Image Registration

Image registration (also called image co-registration or geometric alignment) transforms two or more images of the same scene into a shared coordinate framework so that corresponding ground features align spatially. Accurate registration is essential whenever images from different sensors, dates, or viewpoints must be compared, combined, or analyzed together. Registration methodsFeature-based methods identify matching keypoints (such as road intersections, building corners, or SIFT/SURF features) across images and compute a geometric transformation to align them. Area-based methods use cross-correlation to match image patches. Intensity-based methods optimize a similarity metric across the entire image. Modern approaches increasingly use deep learning for robust feature matching across images with large differences in appearance or resolution. ApplicationsImage registration is a prerequisite for multi-temporal change detectionChange DetectionChange detection uses geospatial data and imagery to track and analyze alterations in landscapes, infrastructure, or ... (ensuring pixels from different dates correspond to the same ground location), pan-sharpeningPan-sharpeningPan-sharpening is an image fusion technique that merges a high-resolution panchromatic band with lower-resolution mul... (aligning panchromatic and multispectral bands), data fusion (combining SARSARSynthetic Aperture Radar (SAR) is an active remote sensing technology that uses microwave radar pulses to create high... and optical imagery), and medical imaging. Sub-pixel registration accuracy is critical for detecting subtle changes in InSARInSARInterferometric Synthetic Aperture Radar (InSAR) is a technique that combines two or more SAR images to measure groun... and long-term time series analysisTime Series AnalysisTime series analysis in remote sensing involves analyzing sequences of satellite images acquired over time to detect .... Image registration is a foundational preprocessing step that underpins the reliability of virtually all multi-source and multi-temporal remote sensingRemote SensingRemote sensing is the science of collecting data about Earth's surface without direct physical contact, primarily usi... analyses. Without precise alignment, comparative analyses produce misleading results.