Zonal complexity based measure for lossy compression of photoplethysmogram using delta encoding
01 Feb 2015-pp 1-5
TL;DR: A modification of delta modulation for effective compression of PPG signal for real time measurements and monitoring applications is proposed.
Abstract: Photoplethysmography (PPG) is one of the prime non-invasive vascular assessment methodology adopted in modern clinical practice. This paper proposes a modification of delta modulation for effective compression of PPG signal for real time measurements and monitoring applications. Based on the energy content and fluctuations, the PPG signal was windowed and categorized into ‘complex’ or ‘plain’ zones. The algorithm applies an adaptive hard thresholding, run length encoding and selective biasing of the first difference array based on zonal complexity. The final stage employs a selective nibble combination or offsetting rule for further compression. For performance assessment of the compression-decompression algorithms, PPG data was collected from fingers of healthy volunteers using Biopac Systems®. An average compression ratio of 3.84, percentage root mean square difference of 5.82 and percentage root mean square difference normalized of 7.57 were obtained with 20 sets of volunteers' data at 10 bit resolution and 125 Hz sampling. The decompressed data were clinically validated by Cardiologists.
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21 Feb 2007
704 citations
TL;DR: A high performing, reliable and robust Photoplethysmogram compression and encryption method is proposed for efficient, safe and secure storage and transmission which is superior to existing PPG compression methods reported to date.
29 citations
TL;DR: An efficient PPG compression algorithm is presented, and is developed on the basis of five major sequential steps: noise elimination through Butterworth low-pass filter, down-sampling, inter-sample difference computation, grouping and American Standard Code for Information Interchange (ASCII) character encoding of reduced dataset.
26 citations
TL;DR: A robust, reliable and highly efficient singular value decomposition and lossless ASCII character encoding (LL-ACE)-based quality-guaranteed PPG compression algorithm that provides a compression ratio that is much higher than that provided by other algorithms that are designed to compress the PPG signals only.
Abstract: Objective: Extraction and analysis of various clinically significant features of photoplethysmogram (PPG) signals for monitoring several physiological parameters, as well as for biometric authentication have become important areas of research in recent years. However, PPG signal compression; particularly quality-guaranteed compression, and steganography of patient's secret information is still lagging behind. Method: This paper presents a robust, reliable and highly efficient singular value decomposition and lossless ASCII character encoding (LL-ACE)-based quality-guaranteed PPG compression algorithm. This algorithm cannot only be used to compress PPG signals, but also do so for steganographed PPG signals that include the patient information. Result and conclusion: It is worth mentioning that such an algorithm is being proposed for the first time to compress steganographed PPG signals. The algorithm is tested on PPG signals collected from four different databases, and its performance is assessed using both quantitative and qualitative measures. The proposed steganographed PPG compression algorithm provides a compression ratio that is much higher than that provided by other algorithms that are designed to compress the PPG signals only. Significance: first, the clinical quality of the reconstructed PPG signal can be controlled precisely, second, the patient's personal information is restored with no errors, third, high compression ratio, and fourth, the PPG signal reconstruction error is neither dependent on the steganographic operation nor on the size of the patient information data.
16 citations
Cites background or methods from "Zonal complexity based measure for ..."
...The values of CC and RMSE of the methods in [14], [15], [16] and [17] are not available in the literature and hence not included in Table IV....
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...The algorithm proposed in [15] is also tested on PPG data recorded at 125 Hz sampling rate....
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...77 at 125 Hz sampling rate, which is higher than that of the CR values reported in [14] or [15]....
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05 Jun 2019
TL;DR: Results demonstrate that the proposed framework provides a promising energy saving solution by discarding the noisy photoplethysmogram (PPG) signals and pulse-free signals before performing data compression and compressing the noise-free PPG signals efficiently with very small feature parameter error.
Abstract: In this article, we propose a new real-time quality-aware quality-control data compression framework for maximizing the battery life of Internet of Things (IoT) and Smartphone based health monitoring devices. The proposed framework is implemented on Arduino Due with a 32-bit Atmel SAM3X8E ARM Cortex-M3 processor and validated using four standard databases and real-time signals obtained by using our sensing hardware. The proposed framework achieves compression ratios between seven and 28 with energy saving between 83% and 92%. Results demonstrate that our framework provides a promising energy saving solution by discarding the noisy photoplethysmogram (PPG) signals and pulse-free signals before performing data compression and compressing the noise-free PPG signals efficiently with very small feature parameter error.
15 citations
Cites methods from "Zonal complexity based measure for ..."
...In past studies [3]–[5], most methods assessed the reconstruction fidelity using the percentage root mean square (PRD) metric, which is computed as...
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...3) Compression Algorithm’s Evaluation Metrics: The compression algorithm is evaluated using the CR as described in (5) and the standard distortion metric, such as percentage root mean square difference (PRD), as described in (2), which is commonly used to evaluate the reconstruction fidelity [3]–[5]....
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...In past studies, few PPG compression algorithms were presented based on the lightweight temporal compression [1]: the Peak Detection and Online Dictionary [1], and the Peak Detection and Auto-Encoders [1], the Cycle-by-cycle Fourier Series Analysis [2], delta modulation (DM) [3], adaptive DM [4], the Zonal complexity measure, adaptive hard thresholding, run-length encoding (RLE), and selective biasing and DM [5], the low-pass filter, down-sampling, first-difference computation, encoding the first sample, sign byte generation and amplification, grouping, and American Standard Code for Information Interchange [6]....
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References
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TL;DR: Photoplethysmography is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue and is often used non-invasively to make measurements at the skin surface.
Abstract: Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.
2,836 citations
"Zonal complexity based measure for ..." refers background in this paper
...The AC component is due to the absorption of light by the pulsating arterial blood at the measuring site, while the DC component is due to the light absorption caused by the non-pulsating arterial blood, venous blood, bones and other tissues [1]....
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TL;DR: Experimental results indicate that the proposed method is insensitive to heart rate variation, introduces negligible error in the processed PPG signals due to the additional processing, preserves all the morphological features of the PPG, provides 35 dB reduction in motion artifacts, and achieves a data compression factor of 12.
Abstract: Pulse oximeters require artifact-free clean photoplethysmograph (PPG) signals obtained at red and infrared (IR) wavelengths for the estimation of the level of oxygen saturation ( SpO2) in the arterial blood of a patient. Movement of a patient corrupts a PPG signal with motion artifacts and introduces large errors in the computation of SpO2. A novel method for removing motion artifacts from corrupted PPG signals by applying Fourier series analysis on a cycle-by-cycle basis is presented in this paper. Aside from artifact reduction, the proposed method also provides data compression. Experimental results indicate that the proposed method is insensitive to heart rate variation, introduces negligible error in the processed PPG signals due to the additional processing, preserves all the morphological features of the PPG, provides 35 dB reduction in motion artifacts, and achieves a data compression factor of 12.
152 citations
"Zonal complexity based measure for ..." refers methods in this paper
...Reddy et al [15] proposed a cycle-by-cycle Fourier series analysis (CFSA) for removing motion artifacts from the PPG signal and to compress the PPG data....
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16 May 1998
TL;DR: The ring sensor is worn by the patient at all times, hence the health status is monitored 24 hours a day for a tele-nursing system and any trait of abnormal health status and possible accidents is detected by analyzing the sensor data.
Abstract: This paper presents the development of the ring sensor to monitor a patient 24 hours a day for a tele-nursing system. The ring sensor is worn by the patient at all times, hence the health status is monitored 24 hours a day. The sensors packed into the ring include LEDs with different wavelengths, and technologies of photoplethysmography and pulse oximetry are implemented on the ring. The sensor data are transmitted to a computer through the digital wireless communication link and the patient status is analyzed continually and remotely. Any trait of abnormal health status and possible accidents is detected by analyzing the sensor data. A combination of a global receiver and multiple local ones are used to estimate the patient's location and activity. Both the physiological data and the position information can be used to make an accurate decision as to whether a warning signal must be sent to a medical professional caring the patient. An issue of power reduction for miniaturization of the ring sensor is also addressed.
124 citations
"Zonal complexity based measure for ..." refers methods in this paper
...With the advent of low power, cheap VLSI technology and wireless communication, commercial PPG sensors are now available in miniature packages and has been used as alternative of Electrocardiogram (ECG) signals for pulmonary and cardiac function assessment in health monitoring applications [5-8]....
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01 Jan 2006
TL;DR: A wavelet-based electrocardiogram (ECG) compression algorithm with a low delay property for instantaneous, continuous ECG transmission suitable for telecardiology applications over a wireless network is proposed.
Abstract: The delay performance of compression algorithms is particularly important when time-critical data transmission is required. In this paper, we propose a wavelet-based electrocardiogram (ECG) compression algorithm with a low delay property for instantaneous, continuous ECG transmission suitable for telecardiology applications over a wireless network. The proposed algorithm reduces the frame size as much as possible to achieve a low delay, while maintaining reconstructed signal quality. To attain both low delay and high quality, it employs waveform partitioning, adaptive frame size adjustment, wavelet compression, flexible bit allocation, and header compression. The performances of the proposed algorithm in terms of reconstructed signal quality, processing delay, and error resilience were evaluated using the Massachusetts Institute of Technology University and Beth Israel Hospital (MIT-BIH) and Creighton University Ventricular Tachyarrhythmia (CU) databases and a code division multiple access-based simulation model with mobile channel noise
81 citations
"Zonal complexity based measure for ..." refers background in this paper
...In health monitoring, data compression plays an important role in reducing the storage space of medical data as well as enhancing the channel efficiency of the communication link [13-14]....
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25 Oct 2001
TL;DR: Presents a new method for obtaining blood pressure readings noninvasively with telemedicine application through the pulse transit time technique, which predicts the systolic, diastolic, and mean blood pressures using the time interval between the electrocardiogram and photoplethysmography.
Abstract: Presents a new method for obtaining blood pressure readings noninvasively with telemedicine application. Through the pulse transit time technique, the systolic, diastolic, and mean blood pressures can be predicted using the time interval between the electrocardiogram (ECG) and photoplethysmography (PPG). The data can then be relayed to the Internet for analysis and viewing. The wireless application protocol (WAP) is used for displaying the information on portable wireless devices. The subjects' cardiovascular condition can thus be obtained for monitoring or pre-diagnosis purposes.
74 citations