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Evaluation of inherent gray‐level dynamic range in a digital image using the runs test and join‐count statistics
Author(s) -
Chuang KehShih,
Huang H. K.
Publication year - 1993
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597058
Subject(s) - residual , dynamic range , digital image , artificial intelligence , computer science , standard test image , statistic , noise (video) , mathematics , computer vision , image processing , image (mathematics) , statistics , algorithm
The dynamic range of the gray level of a digital image is limited by the noise it contains. Two statistical methods called “runs test” and “join‐count statistic” are used to measure the noise level in a digital image. A residual image is formed by subtracting an original image from its smoothed version. Theoretically, the noise level in the residual image should be identical to that in the original image. The noise level is determined by examining each bit plane of the residual image individually starting from the least significant bit up to the bit plane whose statistic does not show a random pattern. Images from three digital modalities: computerized tomography, magnetic resonance, and computed radiography are used to evaluate the gray‐level dynamic range. Both methods are easy to implement and fast to perform.