Quantized Scale-Invariant Feature Embeddings for Mobile Image Retrieval

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Solution Overview

Problem

Augmented reality applications on mobile devices face challenges in efficiently transmitting and processing scale-invariant image features due to limited resources, with existing methods being cumbersome for evolving databases and requiring high bit rates.

Innovation Solution

The method involves extracting scale-invariant features from images, performing random projections, and quantizing them to reduce dimensionality, allowing for efficient transmission and search in a low-dimensional subspace, balancing the number of projections and quantization levels to achieve accurate image retrieval with minimal bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If SIFT features are used for image matching, then matching accuracy is improved, but transmission bandwidth requirement increases prohibitively

Engineering Contradiction:
Improveimage matching accuracyVSAvoidtransmission bandwidth
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential components needed for matching by projecting SIFT features onto a lower-dimensional subspace using random projections. This extracts the core matching information while discarding redundant data, achieving accurate matching with significantly reduced bandwidth transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms high-dimensional SIFT feature vectors into low-dimensional representations through random projections onto a subspace. This dimensionality reduction maintains the essential matching characteristics while dramatically reducing the bandwidth required for transmission from the mobile device to the server.

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

2Measurement precision

If training-based methods are used for compressing image descriptors, then compression accuracy is improved, but system complexity and retraining requirements increase for evolving databases

Engineering Contradiction:
Improvedescriptor compression accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs random projections that do not require training or adaptation to the database content. The method is self-service in the sense that it works universally without needing to learn from or adapt to the specific characteristics of the database, eliminating retraining requirements when the database evolves.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the approach from learning-based parameter optimization to fixed random projection parameters. By using predetermined random projection matrices instead of trained descriptors, the system achieves compression without the complexity of training mechanisms while maintaining effectiveness.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8891878B2Method for representing images using quantized embeddings of scale-invariant image features
Publication Date: 2014.11.18 MITSUBISHI ELECTRIC RESEARCH LABORATORIES INC
  • US8891878B2 patent drawing
  • US8891878B2 patent drawing
  • US8891878B2 patent drawing

AI summary

Scale-invariant features are extracted from an image. The features are projected to a lower dimensional random projection matrix by multiplying the features by a matrix of random entries. The matrix of random projections is quantized to produce a matrix of quantization indices, which form a query vector for searching a database of images to retrieve metadata related to the image.