Zhang Yani, Pham Binh, Eckstein Miguel P
Department of Psychology, University of California, Santa Barbara, CA 93106, USA.
IEEE Trans Med Imaging. 2004 May;23(5):613-32. doi: 10.1109/tmi.2004.826359.
Previous studies have evaluated the effect of the new still image compression standard JPEG 2000 using nontask based image quality metrics, i.e., peak-signal-to-noise-ratio (PSNR) for nonmedical images. In this paper, the effect of JPEG 2000 encoder options was investigated using the performance of human and model observers (nonprewhitening matched filter with an eye filter, square-window Hotelling, Laguerre-Gauss Hotelling and channelized Hotelling model observer) for clinically relevant visual tasks. Two tasks were investigated: the signal known exactly but variable task (SKEV) and the signal known statistically task (SKS). Test images consisted of real X-ray coronary angiograms with simulated filling defects (signals) inserted in one of the four simulated arteries. The signals varied in size and shape. Experimental results indicated that the dependence of task performance on the JPEG 2000 encoder options was similar for all model and human observers. Model observer performance in the more tractable and computationally economic SKEV task can be used to reliably estimate performance in the complex but clinically more realistic SKS task. JPEG 2000 encoder settings different from the default ones resulted in greatly improved model and human observer performance in the studied clinically relevant visual tasks using real angiography backgrounds.
先前的研究使用基于非任务的图像质量指标，即针对非医学图像的峰值信噪比（PSNR），评估了新的静止图像压缩标准JPEG 2000的效果。在本文中，针对临床相关视觉任务，利用人类和模型观察者（带眼滤波器的非白化匹配滤波器、方形窗口霍特林、拉盖尔 - 高斯霍特林和通道化霍特林模型观察者）的性能，研究了JPEG 2000编码器选项的效果。研究了两项任务：确切已知但可变信号任务（SKEV）和统计已知信号任务（SKS）。测试图像由真实的X射线冠状动脉血管造影组成，在四条模拟动脉之一中插入了模拟充盈缺损（信号）。信号的大小和形状各不相同。实验结果表明，对于所有模型和人类观察者而言，任务性能对JPEG 2000编码器选项的依赖性相似。在更易于处理且计算成本较低的SKEV任务中，模型观察者的性能可用于可靠地估计复杂但临床上更现实的SKS任务中的性能。与默认设置不同的JPEG 2000编码器设置，在使用真实血管造影背景的所研究临床相关视觉任务中，极大地提高了模型和人类观察者的性能。
