Kundel H L, Weinstein S P, Conant E F, Toto L C, Nodine C F
Pendergrass Diagnostic Research Laboratory, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA.
Radiographics. 1999 Sep-Oct;19(5):1313-8. doi: 10.1148/radiographics.19.5.g99se191313.
The cathode ray tube of a workstation for use with digital mammograms was calibrated with a photometer to produce an input-output characteristic curve similar to the perceptually linear curve defined by a current display standard. Then, a test pattern consisting of bars of increasing intensity containing disks of decreasing contrast was used by an observer to estimate the minimal detectable contrast (MDC) at different levels of display luminance. The MDC was modeled by a parabola. The shape of the parabola was determined by the observer's perceptual responses, and the range was determined by the maximum and minimum pixel values of the breast parenchyma. As each mammogram was displayed, the contour of the breast was automatically found and pixels within the breast image were sampled to determine the pixel values that were used to compute the maximum and minimum pixel values. The parabola was integrated to determine the look-up table for the initial MDC-tempered display of the mammogram. Preliminary observer performance tests showed no significant differences in the accuracy and speed of three radiologists who read a set of mammograms when the MDC-tempered display was compared with the perceptually linear display.
用于数字乳房X光照片的工作站阴极射线管使用光度计进行校准，以生成与当前显示标准定义的感知线性曲线相似的输入-输出特性曲线。然后，观察者使用由强度递增的条带组成的测试图案，这些条带包含对比度递减的圆盘，以估计不同显示亮度水平下的最小可检测对比度（MDC）。MDC由一条抛物线建模。抛物线的形状由观察者的感知反应决定，范围由乳房实质的最大和最小像素值决定。在显示每幅乳房X光照片时，会自动找到乳房轮廓，并对乳房图像内的像素进行采样，以确定用于计算最大和最小像素值的像素值。对抛物线进行积分，以确定乳房X光照片初始MDC调节显示的查找表。初步的观察者性能测试表明，当将MDC调节显示与感知线性显示进行比较时，三位阅读一组乳房X光照片的放射科医生在准确性和速度上没有显著差异。
