Megalopinakophobia: Its symptoms and cures

H. H. Barrett, K. J. Myers, B. Gallas, E. Clarkson, H. Zhang

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


This paper addresses issues in the calculation of a detectability measure for the ideal linear (Hotelling) observer performing a detection task on a digital radiograph. The main computational problem is that the inverse of a very large covariance matrix is required. The conventional approach is to assume some form of stationarity and argue that the matrix is diagonalized by discrete Fourier transformation, but there are many reasons why this assumption is unrealistic. After a brief review of the underlying mathematics, we present several practical algorithms for computing the detectability and some hints as to when each is applicable. The main conclusion is that large matrices should not be feared.

Original languageEnglish (US)
Pages (from-to)299-307
Number of pages9
JournalProceedings of SPIE- The International Society for Optical Engineering
StatePublished - 2001
Externally publishedYes


  • Covariance matrix
  • DQE
  • Detectability
  • Digital radiology
  • Hotelling
  • Image quality
  • NEQ

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Megalopinakophobia: Its symptoms and cures'. Together they form a unique fingerprint.

Cite this