Human observer detection experiments with mammograms and power-law noise
Human observer detection experiments with mammograms and power-law noise
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DOI：
10.1118/1.1355308
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发表时间：
2001-04-01
期刊：
影响因子：
3.8
通讯作者：
Judy, PF
中科院分区：
文献类型：
--
作者：
Burgess, AE;Jacobson, FL;Judy, PF
我们将病变检测的对比度阈值确定为乳房 X 光照片中病变大小的函数，并使用相同的平均功率谱 P(f) = Blf(3) 过滤噪声背景。实验使用混合图像进行，其中将肿瘤的数字图像添加到数字化的正常背景中，并显示在单色监视器上。从数字化标本射线照片中提取了四个肿瘤。通过数字重新缩放来改变病变大小，以覆盖 0.5 至 16 毫米的范围。改变幅度以确定两种选择强制选择 (2AFC) 中 92% 正确检测所需的值和搜索实验中 90% 正确检测所需的值。三名观察员参加了，两名物理学家和一名放射科医生。 2AFC 乳房 X 光检查结果展示了一种新颖的对比细节 (CD) 图，对于大于 1 毫米的病变，其阈值振幅随着尺寸的增加而稳定增加（斜率为 0.3）。预白化模型观察者的斜率约为 0.4。相对于这些模型，人类的效率高达 90%。过滤噪声的 2AFC 实验的 CD 图斜率对于人类为 0.44，对于模型为 0.5。相对于理想观察者而言，人类的效率约为 40%。两种背景的效率差异表明，对于 2AFC 实验，乳房结构不能被视为纯随机噪声。相反，具有乳腺 X 线摄影背景的 2AFC 人体检测受到噪声和确定性掩蔽效应的限制。搜索实验还给出了随着病变大小而增加的阈值。然而，乳房X线照相和过滤噪声背景的人类结果没有差异，这表明乳房结构可以被认为是这项任务的纯随机噪声。我们的结论是，尽管乳腺X线摄影背景具有非平稳统计数据，但基于统计决策理论的模型仍然可以成功地应用于估计人类表现。 (C) 2001 年美国医学物理学家协会。
We determined contrast thresholds for lesion detection as a function of lesion size in both mammograms and filtered noise backgrounds with the same average power spectrum, P(f) = Blf(3). Experiments were done using hybrid images with digital images of tumors added to digitized normal backgrounds, displayed on a monochrome monitor. Four tumors were extracted from digitized specimen radiographs. The lesion sizes were varied by digital rescaling to cover the range from 0.5 to 16 mm. Amplitudes were varied to determine the value required for 92% correct detection in two-alternative forced-choice (2AFC) and 90% for search experiments. Three observers participated, two physicists and a radiologist. The 2AFC mammographic results demonstrated a novel contrast-detail (CD) diagram with threshold amplitudes that increased steadily (with slope of 0.3) with increasing size for lesions larger than 1 mm. The slopes for prewhitening model observers were about 0.4. Human efficiency relative to these models was as high as 90%. The CD diagram slopes for the 2AFC experiments with filtered noise were 0.44 for humans and 0.5 for models. Human efficiency relative to the ideal observer was about 40%. The difference in efficiencies for the two types of backgrounds indicates that breast structure cannot be considered to be pure random noise for 2AFC experiments. Instead, 2AFC human detection with mammographic backgrounds is limited by a combination of noise and deterministic masking effects. The search experiments also gave thresholds that increased with lesion size. However, there was no difference in human results for mammographic and filtered noise backgrounds, suggesting that breast structure can be considered to be pure random noise for this task. Our conclusion is that, in spite of the fact that mammographic backgrounds have nonstationary statistics, models based on statistical decision theory can still be applied successfully to estimate human performance. (C) 2001 American Association of Physicists in Medicine.