Distributed Image Search via Tree-Based Clustering

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Solution Overview

Problem

Current image search technologies rely heavily on text-based annotations and struggle with efficiently performing nearest-neighbor searches in multi-dimensional feature spaces for image-based queries, leading to suboptimal results and resource inefficiencies.

Innovation Solution

A distributed image retrieval system using a tree-based representation of an image corpus, where images are clustered and mapped to a hash space, enabling a two-stage nearest-neighbor search across multiple leaf servers, allowing for efficient load balancing and flexible clustering assignments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a distributed image retrieval system using tree-based representation and hash space mapping is implemented, then search efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvesearch efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The image corpus is divided into multiple image clusters, each stored on a separate leaf server. The tree-based representation hierarchically organizes these clusters, allowing the system to process queries by traversing only relevant portions of the corpus rather than searching the entire dataset, thereby improving search efficiency while distributing computational load across multiple servers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A root server acts as an intermediary between clients and leaf servers. It receives query images, performs initial processing, determines which image clusters are relevant, and forwards queries to the appropriate leaf servers. This intermediary layer simplifies the overall system architecture by centralizing coordination functions while allowing leaf servers to focus on specialized cluster management and hash-based nearest-neighbor searches.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If images are clustered and mapped to hash space across multiple leaf servers, then load balancing is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improveload balancingVSAvoidsearch accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system transforms image data from the original multi-dimensional feature space into a hash space representation. This parameter transformation allows for efficient nearest-neighbor searches using hash code comparison while maintaining the ability to preserve spatial relationships and similarity metrics, thus balancing computational efficiency with search accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Image clusters are pre-processed and organized into tree-based representations before query execution. The hashing and clustering operations are performed in advance, creating an optimized data structure that enables rapid query processing while maintaining accurate nearest-neighbor relationships. This preliminary organization allows leaf servers to efficiently handle queries without sacrificing search precision.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If nearest-neighbor search is performed in multi-dimensional feature space, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improvesearch accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts and utilizes only the most relevant portions of the image corpus for each query by traversing the tree-based representation. Instead of performing exhaustive nearest-neighbor searches across the entire multi-dimensional feature space, the system identifies and searches only the specific image clusters that are likely to contain relevant results, significantly reducing computation time while maintaining search accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system maps images from multi-dimensional feature space into a hash space representation. This dimensional transformation enables efficient nearest-neighbor searches by converting complex multi-dimensional distance calculations into simpler hash code comparisons, thereby reducing computation time while preserving the ability to accurately measure image similarity.

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

Data Source

PatentUS10013438B2Distributed image search
Publication Date: 2018.07.03 GOOGLE LLC
  • US10013438B2 patent drawing
  • US10013438B2 patent drawing
  • US10013438B2 patent drawing

AI summary

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for distributed nearest-neighbor search for image retrieval are disclosed. An example distributed image retrieval system includes a root server and a plurality of leaf servers. The root server controls the clustering of images in the image corpus, and determines the assignment of image clusters to a collection of leaf servers. Each leaf server is independently configured to perform a two-stage nearest-neighbor search in a locality-sensitive hash space for a received query image within the leaf server's assigned images clusters. Thus, the distributed image retrieval system is modular and amendable to tuning, modifications, duplication, and replacement on a per-server basis. In addition, the design of the image retrieval system allows flexible load balancing among the leaf servers.