# Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery

## Abstract

Median filtering reduces speckle in synthetic aperture radar (SAR) imagery while preserving edges, at the expense of coarsening the resolution, by replacing the center pixel of a sliding window by the median value. For shadow detection, this approach helps distinguish shadows from clutter more easily, while preserving shadow shape delineations. However, the nonlinear operation alters the shadow and clutter distributions and statistics, which must be taken into consideration when computing probability of detection and false alarm metrics. Depending on system parameters, median filtering can improve probability of detection and false alarm by orders of magnitude. Herein, we examine shadow probability of detection and false alarm in a homogeneous, ideal clutter background after median filter post-processing. Some comments on multi-look processing effects with and without median filtering are also made.

- Authors:

- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). ISR Analysis and Applications Dept.
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). ISR Mission Engineering Dept.
- General Atomics Aeronautical Systems, Inc., San Diego, CA (United States). Mission Systems

- Publication Date:

- Research Org.:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); General Atomics Aeronautical Systems, Inc., San Diego, CA (United States)

- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA); General Atomics Aeronautical Systems, Inc. (GA-ASI) (United States)

- OSTI Identifier:
- 1323596

- Report Number(s):
- SAND2014-4877

521035

- DOE Contract Number:
- AC04-94AL85000

- Resource Type:
- Technical Report

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 47 OTHER INSTRUMENTATION

### Citation Formats

```
Raynal, Ann Marie, Doerry, Armin Walter, Miller, John A., Bishop, Edward E., and Horndt, Volker.
```*Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery*. United States: N. p., 2014.
Web. doi:10.2172/1323596.

```
Raynal, Ann Marie, Doerry, Armin Walter, Miller, John A., Bishop, Edward E., & Horndt, Volker.
```*Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery*. United States. doi:10.2172/1323596.

```
Raynal, Ann Marie, Doerry, Armin Walter, Miller, John A., Bishop, Edward E., and Horndt, Volker. Sun .
"Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery". United States.
doi:10.2172/1323596. https://www.osti.gov/servlets/purl/1323596.
```

```
@article{osti_1323596,
```

title = {Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery},

author = {Raynal, Ann Marie and Doerry, Armin Walter and Miller, John A. and Bishop, Edward E. and Horndt, Volker},

abstractNote = {Median filtering reduces speckle in synthetic aperture radar (SAR) imagery while preserving edges, at the expense of coarsening the resolution, by replacing the center pixel of a sliding window by the median value. For shadow detection, this approach helps distinguish shadows from clutter more easily, while preserving shadow shape delineations. However, the nonlinear operation alters the shadow and clutter distributions and statistics, which must be taken into consideration when computing probability of detection and false alarm metrics. Depending on system parameters, median filtering can improve probability of detection and false alarm by orders of magnitude. Herein, we examine shadow probability of detection and false alarm in a homogeneous, ideal clutter background after median filter post-processing. Some comments on multi-look processing effects with and without median filtering are also made.},

doi = {10.2172/1323596},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Sun Jun 01 00:00:00 EDT 2014},

month = {Sun Jun 01 00:00:00 EDT 2014}

}