 485-490, Jun. 09), due to a production error, the captions for Figs. 3-5 were placed incorrectly prior to final printing. The correct figures and their corresponding captions are presented here.