SEARCH · PubMed Health

Results for “Error minimization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources

PubMed1997

Surface-marker cluster design criteria for 3-D bone movement reconstruction.

When three-dimensional (3-D) human or animal movement is recorded using a photogrammetric system, bone-embedded frame positions and orientations are estimated from reconstructed surface marker trajectories using either nonoptimal or optimal algorithms. The effectiveness of these mathematical procedures in accommodating for both photogrammetric errors and skin movement artifacts depends on the number of markers associated with a given bone as well as on the size and shape characteristics of the relevant cluster. One objective of this paper deals with the identification of marker-cluster design criteria aimed at the minimization of error propagation from marker coordinates to bone-embedded frame position and orientation. Findings allow for the quantitative estimation of these errors for any given cluster configuration and suggest the following main design criteria. A cluster made up of four markers represents a good practical compromise. Planar clusters are acceptable, provided in quasi-isotropic distribution. The root mean square distance of the markers from their centroid should be greater than ten times the standard deviation of the marker position error. The second objective of this paper deals with the identification of the optimal cluster position and orientation on the limb aimed at the minimization of error propagation to anatomical landmark laboratory coordinates. Cluster position should be selected to minimize skin movement artifacts. The longest principal axis of the marker distribution should be oriented toward the relevant anatomical landmark position.

Animals↗

PubMed2002

Primary standardization of assays for anticonvulsant drugs: comparison of accuracy and precision.

BACKGROUND: The accuracy and precision of methods for the measurement of the anticonvulsants phenytoin, phenobarbital, primidone, carbamazepine, ethosuximide, and valproate in human serum were assessed in 297 laboratories that were participants in the United Kingdom National External Quality Assessment Scheme (UKNEQAS). METHODS: We distributed lyophilized, serum-based materials containing low, medium, and high weighed-in concentrations of the drugs. The 297 participating laboratories received the materials on two occasions, 7 months apart. Expected concentrations were determined by gas chromatography or HPLC methods in five laboratories using serum-based NIST reference materials as calibrators. RESULTS: In general, bias was consistent across concentrations for a method but often differed in magnitude for different drugs. Bias ranged from -1.9% to 8.6% for phenytoin, -2.7% to 3.1% for phenobarbital, -2.7% to 0.5% for primidone, -8.6% to 0.3% for carbamazepine, -5.6% to 2.0% for ethosuximide, and -7.2% to 0.1% for valproate. Intralaboratory sources of imprecision significantly exceeded interlaboratory sources for many drug/method combinations. The mean CVs for intra- and interlaboratory errors for the different drugs were 6.3-7.8% and 3.3-4.2%, respectively. CONCLUSIONS: For these long-established and relatively high-concentration analytes, the closed analytical platforms generally performed no better than open systems or chromatography, where use of calibrators prepared in house predominated. To improve the accuracy of measurements, work is required principally by the manufacturers of immunoassays to ensure minimal calibration error and to eliminate batch-to-batch variability of reagents. Individual laboratories should concentrate on minimizing dispensing errors.

Anticonvulsants↗

PubMedDate not supplied

Understanding the research methodology: should we trust the researchers' conclusions?

Understanding the methodology section of research articles is difficult for those unfamiliar with research design, but is essential for judging the credibility of the researchers' findings. The methodology section describes measures taken to avoid reaching the wrong conclusions. When comparing two or more treatments, researchers might find a difference in treatments when none exists (type I error) or not find a difference when there actually is one (type II error). Type I errors are minimized by random assignment to treatment and control groups, double blinding, ensuring that the treatment under study is the only difference between groups, and setting the level of significance in advance. Type II errors are minimized by using an adequately sized, homogenous sample, increasing the treatment strength, measuring precisely, and using appropriate statistics. The purpose of this article is to explain these common experimental strategies and statistical terms.

Bias↗

PubMed2000

Fetal MRI in the evaluation of intrauterine myelomeningocele.

BACKGROUND: Accurate fetal imaging is essential to the practice of maternal-fetal medicine. While ultrasonography has been the traditional mainstay of fetal imaging, its ability to resolve critical features of central nervous system (CNS) anatomy remains limited. As interest in intrauterine therapy for myelomeningocele has increased, so has the need for more accurate, noninvasive imaging of the CNS. Fetal magnetic resonance imaging (MRI) promises to fill the gap left by ultrasound. METHODS: Thirty-seven MRI scans of fetuses previously diagnosed with myelomeningocele were reviewed by 2 neuroradiologists. The ability of fetal MRI to resolve the commonest CNS stigmata of spina bifida, and the incidence and extent of interobserver error, was assessed. In 4 cases, postnatal MRIs were also available. These were compared to the corresponding fetal studies. RESULTS: The imaging quality with the technique used in this study was excellent, even without the use of maternal or fetal sedation. There were no complications, and the imaging times were minimal. Interobserver error was minimal with respect to the evaluation of ventricular dilatation and hindbrain herniation, but moderate in the description and location of the spinal lesion. As had previously been documented with ultrasonography, a reduction was seen in hindbrain herniation when comparing pre- and postnatal MRIs. CONCLUSION: It is concluded that fetal MRI is an effective, noninvasive means of assessing fetal CNS anatomy. Its ability to resolve posterior fossa anatomy is superior to ultrasonography while, with respect to the evaluation of hydrocephalus and the level and nature of the spinal lesion, it may be equivalent to inferior. Inclusion of the fetal MRI into the standard diagnostic armamentarium will probably await the next major advance in speed and resolution. It is conceivable that, with further advances, MRI might supplant ultrasonography as the diagnostic tool of choice for evaluation of fetal anomalies including myelomeningocele.

Cranial Fossa, Posterior↗

PubMed1988

Determination of the complete three-dimensional structure of the alpha-amylase inhibitor tendamistat in aqueous solution by nuclear magnetic resonance and distance geometry.

The complete three-dimensional structure of the alpha-amylase inhibitor Tendamistat in aqueous solution was determined by 1H nuclear magnetic resonance and distance geometry calculations using the program DISMAN. Compared to an earlier, preliminary determination of the polypeptide backbone conformation, stereo-specific assignments were obtained for 41 of the 89 prochiral groups in the protein, and a much more extensive set of experimental constraints was collected, including 842 distance constraints from nuclear Overhauser effects and over 100 supplementary constraints from spin-spin coupling constants and the identification of intramolecular hydrogen bonds. The complete protein molecule, including the amino acid side-chains is characterized by a group of nine structures corresponding to the results of the nine DISMAN calculations with minimal residual error functions. The average of the pairwise minimal root-mean-square distances among these nine structures is 0.85 A for the polypeptide backbone, and 1.52 A for all the heavy atoms. The procedures used for the structure determination are described and a detailed analysis is presented of correlations between the experimental input data and the precision of the structure determination.

Amino Acid Sequence↗

PubMed1985

An interdisciplinary method of classifying and monitoring medication errors.

A system is described for reporting medication errors according to practitioner and type and using these data as part of a departmental quality-assessment program. Types of errors committed in prescribing, in dispensing, and in administering drugs in a teaching hospital were listed. Prescribers' and pharmacists' reports of errors committed. Data on dispensing errors by 16 staff pharmacists were collected over a 12-month period in 1982-83, and data on prescribing by resident physicians were collected during three separate one-month periods. For each pharmacist, data on dispensing errors were compiled monthly. Pharmacists were counseled if they had a large number of errors in one category, a high total number of errors, or a substantial number of errors in a single category over several months. Likewise, physicians who committed more errors than their department's mean were counseled by the clinical chairman. After 12 months, each pharmacist's monthly error rate was compared with the departmental average. The number of dispensing errors reported during the study period (average 60.7 per month for the department) was lower than expected. Serious prescribing errors were minimal. In spite of probable underreporting of errors in this voluntary system, these methods of classifying medication errors by type and practitioner group and of recording error rates were useful tools for monitoring and improving performance of pharmacists and prescribers.

Chicago↗

PubMed2001

Washing of marine coastal sand in a batch reactor: sorption and desorption of BTEX.

This study addresses the issues related to decontamination of marine beach sand accidentally contaminated by petroleum products. Sorption and desorption of BTEX (i.e., benzene, toluene, ethylbenzene, and xylene) onto the sand from Uran Beach, located near the city of Mumbai, India, were studied, and isotherms were determined using the bottle point method to estimate sorption coefficients. Alternatively, QSARs (i.e., quantitative structure activity relationships) were developed and used to estimate the sorption coefficients. Experiments for kinetics of volatilization as well as for kinetics of sorption and desorption in the presence of volatilization were conducted in a fabricated laboratory batch reactor. A mathematical model describing the fate of volatile hydrophobic organic pollutants like BTEX (via sorption and desorption in presence of volatilization) in a batch sediment-washing reactor was proposed. The experimental kinetic data were compared with the values predicted using the proposed models for sorption and desorption, and the optimum values of overall mass transfer coefficients for sorption (K(s)a(s)) and desorption (K(d)a(d)) were estimated. This was achieved by minimization of errors while using the sorption coefficients (Kp) obtained from either laboratory isotherm studies or the QSARs developed in the present study. Independent experimental data were also collected and used for calibration of the model for volatilization, and the values of the overall mass transfer coefficient for volatilization (K(g)a(g)) were estimated for BTEX. In these exercises of minimization of errors, comparable cumulative errors were obtained from the use of Kp values derived from experimental isotherms and QSARs.

Adsorption↗

PubMed1994

Pressure and volume control for local drug-delivery catheters: development of a new microprocessor-controlled system.

BACKGROUND: Local drug delivery is a potential solution to postintervention restenosis. Most catheters developed for local delivery depend upon control of pressure and of delivered volume for optimal performance. The present study was designed to assess the accuracy of current methods for inflation of local delivery catheters compared with a new microprocessor-controlled system specifically designed for this application. METHODS: An in vitro gravimetric testing system was constructed to record developed pressure and delivered volume using a variety of inflation devices and a microporous infusion catheter. Experienced catheterization laboratory personnel were given commercial angioplasty indeflators and a pressure-driven syringe and asked to quickly apply 5 atm and deliver 2.0 ml. A new microprocessor-controlled system was then tested using the same protocol. RESULTS: The time required to reach a plateau pressure was lowest with the pressure-driven syringe (0.164 +/- 0.017 s) and much higher with standard indeflators (2.94 +/- 2.54, 4.64 +/- 2.98, 7.69 +/- 4.89, 8.28 +/- 6.31 s). The corresponding microprocessor-controlled value was much lower than that of the manual systems (0.84 +/- 0.37 s). The variability of plateau pressure, as measured by the standard deviation, was lowest with the pressure-driven syringe (0.029 +/- 0.014 atm) and highest with the manual systems (0.37 +/- 0.26, 0.40 +/- 0.18, 0.44 +/- 0.31, 0.32 +/- 0.10 atm). The microprocessor-controlled system also produced very little variability in pressure (0.08 +/- 0.004 atm). The volume delivered varied significantly with all manual devices (1.77 +/- 0.64, 1.74 +/- 0.66, 1.36 +/- 0.45, 1.80 +/- 0.33 ml) as well as with the pressure-driven syringe (1.86 +/- 0.32 ml), but the volume delivered by the microprocessor-controlled system was highly accurate (1.99 +/- 0.06 ml). CONCLUSIONS: Manual inflation devices do not allow precise control of pressure or volume when used with local delivery catheters. Use of a pressure-driven syringe minimizes pressure error, but does not deliver an accurate volume. The microprocessor-controlled system minimizes pressure and volume error and should maximize transfer efficiency for local delivery catheter systems.

Angioplasty, Balloon, Coronary↗

PubMed2005

An adaptive incremental LBG for vector quantization.

This study presents a new vector quantization method that generates codewords incrementally. New codewords are inserted in regions of the input vector space where the distortion error is highest until the desired number of codewords (or a distortion error threshold) is achieved. Adoption of the adaptive distance function greatly increases the proposed method's performance. During the incremental process, a removal-insertion technique is used to fine-tune the codebook to make the proposed method independent of initial conditions. The proposed method works better than some recently published efficient algorithms such as Enhanced LBG (Patane, & Russo, 2001) for traditional tasks: with fixed number of codewords, to find a suitable codebook to minimize distortion error. The proposed method can also be used for new tasks that are insoluble using traditional methods: with fixed distortion error, to minimize the number of codewords and find a suitable codebook. Experiments for some image compression problems indicate that the proposed method works well.

Algorithms↗

PubMed2005

Reliability and validity of static knee strength measurements obtained with a chair-fixed dynamometer in subjects with hip or knee arthroplasty.

OBJECTIVES: To evaluate the reliability (intertrial, interevaluator) and the concurrent validity of strength measurements obtained with a chair-fixed dynamometer and to recommend a clinical protocol that minimizes standard error of measurement (SEM). DESIGN: Within-session repeated measures of maximal static strength of knee flexors and extensors at 30 degrees and 60 degrees of flexion on the chair-fixed and Cybex dynamometers. SETTING: Ambulatory physiotherapy department of a rehabilitation hospital. PARTICIPANTS: Convenience sample of 50 subjects with total hip (n=25) or knee (n=25) arthroplasty. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Reliability was quantified by indices of dependability and corresponding SEMs estimated with the generalizability theory, whereas coefficients of correlation were used to assess the validity. RESULTS: Indices of dependability confirmed excellent intertrial (0.98-1.00) and a very good interevaluator (.92-.99) reliability for the strength measures obtained for different movements and positions. An average of 3 trials minimized the magnitude of the SEMs (>2 Nm for all measurements). When comparing the strength values obtained with the Cybex dynamometer to those measured with the chair-fixed dynamometer, strongest relations were attained when the tested knee was positioned at 60 degrees compared with 30 degrees for subjects with a total knee (.78-.92 vs .87-.93) or hip (.73-.85 vs .86-.91) arthroplasty. CONCLUSIONS: A clinical protocol averaging 3 trials with the knee positioned at 60 degrees after a familiarization period, both for knee flexors and extensors, performed by a trained therapist is recommended to minimize measurement errors on strength values measured with the chair-fixed dynamometer.

Aged↗

PubMed1995

Evaluation of bi-level image converting methods for nuclear medicine image database stored in the IS&C magneto-optical disk.

1. INTRODUCTION. We have developed a report and imaging management system for nuclear medicine. The report and image data are stored in the IS&C magneto-optical disk (IS&C MOD). Nuclear medicine image data are relatively small, but they are large enough to create problems when being transported over a low-speed Hospital Information System (HIS) network. Moreover, gray scale image output devices (i.e., high-resolution displays, sonoprinters) are expensive. If high quality bi-level (black and white) images were available, images could be transferred through low-speed network with inexpensive bi-level terminals or conventional page-printers. We examined images using several bi-level image conversion techniques [1, 2] in order to determine how useful the bi-level images are and to assess their suitability for use in nuclear medicine. The images were compared with original film images by ROC analysis. The modified minimized average error method was found to be superior to other methods in bone and gallium images. Its A-values are 0.83 in gallium scan and 0.85 in bone scan. 2. MATERIALS AND METHODS. Our system consists of three digital gamma cameras, a nuclear medicine data processing unit, two UNIX stations, and two personal computers. The computers and the data processing unit are connected via Ethernet and each computer has an IS&C MOD unit. Image and report data are stored in the IS&C MOD. The computers are also connected off-line through the IS&C MOD. To evaluate image quality, bone scan images and gallium scan images (1024x512, 2048x1024 pixels and 16 bits depth) were converted to bi-level images (same pixels and one bit depth) using four methods: dither method, minimized average error method (MAE)[1], modified regional adaptation method, and constrained average method. For the dither methods, three sets of dither matrix (Fatting's, Bayer's and our original matrix) were employed. The computer images were compared with original film images by ROC analysis. 3. RESULTS. The converted bi-level images were 1/16 the size of the originals. They were transferred via Ethernet, displayed on the monochrome display, and printed using a conventional page-printer (240 dpi or 300 dpi). The A-values of the original gallium and bone images on the films were 0.89 and 0.94. Modified MAE method gave better results than other methods tested, with the gallium image using this technique reading 0.83 on the A-scale; and the bone images were 0.85. 4. DISCUSSION. Generally, nuclear medicine images require lower spatial and gray level resolution than other computer imaging techniques. We compared four bi-level image conversion methods in order to know which methods are suitable to nuclear medicine images. The ROC analysis was employed to evaluate these image qualities. The MAE methods made particular texture pattern as artifacts in the intermediate gray level area. But it can express homogeneity the neutral level. The dither method images are coarse texture. It affects detectabilities of subtle abnormal findings. 5. CONCLUSIONS. The A-z values of the modified MAE images were comparable to those of original film images. Although bone images give slightly lower values, many abnormal findings can be ascertained on bi-level images. High quality bi-level image techniques are considered to be useful for nuclear medicine image database systems.

Japan↗

PubMed2006

Modeling and phantom studies of ultrasonic wall shear rate measurements using coded pulse excitation.

Wall shear rate (WSR) is the derivative of blood velocity with respect to vessel radius at the endothelial cell (EC) surface. The product of WSR and blood viscosity is the wall shear stress (WSS) that has been identified as an important factor for atherosclerosis development. High echo signal-to-noise ratio (eSNR) and high spatial resolution are crucial for minimizing the errors in WSR estimates. By transmitting coded pulses with time-bandwidth product greater than one, high eSNR from weak blood scatter can be achieved without increasing instantaneous power or sacrificing spatial resolution. This paper summarizes a series of measurements in a straight tube (5-mm diameter), constant velocity flow phantom using a 10 MHz transducer (60% bandwidth, f/1.5) imaged with a 72 degrees Doppler angle, 125 MHz sampling frequency and 1 kHz pulse repetition frequency. Measurements were made using a frequency-modulated (FM) code, phase-modulated (PM) codes, and uncoded broadband and narrow band pulse transmissions. Both simulation and experimental results show that coded-pulse excitation increases accuracy and precision in WSR estimation for laminar flow over a broad range of peak velocity values when compared to standard pulsing techniques in noise-limited conditions (eSNR < 30 dB). The code sequence and its length are selected to balance range lobe suppression with eSNR and echo coherence enhancements to minimize WSR errors. In our study, the combination of an eight bit Optimal coded pulse with a Wiener compression filter yielded the highest WSR estimation performance.

Animals↗

PubMed2005

Reproducibility of image interpretation in MRI of the prostate: application of the sextant framework by two different radiologists.

The aim of this study was to reproduce prostate cancer (PCA) localization by MRI based on prostatic sextants (right and left base, middle, and apex) with minimal systematic error. Combined endorectal/body-phased-array-coil MRI of the prostate at 1.5 T was retrospectively evaluated twice, with an interval of more than 1 month, by each of two independent radiologists (R1 readings R11 and R12, and R2 readings R21 and R22) in 23 patients (age 51-75 years) who had radical prostatectomy within 1 month of MRI. PCA stage was pT2 in 14 patients, and pT3 in nine. Median Gleason score was 7 (range 5-9). Histopathology showed 83 sextants with PCA and 55 without. Reproducibility of sextant positions was within one MRI slice (3 mm) in over 80% of cases. For PCA localization, ROC analysis (AUC=0.584+/-0.048-0.724+/-0.043) yielded no significant intra-reader differences. R11 and R21 differed slightly (P=0.035). Intra-observer agreement (kappa=0.52-0.58) exceeded inter-observer agreement (kappa=0.35-0.45). Intra-observer Spearman correlation (r=0.72-0.74) exceeded inter-observer correlation (r=0.43-0.51) for sextants with PCA, but not for sextants without (r=0.69-0.74). Per-sextant localization and reporting provides a highly reliable framework in MRI of the prostate. MRI of the prostate should be followed up by the same radiologists to minimize systematic error of interpretation.

Aged↗

PubMed1997

Errors in cervical smears: minimizing the risk of medicolegal consequences.

Cytologists need to critically evaluate their practices and practice settings to ensure that what they do and how they document what they do will withstand both regulatory and legal scrutiny. Any individual involved in cytology as a laboratory owner, operator, director, supervisor, technical or staff employee, independent agent, or customer representative is a potential target of cytology malpractice litigation. All of these individuals must participate in the risk management process. For the laboratory as a corporate entity, business and technical practices, including quality control and quality assurance procedures, must be contemporary, legitimate, and justifiable. Sound scientific evidence and well-subscribed standards of practice supporting an individual's or laboratory's conduct are the best defenses to malpractice claims. For the near future, litigation will continue to focus on false-negative Pap smears on a case-by-case basis. Laboratories and individuals can reduce the risk of malpractice liability by directing their attention to proactive quality control and quality assurance methods. But in the final analysis, consumer education about the benefits and limitations of the Pap test is key to limiting malpractice claims.

Carcinoma, Squamous Cell↗

PubMed1995

Introduction to perceptual linearization of video display systems for medical image presentation.

The perceptual linearization of video display systems should play a significant role in medical image presentation. It maximizes the faithfulness of information transfer to the human observer; it provides a method for standardizing the appearance of images across different display devices; and it allows for calculation of the inherent contrast resolution of different display devices. This paper provides insight into the process of perceptual linearization by decomposing it into the digital driving level-to-monitor luminance relationship, the monitor luminance-to-human brightness perception relationship, and the construction of a linearization function derived from these two relationships. A discussion of previous work in these areas is given. We then compare and contrast the results of previous work with recent experiments in our laboratory and related work in vision and computer science. We conclude that (1) sufficiently good visual models exist for agreeing on a standard method of calculating the perceptual linearization function; (2) improvements in the resolution and luminance distribution of the digital-to-analog circuitry in display systems are required for medical imaging; and (3), methods for calculating a linearization remapping from a perceptual linearization function currently have significant error and should be replaced with methods that minimize perceptual error.

Analog-Digital Conversion↗

PubMed2000

Neural network analysis of oxygenation signals in infants during sleep.

The use of artificial neural networks (ANNs) to interpret sleep monitoring signals is described. Recordings from ten infants with apparent life threatening episodes were assigned into training feedforward R-PROP networks. In order to separate good signal from artefact, 60 second time frames of SaO2 and TcPO2 signals were processed and the mean and standard deviation values were used as inputs to the networks. Intra-human errors were minimized using this method whilst inter-human errors remained significant. To decrease the latter, the number of hidden units was increased to eight. Sensitivity figures of the SaO2 network were 0.93 and 0.9 for the training and test sets respectively whilst the specificity figures were 0.7 and 0.65 respectively. For the TcPO2 signals the above figures were 0.92, 0.85, 0.77 and 0.61 respectively.

Apnea↗

PubMed2004

A prototype of a liquid ventilator using a novel hollow-fiber oxygenator in a rabbit model.

OBJECTIVE: A functional total liquid ventilator should be simple in design to minimize operating errors and have a low priming volume to minimize the amount of perfluorocarbon needed. Closed system circuits using a membrane oxygenator have partially met these requirements but have high resistance to perfluorocarbon flow and high priming volume. To further this goal, a single piston prototype ventilator with a low priming volume and a new high-efficiency hollow-fiber oxygenator in a circuit with a check valve flow control system was developed. DESIGN: Prospective, controlled animal laboratory study. SETTING: Research facility at a university medical center. SUBJECTS: Seven anesthetized, paralyzed, normal New Zealand rabbits INTERVENTIONS: The prototype oxygenator, consisting of cross-wound silicone hollow fibers with a surface area of 1.5 m2 with a priming volume of 190 mL, was tested in a bench-top model followed by an in vivo rabbit model. Total liquid ventilation was performed for 3 hrs with 20 mL.kg(-1) initial fill volume, 17.5-20 mL.kg(-1) tidal volume, respiratory rate of 5 breaths/min, inspiratory/expiratory ratio 1:2, and countercurrent sweep gas of 100% oxygen. MEASUREMENTS AND MAIN RESULTS: Bench top experiments demonstrated 66-81% elimination of CO2 and 0.64-0.76 mL.min(-1) loss of perfluorocarbon across the fibers. No significant changes in PaCO2 and PaO2 were observed. Dynamic airway pressures were in a safe range in which ventilator lung injury or airway closure was unlikely (3.6 +/- 0.5 and -7.8 +/- 0.3 cm H2O, respectively, for mean peak inspiratory pressure and mean end expiratory pressure). No leakage of perfluorocarbon was noted in the new silicone fiber gas exchange device. Estimated in vivo perfluorocarbon loss from the device was 1.2 mL.min(-1). CONCLUSIONS: These data demonstrate the ability of this novel single-piston, nonporous hollow silicone fiber oxygenator to adequately support gas exchange, allowing successful performance of total liquid ventilation.

Animals↗

PubMed2005

Error concealment for shape in MPEG-4 object-based video coding.

In asynchronus transfer mode networks, cell loss or channel errors can cause data to be dropped in the channel. When digital images/videos are transmitted over these networks, one must be able to reconstruct the missing data so that the impact of the errors is minimized. In this paper, we present an error-concealment technique for shape in MPEG-4 object-based video coding. This method, which is based on using global motion estimation and compensation techniques for boundary recovery, consists of three steps: (1) boundary extraction from shape; (2) boundary patching using global motion compensation; and (3) boundary filling to reconstruct the shape of the damaged video object planes. Global motion parameters are inserted as part of the USER_DATA field in the compressed stream and are utilized in reconstructing the damaged boundaries of compressed video object planes.

Algorithms↗