scholarly journals Are Radiologists Ideal Observers? --Evidence from Observer Studies in Radiology

2013 ◽  
Vol 13 (9) ◽  
pp. 751-751
Author(s):  
X. He ◽  
B. Gallas ◽  
F. Samuelson ◽  
B. Sahiner ◽  
K. Myers
Keyword(s):  
Ideal Observers ◽  
Observer Studies

scholarly journals Bayesian natural selection and the evolution of perceptual systems

2002 ◽  
Vol 357 (1420) ◽  
pp. 419-448 ◽  
Author(s):  
Wilson S. Geisler ◽  
Randy L. Diehl
Keyword(s):  
Natural Selection ◽  
Decision Theory ◽  
Ideal Observer ◽  
Statistical Decision Theory ◽  
Statistical Decision ◽  
Natural Stimuli ◽  
Ideal Observers ◽  
Formal Framework ◽  
Bayesian Statistical Decision Theory ◽  
Perceptual Systems

In recent years, there has been much interest in characterizing statistical properties of natural stimuli in order to better understand the design of perceptual systems. A fruitful approach has been to compare the processing of natural stimuli in real perceptual systems with that of ideal observers derived within the framework of Bayesian statistical decision theory. While this form of optimization theory has provided a deeper understanding of the information contained in natural stimuli as well as of the computational principles employed in perceptual systems, it does not directly consider the process of natural selection, which is ultimately responsible for design. Here we propose a formal framework for analysing how the statistics of natural stimuli and the process of natural selection interact to determine the design of perceptual systems. The framework consists of two complementary components. The first is a maximum fitness ideal observer, a standard Bayesian ideal observer with a utility function appropriate for natural selection. The second component is a formal version of natural selection based upon Bayesian statistical decision theory. Maximum fitness ideal observers and Bayesian natural selection are demonstrated in several examples. We suggest that the Bayesian approach is appropriate not only for the study of perceptual systems but also for the study of many other systems in biology.

Validation of simulation of calcifications for observer studies in digital mammography

2013 ◽  
Vol 58 (16) ◽  
pp. N217-N228 ◽  
Author(s):  
L M Warren ◽  
F H Green ◽  
L Shrestha ◽  
A Mackenzie ◽  
D R Dance ◽  
...  
Keyword(s):  
Digital Mammography ◽  
Observer Studies

scholarly journals Performance of normative and approximate evidence accumulation on the dynamic clicks task

2019 ◽  
Author(s):  
Adrian E. Radillo ◽  
Alan Veliz-Cuba ◽  
Krešimir Josić ◽  
Zachary P. Kilpatrick
Keyword(s):  
Model Fitting ◽  
Decision Making Process ◽  
Response Accuracy ◽  
Parameter Recovery ◽  
Ideal Observers ◽  
Log Likelihood ◽  
Left And Right ◽  
Normative Models ◽  
Task Parameters ◽  
Sensory Noise

The aim of a number of psychophysics tasks is to uncover how mammals make decisions in a world that is in flux. Here we examine the characteristics of ideal and near–ideal observers in a task of this type. We ask when and how performance depends on task parameters and design, and, in turn, what observer performance tells us about their decision-making process. In the dynamic clicks task subjects hear two streams (left and right) of Poisson clicks with different rates. Subjects are rewarded when they correctly identify the side with the higher rate, as this side switches unpredictably. We show that a reduced set of task parameters defines regions in parameter space in which optimal, but not near-optimal observers, maintain constant response accuracy. We also show that for a range of task parameters an approximate normative model must be finely tuned to reach near-optimal performance, illustrating a potential way to distinguish between normative models and their approximations. In addition, we show that using the negative log-likelihood and the 0/1-loss functions to fit these types of models is not equivalent: the 0/1-loss leads to a bias in parameter recovery that increases with sensory noise. These findings suggest ways to tease apart models that are hard to distinguish when tuned exactly, and point to general pitfalls in experimental design, model fitting, and interpretation of the resulting data.

Evaluation and comparison of a CdTe based photon counting detector with an energy integrating detector for X-ray phase sensitive imaging of breast cancer

2021 ◽  
pp. 1-13
Author(s):  
Muhammad U. Ghani ◽  
Farid H. Omoumi ◽  
Xizeng Wu ◽  
Laurie L. Fajardo ◽  
Bin Zheng ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Spatial Resolution ◽  
Standard Dose ◽  
Photon Counting ◽  
High Energy ◽  
Edge Enhancement ◽  
X Ray ◽  
Photon Counting Detector ◽  
Phase Sensitive ◽  
Observer Studies

PURPOSE: To compare imaging performance of a cadmium telluride (CdTe) based photon counting detector (PCD) with a CMOS based energy integrating detector (EID) for potential phase sensitive imaging of breast cancer. METHODS: A high energy inline phase sensitive imaging prototype consisting of a microfocus X-ray source with geometric magnification of 2 was employed. The pixel pitch of the PCD was 55μm, while 50μm for EID. The spatial resolution was quantitatively and qualitatively assessed through modulation transfer function (MTF) and bar pattern images. The edge enhancement visibility was assessed by measuring edge enhancement index (EEI) using the acrylic edge acquired images. A contrast detail (CD) phantom was utilized to compare detectability of simulated tumors, while an American College of Radiology (ACR) accredited phantom for mammography was used to compare detection of simulated calcification clusters. A custom-built phantom was employed to compare detection of fibrous structures. The PCD images were acquired at equal, and 30% less mean glandular dose (MGD) levels as of EID images. Observer studies along with contrast to noise ratio (CNR) and signal to noise ratio (SNR) analyses were performed for comparison of two detection systems. RESULTS: MTF curves and bar pattern images revealed an improvement of about 40% in the cutoff resolution with the PCD. The excellent spatial resolution offered by PCD system complemented superior detection of the diffraction fringes at boundaries of the acrylic edge and resulted in an EEI value of 3.64 as compared to 1.44 produced with EID image. At MGD levels (standard dose), observer studies along with CNR and SNR analyses revealed a substantial improvement of PCD acquired images in detection of simulated tumors, calcification clusters, and fibrous structures. At 30% less MGD, PCD images preserved image quality to yield equivalent (slightly better) detection as compared to the standard dose EID images. CONCLUSION: CdTe-based PCDs are technically feasible to image breast abnormalities (low/high contrast structures) at low radiation dose levels using the high energy inline phase sensitive imaging technique.

72 AUTOMATED OBSERVER STUDIES ON A DIGITAL CHEST SYSTEM

1985 ◽  
Vol 20 (6) ◽  
pp. S19
Author(s):  
R. H. Sherrler ◽  
S. A. Suddarth ◽  
G. A. Johnson ◽  
C. E. Ravin
Keyword(s):  
Digital Chest ◽  
Observer Studies

Shape from texture: Ideal observers and human psychophysics

1993 ◽  
Vol 33 (12) ◽  
pp. 1723-1737 ◽  
Author(s):  
Andrew Blake ◽  
Heinrich H. Bülthoff ◽  
David Sheinberg
Keyword(s):  
Human Psychophysics ◽  
Ideal Observers ◽  
Shape From Texture
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