Two-Layer Sparse Coding for Image Patch Encoding

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Solution Overview

Problem

Existing image classification methods ignore the spatial neighborhood structure of images, leading to suboptimal performance in encoding local patches independently.

Innovation Solution

A two-layer sparse coding model is introduced, where the first layer encodes individual patches and the second layer jointly encodes patches within the same image region, using two codebooks to model high-order dependencies and statistical dependencies among low-level code words.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If local patches are encoded independently using standard sparse coding, then the encoding process is computationally simple, but the spatial neighborhood structure of the image is ignored leading to suboptimal representation

Engineering Contradiction:
Improveencoding process complexityVSAvoidimage representation accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The image is divided into multiple local patches that are processed separately in the first layer, allowing independent encoding of each patch while maintaining computational efficiency. This segmentation enables the system to handle large images by breaking them into manageable units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a two-layer hierarchical encoding structure where the first layer encodes individual patches and the second layer encodes sets of patches within the same image region. This nested structure allows the system to capture both local patch features and broader spatial relationships, resolving the contradiction between simple encoding and accurate representation.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If a two-layer sparse coding model is used to jointly encode patches and model high-order dependencies, then more complex visual patterns are captured improving classification accuracy, but the computational complexity increases

Engineering Contradiction:
Improveclassification accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The first layer performs preliminary encoding of individual patches before the second layer processes sets of patches. This preliminary action simplifies the computational burden of the second layer by providing pre-processed features, allowing the system to capture complex visual patterns while managing computational complexity through staged processing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transitions from single-layer encoding to two-layer hierarchical encoding, adding a dimensional aspect to the processing architecture. This dimensional change enables the system to model high-order dependencies and spatial relationships that cannot be captured by single-layer methods, thereby improving classification accuracy.

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

3Manufacturing precision

If hand-crafted SIFT features are used with sparse coding, then state-of-the-art performance is achieved on image classification benchmarks, but the approach requires manual feature design rather than automatic learning

Engineering Contradiction:
Improveimage classification performanceVSAvoidfeature learning automation
Core Design Contradiction:
Manufacturing precisionVSExtent of automation

Solution Approach 1:

The system uses fully automatic methods to learn features from the pixel level without requiring manual feature design. The two-layer sparse coding model automatically discovers relevant features and dependencies through unsupervised learning, making the system self-sufficient and eliminating the need for hand-crafted SIFT features while maintaining competitive performance.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS8682086B2Systems and methods for determining image representations at a pixel level
Publication Date: 2014.03.25 NEC CORP
  • US8682086B2 patent drawing
  • US8682086B2 patent drawing
  • US8682086B2 patent drawing

AI summary

Systems and methods process an image having a plurality of pixels includes an image sensor to capture an image; a first-layer to encode local patches on an image region; and a second layer to jointly encode patches from the same image region.