Hierarchical Graph Image Matting for Multiple Foreground Objects

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Solution Overview

Problem

Conventional unsupervised image matting techniques are computationally intensive, result in degraded image quality, and produce inconsistent results, especially in cluttered scenes, and are limited to binary partitioning, making them impractical for images with multiple foreground objects.

Innovation Solution

A hierarchical graph model is used to perform image matting, which gradually condenses image data from pixels to cells, then to components, and finally to matting layers, incorporating multi-scale affinity learning and a foreground probability distribution model to estimate alpha matte values and identify foreground regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If conventional unsupervised matting techniques are used, then automatic alpha matte estimation is achieved, but computational complexity increases significantly

Engineering Contradiction:
Improveautomatic alpha matte estimationVSAvoidcomputational complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent segments the image processing task into multiple hierarchical levels: first dividing the image into superpixels, then grouping superpixels into matting cells, and finally organizing cells into matting components. This multi-level segmentation reduces the computational burden by processing smaller units independently before combining results, thereby achieving automatic alpha matte estimation with reduced computational complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to the traditional flat image processing approach. By organizing image elements into multiple levels of abstraction (pixels → superpixels → cells → components), the method adds a structural dimension that enables more efficient computation while maintaining automation for alpha matte estimation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Extent of automation

If conventional unsupervised matting techniques are used, then automatic alpha matte estimation is achieved, but image quality degrades

Engineering Contradiction:
Improveautomatic alpha matte estimationVSAvoidimage quality
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The hierarchical segmentation preserves image quality by maintaining fine-grained superpixels at lower levels while enabling global consistency at higher levels. Each level of segmentation retains important local details, preventing the quality degradation that occurs in conventional single-level approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces matting cells as intermediary structures between superpixels and matting components. These cells serve as mediators that aggregate local superpixel information while preserving global image structure, thereby maintaining image quality throughout the automated matting process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional unsupervised matting techniques are used, then processing speed may be improved, but result consistency deteriorates in cluttered scenes

Engineering Contradiction:
Improveprocessing speedVSAvoidresult consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The hierarchical segmentation into multiple levels enables parallel processing at each level, improving processing speed. Simultaneously, the progressive refinement from superpixels to cells to components ensures that global consistency is maintained even in cluttered scenes, as each level builds upon and constrains the previous level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By adding the hierarchical dimension, the method enables both fast local processing at lower levels and global consistency enforcement at higher levels. This dimensional expansion allows the system to achieve both improved processing speed and enhanced result consistency simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Device complexity

If binary partitioning is used, then computational simplicity is maintained, but ability to handle multiple foreground objects is lost

Engineering Contradiction:
Improvecomputational simplicityVSAvoidhandling multiple foreground objects
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The hierarchical segmentation naturally supports multiple foreground objects by creating separate matting components at higher levels. Each component can represent a distinct foreground object or region, allowing the method to handle multiple objects while maintaining computational efficiency through the structured hierarchy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hierarchical dimension transforms the simple binary partitioning into a multi-layered structure where different levels can represent different semantic meanings. This enables the system to handle multiple foreground objects by organizing them into distinct components in the hierarchy, thereby improving adaptability while maintaining computational simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9449395B2Methods and systems for image matting and foreground estimation based on hierarchical graphs
Publication Date: 2016.09.20 WINBOND ELECTRONICS CORP
  • US9449395B2 patent drawing
  • US9449395B2 patent drawing
  • US9449395B2 patent drawing

AI summary

In accordance with an embodiment, a method for image matting based on a hierarchical graph model, comprises receiving an input image including a plurality of image elements; generating a plurality of matting cells based on the input image, each cell including a group of image elements; calculating affinity values for the plurality of matting cells based on the input image; forming a graph based on the plurality of matting cells and the affinity values, the graph including a plurality of nodes representing the matting cells and a plurality of edges associated with the affinity values of the matting cells; and generating a plurality of matting components for the input image based on the graph.