Seamless Image Mosaic Generation via Graph-Cut Seam Lines
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Solution Overview
Problem
Existing 2-dimensional image processing techniques face distortions and artifacts when projecting multiple images into a single coordinate system, particularly in generating seamless mosaics from oblique images, leading to misalignment and boundary distortions.
Innovation Solution
The method involves segmenting pairs of intersecting images using graph algorithms to generate seam lines, allowing for parallel processing and composition of mosaic tiles, and employing an alpha-expansion algorithm to fill 'holes' and create a seamless mosaic by assigning unassigned nodes to images, while constraining the algorithm to maintain previous assignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple images are projected into a single coordinate system using traditional image processing techniques, then the images can be combined to form a mosaic, but distortions and artifacts occur at boundaries between images due to different points of view
Solution Approach 1:
The patent segments the image mosaic generation process into independent tile-level operations. Each tile is processed separately using graph-cut algorithms to determine optimal seam lines between intersecting images. This segmentation allows parallel processing of multiple tiles while maintaining precise boundary alignment through local optimization at each tile boundary, resolving the contradiction between processing efficiency and boundary precision.
2Manufacturing precision
If traditional sequential image processing methods are used to generate seamless mosaics, then boundary alignment can be optimized, but processing time increases significantly
Solution Approach 1:
The patent divides the large-scale mosaic generation into independent tile segments that can be processed in parallel. Each tile undergoes graph-cut optimization for seamless boundaries independently, then results are composed together. This segmentation enables concurrent processing while maintaining optimal boundary alignment through localized graph-cut algorithms, resolving the time-precision tradeoff.
Solution Approach 2:
The patent transitions from sequential single-image processing to parallel multi-tile processing by adding the tile dimension. Multiple tiles are processed simultaneously in different computational threads or processes, each performing graph-cut optimization locally. This dimensional change from 1D sequential to 2D parallel processing dramatically reduces total processing time while maintaining boundary quality through independent optimization at each tile.
3Productivity
If images are processed independently without considering overlapping regions, then processing speed increases, but misalignment and distortion artifacts appear at intersecting boundaries
Solution Approach 1:
The patent segments images into overlapping tiles and processes each tile independently using graph-cut algorithms that consider all intersecting images within that tile's boundary. The segmentation includes intentional overlap regions that are processed locally with proper weighting, ensuring continuity at boundaries while allowing parallel processing of distinct tiles, thus maintaining both speed and reliability.
Solution Approach 2:
The patent applies local quality optimization by performing graph-cut seam line detection independently at each tile boundary based on local image characteristics. Each overlapping region is analyzed with its own cost function considering local gradients, colors, and textures. This localized processing ensures boundary continuity through context-appropriate seam placement while maintaining parallel processing efficiency across different tiles.
Data Source
AI summary
Many computing services incorporate large mosaics of geo-located images. For example, a user may access and interact with a digital image map comprising thousands of digital images mosaiced together. It may be advantageous to parallelize mosaic creation by splitting the mosaic into tiles, and processing the tiles independently from one another. Unfortunately, visual artifacts between image boundaries may result because of the independent processing. Accordingly, one or more systems and/or techniques for generating a substantially seamless mosaic tile are disclosed herein. A mosaic tile comprising one or more intersecting images may be received. Pair-wise image segmentation may be executed upon pairs of intersecting images within the mosaic tile to generate seam lines between the pair of intersecting images. The seam lines are used to compose the mosaic tile. A constrained alpha-expansion algorithm is executed upon hole regions within the composed mosaic to generate a substantially seamless mosaic.