Satellite Image Shadow Removal via Building Data
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Solution Overview
Problem
Aerial or satellite photographs often include shadows from buildings, which reduce visibility and hinder navigation, as existing technologies have not effectively addressed the removal of these shadows to improve image clarity and route guidance.
Innovation Solution
A method and apparatus that collect photographing information, extract building data, estimate shadow areas based on time and building height, and restore images by adjusting brightness and contrast or substituting with un-shaded images from different photographs, ultimately composing a shadow-free image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aerial or satellite photographs are used for navigation display, then route guidance functionality is provided, but shadow areas from buildings reduce image visibility and hinder route identification
Solution Approach 1:
The patent converts the harmful shadow areas into beneficial information by using building location data to identify shadow regions, then restores these areas using image processing techniques. The shadow problem is transformed into an opportunity to enhance image quality through targeted restoration of identified shadow regions.
Solution Approach 2:
The patent introduces building information data as an intermediary element that bridges the gap between the raw aerial photograph and the final navigable image. This intermediary data enables the system to identify shadow regions and apply appropriate restoration techniques, improving overall image visibility for navigation.
2Illumination intensity
If shadow removal processing is applied to aerial photographs, then image visibility is improved, but processing complexity and computational resources increase
Solution Approach 1:
The patent segments the image processing task into distinct stages: shadow area identification using building data, shadow area estimation, and selective image restoration. This segmentation allows the system to apply complex processing only to specific shadow regions rather than the entire image, reducing overall computational complexity.
Solution Approach 2:
The patent performs preliminary actions by first identifying building locations and estimating shadow areas before applying image restoration. This preliminary analysis enables targeted processing, where restoration algorithms are applied only to predicted shadow regions, significantly reducing the computational burden compared to processing the entire image.
3Manufacturing precision
If shadow areas are estimated and restored, then shadow-free images are produced, but processing time and computational resources are consumed
Solution Approach 1:
The patent applies partial action by restoring only the shadow areas rather than processing the entire image. The system estimates shadow regions based on building data and applies restoration algorithms selectively to these specific areas, achieving high image quality improvement while minimizing processing time and resource consumption.
Data Source
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AI summary
A method for removing a shadow from an aerial or satellite photograph, includes collecting aerial or satellite photographs, by the photographing information collecting unit; extracting buildings at each of the collected aerial or satellite photographs, by the building information extracting unit; and estimating a shadow area cast by the extracted buildings, by the shadow area estimating unit. Further, the method includes restoring a shaded image in the aerial or satellite photograph, which corresponds to the estimated shadow area, by the image restoration unit; and composing the restored image and a residual image of the aerial or satellite photograph except the shadow area, by the image composition unit.