Median Filtration Research Articles

HEPA filters for airliner cabins: State of the art and future development.

The airliner cabin environment is very important to the health of passengers and crew members, and the use of high-efficiency particulate air (HEPA) filters for recirculated air in the environmental control systems (ECS) is essential for the removal of airborne particles such as SARS CoV-2 aerosols. A HEPA filter should be high efficiency, low-pressure drop, high dust-holding capacity (DHC), lightweight, and strong for use in aircraft. We conducted an experimental study on 23 HEPA filters with glass fiber media that are used in different commercial airliner models. The tested filters had a median filtration efficiency of >99.97% for particles with a diameter of 0.3-0.5 μm, a pressure drop of 134-412 Pa at rated airflow rate, and a DHC of 32.2-37.0 g/m2 . The use of nanofiber media instead of glass fiber media can reduce the pressure drop by 66.4%-94.3% and significantly increase the quality factor by analysis of literature data. The disadvantages of poor fire resistance and small DHC can be overcome by the use of flame-retardant polymers and fiber structural design. As a new lightweight and environmentally friendly filter material, nanofiber media could be used as air filters in ECS in the future.

Investigation of the mechanism for median image filtering in computer systems and special purpose networks

A successful solution to solve an impulse noise is to use median filtration proposed by John Tuke in 1971 for the analysis of economic processes. It should be noticed that median filtration is a heuristic processing method, its algorithm is not a mathematical solution to a strictly formulated problem. Therefore, the researchers pay much attention to the analysis of the image effectiveness processing on its basis and comparison with other methods. When applying a median filter, each image pixel is sequentially processed. For median filtration, a two-dimensional window (filter aperture) is used, usually has a central symmetry, with its center located at the current filtration point. The dimensions of the aperture are among the parameters that are optimized in the process of analyzing the algorithm efficiency. Image pixels, that appear within the window, form a working sample of the current step. However median filtering smoothens the image borders to a lesser degree than any linear filtering. The mechanism of this phenomenon is very simple and is as follows. Assume that the filter aperture is near the boundary separating the light and image's dark areas, with its center located in the dark area. Then, most likely, the work sample will contain more elements with small brightness values, and, consequently, the median will be among those elements of the work sample that match this area of the image. The situation changes to the opposite, if the aperture center is shifted to the region of higher brightness. But this means the presence of sensitivity in the median filter to brightness variations.

ОЦЕНКА УСТОЙЧИВОСТИ СТРУКТУРНО-ЯРКОСТНЫХ СВОЙСТВ ПРИ ЦИФРОВОЙ ОБРАБОТКЕ ИЗОБРАЖЕНИЙ

The article considers determining the stability assessment of the structural and brightness properties of raster images. The stability assessment refers to the ability of preserving the image properties due to the original image processing by filtering. Halftone versions of the full-color images presented in the RGB color space are accepted as original images. The grayscale images are filtered using the Gaussian, Wiener, and median filtration algorithms. The next step is to use one of the variants of the SSIM algorithm to obtain the structural similarity index between the control halftone image and the filtered image. In order to create a relative and dimensionless metric there has been calculated the area of the polygon S set by the values of the similarity indices relative to the control grayscale image, and the area of the rectangle Sp that contains the area of the polygon S. Images from the international image database TID2008 (image database 2008), TID2013 (image database 2013) were taken as test bitmaps. The official coats of arms of the Russian Federation entities – territories, regions, republics, etc. - were also considered. The resulting stability score is determined either as the geometric mean of the four calculated values, or as their arithmetic mean. The results of testing the groups of bitmap images that are united by a common theme or purpose are presented. From each group of images, the maximum and minimum values of the estimates of the image stability to structural and brightness changes are determined in accordance with the developed heuristic algorithm. The results obtained can be used for comparative evaluation of competing images in order to select the most resistant to structural and brightness changes.

Measurement of the Concentration of Citrate in Human Biofluids in Patients Undergoing Continuous Renal Replacement Therapy Using Regional Citrate Anticoagulation: Application of a Two-Step Enzymatic Assay

Background: Continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA) is now commonly used to treat acute kidney injury in critically ill patients. The concentration of citrate is not routinely measured, with citrate accumulation and/or toxicity primarily assessed using surrogate measures. Objectives: The aim of this study was to measure the concentration of citrate in plasma and ultrafiltrate in patients receiving CRRT with RCA using a modified commercial enzymatic assay. Methods: After meeting inclusion criteria, blood was sampled from 20 patients before, during, and after episodes of filtration. Using spectrophotometry, samples were tested for citrate concentration. Demographic and other clinical and biochemical data were also collected. Throughout, a 15 mmol/L solution of trisodium citrate was used as the prefilter anticoagulant. Results were analysed using STATA (v15.0) and presented as mean (SD), median (IQR), or simple proportion. Comparisons were made using either the Student t test or the Wilcoxon rank-sum test. Correlation was assessed using Pearson’s r. Results: Twenty patients (17 males) were enrolled in the study. Mean (SD) age was 63.7 years (9.9). Median (IQR) ICU length of stay was 281 h (199, 422) with 85% undergoing intermittent positive pressure ventilation. Median APACHE 3 score was 95 (87, 117) with an overall 30% mortality rate. Median filtration time was 85 h (46, 149). No difference was found between pre- and post-filtration plasma citrate concentrations (79 µmol/L [50] vs. 71 µmol/L [42], p = 0.65). Mean citrate concentration during filtration was 508 µmol/L (221) with a maximum of 1,070 µmol/L. This was significantly higher than the pre/post levels (p < 0.001). Conclusions: Plasma concentrations of citrate rose significantly during episodes of CRRT using RCA returning back to normal after cessation of treatment.

ОБ ОБРАБОТКЕ ЗАШУМЛЕННЫХ КОНТРАСТНЫХ ИЗОБРАЖЕНИЙ

The problem of noise reduction at sharp transitions of brightness in digital noisy contrast images is considered. In addition to the useful signal, digital images obtained by digitizing an analogue signal with a digital photo matrix have a noise component. Moreover, to obtain a digital image in the standard RGB color model, a demosaicing interpolation algorithm must be applied to the image obtained from a digital photo matrix. Due to such transformations, the Gaussian distribution of noise in a digital noisy image is violated. Using a standard image digitization model for noise reduction is not effective. For more effective noise reduction, the digital image is transferred from the RGB color model to the HSV or LAB color model, where the brightness and color components of the digital noise can be filtered separately. Color noise is suppressed in the color channels of the image using a Gaussian filter. Noise reduction in the brightness channel of a digital image is more difficult task, especially at the edge of sharp transitions of brightness. To suppress the brightness noise in contrast images, it is proposed to use a nonlinear filter based on the generalized method of least absolute values (GMLAV). The process of smoothing the contrast noisy transition by the GMLAV-filter is described, and its efficiency is shown in comparison with the median filtration.

Real-Time Interference Artifacts Suppression in Array of ToF Sensors.

Time of Flight (ToF) sensors are the source of various errors, including the multi-camera interference artifact caused by the parallel scanning mode of the sensors. This paper presents the novel Importance Map Based Median filtration algorithm for interference artifacts suppression, as the potential 3D filtration method. The approach is based on the processing of multiple depth frames, using the extraction of the interference region and application of the interpolation. Considering the limitations and good functionalities of proposed algorithm, the combination with some standard methods was suggested. Performance of the algorithm was evaluated on the dataset consisting of the real-world objects with different texture and morphology against popular filtering methods based on neural networks and statistics.

Creatinine filtration kinetics in critically Ill neonates

Background:Creatinine values are unreliable within the first weeks of life; however, creatinine is used most commonly to assess kidney function. Controversy remains surrounding the time required for neonates to clear maternal creatinine.Methods:Eligible infants had multiple creatinine lab values and were admitted to the NICU. A mathematical model was fit to the lab data to estimate the filtration onset delay, creatinine filtration half-life, and steady-state creatinine concentration for each subject. Infants were grouped by gestational age (GA) [(1)22-27, (2)>27-32, (3)>32-37, and (4)>37-42 weeks].Results:4,808 neonates with mean GA 34.4 ± 5 weeks and birth weight 2.34 ± 1.1 kg were enrolled. Median (95% CI) filtration onset delay for Group 1 was 4.3 (3.71,4.89) days and was significantly different than all other groups (p<0.001). Creatinine filtration half-life of Groups 1, 2, and 3 were significantly different from each other (p<0.001). There was no difference in steady-state creatinine concentration amongst the groups.Conclusion:We quantified the observed kidney behavior in a large NICU population as a function of day of life and GA using creatinine lab results. These results can be used to interpret individual creatinine labs for infants to detect those most at-risk for acute kidney injury.

A Modified Trimmed Median Filter Technique for Noise Removal in an Image

A modified trimmed filtration that is actually median when it comes to recovering the original images that are dishonored by the salt &amp; pepper noise is actually presented here.The refined the pixels tend to be checked for high or least pixel values for example, 0 or 255 in this suggested method. Then this expedient pixel is recognized as the noisy one otherwise maybe not a noisy one in the event that processed pixel is actually 0 or 255. A two-dimensional 3*3 window can end up being selected with this specific noisy pixel as center component and being a running pixel. In this 3*3 window, then this algorithm can replace the value of the loud pixel as mean of these 9 elements in the 3*3 screen if all 9 aspects in the window are values like 0’s or 255’s. Then this modified trimmed median filtration technique can be applied if most of the 9 elements tend to be not 0’s or 255’s. This formula can eliminate the 0’s and present that is 255’s the 3*3 window and change the loud pixel value as average of mean and median of this remaining pixel in 3*3 screen. Simulation results imply that the proposed modified trimmed filter that is actually median can be works really in the event that picture can end up being influenced by salt and pepper sound.The outcome obtained from the recommended modified trimmed filter is compared with the AWMF, DBUTVF, and MDBUTMF. This proposed MTMF filtering technique is actually analyzed on various images for different quality testing parameters like PSNR, MSE.

An Approach to Automatic Hard Exudate Detection in Retina Color Images by a Telemedicine System Based on the d-Eye Sensor and Image Processing Algorithms

Hard exudates are one of the most characteristic and dangerous signs of diabetic retinopathy. They can be marked during the routine ophthalmological examination and seen in color fundus photographs (i.e., using a fundus camera). The purpose of this paper is to introduce an algorithm that can extract pathological changes (i.e., hard exudates) in diabetic retinopathy. This was a retrospective, nonrandomized study. A total of 100 photos were included in the analysis—50 sick and 50 normal eyes. Small lesions in diabetic retinopathy could be automatically diagnosed by the system with an accuracy of 98%. During the experiments, the authors used classical image processing methods such as binarization or median filtration, and data was read from the d-Eye sensor. Sixty-seven patients (39 females and 28 males with ages ranging between 50 and 64) were examined. The results have shown that the proposed solution accuracy level equals 98%. Moreover, the algorithm returns correct classification decisions for high quality images and low quality samples. Furthermore, we consider taking retina photos using mobile phones rather than fundus cameras, which is more practical. The paper presents an innovative approach. The results are introduced and the algorithm is described.

The Positioning Accuracy Based on the UWB Technology for an Object on Circular Trajectory

This paper presents the comparison of filtering methods – median filtration, moving average Kalman filtration and filtration based on a distance difference to determine the most accurate arm length for circular motion, as a model of wind turbine propellers movement. The experiments have been performed with the UWB technology system containing four anchors and a tag attached to 90cm arm that was rotated with speed up to 34.5 rad/s (as a linear speed of 50km/h). The trilateration concept based on the signal latency has been described in order to determinate the position of an object on circular trajectory. The main objective is the circle plane rotation (parallel and perpendicular) with respect to the anchors plane reference system. All research tasks have been performed for various cases of motion schemes in order to get the filtration method for object in motion under best accuracy goal. Filtration methods have been applied on one of two stages of the positioning algorithm: (1) on raw data got from the single anchor-tag (before trilateration); (2) on the position obtained from four anchors and tag (after trilateration). It has been proven that the appropriate filtering allows for higher location accuracy. Moreover, location capabilities with the use of UWB technology – shows prospective use of positioning of objects without access to other positioning forms (ex. GPS) in many aspects of life such as currently developing renewable, green energy sources like wind turbines where the circular motion plays an important role, and precise positioning of propellers is a key element in monitoring the work of the whole wind turbine.

Rolling element bearings localized fault diagnosis using signal differencing and median filtration

With the increase complexity of bearings’ processing algorithms and the growing trend of using computationally demanding algorithms, it is advantageous to provide analysts with a simple to use and implement algorithm. In this spirit, this paper combines simple functions to provide machine condition analysts with the capacity to diagnose bearing faults without all the complexity and jargon that comes with existing methods. The paper proposes a simplified surveillance and diagnostic algorithm for diagnosing localized faults in rolling element bearings using measured raw vibration signals. The proposed algorithm is based on analyzing the frequency content obtained from applying a median filter on the squared derivative signal (first or higher derivatives) of the vibration signal. The combination of signal differencing and median filters provides a squared envelope signal, which can be used directly to diagnose faults. Signal differencing gives a measure of jerk forces and lifts the high frequency content of the signal. To select the optimum order of differentiation, Kurtosis and maximum correlated kurtosis (MCK) are proposed. Median filter usage represents a better alternative of normal low pass filtration. This completely suppresses impulses with large magnitudes, which may interfere with the diagnosis. The length of the median filter (odd number 3, 5, 7 etc.) is selected as such to include the first 10 harmonics of the defect frequency. Simulated signals are used to demonstrate the efficiency of the proposed algorithm and give insights into the choices of the differentiation and smoothening orders. The proposed processing algorithm gives a first measure (surveillance) for detecting localized faults in rolling element bearings in a very simple way and can be employed in online learning and diagnosis systems. Results obtained from applying the algorithm on complex vibration signals from two types of gearboxes are compared with a well-established semi-automated technique with good correspondence.

Design of fire detectors capable of self-adjusting by ignition

The concept of guaranteed ignition detection at a site was introduced. A criterion of optimization of guaranteed detection was formulated, which comes down to the equality of probabilities of false detection and missing of ignition source. Algorithms and structure of fire detectors, capable of self-adjusting by ignition of materials, were developed. Their distinctive feature is the possibility of being applied under uncertain conditions for arbitrary and combustible materials that are unknown in advance. To enhance effectiveness of fire detectors capable of self-adjusting by combustion of materials, we proposed adaptation of original threshold value to current observations of ignition components. For this purpose, it was proposed to use the procedure of median filtration of recorded data. As a parameter of convergence of the procedure of threshold self-adjustment, we consider a fixed and dynamic way of its determining. This makes it possible to provide adjustment of original convergence of procedures toward observed components of combustion of various materials. Verification of the proposed self-adjusting fire detectors indicates their capability to provide guaranteed detection of sources of ignition for various materials at the early stages under conditions unknown in advance

Performance Study of Novel Median Filter for Image De-Noising

Most common method of clearing image noise is through median filtration. Median smoothers discard outliers (or impulses) quite effectively at lower noise densities but, fail to provide adequate smoothing for heavily noised images for the simple reason that, in the conventional median filter approaches, each and every pixel of an image is filtered without concern about healthy pixels. To suppress this deficiency, in this paper, an improved median filter by the name Novel Median Filter (NMF) is proposed to enhance the effectiveness of the median filter at higher noise situations to provide a detail preserving de-noising of digital images. Proposed NMF algorithm is a 3-stage filter; first two stages are dedicated to selective switching median filtration in which noisy pixels are first detected and then the filtering operation is applied to restore their values with a valid (or a noise free) median computed for each 3×3 window position. Third level processing enables to remove any distortions present in the de-noised image. The proposed method, Novel Median Filter (NMF) is evaluated for its effectiveness in detail preserving de-noising capability on a large number of digital grey and color images affected with impulsive and non-impulsive noise in terms of objective and subjective quality measures. To better appraise the efficacy of the proposed method, Novel Median Filter (NMF), MATLAB simulation results in terms of peak signal to noise ratio (PSNR), mean square error (MSE) and the de-noised images are obtained and are compared with those obtained for a standard median filter (SMF) and its few variants and meaningful conclusions are derived. Detail preservation capability of the proposed filter has been demonstrated through experimentation on medical samples. General Terms Image Processing, Nonlinear Filter, Median Filtration.

Improvement of measurement results based on scattered data in cases where averaging is ineffective

A common technique applied during an assay is averaging several repeated measurements in order to obtain a more accurate result. This approach is suitable for most applications. However, in the case of impulsive disturbances which affect the measured object, averaging is not optimal. In the paper, the properties of impulsive disturbances are described and it is explained why averaging is suitable for Gaussian disturbances and unsuitable for impulse ones. The iteratively reweighted least squares method, popular among researchers dealing with signal processing, has been simplified, allowing analysts to use it easily, and it has been adopted to calculate a weighted mean which is more reliable. The properties of the weighted mean have been determined based on Monte Carlo simulations and an analytical signal obtained from an ion-selective electrode. The results shown that the most reliable results are obtained when the average is replaced by such weighted mean, which reduces to the median filtration – then the obtained results are in some cases a bit worse but far less sensitive to impulses.

Automatic method for the dermatological diagnosis of selected hand skin features in hyperspectral imaging.

IntroductionHyperspectral imaging has been used in dermatology for many years. The enrichment of hyperspectral imaging with image analysis broadens considerably the possibility of reproducible, quantitative evaluation of, for example, melanin and haemoglobin at any location in the patient's skin. The dedicated image analysis method proposed by the authors enables to automatically perform this type of measurement.Material and methodAs part of the study, an algorithm for the analysis of hyperspectral images of healthy human skin acquired with the use of the Specim camera was proposed. Images were collected from the dorsal side of the hand. The frequency λ of the data obtained ranged from 397 to 1030 nm. A total of 4'000 2D images were obtained for 5 hyperspectral images. The method proposed in the paper uses dedicated image analysis based on human anthropometric data, mathematical morphology, median filtration, normalization and others. The algorithm was implemented in Matlab and C programs and is used in practice.ResultsThe algorithm of image analysis and processing proposed by the authors enables segmentation of any region of the hand (fingers, wrist) in a reproducible manner. In addition, the method allows to quantify the frequency content in different regions of interest which are determined automatically. Owing to this, it is possible to perform analyses for melanin in the frequency range λ E ∈(450,600) nm and for haemoglobin in the range λ H ∈(397,500) nm extending into the ultraviolet for the type of camera used. In these ranges, there are 189 images for melanin and 126 images for haemoglobin. For six areas of the left and right sides of the little finger (digitus minimus manus), the mean values of melanin and haemoglobin content were 17% and 15% respectively compared to the pattern.ConclusionsThe obtained results confirmed the usefulness of the proposed new method of image analysis and processing in dermatology of the hand as it enables reproducible, quantitative assessment of any fragment of this body part. Each image in a sequence was analysed in this way in no more than 100 ms using Intel Core i5 CPU M460 @2.5 GHz 4 GB RAM.

Principal Component and Cluster Analysis for determining diversification of bottom morphology based on bathymetric profiles from Brepollen (Hornsund, Spitsbergen)

Navigation charts of the post-glacial regions of Arctic fjords tend not to cover regions from which glaciers have retreated. Whilst research vessels can make detailed bathymetric models using multibeam echosounders, they are often too large to enter such areas. To map these regions therefore requires smaller boats carrying single beam echosounders. To obtain morphology models of equivalent quality to those generated using multibeam echosounders, new ways of processing data from single beam echosounders have to be found. The results and comprehensive analysis of such measurements conducted in Brepollen (Hornsund, Spitsbergen) are presented in this article. The morphological differentiation of the seafloor was determined by calculating statistical, spectral and wavelet transformation, fractal and median filtration parameters of segments of bathymetric profiles. This set of parameters constituted the input for Principal Component Analysis and then in the form of Principal Components for the Cluster Analysis. As a result of this procedure, three morphological classes are proposed for Brepollen: (i) steep slopes (southern Brepollen), (ii) flat bottoms (central Brepollen) and gentle slopes (the Storebreen glacier valley and the southern part of the Hornbreen glacier valley), (iii) the morphologically most diverse region (the central Storebreen valley, the northern part of the Hornbreen glacier valley and the north-eastern part of central Brepollen).

Classification of genomic signals using dynamic time warping

BackgroundClassification methods of DNA most commonly use comparison of the differences in DNA symbolic records, which requires the global multiple sequence alignment. This solution is often inappropriate, causing a number of imprecisions and requires additional user intervention for exact alignment of the similar segments. The similar segments in DNA represented as a signal are characterized by a similar shape of the curve. The DNA alignment in genomic signals may adjust whole sections not only individual symbols. The dynamic time warping (DTW) is suitable for this purpose and can replace the multiple alignment of symbolic sequences in applications, such as phylogenetic analysis.MethodsThe proposed method is composed of three main parts. The first part represent conversion of symbolic representation of DNA sequences in the form of a string of A,C,G,T symbols to signal representation in the form of cumulated phase of complex components defined for each symbol. Next part represents signals size adjustment realized by standard signal preprocessing methods: median filtration, detrendization and resampling. The final part necessary for genomic signals comparison is position and length alignment of genomic signals by dynamic time warping (DTW).ResultsThe application of the DTW on set of genomic signals was evaluated in dendrogram construction using cluster analysis. The resulting tree was compared with a classical phylogenetic tree reconstructed using multiple alignment. The classification of genomic signals using the DTW is evolutionary closer to phylogeny of organisms. This method is more resistant to errors in the sequences and less dependent on the number of input sequences.ConclusionsClassification of genomic signals using dynamic time warping is an adequate variant to phylogenetic analysis using the symbolic DNA sequences alignment; in addition, it is robust, quick and more precise technique.

Human embryonic serial anatomy : 3D evolutionnary posterior fossa venous system

IntroductionSince the mid 1950's, very little work has been done to contribute to a better understanding of venous vasculature developpement during embryogenesis. We present a new analysis method with multiplanar reformation process based on microscopic sections. This présentation focus on the brain stem arachnoïdo‐pial venous anastomoses evolutive morphology.Material and methodsHigh résolution numerised microscopic continuous sections (10 to 20 μ) from Carnegie stage XIX to XXIII human embryo were used. Specific image treatment was the following : binarisation‐thresholding‐labellisation, rigid shifting, median filtration (cubic matrix) (resolution 10μm/pixel) ; DICOM format images are exported for post‐treatment process. Angiographic rendering was obtained thanks to the Eosine/hematoxylin red cell fixation within the vessels.ResultsAt first step, we confirmed the embryonnic status relatively to the Carnegie classification in assessing the cochlear canal orientation. The evolutive morphology of the brain stem primitive network is presented ; at stage XIX, the initial longitudinal veins are separated from the caudal plexus. During the next stages, we demonstrate how they connected to transverse pial anastomoses. The next period (i.e the early and late post‐embryonic period) show these intrinsic pial veins lying between the arteries and the brain surface leading to a progressive simplication pattern. During the stages XX to XXIII, we present the changing morphology of the trijeminal ganglion venous plexus. These organisations are compared to the Padget and Streeter works.ConclusionWe present the preliminary work of the brain stem venous embryogenesis using 3D and angiographic rendering at the early post‐embryonic stages.

Particle Retention Efficiency of a Coastal Ecosystem in the Northeastern Atlantic Ocean

Based on filtration rates obtained in situ at several habitats (mud flats, sand flats, and seagrass beds of Cymodocea nodosa), particle retention efficiency of benthic communities was estimated at Ria Formosa, a coastal lagoon in southern Portugal. The distinct physical characteristics of the water flow (water depth, current speed) at different tidal regimes (spring tide and neap tide) were also considered. Median filtration rates ranged 5.0−45.0 l m−2 h−1, despite the lack of dense bivalve beds or reefs. Based on median filtration rates of benthic communities on the studied substrate types, a model we developed showed that seagrass bed areas retained 15% of suspended particles during spring tide and 47% during neap tide. These retention efficiencies were much higher than those observed on mud flats (2.8% during spring tide, and 8% during neap tide), sand flats of finer grain size (8.8% during spring tide, and 50% during neap tide), and sand flats of coarser grain size (7% during spring tide, and 31% during neap tide). Removal of particles from water column was higher during the ebb tide than during flow tide, with particles of <5 μm diameter (especially diatoms, flagellates, and small-sized particulate matter) being the most commonly removed.

Acoustic Radiation Force Impulse (ARFI) Imaging-Based Needle Visualization

Ultrasound-guided needle placement is widely used in the clinical setting, particularly for central venous catheter placement, tissue biopsy and regional anesthesia. Difficulties with ultrasound guidance in these areas often result from steep needle insertion angles and spatial offsets between the imaging plane and the needle. Acoustic Radiation Force Impulse (ARFI) imaging leads to improved needle visualization because it uses a standard diagnostic scanner to perform radiation force based elasticity imaging, creating a displacement map that displays tissue stiffness variations. The needle visualization in ARFI images is independent of needle-insertion angle and also extends needle visibility out of plane. Although ARFI images portray needles well, they often do not contain the usual B-mode landmarks. Therefore, a three-step segmentation algorithm has been developed to identify a needle in an ARFI image and overlay the needle prediction on a coregistered B-mode image. The steps are: (1) contrast enhancement by median filtration and Laplacian operator filtration, (2) noise suppression through displacement estimate correlation coefficient thresholding and (3) smoothing by removal of outliers and best-fit line prediction. The algorithm was applied to data sets from horizontal 18, 21 and 25 gauge needles between 0-4 mm offset in elevation from the transducer imaging plane and to 18G needles on the transducer axis (in plane) between 10 degrees and 35 degrees from the horizontal. Needle tips were visualized within 2 mm of their actual position for both horizontal needle orientations up to 1.5 mm offset in elevation from the transducer imaging plane and on-axis angled needles between 10 degrees-35 degrees above the horizontal orientation. We conclude that segmented ARFI images overlaid on matched B-mode images hold promise for improved needle visibility in many clinical applications.