Spatial noise and threshold contrasts in LCD displays

Roehrig, Hans; Krupiński, Elizabeth A.; Chawla, Amarpreet S.; Fan, Jiahua; Gandhi, Kunal

doi:10.1117/12.480358

Cited by 13 publications

(7 citation statements)

References 9 publications

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“…15, 16 However, the SNR cannot be used on temporal subtraction images because there is no signal that is registered completely except for the true interval change. When there is no interval change between current and previous images, a temporal subtraction image registered completely shows a monotonous medium gray; in this case, darker or lighter areas on an image are caused by misregistration artifacts.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the Image Quality of Temporal Subtraction Images Produced Automatically in a PACS Environment

et al. 2006

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The aim of the study is to evaluate the reliable production of temporal subtraction images in a picture archiving and communication system environment and to establish objective criteria for the evaluation of image quality. A total of 117 temporal subtraction chest images (55 in the upright position, 62 in the supine position) were obtained in five consecutive days. In all of these, we confirmed that there were no interval changes on the original images, and cases with diffuse lung disease were excluded. The temporal subtraction images were classified by three chest radiologists into five levels: 5, excellent; 4, good; 3, acceptable; 2, poor; and 1, very poor. The following were examined: (1) the yield of adequate quality of the temporal subtraction images; (2) whether the temporal subtraction images were obtained in the warping or nonwarping mode; and (3) the correlation of the overall subjective image quality with the relative shift angles, relative shift distances, and the standard deviation of gray levels in the temporal subtraction images. The percentages of acceptable temporal subtraction images were 100% and 66% in the upright and supine positions, respectively. Sixteen (26%) of the 62 supine-position images were made in nonwarping mode, whereas all upright images were made in warping mode. Significant correlations were obtained in the relative shift angle (P G 0.05), relative horizontal shift distance (P G 0.05), and standard deviation of gray levels (P G 0.0001). Temporal subtraction images with acceptable image quality were obtained in the upright position. The objective criteria may be useful for the evaluation of image quality.

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Section: Discussionmentioning

confidence: 99%

Evaluation of the Image Quality of Temporal Subtraction Images Produced Automatically in a PACS Environment

et al. 2006

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“…As a result the light intensity fluctuates as a function of time. However, as is seen in [6], for LCDs, temporal noise is practically insignificant as compared to spatial noise. The focus of this paper is to study spatial noise of AMLCDs.…”

Section: Introductionmentioning

confidence: 88%

The effect of spatial noise of LCD displays on the detection capabilities of the human observer

et al. 2005

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This paper presents results of physical as well as psychophysical evaluations of an LCD with respect to its spatial noise. Spatial noise is quantified using a high-resolution CCD camera and a method is developed to compensate for it. This compensation method is based on a spatial noise map, derived from the CCD camera images, and on the application of an error diffusion algorithm. This method of noise compensation reduces the spatial noise by about a factor of 2. Psychophysical evaluation is performed in order to explore the dependence of human contrast sensitivity on display spatial noise. This evaluation uses the two-alternative forced choice (2-AFC) method. Aperiodic Gaussian-shaped objects, which simulate lung nodules, serve as stimuli. The detectability index, d', calculated indicates that spatial noise compensation leads to a lower contrast threshold.

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“…Also, DICOM standard which is based on the Barten's eye model does not take into account the variation of threshold contrasts of the human eye with added display noise. It has been pointed out earlier that LCDs and CRTs in addition to temporal noise are predominantly afflicted with spatial noise [6,16,23]. Also, the DICOM standard is based on variable adaptation of the human visual system.…”

Section: A Standard Based On Appearance Matching Among Various Dismentioning

confidence: 98%

Why should you calibrate your display?

et al. 2004

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This paper discusses the issue of calibration for the growing number of electronic displays used in the filmless and electronic radiology departments. It concentrates on CRT and LCD displays as these are the most matured electronic display systems available at this time. It is shown that grayscale calibration is necessary and useful to optimally display the information contained in the various digital images in diagnostic radiology. In addition properties and drawbacks of four prevalent standards for display function have been discussed.

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Spatial noise and threshold contrasts in LCD displays

Cited by 13 publications

References 9 publications

Evaluation of the Image Quality of Temporal Subtraction Images Produced Automatically in a PACS Environment

Evaluation of the Image Quality of Temporal Subtraction Images Produced Automatically in a PACS Environment

The effect of spatial noise of LCD displays on the detection capabilities of the human observer

Why should you calibrate your display?

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