China
Africa
Explore chapters and articles related to this topic
Technology for sensory impairments (vision and hearing)
Published in Alex Mihailidis, Roger Smith, Rehabilitation Engineering, 2023
J. A. Brabyn, H. Levitt, J.A. Miele
Larger magnification (up to about 60 times) can be obtained with electronic systems that use cameras that display a magnified image on a visual computer or TV-type monitor. Numerous brands and variants are available, including low-cost versions with a camera that connects to the user's existing TV monitor. At the higher end, systems with features such as optical character recognition and computer interfaces are available, as are cameras that can be aimed at distant objects such as the blackboard in a classroom. Most provide features that allow users to reduce glare by reversing the polarity of print (i.e., displaying light characters on a dark background). Users can adjust the magnification, contrast, and (often) the colors displayed to meet personal preferences.
Modern Microscopic Methods of Bioaerosol Analysis
Published in Christopher S. Cox, Christopher M. Wathes, Bioaerosols Handbook, 2020
To suit modern requirements for Good Laboratory Practice, as defined by the UK Department of Health, a pre-prepared sheet for logging scores can be useful, where the operator enters his name, the date, slide details, experiment number, magnification, and other relevant details, prior to scoring. The sheet will be signed when the scan has been completed, once the operator has ensured that the information entered is correct. It is important to ensure that the magnification is recorded correctly, as many microscopes have additional magnification lenses above the turret, typically 1.0 ×, 1.2 ×, 1.6 × and 2.0 ×, and the selection of the incorrect value is very easy and difficult to perceive when viewing. Care also must be taken when switching magnification to identify objects at higher power. Normally the data from the score sheet will be entered into a personal computer spreadsheet, such as Microsoft Excel or Lotus 123. The name of the spreadsheet data file also should be recorded on the score sheet for cross-referencing purposes.
Image Quality
Published in Kwan Hoong Ng, Jeannie Hsiu Ding Wong, Geoffrey D. Clarke, Problems and Solutions in Medical Physics, 2018
Kwan Hoong Ng, Jeannie Hsiu Ding Wong, Geoffrey D. Clarke
Solution:MTF describes the capacity of an imaging detector to transfer the modulation of the input signal at a given spatial frequency to its output. It is expressed as the ratio of the output and input signal modulation.When the magnification of the system is increased, imaging of details improves; hence, the spatial resolution improves. However, the magnification of the system may also increase geometric unsharpness thus compromising the improvement in the MTF.The overall MTF of the imaging system is the product of the MTF of its components. MTFoverall=MTF1×MTF2=0.6×0.8=0.48System A has the highest spatial resolution, followed by systems B and C.
Simultaneous shape and size measurements of irregular rough particles by an IPI system with double receivers
Published in Journal of Modern Optics, 2019
Hongxia Zhang, Zhonghao Li, Jiao Li, Jinlu Sun, Xiaolei Wang, Dagong Jia, Tiegen Liu
Firstly, we calibrated the magnification of the experimental system by measuring the steel ruler located at the central plane of sheet laser beam. The central magnification is calculated by measuring the object height and the image height. The object distance is , and the infocused imaging distance is . To ensure that the defocused images of all emitters overlap in the global images of the particle (18), the defocused imaging distance is set to with the defocused parameter .