Track Registration Research Articles

Application of Image Registration Techniques to Medical CT and MR Images (Dept.E)

Image registration has become one of the most widely used techniques in computer vision. Its applications include optical flow, notion analysis, tracking, face detection, and biomedical image registration. In the present work, three different techniques of image registration were implemented and applied to both Computed Tomography (CT) and Magnetic Resonance (MR) images. The first technique is based on Cross Correlation (CC). The second approach depends on Control Points' Selection (CPS) from both the reference and the input images. The last technique is based on Maximization of Mutual Information (MMI) between We two images. The registrability is calculated for each image to measure its ability to provide unambiguous registration, by providing clear correlation peaks when registered with other subimage. Then, the three registration techniques were evaluated and compared using both the Weighted Peak Signal to Noise Ratio (WPSNR) and the Normalized Cross Correlation Coefficient (NCCC). The application of the selected techniques to CT and MR images has shown that registration based on MMI has given the best results and can be used efficiently for alignment of CT and MR images.

General first-order target registration error model considering a coordinate reference frame in an image-guided surgical system.

Point-based rigid registration (PBRR) techniques are widely used in many aspects of image-guided surgery (IGS). Accurately estimating target registration error (TRE) statistics is of essential value for medical applications such as optically surgical tool-tip tracking and image registration. For example, knowing the TRE distribution statistics of surgical tool tip can help the surgeon make right decisions during surgery. In the meantime, the pose of a surgical tool is usually reported relative to a second rigid body whose local frame is called coordinate reference frame (CRF). In an n-ocular tracking system, fiducial localization error (FLE) should be considered inhomogeneous, that means FLE is different between fiducials, and anisotropic that indicates FLE is different in all directions. In this paper, we extend the TRE estimation algorithm relative to a CRF from homogeneous and anisotropic to heterogeneous FLE cases. Arbitrary weightings can be assumed in solving the registration problems in the proposed TRE estimation algorithm. Monte Carlo simulation results demonstrate the proposed algorithm's effectiveness for both homogeneous and inhomogeneous FLE distributions. The results are further compared with those using the other two algorithms. When FLE distribution is anisotropic and homogeneous, the proposed TRE estimation algorithm's performance is comparable with that of the first one. When FLE distribution is heterogeneous, proposed TRE estimation algorithm outperforms the other two classical algorithms in all test cases when ideal weighting scheme is adopted in solving two registrations. Possible clinical applications include the online estimation of surgical tool-tip tracking error with respect to a CRF in IGS. Graphical Abstract This paper provides the target registration error model considering a coordinate reference frame in surgical navigation.

Quantification of myocardial strain in patients with isolated left ventricular non-compaction and healthy subjects using deformable registration algorithm: comparison with feature tracking

BackgroundSystolic dysfunction of the left ventricle is frequently associated with isolated left ventricular non-compaction (iLVNC). Clinically, the ejection fraction (EF) is the primary index of cardiac function. However, changes of EF usually occur later in the disease course. Feature tracking (FT) and deformable registration algorithm (DRA) have become appealing techniques for myocardial strain assessment.MethodsThirty patients with iLVNC (36.7 ± 13.3 years old) and fifty healthy volunteers (42.3 ± 13.6 years old) underwent cardiovascular magnetic resonance (CMR) examination on a 1.5 T MR scanner. Strain values in the radial, circumferential, longitudinal directions were analyzed based on the short-axis and long-axis cine images using FT and DRA methods. The iLVNC patients were further divided based on the ejection fraction, into EF ≥ 50% group (n = 11) and EF < 50% group (n = 19). Receiver-operating-characteristic (ROC) analysis was performed to assess the diagnostic performance of the global strain values. Intraclass correlation coefficient (ICC) analysis was used to evaluate the intra- and inter-observer agreement.ResultsGlobal radial strain (GRS) was statistically lower in EF ≥ 50% group compared with control group [GRS (DRA)/% vs. controls: 34.6 ± 7.0 vs. 37.6 ± 7.2, P < 0.001; GRS (FT)/% vs. controls: 37.4 ± 13.2 vs. 56.9 ± 16.4, P < 0.01]. ROC analysis of global strain values derived from DRA and FT demonstrated high area under curve (range, 0.743–0.854). DRA showed excellent intra- and inter-observer agreement of global strain in both iLVNC patients (ICC: 0.995–0.999) and normal controls (ICC: 0.934–0.996). While for FT analysis, global radial strain of normal controls showed moderate intra-observer (ICC: 0.509) and poor inter-observer agreement (ICC: 0.394).ConclusionsIn patients with iLVNC, DRA can be used to quantitatively analyze the strain of left ventricle, with global radial strain being an earlier marker of LV systolic dysfunction. DRA has better reproducibility in evaluating both the global and segmental strain.

Impact of infrared radiation on track etching parameters of Lexan track detector to fission fragments from 252Cf source

In this research work, the impact of infrared (IR) radiation on the etching parameters like bulk etch rate VB, track etch rate VT, Sensitivity S, Critical angle of etching θC and track registration efficiency η of Lexan track detector, irradiated to fission fragments from 252Cf source, were investigated. The changes in etching parameters due to infrared radiation for 0, 12 and 24 h at different temperatures (328–348 K) are discussed based on chain scission and cross-linking mechanisms. Bulk and track etch rates increase with infrared radiation in case of post-exposed as compared to un-exposed while sensitivity slightly decreases for 12 h exposure with infrared radiation but slightly increases for 24 h exposure with infrared radiation as compared to un-exposed. On the other hand, bulk and track etch rates decrease with infrared radiation in case of pre-exposed as compared to un-exposed while sensitivity slightly increases. Critical angles increase and track registration efficiency decreases with etching temperatures. Activation energies for bulk and track etching rates have been determined by fitting Arrhenius equation to the experimental data of bulk and track etch rates which show a decrease in bulk activation energies in case of post-exposed but slightly increase in case of pre-exposed as compared to un-exposed Lexan track detectors. Track activation energies show the same trend as for bulk etch rate.

Evaluation and Comparison of Quantitative Right Ventricular Strain Assessment by Cardiac Magnetic Resonance in Pulmonary Hypertension Using Feature Tracking and Deformable Registration Algorithms

Deformable registration algorithms (DRA) has been used to detect left ventricular myocardial changes, however, its clinical utility in right ventricular (RV) function has not been evaluated. In this study, we aim to evaluate and compare quantitative RV strain assessment by cardiac magnetic resonance in pulmonary hypertension (PH) using feature tracking (FT) and DRA. Thirty patients were confirmed to have PH using right heart catheterization, and 16 healthy controls were evaluated with cardiac magnetic resonance. Global and segmental RV strain was measured by DRA and FT methods. Intraclass correlation coefficients (ICCs), coefficient of variation, and Bland-Altman analysis were used to assess and compare the interobserver and intraobserver variability of the DRA and FT methods. DRA was more sensitive than FT in the detection of RV circumferential and septal dysfunction. The global longitudinal strain (GLS) obtained by the two methods was reduced in mild-moderate PH patients (mean pulmonary artery pressure≤45 mm Hg), and the GLS and global circumferential strain (GCS) were reduced in severe PH patients (mean pulmonary artery pressure >45 mm Hg). DRA and FT methods demonstrate similar observer agreement in global strain using ICC (ICC greater than 0.90), but RV strain derived from DRA had lower variability using COV ([8%-14%] for DRA versus [11%-39%] for FT).For segmental longitudinal strain, DRA showed higher ICC and lower COV compared with that of the FT method. Correlations between RVEF and RV global strain parameters were strong (p < 0.01):GLS-DRA, r = -0.696; GLS-FT, r = -0.832; GCS-DRA, r = -0.745; and GCS-FT, r = -0.817. GLS-DRA was weakly correlated with mPAP (r = 0.385, p < 0.05).In multiple linear regression analysis, RVEF and mPAP were independent predictors of GLS-DRA (R2 = 0.57, p < 0.01). The DRA method is more sensitive and robust for RV myocardial strain measurements than FT method.

Image real-time augmented reality technology based on spatial color and depth consistency

Augmented reality can enhance people’s perception of the environment by embedding virtual objects or other information in real-time images. In this paper, the color image is used as a reference to calculate the confidence of the original depth map, and stereo matching is performed according to the feature points. The depth map is mainly enhanced by the color, edge, and segmentation results of the color image. A deep computing system based on augmented reality is designed. The system can use a binocular camera to collect object images in real time and obtain better parallax images by correcting the calibrated image. The semi-global block matching algorithm and depth calculation are used to realize the tracking registration of virtual objects. Experiments in different environments show that the system has good real-time performance, light invariance, and depth consistency.

Radioactivity concentrations in barley and wheat crops in Nineveh plain region in Iraq

Wheat and barley crops are used as food by humans and animals, their health effects on human life must be under the control, so it is important to measure their radiation concentrations. This work aimed to determine radon, radium, and uranium in barley and wheat crops planted in the Nineveh plains region. The technique of alpha track registration by CR-39 detector is used in measurements of the samples from ten planted locations. Radon, radium, and uranium mean concentrations found are 92.58 Bq.m−3, 0.4212 Bq kg−1 and 0.368 ppm, respectively. The uranium activity concentration and the total annual effective dose equivalent mean values are 4.546 Bq.kg−1 and 67.73 μSv/y. The results showed that the activity in locations depends on the agriculture soil of the area, and the amount of fertiliser applied in soil. All results are below the world permissible limits so the wheat and barley in the studied area are safe for consumption.

Radioactivity concentrations in barley and wheat crops in Nineveh plain region in Iraq

Wheat and barley crops are used as food by humans and animals, their health effects on human life must be under the control, so it is important to measure their radiation concentrations. This work aimed to determine radon, radium, and uranium in barley and wheat crops planted in the Nineveh plains region. The technique of alpha track registration by CR-39 detector is used in measurements of the samples from ten planted locations. Radon, radium, and uranium mean concentrations found are 92.58 Bq.m−3, 0.4212 Bq kg−1 and 0.368 ppm, respectively. The uranium activity concentration and the total annual effective dose equivalent mean values are 4.546 Bq.kg−1 and 67.73 μSv/y. The results showed that the activity in locations depends on the agriculture soil of the area, and the amount of fertiliser applied in soil. All results are below the world permissible limits so the wheat and barley in the studied area are safe for consumption.

Application of Radial Electron Fluence around ion tracks for the description of track response data of polyethylene terephthalate as a polymeric nuclear track detector

We try to establish a universal description for the response curve (i.e., relation between the track registration sensitivity and a physical parameters) of polyethylene terephthalate (PET) as a polymeric nuclear track detector. To do so, we adopt a newly developed physical concept Radial Electron Fluence around Ion Tracks (REFIT) using a Monte Carlo simulation in Geant4-DNA, which has been defined as the number of secondary electrons passing through a cylindrical surface that is co-axial to the ion path. We find 11% disagreement for the description of the detection thresholds, from which etch pits start their evolutions when the value of REFIT at a radius of 4.0 nm is used. However, compared to other physical parameters, the REFIT offers improved parameters for the detection thresholds of PET, such as the stopping power, Zeff/β and RELω0=1000 eV. Finally, we discuss future issues affecting implementation of REFIT.

Augmented reality tracking registration and process visualization method for large spacecraft cable assembly

The new generation of spacecraft has the characteristics of large-scale structure and complicated cable assembly process. In order to meet the needs of the augmented reality process visualization technology in its further application exploration, the two aspects of augmented reality tracking registration and process visualization are now studied. In the large-scale spacecraft cable assembly application scenario, the augmented reality process guidance technology puts more stringent requirements on the continuous tracking range and virtual and real registration accuracy of large space. The 3D process visualization method for cable assembly is optimized to improve the accuracy, quality and efficiency of the operator in process interpretation and implementation.

Largest Cretaceous lizard track assemblage, new morphotypes and longest trackways comprise diverse components of an exceptional Korean Konservat-Lagerst\xe4tten ichnofauna

A newly discovered assemblage of lizard tracks from the Lower Cretaceous Jinju Formation (Sindong Group, Gyeongsang Basin) Korea is the largest yet reported from the Cretaceous. It consists of at least 95 tracks comprising five trackways, including a meter-long trackway (T1) with 50 footprints assigned to the new ichnotaxon Neosauroides innovatus ichnosp. nov. Two other trackways (T2 and T3) are designated N. innovatus paratypes characterized by strong heteropody, relatively wide trackways and small narrow manus tracks. These morphological characteristics distinguish Neosauroides innovatus from the previously reported lizard trackways Sauripes hadongensis from the Hasandong Formation and Neosauroides koreaensis from the Haman Formation, both also from the Gyeongsang Basin. These three lizard track assemblages from the Korean Cretaceous constitute the entire global lizard track record for this period. The Mesozoic record of lizard tracksites is more localized than the lizard body fossil record. This limited distribution suggests bias in the track record and the fossil record more generally. However, due to deposition of fine-grained substrates, suitable for high definition track registration, the Jinju Formation is increasingly well known as an ichnological window on small tetrapod activity and based on diversity, abundance and high-quality preservation, is regarded as an exceptional Konservat-Lagerstätten.

Tracking Registration Algorithm for Augmented Reality Based on Template Tracking

Tracking registration is a key issue in augmented reality applications, particularly where there are no artificial identifier placed manually. In this paper, an efficient markerless tracking registration algorithm which combines the detector and the tracker is presented for the augmented reality system. We capture the target images in real scenes as template images, use the random ferns classi- fier for target detection and solve the problem of reinitialization after tracking registration failures due to changes in ambient lighting or occlusion of targets. Once the target has been successfully detected, the pyramid Lucas-Kanade (LK) optical flow tracker is used to track the detected target in real time to solve the problem of slow speed. The least median of squares (LMedS) method is used to adaptively calculate the homography matrix, and then the three-dimensional pose is estimated and the virtual object is rendered and registered. Experimental results demonstrate that the algorithm is more accurate, faster and more robust.

Quantitative evaluation of image recognition performance of fiducial markers in real-time tumor-tracking radiation therapy

PurposeTo quantitatively evaluate and compare the image recognition performance of multiple fiducial markers available in real-time tumor-tracking radiation therapy (RTRT). MethodsClinically available markers including sphere shape, coil shape, cylinder shape, line shape, and ball shape (folded line shape) were evaluated in liver and lung models of RTRT. Maximum thickness of the polymethyl metacrylate (PMMA) phantom that could automatically recognize the marker was determined by template-pattern matching. Image registration accuracy of the fiducial marker was determined using liver RTRT model. Lung RTRT was mimicked with an anthropomorphic chest phantom and a one-dimensional motion stage in order to simulate marker motion in heterogeneous fluoroscopic images. The success or failure of marker tracking and image registration accuracy for the lung model were evaluated in the same manner as that for the liver model. ResultsAll fiducial markers except for line shape and coil shape of thinner diameter were recognized by the PMMA phantom, which is assumed to have the typical thickness of an abdomen, with two-dimensional image registration accuracy of <2 pixels. Three-dimensional calculation error with the use of real-time stereoscopic fluoroscopy in RTRT was thought to be within 1 mm. In the evaluation using the lung model, the fiducial markers were recognized stably with sufficient accuracy for clinical application. The same was true for the evaluation using the liver model. ConclusionsThe image recognition performance of fiducial markers was quantified and compared. The results presented here may be useful for the selection of fiducial markers.

Radon and uranium concentration in ground water of nineveh plain region in iraq

The track registration technique with a CR-39 detector was used to measure radon concentrations, and uranium contents in ground water samples from the Nineveh plain region wells. Samples were selected from 20 locations for measurements. This research aimed to assess radiological risks from uranium ingestion, and measure annual effective dose AED resulting from the intake of radon in the ingested water. Radon concentrations in these water samples were found to vary from 0.362 to 1.485 BqL−1, which were below the safety recommended limits 4 to 40 BqL−1 based on the Scientific Committee of United Nations on Atomic Radiation Effects. AED was found to vary from 1.32 to 5.42 µSv/y. Uranium activity concentrations ranged from 0.356 to 1.488 BqL−1, and the corresponding uranium concentrations in water samples were found to vary from 28.76 to 120 μgL−1. Uranium concentrations were over the safety recommended limits when, compared with recommended limits of of 30 μgL−1 for drinking water based on the US environmental protection agency. The excess cancer risk varied from 0.398 to 1.666 x10-4 with a mean value of 0.9 x10-4, indicating that 9/100,000 people in these areas haves a cancer risk from the water.

A SLAM-Based Mobile Augmented Reality Tracking Registration Algorithm

This paper proposes a simultaneous localization and mapping (SLAM)-based markerless mobile-end tracking registration algorithm to address the problem of virtual image drift caused by fast camera motion in mobile-augmented reality (AR). The proposed algorithm combines the AGAST-FREAK-SLAM algorithm with inertial measurement unit (IMU) data to construct a scene map and localize the camera’s pose. The extracted feature points are matched with feature points in a map library for real-time camera localization and precise registration of virtual objects. Experimental results show that the proposed method can track feature points in real time, accurately construct scene maps, and locate cameras; moreover, it improves upon the tracking and registration robustness of earlier algorithms.

Synthetic Aperture Sonar Track Registration With Motion Compensation for Coherent Change Detection

The capability to detect changes in an underwater scene has many applications, including environmental monitoring, surveillance of strategic maritime waterways, and naval mine countermeasures. This paper examines the automated detection of changes in repeat-pass synthetic aperture sonar (SAS) imagery by exploiting the loss of phase coherence caused by differences in the scene. A renavigation method based on track registration is developed for performing the coregistration of images. The method first determines the corrections to be applied to the repeat-pass navigation data by optimizing a linear track model using the estimated across-track pixel displacements. A second optimization is then performed using the along-track pixel displacements to determine a velocity correction for each ping location of the repeat-pass image to compensate for residual motion errors. The corrected navigation solution is then used to rebeamform the repeat-pass image onto the same focal points as the reference image. The method is demonstrated on a pair of repeat-pass SAS images acquired using the AquaPix INSAS2 sonar, where it is shown that it is not necessary to have access to raw element data to coregister images accurately enough for coherent change detection requirements. This technique is then applied to the second data set obtained using the HISAS 1030 sonar for the purpose of comparing both coherent and noncoherent (amplitude-only) approaches to change detection in scenes with low and high clutters. False alarms caused by the acoustic shadows of objects in high-clutter areas are mitigated using the single-pass interferometric coherence as a reference mask. The results show the successful use of the repeat-pass coherence to detect changes between SAS images with temporal baselines of several days on scenes consisting of mud, gravel, and sand, and demonstrate that a coherent approach is capable of detecting large-scale differences (caused by the introduction or removal of targets) as well as subtle scene changes that are not detectable using noncoherent methods.

Markerless Tumor Motion Tracking in Cine Images from Megavoltage Electronic Portal Imaging Device

Lung tumor motion is challenging for image guided radiation treatment (IGRT) with a margin reduction. Locating the tumor using megavoltage (MV) cine image from electronic portal imaging device (EPID) is one solution. In this study, tumor localization was conducted for original image and processed image using deblurring and contrast enhancement. For the locating algorithm, searching of the minimum position of the mean of the sum of squared pixel differences (MSSD) between two images was used. Along with usual manual drawn masks, a novel detection mask based on Harris-Stephen (HS) corner detector was devised and tested. After conducting experiment, the detection accuracy was the best for the original set. The HS corner-based mask produced detection accuracy equivalent to or better than others. This feature-based mask creation can be used to develop automated tumor tracking or tumor registration widely needed by clinics.

Markerless high-frequency prospective motion correction for neuroanatomical MRI.

To integrate markerless head motion tracking with prospectively corrected neuroanatomical MRI sequences and to investigate high-frequency motion correction during imaging echo trains. A commercial 3D surface tracking system, which estimates head motion by registering point cloud reconstructions of the face, was used to adapt the imaging FOV based on head movement during MPRAGE and T2 SPACE (3D variable flip-angle turbo spin-echo) sequences. The FOV position and orientation were updated every 6 lines of k-space (< 50 ms) to enable "within-echo-train" prospective motion correction (PMC). Comparisons were made with scans using "before-echo-train" PMC, in which the FOV was updated only once per TR, before the start of each echo train (ET). Continuous-motion experiments with phantoms and in vivo were used to compare these high-frequency and low-frequency correction strategies. MPRAGE images were processed with FreeSurfer to compare estimates of brain structure volumes and cortical thickness in scans with different PMC. The median absolute pose differences between markerless tracking and MR image registration were 0.07/0.26/0.15 mm for x/y/z translation and 0.06º/0.02º/0.12° for rotation about x/y/z. The PMC with markerless tracking substantially reduced motion artifacts. The continuous-motion experiments showed that within-ET PMC, which minimizes FOV encoding errors during ETs that last over 1 second, reduces artifacts compared with before-ET PMC. T2 SPACE was found to be more sensitive to motion during ETs than MPRAGE. FreeSurfer morphometry estimates from within-ET PMC MPRAGE images were the most accurate. Markerless head tracking can be used for PMC, and high-frequency within-ET PMC can reduce sensitivity to motion during long imaging ETs.

Measuring the concentration of uranium for adults teeth in adjacent areas of Tigris river in Baghdad city using nuclear track detector CR-39

In this study, the fission track registration technique with the CR-39 detector are using to determination the uranium concentrations for seventeen samples of teeth distributed in four districts in Baghdad City .Five samples taken from both Al-Durra District and Al-Jadiriyia District, Four samples taken from Al-Karrda (Alaatar street) Taken four samples and three samples taken from Al-Zuafrania and by 0.5gm in weight and 1.5 mm in thickness. The uranium concentrations in teeth samples measured by using fission tracks registration in (CR-39) track detector that caused by the bombardment of (U) with thermal neutrons from (241 Am-Be) neutron source that has flux of (5 ×103 n cm-2 s-1). The concentrations values were calculated by a comparison with standard samples. The results showed that the maximum value of uranium is (0.071 ppm) equal to (0.686Bq) in Al-Zuafaraniya district and the minimum is (0.035 ppm) equal to (0.31Bq) in Al-Jadiriah district.

A 3D Tracking and Registration Method Based on Point Cloud and Visual Features for Augmented Reality Aided Assembly System

To improve the robustness and applicability of 3D tracking and registration for augmented reality(AR) aided mechanical assembly system, a 3D registration and tracking method based on the point cloud and visual features is proposed. Firstly, the reference model point cloud is used to definite absolute tracking coordinate system, thus the locating datum of the virtual assembly guidance information is determined. Then by adding visual features matching to the iterative closest points (ICP) registration process, the robustness of tracking and registration is improved. In order to obtain sufficient number of visual feature matching points in this process, a visual feature matching strategy based on orientation vector consistency is proposed. Finally, the loop closure detection and global pose optimization from key frames are added in the tracking registration process. The experimental result shows that the proposed method has good real-time performance and accuracy, and the running speed can reach 30 frames per second. Moreover, it also shows good robustness when the camera is moving fast and the depth information is inaccurate, and the comprehensive performance of the proposed method is better than the KinectFusion method.