© The Institution of Electrical Engineers
The application of standard psychophysical techniques to the measurement of the quality of noisy images is shown using examples taken from clinical radionuclide imaging. In clinical radionuclide imaging the distribution of a radiopharmaceutical injected into a patient is mapped in vivo by using a scintillation detector to record the emitted gamma rays. Areas of above or below average radiopharmaceutical concentration may indicate clinical abnormalities, such as tumours. As the images have only a few hundred photons/cm2, random (Poisson) fluctuations in intensity are large and may mask changes in radiopharmaceutical concentration. The quality of these images is assessed by using either the method of constant stimulus or signal-detection theory to measure an observer's ability to detect small changes in image intensity. The method of constant stimulus is used to compare analogue with digital images. It is shown that smaller changes in intensity can be detected on digital images than on the analogue ones. Signal detection theory is used to measure the effect of filtering on image quality. For a given rate of false positive responses, the filtered images produce a higher true positive response rate than for the unfiltered ones.
References
-
-
1)
-
C.E. Metz ,
S.J.S. Starr ,
L.B. Lusted ,
G.A. Hay
.
(1976)
Quantitative evaluation of visual detection performance in medicine: R.O.C. analysis and determination of diagnostic benefit, Medical images: formation, perception and measurement.
-
2)
-
P.F. Sharp ,
G.A. Hay
.
(1976)
Psychophysical assessment of the performance of clinical radioisotope imaging devices, Medical images: formation, perception and measurement.
-
3)
-
H.O. Anger
.
(1967)
, Instrumentation in nuclear medicine –.
-
4)
-
J.R. Mallard
.
The radionuclide imaging process and factors influencing the choice of an instrument for brain scanning.
Prog. Nucl. Med.
,
1 -
114
-
5)
-
J.F. Corso
.
(1967)
, The experimental psychology of sensory behaviour.
-
6)
-
J.R. Mallard ,
M.H. Duggan ,
M.J. Myers ,
R.J. Wilks
.
(1964)
An analysis of quantitative colour display for scanning, Medical radioisotope scintigraphy –.
-
7)
-
S.J. Starr ,
C.E. Metz ,
L.B. Lusted ,
D.J. Goodenough
.
Visual detection and localization of radiographic images.
Radiology
,
533 -
538
-
8)
-
P.F. Sharp ,
J.R. Mallard
.
Measurement of the performance of the gamma camera oscilloscope display.
Br. J. Radiol.
,
822 -
824
-
9)
-
D.M. Green ,
J.A. Swets
.
(1966)
, Signal detection theory and psychophysics.
-
10)
-
R.H. Morgan
.
Visual perception in fluoroscopy and radiography.
Radiology
,
403 -
416
-
11)
-
G.D.S. Neill ,
F. Hutchinson
.
Computer detection and display of focal lesions on scintigrams.
Br. J. Radiol.
,
962 -
969
-
12)
-
R.J. Goodenough ,
K. Rossman ,
L.B. Lusted
.
Radiographic applications of receiver operating characteristic (R.O.C.) curves.
Radiology
,
89 -
95
-
13)
-
P.F. Sharp ,
J.R. Mallard
.
The performance of multielement band displays in radioisotope imaging.
Br. J. Radiol.
-
14)
-
W.K. Pratt
.
(1978)
, Digital image processing.
-
15)
-
J.L. Mannos ,
D.J. Sakrison
.
The effects of a visual fidelity criterion on the encoding of images.
IEEE Trans.
,
525 -
536
-
16)
-
P.F. Sharp ,
J.R. Mallard
.
The measurement of the performance of the display system of a radioisotope imaging device: the mutlielement band display.
Br. J. Radiol.
,
270 -
277
-
17)
-
J.A. Swets
.
(1964)
, Signal detection and recognition by human observers.
-
18)
-
A.S. Houston ,
P.F. Sharp ,
P.S. Tofts ,
B.L. Diffey
.
A multicentre comparison of computer assisted image processing and display methods in scintigraphy.
Phys. Med. & Biol.
,
547 -
558
-
19)
-
K.B. Herath ,
P.F. Sharp
.
Effects of “matched filter” smoothing as measured by receiver operating characteristic curve.
Phys. Med. & Biol.
,
442 -
446
http://iet.metastore.ingenta.com/content/journals/10.1049/ip-e.1980.0041
Related content
content/journals/10.1049/ip-e.1980.0041
pub_keyword,iet_inspecKeyword,pub_concept
6
6