Oblique Mosaic Image Generation Using Virtual Camera Reprojection
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Solution Overview
Problem
Current methods for creating composite images from oblique aerial views fail to produce visually pleasing and geographically accurate mosaics due to issues with building lean, elevation differences, and non-square pixels, which are exacerbated by the oblique perspective, making it difficult to align pixels to a rectilinear grid without distorting the natural appearance of the images.
Innovation Solution
A method involving the creation of a virtual camera with an oblique-mosaic pixel map, where source oblique images are reprojected to match the natural perspective and size of the virtual camera's view, accounting for elevation and minimizing building lean by using a mathematical model that includes ground elevation and vertical structures, allowing for the combination of oblique images into a composite image that maintains their natural appearance and geographic accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ortho-rectification methods are used to align pixels to a rectilinear grid, then geographic accuracy is improved, but the natural appearance of oblique images is distorted
Solution Approach 1:
Instead of forcing oblique image pixels to conform to a rectilinear grid (traditional approach), the patent inverts the approach by creating a virtual camera model that naturally captures the oblique perspective and allowing the rectilinear grid to adapt to this perspective. This preserves the natural appearance of buildings and structures while maintaining geographic accuracy through the mathematical model.
Solution Approach 2:
The patent changes the fundamental parameters of the imaging model by introducing a virtual camera with specific oblique viewing angles and elevation parameters. This allows the system to work with non-square pixels and non-rectilinear projections, transforming the problem from one of distortion correction to one of natural perspective representation.
2Area of stationary object
If multiple oblique images are combined into a mosaic, then coverage area is improved, but alignment accuracy deteriorates due to building lean and elevation differences
Solution Approach 1:
The patent introduces a virtual camera mathematical model as an intermediary between multiple source oblique images. This virtual camera serves as a common reference framework that accounts for building lean and elevation differences, allowing accurate alignment and merging of multiple images into a seamless mosaic while preserving the natural oblique appearance.
3Ease of operation
If pixels are reprojected to a rectilinear grid, then ease of navigation is improved, but visual pleasing appearance is lost
Solution Approach 1:
The patent moves the problem from two-dimensional rectilinear grid alignment to three-dimensional virtual camera space. By working in this additional dimension, the system can preserve the natural oblique perspective and building appearances while still providing navigational capabilities through the mathematical model of the virtual camera position and orientation.
Data Source
AI summary
Systems and methods for creating oblique-mosaic image(s) for geographical area(s) are disclosed, including a computer system running software that when executed causes the system to create a mathematical model of a sensor of a virtual camera having an elevation greater than an elevation of a desired geographical area to be imaged, the mathematical model having an oblique-mosaic pixel map; determine surface locations for pixels included in the oblique-mosaic pixel map; select source oblique images of the surface locations of the pixels captured at an oblique angle and compass direction similar to an oblique angle and compass direction of the virtual camera; and reproject source oblique image pixels for pixels included in the oblique-mosaic pixel map such that reprojected pixels have differing sizes determined by matching projections from the virtual camera so as to present an oblique appearance, and thereby create the oblique-mosaic image of the desired geographical area.