Designing interpolation kernels for SAR data resampling

Abstract

It is fairly common in radar signal processing that sampled data is not sampled precisely at the desired positions within a function. Resampling the data to more advantageous sample locations entails interpolation of the data. The radar engineer often picks a resampling or an interpolation technique that "is handy", or "seems to work", without any analytical justification for his choice. However, understanding the science and mathematics that underpin interpolation can avoid unexpected and undesirable side effects from a suboptimal choice. This paper details interpolation kernel characteristics, allowing intelligent choices for algorithm design, tailored for radar signal processing applications.

Wide-area, persistent SAR imaging: Algorithm tradeoffs

“…We as sume that the number of real-valued operations required to compute each output sample is 175, based on four instances of multiplication and three instances of addition per com plex-valued filter tap and an assumed 25 filter taps [22]. Al ternatively, the spotlighting may be implemented recursive ly, as shown in Figure 6, to lower the computational cost to (7) where log 2 Nd is the number of spotlighting stages.…”

GMTI processing using back projection.

“…There is definitely a science to it, meaning that interpolation algorithm details need to be chosen with purpose, else undesired artifacts in the image are likely. A thorough discussion of interpolation is beyond the scope of this report, but good insight can be had in a paper by Doerry, et al 5…”

Enhanced Feature Extraction for Ship Detection from Multi-Resolution and Multi-Scene Synthetic Aperture Radar (SAR) Images

“…In order to enhance the details of small targets, a standard method is to interpolate and zoom the small targets [32]. However, the interpolation of a SAR image will damage the original features of the SAR image and destroy the ground resolution [33,34]. Aiming at the small SAR targets detection in complex backgrounds, we propose a new convolution block, namely the split convolution block (SCB).…”