Temporal Properties of Liquid Crystal Displays: Implications for Vision Science Experiments

Elze, Tobias; Tanner, Thomas

doi:10.1371/journal.pone.0044048

Cited by 50 publications

(73 citation statements)

References 39 publications

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“…Certain LCD models perform comparably to CRTs on various aspects of timing. There are also certain characteristics, which are preferable using one type of monitor or the other (Elze & Tanner, 2012;Wang & Nikolić, 2011). In this study, a CRT was selected because of the historical timing challenges with LCD displays.…”

Section: Discussionmentioning

confidence: 99%

Testing the accuracy of timing reports in visual timing tasks with a consumer-grade digital camera

2016

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This study tested the accuracy of a visual timing task using a readily available and relatively inexpensive consumer grade digital camera. A visual inspection time task was recorded using short high-speed video clips and the timing as reported by the task's program was compared to the timing as recorded in the video clips. Discrepancies in these two timing reports were investigated further and based on display refresh rate, a decision was made whether the discrepancy was large enough to affect the results as reported by the task. In this particular study, the errors in timing were not large enough to impact the results of the study. The procedure presented in this article offers an alternative method for performing a timing test, which uses readily available hardware and can be used to test the timing in any software program on any operating system and display.

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Section: Discussionmentioning

confidence: 99%

Testing the accuracy of timing reports in visual timing tasks with a consumer-grade digital camera

2016

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“…Despite their advantages, however, computer monitors also have a number of limitations that must be taken into account before they can be used in psychological and neuroscientific experiments (Bauer, 2015;Elze & Tanner, 2012;Klein, Zlatkova, Lauritzen, & Pierscionek, 2013;Metha, Vingrys, & Badcock, 1993). Doing so is complicated by the fact that the specific stimulus (Goris, Wagemans, & Wichmann, 2008), the stimulus presentation software, the specific monitor technology (Foerster, Poth, Behler, Botsch, & Schneider, 2016;Poth, Foerster, Behler, Schneider, & Botsch, under review) and even the individual monitor (e.g.…”

Section: Introductionmentioning

confidence: 99%

Assessing the monitor warm-up time required before a psychological experiment can begin

Poth¹,

Horstmann²

2017

TQMP

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Visual experiments in psychology, psychophysics, and cognitive neuroscience require precise control over stimulus characteristics, such as luminance and contrast. In such experiments, stimuli are most often presented using computer monitors. These monitors bear an often neglected and rarely reported source of experimental confounds and uncontrolled variation: they take a warm-up time in which their luminance systematically changes until a stable level is eventually reached. Here we demonstrate this problem by measuring luminance over time for five different monitors. Results indicate that not only the warm-up time but also the course that the warm-up takes can vary greatly between different monitors. To address this problem, we propose a simple method of approximating a monitor's warm-up time, which takes into account theoretical considerations of the specific experiment. On this basis, we suggest a standardized experimental procedure and a standardized way of reporting its results to enable experimenters to control for monitor warm-up time.

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“…The dominant medical display technology, liquid crystal displays (LCDs), have been assessed for medical applications [1][2][3] and medical research, [4][5][6][7] and their temporal properties have been criticized. In particular, the duration and variability of luminance transition times (response times) of LCD monitors might impair stack-mode reading of computed tomography image datasets, i.e., the rapid serial presentations of medical images used by radiologists to detect subtle visual differences.…”

Section: Introductionmentioning

confidence: 99%

“…1,2 Moreover, long response times in combination with the sample and hold nature of LCDs causes visible motion blur. [7][8][9][10] Organic light-emitting diode (OLED) monitors are currently niche products on the medical display market, but are expected to become more popular due to their promising temporal properties. While dynamical presentations on LCD devices are realized by the time-consuming reorientation of liquid crystal molecules in response to changing an electrical voltage (LC reorientation), OLED monitors control luminance changes by separately controllable light-emitting diodes for each pixel and are therefore supposed to be substantially faster than even the fastest LCDs.…”

Section: Introductionmentioning

confidence: 99%

“…While dynamical presentations on LCD devices are realized by the time-consuming reorientation of liquid crystal molecules in response to changing an electrical voltage (LC reorientation), OLED monitors control luminance changes by separately controllable light-emitting diodes for each pixel and are therefore supposed to be substantially faster than even the fastest LCDs. In addition, while luminance transition times on LCD monitors from frame i with luminace l i to frame i + 1 with luminace l i+1 may considerably vary depending on the specific choices for l i and l i+1 due to LC reorientation, 1,7 on OLED devices, transition times are supposed to be independent of the luminance in the previous frame.…”

Section: Introductionmentioning

confidence: 99%

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An evaluation of organic light emitting diode monitors for medical applications: Great timing, but luminance artifacts

2013

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Purpose: In contrast to the dominant medical liquid crystal display (LCD) technology, organic light-emitting diode (OLED) monitors control the display luminance via separate light-emitting diodes for each pixel and are therefore supposed to overcome many previously documented temporal artifacts of medical LCDs. We assessed the temporal and luminance characteristics of the only currently available OLED monitor designed for use in the medical treatment field (SONY PVM2551MD) and checked the authors' main findings with another SONY OLED device (PVM2541). Methods: Temporal properties of the photometric output were measured with an optical transient recorder. Luminances of the three color primaries and white for all 256 digital driving levels (DDLs) were measured with a spectroradiometer. Between the luminances of neighboring DDLs, just noticeable differences were calculated according to a perceptual model developed for medical displays. Luminances of full screen (FS) stimuli were compared to luminances of smaller stimuli with identical DDLs. Results: All measured luminance transition times were below 300 μs. Luminances were independent of the luminance in the preceding frame. However, for the single color primaries, up to 50.5% of the luminances of neighboring DDLs were not perceptually distinguishable. If two color primaries were active simultaneously, between 36.7% and 55.1% of neighboring luminances for increasing DDLs of the third primary were even decreasing. Moreover, luminance saturation effects were observed when too many pixels were active simultaneously. This effect was strongest for white; a small white patch was close to 400 cd/m 2 , but in FS the luminance of white saturated at 162 cd/m 2 . Due to different saturation levels, the luminance of FS green and FS yellow could exceed the luminance of FS white for identical DDLs. Conclusions: The OLED temporal characteristics are excellent and superior to those of LCDs. However, the OLEDs revealed severe perceptually relevant artifacts with implications for applicability to medical imaging.

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Temporal Properties of Liquid Crystal Displays: Implications for Vision Science Experiments

Cited by 50 publications

References 39 publications

Testing the accuracy of timing reports in visual timing tasks with a consumer-grade digital camera

Testing the accuracy of timing reports in visual timing tasks with a consumer-grade digital camera

Assessing the monitor warm-up time required before a psychological experiment can begin

An evaluation of organic light emitting diode monitors for medical applications: Great timing, but luminance artifacts

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