| 摘要 |
A method for evaluation of signal-dependent noise of digital medical roentgenograms involves original image acquisition, low-pass filtering of original image for evaluation image acquisition, noise imaging as difference between original and evaluation image, removal of noise image pixel values corresponding to boundaries of original image by means of morphological filtration, decomposition of evaluation image intensity range to intervals wherein each pixel of evaluation image belongs to certain interval, accumulation for each interval of noise image pixel values corresponding to pixels of evaluation image, calculation of interval estimates of noise dispersion according to accumulated values of noise image pixels, refining of interval estimates of dispersion by dropping noise pixel values by 3-sigma criterion, robust local linear approximation of noise dispersion interval estimates from which obtained is a table function describing dependence of noise from signal intensity, calculation of noise map as image which each pixel estimates original digital image noise dispersion , wherein calculation is based on estimated image and plotted table dependence of noise dispersion from signal intensity. The technical result is in enhancement of speed and quality of digital roentgenogram noise evaluation. |
