Target detection threshold in noisy color imagery

2001 ◽  
Author(s):  
Ronald G. Driggers ◽  
Keith A. Krapels ◽  
Richard H. Vollmerhausen ◽  
Penny R. Warren ◽  
Dean A. Scribner ◽  
...  
Keyword(s):  
Target Detection ◽  
Detection Threshold ◽  
Color Imagery

scholarly journals Offshore Platform Extraction Using RadarSat-2 SAR Imagery: A Two-Parameter CFAR Method Based on Maximum Entropy

Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 556 ◽  
Author(s):  
Qi Wang ◽  
Jing Zhang ◽  
Fenzhen Su
Keyword(s):  
False Alarm ◽  
Maximum Entropy ◽  
Target Detection ◽  
Detection Threshold ◽  
River Estuary ◽  
Offshore Platform ◽  
Accuracy Evaluation ◽  
Oil And Gas Development ◽  
Offshore Oil ◽  
Two Parameter

The ability to determine the number and location of offshore platforms is of great significance for offshore oil spill monitoring and offshore oil and gas development. Considering the problem that the detection threshold parameters of the two-parameter constant false alarm rate (CFAR) algorithm require manual and repeated adjustment of the during the extraction of offshore platform targets, this paper proposes a two-parameter CFAR target detection method based on maximum entropy based on information entropy theory. First, a series of threshold parameters are obtained using the two-parameter CFAR algorithm for target detection. Then, according to the maximum entropy principle, the optimal threshold is estimated to obtain the target detection results of the possible offshore platform. Finally, the neighborhood analysis method is used to eliminate false alarm targets such as ships, and the final target of the offshore platform is obtained. In this study, we conducted offshore platform extraction experiments and an accuracy evaluation using data from the Pearl River Estuary Basin of the South China Sea. The results show that the proposed method for platform extraction achieves an accuracy rate of 97.5% and obtains the ideal offshore platform distribution information. Thus, the proposed method can objectively obtain the optimal target detection threshold parameters, greatly reduce the influence of subjective parameter setting on the extraction results during the target detection process and effectively extract offshore platform targets.

scholarly journals Target Detection in High-Resolution SAR Image via Iterating Outliers and Recursing Saliency Depth

2021 ◽  
Vol 13 (21) ◽  
pp. 4315
Author(s):  
Zongyong Cui ◽  
Yi Qin ◽  
Yating Zhong ◽  
Zongjie Cao ◽  
Haiyi Yang
Keyword(s):  
High Resolution ◽  
False Alarm ◽  
Target Detection ◽  
Detection Threshold ◽  
Graph Model ◽  
Conditional Entropy ◽  
Image Features ◽  
Feature Model ◽  
Sar Image ◽  
Constant False Alarm Rate

In dealing with the problem of target detection in high-resolution Synthetic Aperture Radar (SAR) images, segmenting before detecting is the most commonly used approach. After the image is segmented by the superpixel method, the segmented area is usually a mixture of target and background, but the existing regional feature model does not take this into account, and cannot accurately reflect the features of the SAR image. Therefore, we propose a target detection method based on iterative outliers and recursive saliency depth. At first, we use the conditional entropy to model the features of the superpixel region, which is more in line with the actual SAR image features. Then, through iterative anomaly detection, we achieve effective background selection and detection threshold design. After that, recursing saliency depth is used to enhance the effective outliers and suppress the background false alarm to realize the correction of superpixel saliency value. Finally, the local graph model is used to optimize the detection results. Compared with Constant False Alarm Rate (CFAR) and Weighted Information Entropy (WIE) methods, the results show that our method has better performance and is more in line with the actual situation.

Anisotropy in Oriented-Line-Target Detection at High and Low Luminance Contrast

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 38-38 ◽  
Author(s):  
L M Doherty ◽  
D H Foster
Keyword(s):  
Target Detection ◽  
Line Segment ◽  
Visual Angle ◽  
Detection Threshold ◽  
Luminance Contrast ◽  
High Luminance ◽  
Line Segments ◽  
Low Luminance ◽  
Line Target ◽  
Oriented Line

Observers can detect a uniquely oriented line segment (‘target’) in a background field of uniformly oriented line segments (‘nontargets’) even if viewing time is brief. When the lines have high luminance contrast, the variation of orientation increment threshold with nontarget orientation is periodic, generally with a period of about 90° although smaller periods have been found. Do the orientation-sensitive mechanisms giving rise to periodicities function only at high contrast? This question was addressed in a line-target detection experiment. Twenty white line segments of length 1 deg visual angle were presented in a circular field of diameter 20 deg visual angle. Nontarget orientations were in the range 0°, 5°, …, 175°, and the difference between nontarget and target orientations was varied adaptively. Stimulus displays lasting 40 ms were followed by a blank interstimulus interval lasting 60 ms and then a random-line mask. A view-tunnel provided a grey background of luminance 35 cd m−2 and stimulus contrast was 0.1, 0.3, 0.5, 0.7, or 0.9 log unit above the observer's luminance detection threshold for one line segment. When contrast was 0.1 log unit above this threshold, performance was near chance level. As contrast increased from 0.3 to 0.9 log unit above luminance detection threshold, performance improved and orientation increment thresholds decreased, showing that early orientation-processing is most effective at high luminance contrast. Nonetheless, periodicities were found in all conditions where performance was better than chance which suggests that the orientation-sensitive mechanisms associated with periodicities operate at both high and low luminance contrast.

Target detection in color imagery: on the path to a color target acquisition model

2004 ◽  
Author(s):  
Keith A. Krapels ◽  
Tarik Jones ◽  
Ronald G. Driggers ◽  
Brian Teaney
Keyword(s):  
Target Detection ◽  
Target Acquisition ◽  
Color Target ◽  
Color Imagery

Selective Attention and Error Processing in an Illusory Conjunction Task

2005 ◽  
Vol 19 (3) ◽  
pp. 216-231 ◽  
Author(s):  
Albertus A. Wijers ◽  
Maarten A.S. Boksem
Keyword(s):  
Target Detection ◽  
Event Related Potentials ◽  
Illusory Conjunction ◽  
Conjunction Error ◽  
Error Related Negativity ◽  
Display Element ◽  
Related Potentials ◽  
Feature Error ◽  
High Level ◽  
Correct Target

Abstract. We recorded event-related potentials in an illusory conjunction task, in which subjects were cued on each trial to search for a particular colored letter in a subsequently presented test array, consisting of three different letters in three different colors. In a proportion of trials the target letter was present and in other trials none of the relevant features were present. In still other trials one of the features (color or letter identity) were present or both features were present but not combined in the same display element. When relevant features were present this resulted in an early posterior selection negativity (SN) and a frontal selection positivity (FSP). When a target was presented, this resulted in a FSP that was enhanced after 250 ms as compared to when both relevant features were present but not combined in the same display element. This suggests that this effect reflects an extra process of attending to both features bound to the same object. There were no differences between the ERPs in feature error and conjunction error trials, contrary to the idea that these two types of errors are due to different (perceptual and attentional) mechanisms. The P300 in conjunction error trials was much reduced relative to the P300 in correct target detection trials. A similar, error-related negativity-like component was visible in the response-locked averages in correct target detection trials, in feature error trials, and in conjunction error trials. Dipole modeling of this component resulted in a source in a deep medial-frontal location. These results suggested that this type of task induces a high level of response conflict, in which decision-related processes may play a major role.

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