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Detection of low contrast test patterns on an LCD with different luminance and illuminance settings

Författare och institution:
Patrik Sund (Institutionen för kliniska vetenskaper, sektionen för onkologi, radiofysik, radiologi och urologi, Avdelningen för radiofysik); Magnus Båth (Institutionen för kliniska vetenskaper, sektionen för onkologi, radiofysik, radiologi och urologi, Avdelningen för radiofysik); Lars Gunnar Månsson (Institutionen för kliniska vetenskaper, sektionen för onkologi, radiofysik, radiologi och urologi, Avdelningen för radiofysik)
Publicerad i:
Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 6917 s. 69170N
ISSN:
1605-7422
Publikationstyp:
Artikel, övrig vetenskaplig
Publiceringsår:
2008
Språk:
engelska
Fulltextlänk:
Sammanfattning (abstract):
The DICOM part 14 grayscale standard display function provides one way of harmonizing image appearance under different monitor luminance settings. This function is based on ideal observer conditions where the eye is always adapted to the target luminance and thereby also at peak contrast sensitivity. Clinical workstations are however often exposed to variations in ambient light due to a sub-optimal reading room light environment. Also, clinical images are inhomogeneous and low-contrast patterns must be detected even at luminance levels that differ from the eye adaptation level. All deviations from ideal luminance conditions cause the observer to detect patterns with reduced eye sensitivity but the magnitude of this reduction is unclear. The purpose of this paper was to quantify the effect different luminance settings have on the contrast threshold. A method to display well-defined sinusoidal low-contrast test patterns on an LCD has previously been developed and was used in this study. The observers were exposed to light from three different areas: 1) A small sinusoidal test pattern. 2) The remaining of the display surface. 3) Ambient light from outside the display area covering most of the observer's field of view. By adjusting the luminance from each of these three areas, two major effects could be quantified. The first effect was similar to Barten's f-factor where the target luminance differs from the observer's adaptation level while the second effect concerned the influence of areas outside the display surface. When a luminance range of 1-350 cd/m2 was used, the contrast needed to detect a dark object in a gray surrounding was almost doubled compared to a dark object in a dark surrounding. Ambient light from outside the display area has a moderate effect on the contrast threshold, except for the combination of high ambient light and dark objects where the contrast threshold increased considerably.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
TEKNIK OCH TEKNOLOGIER ->
Medicinteknik ->
Medicinsk bildbehandling
MEDICIN OCH HÄLSOVETENSKAP ->
Klinisk medicin ->
Radiologi och bildbehandling ->
Radiofysik
MEDICIN OCH HÄLSOVETENSKAP ->
Medicinsk bioteknologi ->
Biomedicinsk laboratorievetenskap/teknologi ->
Medicinsk teknik
Nyckelord:
Image Display , Image perception , LCD , Low-contrast detection
Postens nummer:
235485
Posten skapad:
2016-04-28 16:47

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