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Hartwig R Blume - One of the best experts on this subject based on the ideXlab platform.
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25 2 characterization of physical image quality of 2 and 5 million pixel monochrome amlcds for medical imaging
SID Symposium Digest of Technical Papers, 2003Co-Authors: Hartwig R Blume, Peter M Steven, Annie Ho, Hans Roehrig, Chawla Amarpreet, Kunal GandhiAbstract:The physical image quality of two new high-performance monochrome active matrix liquid crystal Displays (AMLCDs), a 2- and a 5-million-pixel Display, is reviewed. The performance is illustrated by examples (because of space limitations) of on-axis and off-axis characteristic curves, luminance range and contrast, luminance uniformity across the Display screen, temporal modulation transfer Function (MTF), spatial MTF, spatial noise power spectra and spatial signal-to-noise ratios. The LCDs are equipped with an internal photosensor that maintains a desired maximum luminance and calibration to a given Display Function. The systems offer aperture and temporal modulation to place luminance levels with more than 12-bit precision on a desired Display Function and achieve uniform contrast distribution over the luminance range for a narrow viewing angle perpendicular to the LCD face. The image quality of the LCDs is compared with that of high-performance high-resolution cathode-ray-tube (CRT) Displays.
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8 3 characterization of physical image quality of a 3 million pixel monochrome amlcd dicom conformance spatial mtf and spatial nps
SID Symposium Digest of Technical Papers, 2002Co-Authors: Hartwig R Blume, Peter M Steven, Annie Ho, Marlin E Cobb, Fred Stevens, Hans RoehrigAbstract:A high degree of conformance of a 3-million-pixel monochrome LCD with the DICOM Standard Display Function is achieved by spatial and temporal modulation. The spatial modulation transfer Function (MTF) is found to be very close to 1 up to the Nyquist frequency. Visual comparisons of the LCD and high-resolution monochrome CRTs with P45 phosphors indicate that the spatial noise levels are comparable. The measured spatial noise power spectra (NPS) on the other hand are higher than the actual noise powers appear to be. The measured noise levels are affected by the systematic structures of the Display which we have not been able to eliminate totally from the noise power spectra.
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image presentation in digital radiology perspectives on the emerging dicom Display Function standard and its application
Radiographics, 1997Co-Authors: Hartwig R Blume, Bradley M HemmingerAbstract:DICOM (Digital Imaging and Communications in Medicine) Working Group XI, formerly called ACR/NEMA (American College of Radiology/National Electrical Manufacturers' Association) Working Group XI, is currently developing a Display Function standard. The main objective of the standard is to define mathematically a Display Function for all image presentation systems. As a secondary objective, the standard aims at providing similarity in gray-scale perception for a given image between Display systems of different luminance and at facilitating efficient utilization of the available digital input levels of a Display system. The design of the Display Function incorporates the concept of perceptual linearization. The proposed standard applies to monochrome image presentation devices such as cathode ray tube monitor-Display controller systems and digital laser image printers. The standard does not eliminate the use of application-specific Display Functions but rather ensures their effectiveness. Neither does the st...
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acr nema proposal for a gray scale Display Function standard
Medical Imaging 1996: Image Display, 1996Co-Authors: Hartwig R BlumeAbstract:The proposed standard defines a gray-scale Display Function for monochrome image presentation devices, such as cathode-ray-tube (CRT) monitor/Display-controller systems and digital laser image printers. The Display Function is based on perceptual linearization. It is defined for the luminance range of 0.05 to 4000 cd/m2. The standard provides a mathematical formula for the standard Display Function as well as a table of the luminance levels of the just-noticeable differences (JNDs) of a standard target. The standard facilitates similarity in gray-scale between different image Display devices independent of their luminance. The standard does not eliminate the use of application-specific Display Functions, but rather assures their effectiveness through the standard Display Function. To realize conformance of an image presentation device with the Display Function standard, standard test patterns are defined. The patterns are used to measure the luminance of the Display or optical density of a print as a Function of digital input. By proper interpolation of the inverted measured characteristic Function of the Display system and inserting the desired standard luminance values for every digital input, a transformation can be computed so that the Display system may conform with the Display Function standard. The standard also defines the dynamic range of an image presentation device as the number of JNDs that theoretically can be realized for a given digitization resolution and the standard target. Interpolation processes and potential conformance measures for the standard are discussed. The proposed Display Function standard is essential for the proper realization of image presentation services according to the DICOM Standard. The relation of the standard Display Function to DICOM-defined look-up tables is outlined.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Takafumi Matsumaru - One of the best experts on this subject based on the ideXlab platform.
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mobile robot with preliminary announcement and Display Function of forthcoming motion using projection equipment
Robot and Human Interactive Communication, 2006Co-Authors: Takafumi MatsumaruAbstract:This paper discusses the mobile robot PMR-5 with the preliminary-announcement and Display Function which indicates the forthcoming operations to the people near the robot by using a projector. The projector is set on a mobile robot and a 2-dimensional frame is projected on a running surface. In the frame, not only the scheduled course but also the states of operation can be clearly announced as the information about movement. We examine the presentation of the states of operation such as stop or going back including the time information of the scheduled course on the developed robot. Scheduled course is expressed as the arrows considering the intelligibility at sight. Arrow expresses the direction of motion directly and the length of arrow can announce the speed of motion. Operation until 3-second-later is indicated and three arrows classified by color for each second are connected and Displayed so these might show the changing of speed during 3-second period. The sign for spot revolution and the characters for stop and going back are also Displayed. We exhibited the robot and about 200 visitors did the questionnaire evaluation. The average of 5-stage evaluation is 3.9 points and 4.5 points for the direction of motion and the speed of motion respectively. So we obtained the evaluation that it is intelligible in general.
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examination by software simulation on preliminary announcement and Display of mobile robot s following action by lamp or blowouts
International Conference on Robotics and Automation, 2003Co-Authors: Takafumi Matsumaru, H Endo, T ItoAbstract:This paper discusses the preliminary-announcement and Display Function of the robot's following action and intention, especially about the direction of motion and the speed of motion for mobile robot which moves on a 2-dimensional plane. We started with a software simulation about the announcement method indicating a state just after the moment, with lighting lamps and with using blowouts (elastic arrow) on translation and rotation separately. As a result, the following three remarks have been obtained: not only the direction of motion but also the speed of motion is effective to estimate the following translation. Not the rotation speed but the rotation angle (the target direction) is efficient to understand the following revolution. Around 1-second before the actual motion is the optimal timing to recognize the robot's following motion both on translation and rotation. Moreover we have verified the validity of the preliminary-announcement and Display also for the general movement on a plane.
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simulation of preliminary announcement and Display of mobile robot s following action by lamp party blowouts or beam light
International Conference on Advanced Intelligent Mechatronics, 2003Co-Authors: Takafumi Matsumaru, S Kudo, T Kusada, K Iwase, K Akiyama, T ItoAbstract:This paper examines the preliminary-announcement and Display Function of the robot's following action and intention, especially about the direction of motion and the speed of motion for mobile robot which moves on a 2D plane. Based on the result of the fundamental examination, the validity of the preliminary-announcement and Display at around 1 second before the actual motion has been verified on a 2D plane. Moreover we have found that human being tends to understand the change of speed of the mobile robot more with some transforming object than with some changing-color object. Comparing two types of the proposed methods, the efficiency of the preliminary-announcement and Display by indicating the continuous information as drawing with beam-light more than by Displaying a state as lighting lamp or using blowouts have been declared. Moreover, we have found that the scheduled path needs some amount of length for a person to understand the mobile robot's following action.
T Ito - One of the best experts on this subject based on the ideXlab platform.
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examination by software simulation on preliminary announcement and Display of mobile robot s following action by lamp or blowouts
International Conference on Robotics and Automation, 2003Co-Authors: Takafumi Matsumaru, H Endo, T ItoAbstract:This paper discusses the preliminary-announcement and Display Function of the robot's following action and intention, especially about the direction of motion and the speed of motion for mobile robot which moves on a 2-dimensional plane. We started with a software simulation about the announcement method indicating a state just after the moment, with lighting lamps and with using blowouts (elastic arrow) on translation and rotation separately. As a result, the following three remarks have been obtained: not only the direction of motion but also the speed of motion is effective to estimate the following translation. Not the rotation speed but the rotation angle (the target direction) is efficient to understand the following revolution. Around 1-second before the actual motion is the optimal timing to recognize the robot's following motion both on translation and rotation. Moreover we have verified the validity of the preliminary-announcement and Display also for the general movement on a plane.
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simulation of preliminary announcement and Display of mobile robot s following action by lamp party blowouts or beam light
International Conference on Advanced Intelligent Mechatronics, 2003Co-Authors: Takafumi Matsumaru, S Kudo, T Kusada, K Iwase, K Akiyama, T ItoAbstract:This paper examines the preliminary-announcement and Display Function of the robot's following action and intention, especially about the direction of motion and the speed of motion for mobile robot which moves on a 2D plane. Based on the result of the fundamental examination, the validity of the preliminary-announcement and Display at around 1 second before the actual motion has been verified on a 2D plane. Moreover we have found that human being tends to understand the change of speed of the mobile robot more with some transforming object than with some changing-color object. Comparing two types of the proposed methods, the efficiency of the preliminary-announcement and Display by indicating the continuous information as drawing with beam-light more than by Displaying a state as lighting lamp or using blowouts have been declared. Moreover, we have found that the scheduled path needs some amount of length for a person to understand the mobile robot's following action.
Aldo Badano - One of the best experts on this subject based on the ideXlab platform.
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assessment of Display performance for medical imaging systems executive summary of aapm tg18 report
Medical Physics, 2005Co-Authors: Ehsan Samei, Bradley M Hemminger, Aldo Badano, Michael J Flynn, Dev P Chakraborty, Ken Compton, Craig W Cornelius, Kevin Corrigan, N HangiandreouAbstract:Digital imaging provides an effective means to electronically acquire, archive, distribute, and view medical images. Medical imaging Display stations are an integral part of these operations. Therefore, it is vitally important to assure that electronic Display devices do not compromise image quality and ultimately patient care. The AAPM Task Group 18 (TG18) recently published guidelines and acceptance criteria for acceptance testing and quality control of medical Display devices. This paper is an executive summary of the TG18 report. TG18 guidelines include visual, quantitative, and advanced testing methodologies for primary and secondary class Display devices. The characteristics, tested in conjunction with specially designed test patterns (i.e., TG18 patterns), include reflection, geometric distortion, luminance, the spatial and angular dependencies of luminance, resolution, noise, glare, chromaticity, and Display artifacts. Geometric distortions are evaluated by linear measurements of the TG18-QC test pattern, which should render distortion coefficients less than 2%/5% for primary/secondary Displays, respectively. Reflection measurements include specular and diffuse reflection coefficients from which the maximum allowable ambient lighting is determined such that contrast degradation due to Display reflection remains below a 20% limit and the level of ambient luminance (Lamb) does not unduly compromise luminance ratio (LR) and contrast at low luminance levels. Luminance evaluation relies on visual assessment of low contrast features in the TG18-CT and TG18-MP test patterns, or quantitative measurements at 18 distinct luminance levels of the TG18-LN test patterns. The major acceptable criteria for primary/secondary Displays are maximum luminance of greater than 170∕100cd∕m2, LR of greater than 250∕100, and contrast conformance to that of the grayscale standard Display Function (GSDF) of better than 10%∕20%, respectively. The angular response is tested to ascertain the viewing cone within which contrast conformance to the GSDF is better than 30%∕60% and LR is greater than 175∕70 for primary/secondary Displays, or alternatively, within which the on-axis contrast thresholds of the TG18-CT test pattern remain discernible. The evaluation of luminance spatial uniformity at two distinct luminance levels across the Display faceplate using TG18-UNL test patterns should yield nonuniformity coefficients smaller than 30%. The resolution evaluation includes the visual scoring of the CX test target in the TG18-QC or TG18-CX test patterns, which should yield scores greater than 4∕6 for primary/secondary Displays. Noise evaluation includes visual evaluation of the contrast threshold in the TG18-AFC test pattern, which should yield a minimum of 3∕2 targets visible for primary/secondary Displays. The guidelines also include methodologies for more quantitative resolution and noise measurements based on MTF and NPS analyses. The Display glare test, based on the visibility of the low-contrast targets of the TG18-GV test pattern or the measurement of the glare ratio (GR), is expected to yield scores greater than 3∕1 and GRs greater than 400∕150 for primary/secondary Displays. Chromaticity, measured across a Display faceplate or between two Display devices, is expected to render a u′,v′ color separation of less than 0.01 for primary Displays. The report offers further descriptions of prior standardization efforts, current Display technologies, testing prerequisites, streamlined procedures and timelines, and TG18 test patterns.
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angular dependence of the luminance and contrast in medical monochrome liquid crystal Displays
Medical Physics, 2003Co-Authors: Aldo Badano, Michael J Flynn, Sandrine Martin, Jerzy KanickiAbstract:Active-matrix liquid crystal Displays (AMLCDs) are light-modulating devices that generate images by differentially transmitting a nearly uniform luminous field provided by a backlight. While emissive Displays exhibit a quasi-Lambertian emission with almost constant contrast at off-normal viewing, the anisotropy of the electro-optic effect that controls light transmission in AMLCDs causes a pixel luminance that varies, sometimes strongly, with viewing angle. These variations are not identical for all gray levels and can eventually cause grayscale inversions. In this paper, we measured the luminance emission of a monochrome medical AMLCD, a medical cathode-ray tube monitor, and a color desktop AMLCD, using a collimated photopic probe positioned on a manual rotation arm, and a research radiometer with automatic readout. The probe measures luminance with a small acceptance angle and provides optical shielding from emissions at other viewing directions that contaminate the readings. We obtained luminance response curves versus angle in the vertical, horizontal and at 45 degrees diagonal directions. The Display systems were calibrated to reflect the DICOM Part 3.14 standard grayscale Display Function (GDF) when measured using the manufacturer's probe and software tools. We analyzed the measurements at different viewing directions with respect to their departure from the GDF by computing the normalized contrast (deltaL/L) as a Function of the DICOM just-noticeable difference index. Although cathode-ray tubes are known to be quasi-Lambertian emitters, the luminance at normal viewing is higher than the luminance observed at large angles. This decrease in luminance is however proportionally similar for all gray levels, resulting in a relatively flat contrast response for all angles. In addition to being more pronounced, the angular variation in AMLCDs does not follow the same profile at different intensities with the subsequent variation in the achieved Display contrast. The changes due to off-normal viewing are substantial at large angles in the horizontal and vertical directions, and much worse in the diagonal viewing directions.
Bradley M Hemminger - One of the best experts on this subject based on the ideXlab platform.
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assessment of Display performance for medical imaging systems executive summary of aapm tg18 report
Medical Physics, 2005Co-Authors: Ehsan Samei, Bradley M Hemminger, Aldo Badano, Michael J Flynn, Dev P Chakraborty, Ken Compton, Craig W Cornelius, Kevin Corrigan, N HangiandreouAbstract:Digital imaging provides an effective means to electronically acquire, archive, distribute, and view medical images. Medical imaging Display stations are an integral part of these operations. Therefore, it is vitally important to assure that electronic Display devices do not compromise image quality and ultimately patient care. The AAPM Task Group 18 (TG18) recently published guidelines and acceptance criteria for acceptance testing and quality control of medical Display devices. This paper is an executive summary of the TG18 report. TG18 guidelines include visual, quantitative, and advanced testing methodologies for primary and secondary class Display devices. The characteristics, tested in conjunction with specially designed test patterns (i.e., TG18 patterns), include reflection, geometric distortion, luminance, the spatial and angular dependencies of luminance, resolution, noise, glare, chromaticity, and Display artifacts. Geometric distortions are evaluated by linear measurements of the TG18-QC test pattern, which should render distortion coefficients less than 2%/5% for primary/secondary Displays, respectively. Reflection measurements include specular and diffuse reflection coefficients from which the maximum allowable ambient lighting is determined such that contrast degradation due to Display reflection remains below a 20% limit and the level of ambient luminance (Lamb) does not unduly compromise luminance ratio (LR) and contrast at low luminance levels. Luminance evaluation relies on visual assessment of low contrast features in the TG18-CT and TG18-MP test patterns, or quantitative measurements at 18 distinct luminance levels of the TG18-LN test patterns. The major acceptable criteria for primary/secondary Displays are maximum luminance of greater than 170∕100cd∕m2, LR of greater than 250∕100, and contrast conformance to that of the grayscale standard Display Function (GSDF) of better than 10%∕20%, respectively. The angular response is tested to ascertain the viewing cone within which contrast conformance to the GSDF is better than 30%∕60% and LR is greater than 175∕70 for primary/secondary Displays, or alternatively, within which the on-axis contrast thresholds of the TG18-CT test pattern remain discernible. The evaluation of luminance spatial uniformity at two distinct luminance levels across the Display faceplate using TG18-UNL test patterns should yield nonuniformity coefficients smaller than 30%. The resolution evaluation includes the visual scoring of the CX test target in the TG18-QC or TG18-CX test patterns, which should yield scores greater than 4∕6 for primary/secondary Displays. Noise evaluation includes visual evaluation of the contrast threshold in the TG18-AFC test pattern, which should yield a minimum of 3∕2 targets visible for primary/secondary Displays. The guidelines also include methodologies for more quantitative resolution and noise measurements based on MTF and NPS analyses. The Display glare test, based on the visibility of the low-contrast targets of the TG18-GV test pattern or the measurement of the glare ratio (GR), is expected to yield scores greater than 3∕1 and GRs greater than 400∕150 for primary/secondary Displays. Chromaticity, measured across a Display faceplate or between two Display devices, is expected to render a u′,v′ color separation of less than 0.01 for primary Displays. The report offers further descriptions of prior standardization efforts, current Display technologies, testing prerequisites, streamlined procedures and timelines, and TG18 test patterns.
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image presentation in digital radiology perspectives on the emerging dicom Display Function standard and its application
Radiographics, 1997Co-Authors: Hartwig R Blume, Bradley M HemmingerAbstract:DICOM (Digital Imaging and Communications in Medicine) Working Group XI, formerly called ACR/NEMA (American College of Radiology/National Electrical Manufacturers' Association) Working Group XI, is currently developing a Display Function standard. The main objective of the standard is to define mathematically a Display Function for all image presentation systems. As a secondary objective, the standard aims at providing similarity in gray-scale perception for a given image between Display systems of different luminance and at facilitating efficient utilization of the available digital input levels of a Display system. The design of the Display Function incorporates the concept of perceptual linearization. The proposed standard applies to monochrome image presentation devices such as cathode ray tube monitor-Display controller systems and digital laser image printers. The standard does not eliminate the use of application-specific Display Functions but rather ensures their effectiveness. Neither does the st...