3D Object Localization using Forward Looking Sonar (FLS) and Optical Camera via particle filter based calibration and fusion

Underwater Object Localization is widely used in the industry in Autonomous Underwater Vehicles (AUV), both in sea and lake environments for various applications. Sonars and Cameras are popular choices for this, but each sensor alone poses several problems. Data extraction from Optical Cameras underwater is a challenge due to poor lighting conditions, hazing over large distances and spatio-temporal irradiate (flickering), while Sonars tend to have coarser sensor resolution and a lower signal-to-noise ratio (SNR) making it difficult to extract data. This makes false positives more likely. In this paper, we present a robust method to localize objects in front of an AUV in 3D space, using camera imagery, sonar imagery and odometry information from onboard sensors. This is done through various image processing techniques, and a hybrid sonar/camera particle filter based calibration step and fusion step.