scholarly journals From pixel to image analysis

2020 ◽  
pp. 20200305
Author(s):  
PF van der Stelt

Over the past 50 years, computer technology has evolved enormously. This has made it possible to carry out radiography in a completely new way, allowing to process X-ray images in an advanced manner and to extract the information from the image data. This article gives an overview of some of the most important developments in dental radiology. These include capturing the images, analysing and interpreting the image information and using the images for 3D reconstruction.

2016 ◽  
Author(s):  
Toshifumi Mukunoki ◽  
Yoshihisa Miyata ◽  
Kazuaki Mikami ◽  
Erika Shiota

Abstract. The development of a micro-focused X-ray CT device enables digital imaging analysis at the pore-scale. The applications have been diverse, for instance, in soil mechanics, geotechnical and geoenvironmental engineering, petroleum engineering, and agricultural engineering. In particular, imaging of the pore space of porous media has contributed to numerical simulations for single and multi-phase flow, or contaminant transport, through the pore structure as three-dimensional image data. These obtained results are affected by the pore diameter so it is necessary to verify the image pre-processing for image analysis, and validate the pore diameters obtained from the CT image data. Besides, it is meaningful to produce the parameters in a representative element volume (REV) and significant to define the dimension of REV. This paper describes the underlying method of image processing and analysis and discusses the physical properties of Toyoura sand for the verification of image analysis based on the definition of REV. Based on the obtained verification results, pore diameter analysis can be conducted and validated by the comparison of the experimental work and image analysis. The pore diameter was deduced by Laplace’s law and the water retentively test for the drainage process. The referenced result sand perforated pore diameter proposed originally in this study, called the voxel-percolation method (VPM), are compared in this paper. The paper describes the limitation of REV, the definition of pore diameter, and the effectiveness of VPM for the assessment of pore diameter.


Solid Earth ◽  
2016 ◽  
Vol 7 (3) ◽  
pp. 929-942 ◽  
Author(s):  
Toshifumi Mukunoki ◽  
Yoshihisa Miyata ◽  
Kazuaki Mikami ◽  
Erika Shiota

Abstract. The development of microfocused X-ray computed tomography (CT) devices enables digital imaging analysis at the pore scale. The applications of these devices are diverse in soil mechanics, geotechnical and geoenvironmental engineering, petroleum engineering, and agricultural engineering. In particular, the imaging of the pore space in porous media has contributed to numerical simulations for single-phase and multiphase flows or contaminant transport through the pore structure as three-dimensional image data. These obtained results are affected by the pore diameter; therefore, it is necessary to verify the image preprocessing for the image analysis and to validate the pore diameters obtained from the CT image data. Moreover, it is meaningful to produce the physical parameters in a representative element volume (REV) and significant to define the dimension of the REV. This paper describes the underlying method of image processing and analysis and discusses the physical properties of Toyoura sand for the verification of the image analysis based on the definition of the REV. On the basis of the obtained verification results, a pore-diameter analysis can be conducted and validated by a comparison with the experimental work and image analysis. The pore diameter is deduced from Young–Laplace's law and a water retention test for the drainage process. The results from previous study and perforated-pore diameter originally proposed in this study, called the voxel-percolation method (VPM), are compared in this paper. In addition, the limitations of the REV, the definition of the pore diameter, and the effectiveness of the VPM for an assessment of the pore diameter are discussed.


Geoderma ◽  
2002 ◽  
Vol 106 (3-4) ◽  
pp. 247-271 ◽  
Author(s):  
A Pierret ◽  
Y Capowiez ◽  
L Belzunces ◽  
C.J Moran

Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.


Author(s):  
Robert W. Mackin

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.


2020 ◽  
Author(s):  
Yanping Chen ◽  
Dongjie Yu ◽  
Jane Cansoni

BACKGROUND Background: Nowadays, the application of computer technology in the medical field is more and more extensive, and many diseases can achieve better diagnosis and treatment effects through computer technology. OBJECTIVE Objective: The paper applies intelligent facial dynamic image information to the clinical treatment of peripheral acupuncture and moxibustion for the treatment of peripheral facial paralysis. An automatic acupoint positioning algorithm based on facial information dynamic image is proposed, which provides an objective and standard basis for the treatment of facial acupuncture and moxibustion. METHODS Methods: The paper selects the head threshold, that is, the facial dynamic image information as the research background, and divides the facial features according to the "three courts and five eyes" rule, and uses the Minimum Eigenvalue operator to detect the corner points of the facial features, locate the facial features, and use the face. The feature position is used as a reference coordinate for facial acupoint positioning. RESULTS Results: After verification, it was found that the positioning was accurate, and the peripheral facial paralysis of the patient was improved after warm acupuncture point positioning treatment, which improved the facial nerve function of the patient, improved the treatment efficiency and shortened the treatment time. Therefore, this technology is worthy of clinical promotion. CONCLUSIONS Conclusion: Through experimental analysis, the algorithm is proved to be effective and accurate. Based on facial dynamic image information to locate acupoints, warm acupuncture has a significant effect on peripheral facial paralysis, which can significantly improve facial nerve function and shorten treatment time, which is worthy of clinical promotion.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
R. J. M. Bruls ◽  
R. M. Kwee

Abstract Background The objective of this study is to investigate the workload for radiologists during on-call hours and to quantify the 15-year trend in a large general hospital in Western Europe. Methods Data regarding the number of X-ray, ultrasound and computed tomography (CT) studies during on-call hours (weekdays between 6.00 p.m. and 7.00 a.m., weekends, and national holidays) between 2006 and 2020 were extracted from the picture archiving and communication system. All studies were converted into relative value units (RVUs) to estimate the on-call workload. The Mann–Kendall test was performed to assess the temporal trend. Results The total RVUs during on-call hours showed a significant increase between 2006 and 2020 (Kendall's tau-b = 0.657, p = 0.001). The overall workload in terms of RVUs during on-call hours has quadrupled. The number of X-ray studies significantly decreased (Kendall's tau-b = − 0.433, p = 0.026), whereas the number of CT studies significantly increased (Kendall's tau-b = 0.875, p < 0.001) between 2006 and 2020. CT studies which increased by more than 500% between 2006 and 2020 are CT for head trauma, brain CTA, brain CTV, chest CT (for suspected pulmonary embolism), spinal CT, neck CT, pelvic CT, and CT for suspected aortic dissection. The number of ultrasound studies did not change significantly (Kendall's tau-b = 0.202, p = 0.298). Conclusions The workload for radiologists during on-call hours increased dramatically in the past 15 years. The growing amount of CT studies is responsible for this increase. Radiologist and technician workforce should be matched to this ongoing increasing trend to avoid potential burn-out and to maintain quality and safety of radiological care.


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