Spatial-Spectral Chromatic Coding of Interference Signatures in SAR Imagery: Signal Modeling and Physical-Visual Interpretation

Abstract: Synthetic Aperture Radar (SAR) images are conventionally visualized as grayscale amplitude representations, which often fail to explicitly reveal interference characteristics caused by external radio emitters and unfocused signals. This paper proposes a novel spatial-spectral chromatic coding method for visual analysis of interference patterns in single-look complex (SLC) SAR imagery. The method first generates a series of spatial-spectral images via spectral subband decomposition that preserve both spatial structures and spectral signatures. These images are subsequently chromatically coded into a color representation using RGB/HSV dual-space coding, using a set of specifically designed color palette. This method intrinsically encodes the spatial-spectral properties of interference into visually discernible patterns, enabling rapid visual interpretation without additional processing. To facilitate physical interpretation, mathematical models are established to theoretically analyze the physical mechanisms of responses to various interference types. Experiments using real datasets demonstrate that the method effectively highlights interference regions and unfocused echo or signal responses (e.g., blurring, ambiguities, and moving target effects), providing analysts with a practical tool for visual interpretation, quality assessment, and data diagnosis in SAR imagery.