Sweep detection and alignment in handheld GPR detection devices

Handheld ground penetrating radar (GPR) devices, such as the AN/PSS-14, produce image data for a detection sequence. Sequences contain sweeps of left to right and right to left swings of the device. By smoothing the image scan and examining local minima, we can determine the sweep ranges and turn around points contained within the data. Different filters are used to determine the interval between sweeps and approximate the exact turn around point for each sweep. Images are then annotated with the start and end of sweep locations. Results presented are both qualitative, based on comparison to labeling by humans, and quantitative, based on robot- collected data. Dynamic Time Warping (DTW) helps us align overlapping regions of a left to right sweep with its corresponding right to left sweep.