Radiometric Normalization for Geospatial Image Mosaics
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Solution Overview
Problem
Geospatial imagery mosaics with different spatial resolutions exhibit radiometric inconsistencies when zooming or panning, leading to discontinuous color changes and aesthetically unpleasant user experiences.
Innovation Solution
A method for radiometric normalization of mosaic image layers with different spatial resolutions, involving the calculation of image metadata, determination of a normalization function, and application of this function to normalize the layers, ensuring consistent radiometric characteristics across zoom levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple mosaic image layers with different spatial resolutions are used for zooming, then data management efficiency is improved, but radiometric inconsistencies and discontinuous color changes occur
Solution Approach 1:
The patent applies radiometric normalization processing to mosaic image layers before they are stored and used for zooming operations. By pre-calculating and applying normalization functions to align radiometric characteristics across different spatial resolutions, the system eliminates discontinuous color changes that would otherwise occur during zooming, while maintaining efficient data management through the use of multiple resolution layers
2Quantity of substance
If lower resolution images are used for higher zoom levels, then memory usage is reduced, but radiometric discontinuities become apparent
Solution Approach 1:
The patent applies different spatial resolutions to different zoom levels while maintaining radiometric consistency through normalization. Each zoom level uses appropriately optimized resolution (lower resolution for higher zoom levels to reduce memory usage) but radiometric normalization ensures that the color and brightness characteristics remain consistent across all resolutions, preventing radiometric discontinuities from becoming apparent
3Area of stationary object
If multiple geospatial images are pieced together to form an orthomosaic, then coverage of larger geographic areas is achieved, but discontinuous color changes occur due to radiometric distortion
Solution Approach 1:
The patent applies radiometric normalization processing that transforms the radiometric parameters (brightness, contrast, color balance) of individual geospatial images to match a reference standard. This parameter adjustment eliminates radiometric distortion between adjacent images, ensuring continuous and uniform color appearance across the entire orthomosaic while maintaining comprehensive geographic coverage
Data Source
AI summary
Generation of a plurality of orthomosaic image layers for a geographical area, wherein the layers comprise different spatial resolutions and are radiometrically normalized to facilitate improved radiometric consistency when zooming relative to the geographic area. In applications that facilitate zooming with respect to a geographic area imaged by the orthomosaic layers, radiometric normalization of the orthomosaic image layers may reduce radiometric discontinuities when zooming in, zooming out, and/or panning a displayed portion that is output to the user. The orthomosaic layers may be generated based on one or more orthomosaic image layer or may be developed independently using a source images. In any regard, the radiometric normalization may include generating a normalization function based on image metadata that is calculated and may be independent of the spatial resolution of the image.