Dr. Yani Zhang Profile

Dr. Yani Zhang

Researcher at Univ of California Santa Barbara

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Publications (7)

Proceedings Article | 17 March 2006 Paper

Observer performance detecting signals in globally non-stationary oriented noise

Yani Zhang, Craig Abbey, Miguel Eckstein

Proceedings Volume 6146, 61460Z (2006) https://doi.org/10.1117/12.655749

KEYWORDS: Signal detection, Performance modeling, Image filtering, Interference (communication), Statistical modeling, Eye models, Electronic filtering, Visual process modeling, Information operations, Medical imaging

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Proceedings Article | 17 March 2006 Paper

The efficiency of reading around learned backgrounds

Miguel Eckstein, Binh Pham, Craig Abbey, Yani Zhang

Proceedings Volume 6146, 61460N (2006) https://doi.org/10.1117/12.655750

KEYWORDS: Signal to noise ratio, Interference (communication), Medical imaging, Performance modeling, Image quality, Image processing, Image filtering, Optical filters, Signal processing, Data modeling

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Most metrics of medical image quality typically treat all variability components of the background as a Gaussian noise process. This includes task based model observers (non-prewhitening matched filter without and with an eye filter, NPW and NPWE; Hotelling and Channelized Hotelling) as well as Fourier metrics of medical image quality based on the noise power spectra. However, many investigators have observed that unlike many of the models/metrics, physicians often can discount signal-looking structures that are part of the normal anatomic background. This process has been referred to as reading around the background or noise. The purpose of this paper is to develop an experimental framework to systematically study the ability of human observers to read around learned backgrounds and compare their ability to that of an optimal ideal observer which has knowledge of the background. We measured human localization performance of one of twelve targets in the presence of a fixed background consisting of randomly placed Gaussians with random contrasts and sizes, and white noise. Performance was compared to a condition in which the test images contained only white noise but with higher contrast. Human performance was compared to standard model observers that treat the background as a Gaussian noise process (NPW, NPWE and Hotelling), a Fourier-based prewhitening matched filter, and an ideal observer. The Hotelling, NPW, NPWE models as well as the Fourier-based prewhitening matched filter predicted higher performance for the white noise test images than the background plus white noise. In contrast, ideal and human performance was higher for the background plus white noise condition. Furthermore, human performance exceeded that of the NPW, NPWE and Hotelling models and reached an efficiency of 19% relative to the ideal observer. Our results demonstrate that for some types of images human signal localization performance is consistent with use of knowledge about the high order moments of the backgrounds to discount signal-looking structures that belong to the background. In such scenarios model observers and metrics that either ignore the background or treat the background as a Gaussian process (Hotelling, Channelized Hotelling, Task-based SNR) under predict human performance.

Proceedings Article | 6 April 2005 Paper

Evaluation of internal noise methods for Hotelling observers

Yani Zhang, Binh Pham, Miguel Eckstein

Proceedings Volume 5749, (2005) https://doi.org/10.1117/12.595861

KEYWORDS: Performance modeling, Signal detection, Arteries, Interference (communication), Computer simulations, Visual process modeling, Angiography, Image compression, Chromium, X-rays

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Proceedings Article | 4 May 2004 Paper

The effect of non-linear human visual system components on linear model observers

Yani Zhang, Binh Pham, Miguel Eckstein

Proceedings Volume 5372, (2004) https://doi.org/10.1117/12.534357

KEYWORDS: Visual process modeling, Performance modeling, Signal detection, Medical imaging, Image processing, Visualization, Image quality, Image compression, Arteries, Eye models

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Proceedings Article | 4 May 2004 Paper

Metrics of medical image quality: task-based model observers vs. image discrimination/perceptual difference models

Miguel Eckstein, Yani Zhang, Binh Pham

Proceedings Volume 5372, (2004) https://doi.org/10.1117/12.536270

KEYWORDS: Computer programming, Image compression, Performance modeling, Image quality, Signal detection, Medical imaging, Visual process modeling, Eye models, Optimization (mathematics), Statistical modeling

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Proceedings Article | 22 May 2003 Paper

Investigation of JPEG 2000 encoder options on model observer performance in signal known exactly but variable tasks (SKEV)

Yani Zhang, Binh Pham, Miguel Eckstein

Proceedings Volume 5034, (2003) https://doi.org/10.1117/12.480078

KEYWORDS: Image compression, Computer programming, Performance modeling, Arteries, Image quality, Angiography, Discrete wavelet transforms, Medical imaging, Image quality standards, X-rays

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Proceedings Article | 22 May 2003 Paper

Optimization of model observer performance for signal known exactly but variable tasks leads to optimized performance in signal known statistically tasks

Miguel Eckstein, Yani Zhang, Binh Pham, Craig Abbey

Proceedings Volume 5034, (2003) https://doi.org/10.1117/12.480344

KEYWORDS: Performance modeling, Computer programming, Optimization (mathematics), Image compression, Eye models, Statistical modeling, Signal detection, Eye, Angiography, Data modeling

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Showing 5 of 7 publications

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