Amjad Khan, Syed Saad Azhar Ali, Atif Anwer, Syed Hasan Adil, Fabrice Mériaudeau
IEEE Access, vol. 6, pp. 40585-40601, 2018.
Publication year: 2018
Subsea pipeline corrosion is considered as a severe problem in offshore oil and gas industry. It directly affects the integrity of the pipeline which further leads to cracks and leakages. At present, subsea visual inspection and monitoring is performed by trained human divers; however, offshore infrastructures are moving from shallow to deep waters due to exhaustion of fossil fuels. Therefore, inhospitable underwater environmental conditions for human diver demand imaging-based robotic solution as an alternate for visual inspection and monitoring of subsea pipelines. However, an unfriendly medium is a challenge for underwater imaging-based inspection and monitoring activities due to absorption and scattering of light that further leads to blur, color attenuation, and low contrast. This paper presents a new method for subsea pipeline corrosion estimation by using color information of corroded pipe.
Underwater surveying and mapping using rotational potential fields for multiple autonomous vehicles
David McIntyre ; Wasif Naeem ; Syed Saad Azhar Ali ; Atif Anwer
IEEE 6th International Conference on Underwater System Technology: Theory and Applications (USYS2016). 13-14 December
Publication year: 2016
his paper presents a new technique for exploration and mapping/surveying of underwater infrastructure and/or objects of interest, using multiple autonomous underwater vehicles (AUVs). The proposed method employs rotational potential fields, and extends them for use on multiple vehicles within a three dimensional environment. An inter-vehicle fluid formation is maintained throughout, free of angular constraints (or the need of a virtual vehicle). When an object of interest is approached, the formation is split and follows a smooth trajectory around opposite sides of its boundary. To fully utilise the potential of rotational fields, a unique local 2D-plane is created around every object within the 3D environment, which is employed for boundary coverage. Traditional artificial potential fields are used to guide vehicles towards each object in turn (and maintain the fluid formation), while rotational fields are employed within the local 2D-plane providing a smooth trajectory around opposing sides of every object. Simulation results show the method to be effective, providing a more stable trajectory. Comparison with the standard technique shows that the formation is maintained throughout and overall journey time is significantly reduced using this method.
Control of autonomous underwater vehicle based on visual feedback for pipeline inspection
Amjad Khan ; Syed Saad Azhar Ali ; Aamir Saeed Malik ; Atif Anwer ; Nur Afande Ali Hussain ; Fabrice Meriaudeau
Robotics and Manufacturing Automation (ROMA), 2016 2nd IEEE International Symposium on
Publication year: 2016
For everyday inspection jobs in offshore oil and gas industry, the human divers are being replaced by underwater vehicles. This paper proposes a visual feedback based control of an autonomous underwater vehicle for pipeline inspection. The hydrodynamic disturbances in water severely affect the movement of the vehicle resulting in performance degrading. The heading of the autonomous underwater vehicle under such disturbances is controlled using visual feedback to track the pipeline for inspection. The proposed method does not demand expensive position feedback devices such as underwater acoustic positioning system. By using built-in camera of the vehicle and few image processing techniques a simpler, easier and low-cost solution is proposed. The performance evaluation of the proposed technique on sample underwater images is also presented.
Underwater image enhancement by wavelet based fusion
Amjad Khan ; Syed Saad Azhar Ali ; Aamir Saeed Malik ; Atif Anwer ; Fabrice Meriaudeau
Underwater System Technology: Theory and Applications (USYS), IEEE International Conference on
Publication year: 2016
The image captured in water is hazy due to the several effects of the underwater medium. These effects are governed by the suspended particles that lead to absorption and scattering of light during image formation process. The underwater medium is not friendly for imaging data and brings low contrast and fade color issues. Therefore, during any image based exploration and inspection activity, it is essential to enhance the imaging data before going for further processing. This paper presents a wavelet-based fusion method to enhance the hazy underwater images by addressing the low contrast and color alteration issues. The publicly available hazy underwater images are enhanced and analyzed qualitatively with some state of the art methods. The quantitative study of image quality depicts promising results.