Impact of luminance distribution in the visual field on foveal contrast sensitivity in the context of mammographic softcopy reading
Impact of luminance distribution in the visual field on foveal contrast sensitivity in the context of mammographic softcopy reading
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乳腺X光软拷贝阅读中视野亮度分布对中心凹对比敏感度的影响
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
H. Peitgen
中科院分区：
文献类型：
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作者：
D. Apelt;R. Rascher;J. Klein;H. Strasburger;B. Preim;H. Peitgen
对于乳房X光摄影软拷贝阅读(SCR)中的质量控制，存在一些建议。其中一个房间的照度为10lx。此外，在图像上使用面具似乎是有利的，因为减少了视野焦点中的散射光。房间照度影响全局亮度自适应和最大监视器对比度；遮罩会降低中央和周边区域的亮度。我们研究了掩蔽和照度对中心凹对比敏感度的影响。一项有8名观察员参加的研究是在乳房X光照相软拷贝阅读的背景下进行的。使用不同空间频率、方位和对比度水平的Gabor图案作为刺激和方位辨别任务，确定了中心凹视觉的观察者内部对比敏感度。非遮罩图像的测试照度为10、30、50和90 lx，遮罩图像的测试照度为10 lx。主要发现：(1)掩蔽并不能提高对比敏感度。取而代之的是，所有的观察者都报告了在展示蒙面图像期间的强烈疲劳效应。(2)在所测试的照度中，只有一半的观察者在10lx时表现出最佳的对比敏感度。对于其他观察者，在照度水平分别为50或90 lx时获得最佳结果。该结果可用于评价观察条件的影响，目的是为乳房摄影SCR得出结论，并启动进一步的研究。
For quality control in mammographic softcopy reading (SCR) a number of recommendations exists. Among them is a room illuminance of 10 lx. Moreover, the use of masks on the image seems to be advantageous, due to a reduction of scattered light in the focus of view. Room illuminance affects the global luminance adaptation and the maximal monitor contrast; masking decreases the luminance in the central and near-peripheral region. We investigated the effects of masking and illuminance on foveal contrast sensitivity. A study with eight observers was conducted in the context of mammographic softcopy reading. Using Gabor patterns with varying spatial frequencies, orientations and contrast levels as stimuli and an orientation discrimination task, the intraobserver contrast sensitivity was determined for foveal vision. Tested illuminances for a non-masked image were 10, 30, 50 and 90 lx, and for a masked image 10 lx. Major findings are: (1) Masking does not lead to improved contrast sensitivity. Instead, all observers reported a strong fatigue effect during the presentation of the masked image. (2) Among the illuminances tested, only half of the observers showed the best contrast sensitivity at 10 lx. For the other observers best results were achieved at illuminance levels of 50 or 90 lx, respectively. The results can be used to appraise the effects of viewing conditions with the aim of drawing conclusions for mammographic SCR, and to initiate further studies.