The Experts below are selected from a list of 141 Experts worldwide ranked by ideXlab platform

Rasika Rajapakshe - One of the best experts on this subject based on the ideXlab platform.

  • Poster — Wed Eve—08: Effectiveness RMI‐156 Mammography Accreditation Phantom in Evaluating Digital Mammography Systems
    Medical Physics, 2009
    Co-Authors: Rasika Rajapakshe
    Abstract:

    PURPOSE: Evaluation of the Effectiveness RMI‐156 Mammography Accreditation Phantom in Digital Mammography METHOD AND MATERIALS: Modulation Transfer Function(MTF) and Signal Difference‐to‐Noise Ratio (SDNR) are considered to be the quantitative Image Quality matrices that can be used to characterize Image Quality in digital mammography. However there is no established information regarding the acceptable values for these quantities. This is further complicated by the fact that different detector technologies (pixel size, DQE etc.) are used in digital mammography. Recent experience with two different digital mammographysystems (incorporating different digital detectors) from the same manufacturer indicated that the RMI‐156 phantom Image Quality is better suited for clinical evaluation and comparison of digital mammographysystems. RESULTS: SDNR values for a 1 mm disk placed on a 4 cm Lucite phantom for Siemens Novation (70 μm pixel) and Inspiration (85 μm pixel) were calculated to be 3.0 and 3.2 respectively during acceptance testing. However, the evaluation of RMI‐156 phantom Image from both systems indicated the Image from Inspiration system with higher SDNR had inferior Image Quality. The Inspiration system was therefore re‐calibrated to increase exposure factors by 33% leading to a new SDNR value of 3.5. This clearly demonstrated that SDNR and MTF measures are not yet established for digital mammographysystems for acceptance testing and that RMI‐156 phantom can still be used for digital mammographysystem evaluations. CONCLUSION: RMI‐156 mammography accreditation phantom is found to be a better Image Quality Indicator in comparing and calibratingdigital mammographysystems than SDNR and MTF estimates.

Le L Dain - One of the best experts on this subject based on the ideXlab platform.

  • characterisation of a mev bremsstrahlung x ray source produced from a high intensity laser for high areal density object radiography
    Physics of Plasmas, 2013
    Co-Authors: C Courtois, R Edwards, Compant A La Fontaine, C Aedy, S Bazzoli, J L Bourgade, J Gazave, J M Lagrange, O Landoas, Le L Dain
    Abstract:

    Results of an experiment to characterise a MeV Bremsstrahlung x-ray emission created by a short (<10 ps) pulse, high intensity (1.4 × 1019 W/cm2) laser are presented. X-ray emission is characterized using several diagnostics; nuclear activation measurements, a calibrated hard x-ray spectrometer, and dosimeters. Results from the reconstructed x-ray energy spectra are consistent with numerical simulations using the PIC and Monte Carlo codes between 0.3 and 30 MeV. The intense Bremsstrahlung x-ray source is used to radiograph an Image Quality Indicator (IQI) heavily filtered with thick tungsten absorbers. Observations suggest that internal features of the IQI can be resolved up to an external areal density of 85 g/cm2. The x-ray source size, inferred by the radiography of a thick resolution grid, is estimated to be approximately 400 μm (full width half maximum of the x-ray source Point Spread Function).

Wang Zeng-yong - One of the best experts on this subject based on the ideXlab platform.

  • Discussion on Evaluation and Control of Image Quality for X-ray Linear Array Detector
    Computerized Tomography Theory and Applications, 2010
    Co-Authors: Wang Zeng-yong
    Abstract:

    Digital radiography (DR) is used more and more in practice, and it is becoming the development trend of radiographic testing. But the standards about digital radiography are brief on the control of Image Quality, so the digital Images are easily to be degenerated by random factors, thus the accuracy of results is likely to be affected. Digital radiography system with Complementary Metal-Oxide-Semiconductor Transistor (CMOS) linear array detector was used to test a specimen, which has 8 different steps. Then the Image Quality was evaluated, the contrast, SNR(Signal Noise Ratio) and Image Quality Indicator (IQI) sensitivity of different Images were comprehensively analyzed. Finally, how to properly control the Image Quality was discussed.

  • Radioscopy Applying to Thin-wall Laser Jointing Rings
    Nondestructive Testing, 2006
    Co-Authors: Wang Zeng-yong
    Abstract:

    As a new technology substitution of film radiography,radioscopy is used to test the welding of jointing ring.The result shows that the hole style defect with  0.4 mm can be detected and its Image Quality Indicator sensitivity is lower than 2%.

Yoshimitsu Aoki - One of the best experts on this subject based on the ideXlab platform.

  • a method for improving the Quality of Images used in digital radiographic testing
    Volume 1: Plant Operations Maintenance Engineering Modifications Life Cycle and Balance of Plant; Component Reliability and Materials Issues; Steam Ge, 2012
    Co-Authors: Mitsutoshi Kobayashi, Masako Mori, Atsushi Taniguchi, Kaoru Sakai, Kenichi Kawai, Takahiko Kotani, Yoshimitsu Aoki
    Abstract:

    Owing to recent developments in digital imaging technology, digital radiographic testing (RT) using computed radiography (CR) has begun to replace film RT in the inspection of piping at nuclear power plants. Digital RT enables inspection records to be preserved almost permanently without degradation and improves the efficiency of inspection by supporting inspectors using various Image processing techniques. Defects can be quickly and reliably detected by applying Image processing techniques such as Image expansion and contrast adjustment. In addition, fluctuations in measured defect size are minimized due to quantitative evaluation using the Image data.In the present paper, a method for improving the Image Quality of digital RT Images, which is generally inferior to that of film (analog) Images, is proposed in order to improve the practicality of digital RT. In this method, denoising via wavelet shrinkage and deblurring using the point spread function (PSF) estimated from Image data are applied in order to accentuate the detection target in a noisy Image and to improve the resolution.The enhancement of Image Quality is evaluated experimentally using digital RT Images of a specimen with a small hole and duplex wire Image Quality Indicator (IQI). As a result, the proposed method is confirmed to improve the Quality of Images with respect to noise and visibility. In particular, the visibility of the duplex wire IQI is 1.7 times.Copyright © 2012 by ASME

  • Digital Image Evaluation Method for Digital Radiography
    ASME 2010 Pressure Vessels and Piping Conference: Volume 5, 2010
    Co-Authors: Masako Mori, Toshibumi Kashiwa, Yoshimitsu Aoki
    Abstract:

    Digital radiography is becoming one of the common radiographic testing techniques in various industries. However, to apply this new technique to nuclear components, one big issue is how to evaluate the Images and ensure that the Images have enough Quality to be used as inspection record. In film radiography, the IQI, which stands for Image Quality Indicator, have been used to ensure that the films have enough Quality to detect any specified defects in the products. In this paper, new alternative IQI that was developed in our previous study for digital radiography to evaluate digital Image Quality is tested and evaluated. In addition, new Image evaluation criteria are also developed and evaluated by calculating MTF, which stands for Modulation Transfer Function, from the IQI Images of the products. Finally, the recommended procedures to evaluate radiographic testing Image are summarized.Copyright © 2010 by ASME

  • Digital Image Evaluation Method for Digital Radiography
    18th International Conference on Nuclear Engineering: Volume 1, 2010
    Co-Authors: Masako Mori, Toshibumi Kashiwa, Yoshimitsu Aoki
    Abstract:

    Digital radiography is getting one of the common radiographic testing techniques in various industries now. However, to apply this new technique to nuclear components radiographic testing, one big issue is how we can evaluate and ensure that the taken Images have enough Image qualities to be used as inspection record. In film radiography, the IQI, which stands for Image Quality Indicator, have been used to ensure that taken films have enough Quality to detect any specified defects in the products. So in this paper, new alternative IQI that developed in our previous study for digital radiography to evaluate digital Image Quality are tested and evaluated. In addition, Image evaluation criteria are also developed and evaluated by calculating MTF, which stands for Modulation Transfer Function, from the IQI Images taken with the products. Finally, the recommended procedures to evaluate radiographic testing Image are summarized.Copyright © 2010 by ASME

  • New IQI for Digital Radiography
    Volume 1: Codes and Standards, 2007
    Co-Authors: Masako Mori, Toshibumi Kashiwa, Yoshimitsu Aoki
    Abstract:

    Radiographic Test (RT) has been widely used in industries to detect inner defects of welded structures or any other significant components. Especially in the nuclear industry, film radiography is the dominant and standardized procedure in performing radiographic testing. Lately emphasis is on digital radiography. One of the most serious concerns for digitization is the lack of Image resolution standardizing device like resolution gauge which would determine imaging parameters such as modular transfer function (MTF). This paper proposes line pair type Image Quality Indicator (IQI) corresponding to the current IQIs for both hole and wire type. The advantage of this IQI is to enable easier calibration of testing conditions and quantification of digital RT Image Quality with required MTF that should be clearly defined in the examination procedures. Furthermore, to acquire “resolution-ensured” digital Image of existing RT films, we developed line pair type standardization film. Prototypes of line pair type IQI and line pair type standardization film are currently in the validation study and trial implementing process. These results are also reported in this paper.© 2007 ASME

Wu Zhifang - One of the best experts on this subject based on the ideXlab platform.

  • Vehicle mobile ~(60)Co container inspection system
    Nuclear Techniques, 2004
    Co-Authors: Wu Zhifang
    Abstract:

    This paper presents a mobile 60Co container inspection system (CIS) and its performance. With all devices including industrial 60Co source, high sensitive gas-ionized array detector, Image treatment and control system, inspection driving device on a vehicle, the vehicle mobile CIS has advantages of high agility and climate resistance, and it can complete emergent inspection. The mobile CIS contains equipment-vehicle and control-vehicle. Equipment-vehicle and object-container are still, while a folding detector gantry is moving through a folding rail on the equipment-vehicle and completes the inspection. The mobile CIS has the inspection characteristics similar to the fixed system and it can be used in worse circumstances. Its CI (Contrast Indicator) and IQI (Image Quality Indicator) for 100 mm steel plate attain to 0.5 % and 2.5 % respectively, and the SP (Space Penetration) is about 240 mm (Fe). Maximum dose per scanning is about 5 μ. Gy, scanning speed is varied from 6 to 18 m/min, and maximum transformational speed is 90 km/h.