Variable-Length Deep Hashing for Image Retrieval

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Solution Overview

Problem

Existing image retrieval methods face challenges in optimizing feature expression during hash learning, relying on manual feature design and fixed-length hashing codes, which limits adaptability to different tasks and increases computational and storage waste.

Innovation Solution

An image retrieval method based on variable-length deep hashing learning using a convolutional neural network to directly extract hashing codes, maximizing the margin between matched and unmatched image pairs in Hamming space, allowing for dynamic code length adjustment by weighting each bit's significance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual feature descriptors are used for image hashing learning, then domain knowledge can be incorporated, but the method cannot adapt to different application tasks and requires significant manual design effort

Engineering Contradiction:
Improveadaptability to different application tasksVSAvoidmanual feature design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs self-service by automatically learning image features through the convolutional neural network without requiring manual feature design. The CNN automatically extracts relevant features from images and learns optimal hashing functions, eliminating the need for domain expertise in feature engineering while adapting to different application tasks through data-driven learning

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical process of feature design and selection is replaced by an automated neural network system. The CNN automatically performs feature extraction and hashing function learning through iterative optimization, substituting the manual expert-driven approach with an automated learning system that adapts to different tasks

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If fixed-length hashing codes are used, then storage and retrieval are simplified, but computational and storage resources are wasted when longer codes are stored for all tasks

Engineering Contradiction:
Improvestorage space efficiencyVSAvoidflexibility in code length selection
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The hashing code system transitions from a static fixed-length design to a dynamic variable-length design. The system can adaptively select different code lengths based on retrieval precision requirements, allowing shorter codes for resource-constrained applications and longer codes for high-precision tasks, thereby optimizing both storage efficiency and adaptability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The code length parameter is made changeable rather than fixed. The system learns multiple hashing functions that can generate codes of different lengths, allowing the parameter to be adjusted according to specific application requirements, thus achieving both storage efficiency and task flexibility

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If variable-length hashing learning algorithms generate codes bit by bit according to importance, then code length can be selected flexibly, but retrieval accuracy drops sharply with decreased hashing code bits

Engineering Contradiction:
Improvecode length selection flexibilityVSAvoidretrieval accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by learning multiple hashing functions of different lengths in advance during training. Instead of generating codes bit by bit during retrieval, the system pre-learns optimal hashing functions for various code lengths, so that when retrieval is needed, the appropriate pre-learned function can be selected to maintain high accuracy across different code lengths

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If deep neural networks are used for end-to-end hashing learning, then feature extraction and hashing can be optimized jointly, but the optimization process becomes very complex and limited in practical applications

Engineering Contradiction:
Improvefeature expression optimizationVSAvoidoptimization process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The complex end-to-end optimization problem is segmented into multiple independent hashing functions of different lengths. Instead of optimizing one complex function, the system learns several simpler hashing functions that can be selected based on requirements, reducing the complexity of each individual optimization task while maintaining overall feature expression quality

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10776685B2Image retrieval method based on variable-length deep hash learning
Publication Date: 2020.09.15 SUN YAT SEN UNIV
  • US10776685B2 patent drawing
  • US10776685B2 patent drawing
  • US10776685B2 patent drawing

AI summary

This invention is an image retrieval method based on bit-scalable deep hashing learning. According to the method, the training images is used to generate a batch of image triples, wherein each of the triples contains two images with the same label and one image with a different label. The purpose of model training is to maximize a margin between matched image pairs and unmatched image pairs in the Hamming space. The deep convolutional neural network is utilized to train the model in an end-to-end fasion, where discriminative images features and has functions are simultaneously optimized. Furthermore, each bit of the hashing codes is unequally weighted so that we can manipulate the code length by truncating the insignificant bits. It is also shown that the generated bit-scalable hashing codes well preserve the discriminative powers with sorter code lengths.