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Nonrigid reconstruction of 3D breast surfaces with a low-cost RGBD camera for surgical planning and aesthetic evaluation
摘要： Accounting for 26% of all new cancer cases worldwide, breast cancer remains the most common form of cancer in women. Although early breast cancer has a favourable long-term prognosis, roughly a third of patients suffer from a suboptimal aesthetic outcome despite breast conserving cancer treatment. Clinical-quality 3D modelling of the breast surface therefore assumes an increasingly important role in advancing treatment planning, prediction and evaluation of breast cosmesis. Yet, existing 3D torso scanners are expensive and either infrastructure-heavy or subject to motion artefacts. In this paper we employ a single consumer-grade RGBD camera with an ICP-based registration approach to jointly align all points from a sequence of depth images non-rigidly. Subtle body deformation due to postural sway and respiration is successfully mitigated leading to a higher geometric accuracy through regularised locally affine transformations. We present results from 6 clinical cases where our method compares well with the gold standard and outperforms a previous approach. We show that our method produces better reconstructions qualitatively by visual assessment and quantitatively by consistently obtaining lower landmark error scores and yielding more accurate breast volume estimates.
关键词： Breast cancer treatment,Nonrigid registration,Depth camera,3D surface reconstruction,Aesthetic evaluation
更新于2025-09-23 15:23:52
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3D surface reconstruction of retinal vascular structures
摘要： We propose in this paper, a three-dimensional surface reconstruction of a retinal vascular network from a pair of 2D retinal images. Our approach attempts to address the above challenges by incorporating an epipolar geometry estimation and adaptive surface modelling in a 3D reconstruction, using three steps: segmentation, 3D skeleton reconstruction and 3D surface modelling of vascular structures. The intrinsic calibration matrices are found via the solution of simplified Kruppa equations. A simple essential matrix based on a self-calibration method has been used for the ‘fundus camera-eye’ system. The used method has eventually produced vessel surfaces that could be fit for various applications, such as applications for computational fluid dynamics simulations and applications for real-time virtual interventional.
关键词： Kruppa equations,curvature-dependent subdivision,surface reconstruction,epipolar geometry,segmentation,retinal vascular network,self-calibration
更新于2025-09-23 15:22:29
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A 3-D Surface Reconstruction with Shadow Processing for Optical Tactile Sensors
摘要： An optical tactile sensor technique with 3-dimension (3-D) surface reconstruction is proposed for robotic fingers. The hardware of the tactile sensor consists of a surface deformation sensing layer, an image sensor and four individually controlled flashing light emitting diodes (LEDs). The image sensor records the deformation images when the robotic finger touches an object. For each object, four deformation images are taken with the LEDs providing different illumination directions. Before the 3-D reconstruction, the look-up tables are built to map the intensity distribution to the image gradient data. The possible image shadow will be detected and amended. Then the 3-D depth distribution of the object surface can be reconstructed from the 2-D gradient obtained using the look-up tables. The architecture of the tactile sensor and the proposed signal processing flow have been presented in details. A prototype tactile sensor has been built. Both the simulation and experimental results have validated the effectiveness of the proposed 3-D surface reconstruction method for the optical tactile sensors. The proposed 3-D surface reconstruction method has the unique feature of image shadow detection and compensation, which differentiates itself from those in the literature.
关键词： shadow detection,3-D reconstruction,robotic finger,tactile sensor,surface reconstruction
更新于2025-09-23 15:21:01
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[IEEE 2018 17th IEEE International Conference on Machine Learning and Applications (ICMLA) - Orlando, FL, USA (2018.12.17-2018.12.20)] 2018 17th IEEE International Conference on Machine Learning and Applications (ICMLA) - GAN-Based Super Resolution for Accurate 3D Surface Reconstruction from Light Field Skin Images Towards Haptic Palpation
摘要： The development of vision technology for observation of skin surface and diagnosis of skin disease for preventing secondary infections caused by direct skin touch has consistently been in the medical field spotlight. Many studies have been conducted to acquire three dimensional (3D) data through stereo images, multiple images, and lasers because (3D) data of in-vivo skin image is essential for accurate medical diagnosis. However, stereo vision systems or 3D laser systems for obtaining 3D information require high cost and have high computational complexity, and hence they have not been used universally. Additionally, the use of such systems is still not preferred in the medical field due to limitations on visual decision making. Therefore, a haptic diagnosis system that can blend vision information from a camera and palpation information from a dermatologist has been considered. In this study, we propose a 3D skin surface reconstruction method using a light field camera for haptic rendering and palpation. To achieve this goal, we addressed the low resolution problem, which has been consistently present in light field cameras, through the generative adversarial nets (GANs)-based super resolution method, and exploited the light field system which has been applied only to the object scene for obtaining 3D skin surface texture. Experimental results show that the method proposed in this study is promising and offers sufficient potential for haptic diagnosis.
关键词： Light field images,deep learning,3D skin surface reconstruction,disparity map,haptic palpation,super resolution
更新于2025-09-19 17:15:36
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[IEEE 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS) - Vancouver, BC, Canada (2020.1.18-2020.1.22)] 2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS) - 3D Laser Nanoprinting
摘要： Digital phantoms are vital for various biomedical researches. Traditional phantoms include theoretical models and voxel models reconstructed from medical images. It has been demonstrated that the homogeneous phantom filled with uniform tissue is accurate enough for wearable antenna design, body-centric channel modeling, etc. Therefore, it is interesting and necessary to investigate the novel approach of generating digital phantoms using an optical noncontact measurement system. In this letter, the point cloud data are first obtained; then, they are simplified via principal component analysis; finally, by applying surface reconstruction and mesh simplification techniques, a digital Chinese phantom is established. To verify the usability of the phantom, numerical calculation is performed to check E-fields at different positions on the body. Results sufficiently prove the feasibility of the train of thought presented in this letter.
关键词： noncontact measurement system,point cloud data,Digital phantom,numerical calculation,surface reconstruction,principal component analysis (PCA)
更新于2025-09-19 17:13:59
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High-detectivity infrared photodetector based on InAs submonolayer quantum dots grown on GaAs(001) with a 2?×?4 surface reconstruction
摘要： The submonolayer quantum dots of an infrared photodetector were grown by molecular beam epitaxy in the presence of a very low As ?ux and a 2 × 4 surface reconstruction in order to e?ectively nucleate small two-dimensional InAs islands that are required to form such nano-structures. A speci?c detectivity of 9.2 × 1010 cm Hz1/2 W?1 was obtained at 10 K with a bias of 1.0 V.
关键词： InAs submonolayer quantum dots,2 × 4 surface reconstruction,molecular beam epitaxy,infrared photodetector,GaAs(001)
更新于2025-09-12 10:27:22
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A Two-stage Improvement Method for Robot Based 3D Surface Scanning
摘要： As known that the surface of unknown object was difficult to measure or recognize precisely, hence the 3D laser scanning technology was introduced and used properly in surface reconstruction. Usually, the surface scanning speed was slower and the scanning quality would be better, while the speed was faster and the quality would be worse. In this case, the paper presented a new two-stage scanning method in order to pursuit the quality of surface scanning in a faster speed. The first stage was rough scanning to get general point cloud data of object’s surface, and then the second stage was specific scanning to repair missing regions which were determined by chord length discrete method. Meanwhile, a system containing a robotic manipulator and a handy scanner was also developed to implement the two-stage scanning method, and relevant paths were planned according to minimum enclosing ball and regional coverage theories.
关键词： robotic manipulator,two-stage scanning method,3D laser scanning,handy scanner,surface reconstruction
更新于2025-09-11 14:15:04
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Study and characterization of morphogeometric parameters to assist diagnosis of keratoconus
摘要： Background: In case of significant imperfections on the cornea, data acquisition is difficult and a significant level of missing data could require the interpolation of important areas of the cornea, resulting in a very ambiguous model. The development of methods to define in vivo customised geometric properties of the cornea based only on real raw data is extremely useful to diagnose and assess the progression of diseases directly related to the corneal architecture. The present work tries to improve the prognostic of corneal ectasia creating a 3D customised model of the cornea and analysing different geometric variables from this model to determine which variables or combination of them could be defined as an indicator of susceptibility to develop keratoconus. Methods: A corneal geometric reconstruction was performed using zonal functions and retrospective Scheimpflug tomography data from 187 eyes of 187 patients. Morphology of healthy and keratoconic corneas was characterized by means of geometric variables. The performance of these variables as predictors of a new geometric marker was assessed and their correlations were analysed. Results: The more representative variable to classify the corneal anomalies related to keratoconus was posterior apex deviation (area under receiver operating characteristic curve > 0.899; p < 0.0001). However, the strongest correlations in both healthy and pathological corneas were provided by the metrics directly related to the thickness, as deviations of the anterior/posterior minimum thickness points. Conclusions: The presented morphogeometric approach based on the analysis and custom geometric modelling of the cornea demonstrates to be useful for the characterization and diagnosis of keratoconus disease, stating that geometrical deformation is an effective marker of the ectatic disease’s progression.
关键词： Scheimpflug,Keratoconus,Virtual model,CAD,Surface reconstruction
更新于2025-09-10 09:29:36
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Surface structures of tellurium on Si(111)–(7?×?7) studied by low-energy electron diffraction and scanning tunneling microscopy
摘要： The Te-covered Si(111) surface has received recent interest as a template for the epitaxy of van der Waals (vdW) materials, e.g. Bi2Te3. Here, we report the formation of a Te buffer layer on Si(111)–(7×7) by low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). While deposition of several monolayer (ML) of Te on the Si(111)–(7×7) surface at room temperature results in an amorphous Te layer, increasing the substrate temperature to 770 K results in a weak (7×7) electron diffraction pattern. Scanning tunneling microscopy of this surface shows remaining corner holes from the Si(111)–(7×7) surface reconstruction and clusters in the faulted and unfaulted halves of the (7×7) unit cells. Increasing the substrate temperature further to 920 K leads to a Te/Si(111)–(2√3×2√3)R30° surface reconstruction. We find that this surface configuration has an atomically flat structure with threefold symmetry.
关键词： scanning tunneling microscopy,surface reconstruction,Si(111),tellurium,low-energy electron diffraction
更新于2025-09-10 09:29:36
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Unraveling the Structural and Electronic Properties of Graphene/Ge(110)
摘要： The direct growth of graphene on a semiconducting substrate opens a new avenue for future graphene-based applications. Understanding the structural and electronic properties of the graphene on a semiconducting surface is key for realizing such structures; however, these properties are poorly understood thus far. Here, we provide an insight into the structural and electronic properties of graphene grown directly on a Ge(110) substrate. Our scanning tunneling microscopy (STM) study reveals that overlaying graphene on Ge(110) promotes the formation of a new Ge surface reconstruction, i.e., a (6 × 2) superstructure, which has been never observed for a bare Ge(110) surface. The electronic properties of the system exhibit the characteristics of both graphene and Ge. The differential conductance (dI/dV) spectrum from a scanning tunneling spectroscopy (STS) study bears a parabolic structure, corresponding to a reduction in the graphene Fermi velocity, with exhibiting additional peaks stemming from the p-orbitals of Ge. The density functional theory (DFT) calculations confirm the existence of surface states due to the p-orbitals of Ge.
关键词： density functional theory calculations,scanning tunneling microscopy,Ge(110),scanning tunneling spectroscopy,Graphene,Ge surface reconstruction
更新于2025-09-10 09:29:36