Template models for forced-localization tasks

Craig K. Abbey, Frank W. Samuelson, Rongping Zeng, John M Boone, Miguel P. Eckstein, Kyle Myers

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We have previously presented the results of a psychophysical study of forced localization performance in tasks that include ramp-spectrum noise as a model of CT acquisition noise. The study used efficiency analysis and the classification image technique to better understand the mechanisms of performance. In this work, we begin the process of developing models of observer performance for these tasks. Since the image statistics for these tasks are well defined, we can use the ensemble image mean and covariance to compute templates for several standard model observers (PWMF, NPW, NPWE, and four implementations of the CHO). The goal of this work is to compare these with the human observer classification images to see if they are using spatial weighting of images in similar ways to perform the tasks. The most direct comparison would be of a model-observer template to the average human-observer classification image. However it may be the case that the classification image estimation procedure introduces bias into the classification image. Additionally, classification images may have effects from internal noise. Thus we also explore a comparison of humans and models in which the model is elaborated with internal noise and used as a scanning linear filter to generate localization responses. A classification image is then estimated for the model and compared with human-observer classification images. We compare both performance and the classification-image profile to the human-subject data. We find very limited ability to fit both endpoints.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2019
Subtitle of host publicationImage Perception, Observer Performance, and Technology Assessment
EditorsRobert M. Nishikawa, Frank W. Samuelson
ISBN (Electronic)9781510625518
StatePublished - Jan 1 2019
EventMedical Imaging 2019: Image Perception, Observer Performance, and Technology Assessment - San Diego, United States
Duration: Feb 20 2019Feb 21 2019

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceMedical Imaging 2019: Image Perception, Observer Performance, and Technology Assessment
Country/TerritoryUnited States
CitySan Diego


  • Classification Images
  • Localization tasks
  • Observer templates

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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