
Proceedings IEEE International Symposium on Biomedical Imaging
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Thực tế ảo trong hình ảnh vi sinh học Dịch bởi AI
- Trang 879-882
Kính hiển vi huỳnh quang gần đây đã cho phép các nhà sinh học và nhà nghiên cứu y sinh thu thập các tập dữ liệu 3D phụ thuộc theo thời gian của các đối tượng sinh học, chẳng hạn như tế bào và mô. Việc trực quan hóa khoa học có thể cung cấp các trình bày trực quan về các đặc điểm cấu trúc của các tập dữ liệu này. Bài báo này đề cập đến vai trò của thực tế ảo trong việc hiểu biết về những trình bày này. Sự hiểu biết về các đặc điểm cấu trúc của dữ liệu sinh học 3D huỳnh quang phụ thuộc theo thời gian yêu cầu các phán đoán không gian. Việc cảm nhận những đặc điểm này được nâng cao bằng cách sử dụng công nghệ thực tế ảo. Ưu điểm của thực tế ảo đặc biệt rõ ràng trong giai đoạn khám phá của phân tích khi hành vi của các quá trình sinh học cơ bản không được biết trước.
#Virtual reality #Microscopy #Data visualization #Biomedical imaging #Cells (biology) #Biology #Biological cells #Computer graphics #Proteins #Biological processes
Image reconstruction of reflectivity from short scan data
- Trang 1027-1030
In reflectivity tomography, a weakly reflecting object that is immersed in an acoustically homogeneous background medium is interrogated with an infinitesimally short ultrasonic pulse and the corresponding reflected signal is measured at the source location as a function of time. The goal of reflectivity tomography is to reconstruct a function that describes the reflectivity of an inhomogeneous object, from knowledge of the reflected signal measured at different source-receiver positions. In this work, we identify symmetries in the reflectivity tomography data function and demonstrated that they can be exploited to reduce the amount of data that needs to be measured in order to accurately reconstruct the reflectivity function, propose and numerically investigate reconstruction algorithms for reconstructing the reflectivity function from a /spl pi/-scheme data set.
#Image reconstruction #Reflectivity #Tomography #Pulse measurements #Ultrasonic variables measurement #Position measurement #Acoustic pulses #Acoustic measurements #Time measurement #Reconstruction algorithms
3D atlases - bridges between neurogenomics and neuroanatomy
- Trang 357-360
Neuroscience research in the post-genomic era requires rapid screening and analysis of large tissue expanse. It demands close integration of information derived from histological procedures and genomic data. This is impeded by the absence of technology to automatically extract histological information and to link it to genomic data. We are developing the necessary tools. At the core of these are atlases, visualization tools and registration algorithms. This paper describes a cooperative effort in research and development of these technologies.
#Bridges #Bioinformatics #Genomics #Anatomy #Neuroscience #Data mining #Spatial resolution #Impedance #Data visualization #Research and development
A new high-resolution processing method for the deconvolution of optical coherence tomography signals
- Trang 777-780
We show the feasibility and the potential of a new signal processing algorithm for the high-resolution deconvolution of OCT signals. Our technique relies on the description of the measures in a parametric form, each set of four parameters describing the optical characteristics of a physical interface (e.g., complex refractive index, depth). Under the hypothesis of a Gaussian source light, we show that it is possible to recover the 4K parameters corresponding to K interfaces using as few as 4K uniform samples of the OCT signal. With noisy data, we can expect the robustness of our method to increase with the oversampling rate - or with the redundancy of the measures. The validation results show that the quality of the estimation of the parameters (in particular the depth of the interfaces) is narrowly linked to the noise level of the OCT measures - and not to the coherence length of the source light - and to their degree of redundancy.
#Deconvolution #Tomography #Signal processing #Nonlinear optics #Optical refraction #Optical signal processing #Optical variables control #Signal processing algorithms #Refractive index #Optical noise
Partial non-Fourier encoded MRI
- Trang 729-732
MRI is by nature a Fourier encoded imaging modality. But MRI is enriched and made all the more powerful and flexible by the fact that it also includes elements of non-Fourier encoding, such as slice selection. Our goal is to develop a partial non-Fourier encoding methodology that is fully integrated with, and is complementary to, existing MR encoding approaches. The word 'partial' is used to emphasize that non-Fourier encoding is presented as complement to standard Fourier-encoded methods. Our focus is to determine where and how non-Fourier encoding can enhance existing MRI data acquisition protocols, particularly to increase the speed of dynamic applications. The specific advantages of non-Fourier encoding we have identified are; (1) that it offers the flexibility to employ encoding functions that are close to the theoretical optimum for a given application, (2) that it offers the ability to employ true multiple resolutions within the imaging volume, (3) that point-spread-functions free of ringing artifact can be made, (4) that robust reduced field-of-view imaging is enabled, and (5) that its flexibility can be exploited to enhance parallel imaging approaches. To realize the significant advantages of non-Fourier encoding, technical advances, in particular the development of practical 2D RF excitation approaches, are necessary. This is the focus of the current report.
#Magnetic resonance imaging #Encoding #Radio frequency #Vectors #Data acquisition #Protocols #Fourier transforms #Radiology #Biomedical imaging #Hospitals
Optical coherence tomography: state of the art
- Trang 102-105
Our setup has been devised in which the spatial focus and the interference condition coincide at an assumed average refractive index of the sample, independently of the position /spl Delta/z/sub Fiber/,, of the fiber tip which causes the depth scanning. Local deviations in refractive index on the order of 25 /spl mu/m can be tracked by small position changes /spl Delta/Z/sub L1/ of one lens within the sample arm. Depending on the type of skin, refractive indices can be evaluated down to 400 /spl mu/m. The hydration level could clearly be delineated as it was demonstrated in the vicinity of a sweatgland duct in a palm. Images with a resolution of around 5 /spl mu/m have been obtained from various sites of the body. Beyond high resolution morphology in OCT images, additional local physical parameters can be desired for cosmetics/pharmaceutical and medical applications. Spatially confined refractive indices have been shown to provide a distribution map of moisture levels. Further studies (not shown) exhibit effects of hydration cremes. In skin disease characterization refractive index distribution may supplement clinical diagnosis.
#Tomography #Refractive index #Skin #Spatial resolution #Image resolution #Biomedical optical imaging #Optical refraction #Optical variables control #Coherence #Focusing
A multi-resolution admissible solution approach for diffuse optical tomography
- Trang 1005-1008
We address the use of diffuse light to characterize the space-varying absorption coefficient in tissue, posed as an inverse problem, ill-posed due to the physics and limitations on source-detector location. Accurate reliable solutions require a priori constraints. We extend our previously utilized admissible solution approach, with convex constraint functions defining admissibility conditions, by using the deep-cut ellipsoid algorithm, iteratively choosing the most important constraint value, and introducing a multi-resolution grid method to decrease the computational burden. Simulations in representative 2-D scenarios indicate that we successfully reconstruct relatively deep anomalies while reducing the computational time more than 95%.
#Tomography #Absorption #Image reconstruction #Optical scattering #Biomedical optical imaging #US Department of Transportation #Optical imaging #Inverse problems #Ellipsoids #Biology computing
Locating molecules using optical microscopy: 3-D imaging by coherent antistokes Raman scattering
- Trang 781-784
Most microscopy methods do not directly reveal the chemical identity responsible for image formation. Fluorescence imaging, resulting from either intrinsic species or added dyes, is molecule specific but generally does not reveal bulk species. All chemical species have a characteristic Raman spectrum. We demonstrate a nonlinear microscopy method that provides a new solution to the problems of signal level and background fluorescence present in Raman microscopy. Signal production is due to vibrational, not electronic, resonances. Unlike fluorescence microscopy, Coherent Anti-Stokes Raman Scattering, or CARS, is resistant to photobleaching. Live cell imaging is performed routinely. Like other multiphoton microscopy methods, 3-D images are created by scanning the focal region of the laser beams through the sample.
#Optical microscopy #Optical scattering #Optical imaging #Raman scattering #Fluorescence #Chemicals #Nonlinear optics #Production #Resonance #Photobleaching
Phế quản CT 3D định lượng Dịch bởi AI
- Trang 221-224
Trong khuôn khổ chẩn đoán hỗ trợ máy tính, bài báo này đề xuất một chức năng mới cho nghiên cứu phế quản phổi dựa trên chụp cắt lớp vi tính (CT). Nó cung cấp một phương thức hình ảnh cụ thể - phế quản CT ảo - cùng với việc điều tra định lượng thông qua một mô tả dựa trên trục trung tâm. Chức năng này dựa trên việc tái cấu trúc 3D dựa trên năng lượng của cây phế quản cho đến các phân nhánh thứ 6. Sự độc đáo của phương pháp tái cấu trúc 3D nằm ở việc kết hợp các tiềm năng lan tỏa trục và bán kính trong một quy trình tăng trưởng, được áp dụng cho một tập con các phế quản có bậc thấp được trích xuất từ khối lượng CT bằng một toán tử hình thái học toán học mạnh. Trục trung tâm của cây, cung cấp khả năng điều hướng và định lượng, được tính toán thông qua một quy trình đệ quy áp dụng cho từng đoạn phế quản, dựa trên sự lan tỏa của đường biên địa lý. Được xác thực bởi các bác sĩ chẩn đoán hình ảnh chuyên nghiệp, các ví dụ về phế quản CT ảo được trình bày cho cả phế quản bình thường và bệnh lý, và mối quan tâm về phế quản CT định lượng trong chẩn đoán lâm sàng và theo dõi bệnh được thảo luận.
#Computed tomography #Image reconstruction #Respiratory system #Thorax #Visualization #Geophysics computing #Pathology #Computer aided diagnosis #Robustness #Morphology
Prostate surface segmentation from 3D ultrasound images
- Trang 613-616
Segmenting, or outlining, the prostate boundary is a very important task in diagnosing and treating cancer. In this paper, an algorithm is described for semiautomatic segmentation of the prostate from 3D ultrasound images. The algorithm uses model-based initialization and mesh refinement using an efficient deformable model. Initialization requires the user to select only six points from which the outline of the prostate is estimated using shape information. The estimated outline is then automatically deformed to better fit the prostate boundary. The performance of the algorithm with a single user was compared to manual outlining by the same user. The average distance between semiautomatically and manually outlined boundaries was found to be 1.19 mm, and the average difference in volumes was 7.2%.
#Image segmentation #Ultrasonic imaging #Deformable models #Cancer #Shape #Image processing #Image edge detection #Visualization #Ellipsoids #Biomedical engineering