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Image-based guidance of percutaneous abdomen intervention based on markers for semi-automatic rigid registration
摘要： Introduction: For percutaneous abdomen intervention (e.g. liver radiofrequency (RF) tumor ablation, liver biopsy), surgeons lack real-time visual feedback about the location of the needle on planning images, typically computed tomography (CT). One difficulty lies in tracking and synchronizing both the tool movement and the patient breathing motion. Aim: To verify the correspondence between rigid registration fiducial registration error signal and breathing phase. Material and methods: Designed markers that are clearly visible both in planning CT and on the patient during the intervention are proposed. Registration and breathing synchronization is then performed by a point-based approach. The method was tested in a clinical environment on 10 patients with liver cancer using 3D abdominal CT in the exhale position. Median rigid fiducial registration error (FRE) in the breathing cycle was used as a criterion to distinguish the inhale and exhale phase. Results: The correlation between breathing phase and FRE value can be observed for every patient. We obtained mean median FRE equal to 9.37 mm in exhale positions and 15.56 mm in the whole breathing cycle. Conclusions: The presented real time approach, based on FRE calculation, was integrated in the clinical pipeline, and can help to select the best respiratory phase for needle insertion for percutaneous abdomen intervention, in cases where only 3D CT is performed. Moreover, this method allows semi-automated rigid registration to establish the correspondence between preoperative patient anatomical model and patient position.
关键词： real-time rigid registration,percutaneous abdomen intervention,respiratory phase synchronization
更新于2025-09-09 09:28:46
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Gaussian Field Estimator with Manifold Regularization for Retinal Image Registration
摘要： Retinal image registration, which combines the information of retinal images from different modalities, viewpoints or times, plays an important role in diagnosing and treating many eye diseases. In this work, we propose an efficient algorithm called Gaussian field estimator with manifold regularization to address this requirement. We formulate the registration problem as a probabilistic model, that is, a Gaussian field estimator, to achieve a robust estimation, associated with a prior involving manifold regularization to preserve the intrinsic geometry of input data. A non-rigid transformation is specified in a reproducing kernel Hilbert space. Moreover, a sparse approximation is applied to the non-rigid transformation for a fast implementation. Extensive experiments on retinal images show the effectiveness of our approach, which can yield superior results compared with other state-of-the-art methods, especially in the case of severely degraded data.
关键词： mismatch removal,Gaussian field estimator,manifold regularization,Retinal image registration
更新于2025-09-09 09:28:46
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Gesture-based registration correction using a mobile augmented reality image-guided neurosurgery system
摘要： In image-guided neurosurgery, a registration between the patient and their pre-operative images and the tracking of surgical tools enables GPS-like guidance to the surgeon. However, factors such as brainshift, image distortion, and registration error cause the patient-to-image alignment accuracy to degrade throughout the surgical procedure no longer providing accurate guidance. The authors present a gesture-based method for manual registration correction to extend the usage of augmented reality (AR) neuronavigation systems. The authors’ method, which makes use of the touchscreen capabilities of a tablet on which the AR navigation view is presented, enables surgeons to compensate for the effects of brainshift, misregistration, or tracking errors. They tested their system in a laboratory user study with ten subjects and found that they were able to achieve a median registration RMS error of 3.51 mm on landmarks around the craniotomy of interest. This is comparable to the level of accuracy attainable with previously proposed methods and currently available commercial systems while being simpler and quicker to use. The method could enable surgeons to quickly and easily compensate for most of the observed shift. Further advantages of their method include its ease of use, its small impact on the surgical workflow and its small-time requirement.
关键词： registration correction,brainshift,image-guided neurosurgery,neuronavigation,augmented reality
更新于2025-09-09 09:28:46
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Quantification of image artifacts from navigation markers in dynamic guided implant surgery and the effect on registration performance in different clinical scenarios
摘要： Purpose: Different navigation markers in dynamic guided implant surgery could cause different degrees of artifacts, which would affect the accuracy and efficiency of the implant navigation system. This study aimed to quantify artifacts caused by navigation markers made of different materials and to evaluate their effects on registration accuracy under various oral conditions. Materials and Methods: Four U-shaped tubes with different navigation markers (440c stainless steel, silicon nitride, zirconium oxide, and aluminium oxide) were produced by three-dimensional printing. Four kinds of maxillary plaster models were prepared to stimulate four tooth crown conditions. U-shaped tubes combined with different tooth models were scanned using cone beam computed tomography (CBCT). The size of artifacts from different navigation markers and registration rate were measured. Abrasion performance of navigation markers was evaluated by scanning electron microscopy (SEM) images. Results: Aluminium oxide navigation markers showed the fewest artifacts. Silicon nitride markers caused fewer artifacts than zirconium oxide and 440c stainless steel ones (P < .05) and had the best registration performance under all tooth crown conditions with the lowest volume of abrasion. Registration data suggested aluminium oxide worked badly under artificial crown and natural tooth conditions for its lower radiopacity, and zirconium oxide worked undesirably in edentulous conditions. 440c stainless steel was worst in all dental conditions. Conclusion: Navigation markers made of silicon nitride have the best overall performance and perform the best in registration under all circumstances owing to less artifact generation, better radiopacity, and desirable abrasion resistance. Silicon nitride can be regarded as an ideal material, including but not limited to oral implant navigator-guided surgery.
关键词： Dental implants,Navigation marker,Cone-Beam Computed Tomography,Artefacts,Dynamic guided,Registration
更新于2025-09-09 09:28:46
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A New Probabilistic Representation of Color Image Pixels and Its Applications
摘要： This paper proposes a novel probabilistic representation of color image pixels (PRCI) and investigates its applications to similarity construction in motion estimation and image segmentation problems. The PRCI explores the mixture representation of the input image(s) as prior information and describes a given color pixel in terms of its membership in the mixture. Such representation greatly simplifies the estimation of the probability density function from limited observations and allows us to derive a new probabilistic pixel-wise similarity measure based on the continuous domain Bhattacharyya coefficient. This yields a convenient expression of the similarity measure in terms of the pixel memberships. Furthermore, this pixel-wise similarity is extended to measure the similarity between two image regions. The usefulness of the proposed pixel/region-wise similarities is demonstrated by incorporating them respectively in a dense image descriptor-based multi-layered motion estimation problem and an unsupervised image segmentation problem. Experimental results show that i) the integration of the proposed pixel-wise similarity in dense image-descriptor construction yields improved peak signal to noise ratio performance and higher tracking accuracy in the multi-layered motion estimation problem, and ii) the proposed similarity measures give the best performance in terms of all quantitative measurements in the unsupervised superpixel-based image segmentation of the MSRC and BSD300 datasets.
关键词： Pixel-wise similarity,registration,Region-wise similarity,Image matching,and segmentation,Image descriptors,Probabilistic color representation
更新于2025-09-09 09:28:46
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Non-contact fatigue crack detection in civil infrastructure through image overlapping and crack breathing sensing
摘要： Fatigue cracks are of critical structural safety concern in civil infrastructure. Many existing fatigue crack sensing methods are contact-based, hence extensive human operation is necessary for sensor and/or actuator deployment. In this study, we propose a vision-based non-contact approach to detect fatigue cracks through image overlapping. We treat crack breathing behavior, the small cyclic movement of the crack perpendicular to the crack path under repetitive fatigue loads, as a robust indicator for crack identification. The differential image features provoked by a breathing crack can be extracted, enhanced, and visualized through a series of image processing techniques. The performance of the proposed approach is experimentally validated through two laboratory setups including a small-scale steel compact specimen and a large-scale bridge to cross-frame connection specimen. Test results demonstrate the capability of the proposed approach in reliably identifying the fatigue crack, even the true crack is surrounded by other non-crack features.
关键词： Computer vision,Bridges,Civil infrastructure,Feature matching,Non-contact sensing,Image processing,Structural health monitoring,Image registration,Breathing crack,Fatigue crack detection
更新于2025-09-04 15:30:14
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A New Image Similarity Metric for Improving Deformation Consistency in Graph Based Groupwise Image Registration
摘要： Graph-based groupwise image registration (G-GIR) aims to register a group of input images accurately without bias. In G-GIR, an image similarity metric (ISM) is used to construct a graph that links similar images with graph edges. From the graph, a group center image and the shortest paths linking it to all other images can be determined. The deformation field aligning each image to the group center image can be obtained by composing sub-deformation fields which come from registration of adjacent images along the corresponding shortest path. The majority of ISMs used in G-GIR are based on image intensity. Since image intensity can be ambiguous and is not directly related to deformation directions, inconsistency problem in the sub-deformation fields along the shortest paths can occur. The inconsistency mentioned here refers to the directions of deformation vectors in the sub-deformation fields along each shortest path are significantly different or even opposite at corresponding locations. Such problem can make G-GIR inefficient and easily to be trapped in local minimum. In this paper, we propose a new ISM for G-GIR, by which consistency in the sub-deformation fields along the shortest paths can be significantly improved. We evaluate our method in comparison with three state-of-the-art ISMs using a common G-GIR framework. The experimental results with both toy and real images show that our method significantly improves registration accuracy.
关键词： image similarity metric,Graph,groupwise image registration,MR brain images
更新于2025-09-04 15:30:14
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High-resolution angle-resolved lateral piezoresponse force microscopy: Visualization of in-plane piezoresponse vectors
摘要： Piezoresponse force microscopy (PFM) is a widely used tool for ferroelectric domain imaging. Lateral PFM (LPFM) utilizes the torsional vibration mode of a probe cantilever; it can distinguish ferroelectric domains having different polarizations with respect to the axis perpendicular to the cantilever, but it is blind to the parallel axis innately. We introduce a high-resolution angle-resolved-LPFM technique that is capable of visualizing full two-dimensional in-plane piezoresponse vector fields. The LPFM signal is analyzed for each pixel with respect to the sample-probe orientation angle with the aid of an image registration technique, and the corresponding local in-plane piezoresponse vector is deduced from the amplitude and phase of the trigonometric curve fitting. This technique provides a pathway for the visualization of complicated ferroelectric and piezoelectric structures.
关键词： Piezoresponse force microscopy,image registration technique,ferroelectric domain imaging,in-plane piezoresponse vector fields
更新于2025-09-04 15:30:14
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Simulation of Range Imaging-based Estimation of Respiratory Lung Motion
摘要： Objectives: A major problem associated with the irradiation of thoracic and abdominal tumors is respiratory motion. In clinical practice, motion compensation approaches are frequently steered by low-dimensional breathing signals (e.g., spirometry) and patient-specific correspondence models, which are used to estimate the sought internal motion given a signal measurement. Recently, the use of multidimensional signals derived from range images of the moving skin surface has been proposed to better account for complex motion patterns. In this work, a simulation study is carried out to investigate the motion estimation accuracy of such multidimensional signals and the influence of noise, the signal dimensionality, and different sampling patterns (points, lines, regions). Methods: A diffeomorphic correspondence modeling framework is employed to relate multidimensional breathing signals derived from simulated range images to internal motion patterns represented by diffeomorphic non-linear transformations. Furthermore, an automatic approach for the selection of optimal signal combinations/patterns within this framework is presented. Results: This simulation study focuses on lung motion estimation and is based on 28 4D CT data sets. The results show that the use of multidimensional signals instead of one-dimensional signals significantly improves the motion estimation accuracy, which is, however, highly affected by noise. Only small differences exist between different multidimensional sampling patterns (lines and regions). Automatically determined optimal combinations of points and lines do not lead to accuracy improvements compared to results obtained by using all points or lines. Conclusions: Our results show the potential of multidimensional breathing signals derived from range images for the model-based estimation of respiratory motion in radiation therapy.
关键词： regression,image registration,Respiratory motion,motion estimation,correspondence modeling
更新于2025-09-04 15:30:14
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A Point Pattern Chamfer Registration of Optical and SAR Images Based on Mesh Grids
摘要： Automatic image registration of optical-to-Synthetic aperture radar (SAR) images is difficult because of the inconsistency of radiometric and geometric properties between the optical image and the SAR image. The intensity-based methods may require many calculations and be ineffective when there are geometric distortions between these two images. The feature-based methods have high requirements on features, and there are certain challenges in feature extraction and matching. A new automatic optical-to-SAR image registration framework is proposed in this paper. First, modified holistically nested edge detection is employed to detect the main contours in both the optical and SAR images. Second, a mesh grid strategy is presented to perform a coarse-to-fine registration. The coarse registration calculates the feature matching and summarizes the preliminary results for the fine registration process. Finally, moving direct linear transformation is introduced to perform a homography warp to alleviate parallax. The experimental results show the effectiveness and accuracy of our proposed method.
关键词： mesh grid strategy,optical-to-SAR image registration,edge detection
更新于2025-09-04 15:30:14