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PTZ Camera-Based Displacement Sensor System with Perspective Distortion Correction Unit for Early Detection of Building Destruction

View Article: PubMed Central - PubMed

ABSTRACT

This paper presents a pan-tilt-zoom (PTZ) camera-based displacement measurement system, specially based on the perspective distortion correction technique for the early detection of building destruction. The proposed PTZ-based vision system rotates the camera to monitor the specific targets from various distances and controls the zoom level of the lens for a constant field of view (FOV). The proposed approach adopts perspective distortion correction to expand the measurable range in monitoring the displacement of the target structure. The implemented system successfully obtains the displacement information in structures, which is not easily accessible on the remote site. We manually measured the displacement acquired from markers which is attached on a sample of structures covering a wide geographic region. Our approach using a PTZ-based camera reduces the perspective distortion, so that the improved system could overcome limitations of previous works related to displacement measurement. Evaluation results show that a PTZ-based displacement sensor system with the proposed distortion correction unit is possibly a cost effective and easy-to-install solution for commercialization.

No MeSH data available.


Experimental setup.
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sensors-17-00430-f012: Experimental setup.

Mentions: The test environment setup is described in Figure 12. The nine markers are distributed on the several structures, which are at various distance. The PTZ-camera rotates its angle, sequentially captures the markers and transmits the projected image via a wireless channel. A Hanwha Techwin PTZ camera (model SNP-6321H) was used to capture marker images, for which our proposed software performs the image processing algorithm in the host side, which is implemented using C/C++ programming language. The SNP-6321H model has a CMOS-type sensor, with a maximum resolution of 1920 × 1080 pixels and a video transmission rate of 30 frames per second (FPS), and the focal length of the optical lens varies in the range of 4.44~142.6 mm with 32× optical zoom and automatic focus. The angle of view (AOV) is 62.8 (Wide)~2.23 (Tele) in the horizontal direction and 36.8 (Wide)~1.26 (Tele) in the vertical direction. The camera SNP-6321H is installed on a tripod to monitor three buildings with nine markers. The PTZ camera sequentially obtains the images by rotating its angle and zooming, with the PTZ coordinates in preset data, to monitor the other markers; it then wirelessly transfers the data to the host computer.


PTZ Camera-Based Displacement Sensor System with Perspective Distortion Correction Unit for Early Detection of Building Destruction
Experimental setup.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5375716&req=5

sensors-17-00430-f012: Experimental setup.
Mentions: The test environment setup is described in Figure 12. The nine markers are distributed on the several structures, which are at various distance. The PTZ-camera rotates its angle, sequentially captures the markers and transmits the projected image via a wireless channel. A Hanwha Techwin PTZ camera (model SNP-6321H) was used to capture marker images, for which our proposed software performs the image processing algorithm in the host side, which is implemented using C/C++ programming language. The SNP-6321H model has a CMOS-type sensor, with a maximum resolution of 1920 × 1080 pixels and a video transmission rate of 30 frames per second (FPS), and the focal length of the optical lens varies in the range of 4.44~142.6 mm with 32× optical zoom and automatic focus. The angle of view (AOV) is 62.8 (Wide)~2.23 (Tele) in the horizontal direction and 36.8 (Wide)~1.26 (Tele) in the vertical direction. The camera SNP-6321H is installed on a tripod to monitor three buildings with nine markers. The PTZ camera sequentially obtains the images by rotating its angle and zooming, with the PTZ coordinates in preset data, to monitor the other markers; it then wirelessly transfers the data to the host computer.

View Article: PubMed Central - PubMed

ABSTRACT

This paper presents a pan-tilt-zoom (PTZ) camera-based displacement measurement system, specially based on the perspective distortion correction technique for the early detection of building destruction. The proposed PTZ-based vision system rotates the camera to monitor the specific targets from various distances and controls the zoom level of the lens for a constant field of view (FOV). The proposed approach adopts perspective distortion correction to expand the measurable range in monitoring the displacement of the target structure. The implemented system successfully obtains the displacement information in structures, which is not easily accessible on the remote site. We manually measured the displacement acquired from markers which is attached on a sample of structures covering a wide geographic region. Our approach using a PTZ-based camera reduces the perspective distortion, so that the improved system could overcome limitations of previous works related to displacement measurement. Evaluation results show that a PTZ-based displacement sensor system with the proposed distortion correction unit is possibly a cost effective and easy-to-install solution for commercialization.

No MeSH data available.