Nj. Hangiandreou et al., Optimization of a contrast-detail-based method for electronic image display quality evaluation, J DIGIT IM, 12(2), 1999, pp. 60-67
The authors previously reported a general technique based on contrast-detai
l methods to provide an overall quantitative evaluation of electronic image
display quality. The figure-of-merit reflecting overall display quality is
called maximum threshold contrast or MTC. In this work we have optimized t
he MTC technique through improvements in both the test images and the figur
e-of-merit computation. The test images were altered to match the average l
uminance with that observed for clinical computed radiographic images. The
figure-of-merit calculation was altered to allow for contrast-detail data w
ith slopes not equal to -1. Preliminary experiments also were conducted to
demonstrate the response of the MTC measurements to increased noise in the
displayed image. MTC measurements were obtained from five observers using t
he improved test images displayed with maximum monitor luminance settings o
f 30-, 50-, and 70-ft-Lamberts. Similar measurements were obtained from two
observers using test images altered by the addition of a low level of imag
e noise. The noise-free MTC and MTC difference measurements exhibited stand
ard deviations of 0.77 and 1.55, respectively. This indicates good measurem
ent precision, comparable or superior to that observed using the earlier MT
C technique. No statistically significant image quality differences versus
maximum monitor luminance were seen. The noise-added MTC measurements were
greater than the noise-free values by an average of 4.08 pixel values, and
this difference was statistically significant. This response is qualitative
ly correct, and is judged to indicate good sensitivity of the MTC measureme
nt to increased noise levels. Copyright (C) 1999 by W.B. Saunders Company.