A method to determine spectral performance of image post-processing algorithms

Alex Salsali; Paul Picot; Jesse Tanguay; Ian A. Cunningham

doi:10.1117/12.2580057

15 February 2021 A method to determine spectral performance of image post-processing algorithms

Alex Salsali, Paul Picot, Jesse Tanguay, Ian A. Cunningham

Proceedings Volume 11595, Medical Imaging 2021: Physics of Medical Imaging; 115951A (2021) https://doi.org/10.1117/12.2580057
Event: SPIE Medical Imaging, 2021, Online Only

Abstract

The MTF and DQE of an x-ray detector are important metrics of performance. They are generally measured following IEC guidelines which requires the use of raw (unprocessed) images. However, many detectors now incorporate processing algorithms that are deeply embedded in the imaging chain and may be difficult or impossible to disable, blurring the line between processed and unprocessed image data, and questioning the relevance of MTF and DQE testing. This study develops a framework to represent the spectral performance of linear and shift-invariant digital-processing algorithms and examines their effects on MTF and DQE measurements with examples. Processing algorithms are represented as a cascade of operations where images are represented using an integrable impulse-sampled notation. This allows the use of Fourier transform theorems and relationships, which differ to a discrete Fourier transform notation, including a specific representation of signal and noise aliasing. It is concluded that: i) digital convolution of image data gives the same result, with the same aliasing artifacts, as a true convolution integral of presampling image data followed by sampling; ii) the slanted-edge method to measure MTF provides the presampling MTF even when processing algorithms operate on aliased image data; iii) the DQE is largely unaffected by LSI post processing, however spectral zero-crossings can suppress specific frequency content in both the MTF and DQE, and unsharp masking algorithms can decrease the DQE at low frequencies.

Conference Presentation

Citation Download Citation

Alex Salsali, Paul Picot, Jesse Tanguay, and Ian A. Cunningham "A method to determine spectral performance of image post-processing algorithms", Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115951A (15 February 2021); https://doi.org/10.1117/12.2580057

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available