Pooling Layer Parameter Minimization in CNN Feature Learning

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Solution Overview

Problem

Existing image feature extraction methods using deep learning face challenges in optimizing the pooling layer parameters, leading to poor performance due to undiscriminating image regions and excessive parameter numbers.

Innovation Solution

An image feature learning device and method that incorporates a convolutional neural network with a fully convolutional layer, a weighting matrix estimation layer, and a pooling layer to learn feature vectors based on training data, minimizing the number of parameters and enhancing robustness by estimating weightings for each element of the feature tensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fully connected layer is used as a pooling layer in CNN, then the flexibility of parameter adjustment is improved, but the number of parameters becomes enormous and optimization becomes difficult

Engineering Contradiction:
Improveflexibility of parameter adjustmentVSAvoidnumber of parameters
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the pooling layer into multiple independent pooling units, where each unit processes a specific region of the feature map. This segmentation reduces the overall parameter count while maintaining adaptability, as each pooling unit has its own learnable parameters that can be independently optimized.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by allowing different pooling operations with distinct parameters to be applied to different spatial regions of the feature map. This enables the network to adapt to local variations in the data while keeping the total number of parameters manageable through regional specialization.

Inventive Principle:
Principle #3Local quality

2Productivity

If traditional pooling operations are used, then the computational efficiency is improved, but the performance is adversely affected by undiscriminating image regions

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidperformance robustness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces dynamic pooling by making pooling parameters learnable through backpropagation, allowing the pooling operation to adapt dynamically to the input data characteristics. This dynamic adjustment enables the network to handle undiscriminating regions effectively while maintaining computational efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the pooling parameters from fixed values to learnable parameters that can be optimized during training. This parameter change allows the pooling layer to adapt to different image regions and conditions, improving robustness without sacrificing computational efficiency.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11748619B2Image feature learning device, image feature learning method, image feature extraction device, image feature extraction method, and program
Publication Date: 2023.09.05 NIPPON TELEGRAPH & TELEPHONE CORP
  • US11748619B2 patent drawing
  • US11748619B2 patent drawing
  • US11748619B2 patent drawing

AI summary

The purpose of the present invention is to enable learning of a neural network for extracting features of images having high robustness from an undiscriminating image region while minimizing the number of parameters of a pooling layer. A parameter learning unit 130 learns parameters of each layer in a convolutional neural network configured by including a fully convolutional layer for performing convolution of an input image to output a feature tensor of the input image, a weighting matrix estimation layer for estimating a weighting matrix indicating a weighting of each element of the feature tensor, and a pooling layer for extracting a feature vector of the input image based on the feature tensor and the weighting matrix. The parameter learning unit 130 learns the parameters such that a loss function value obtained by calculating a loss function expressed by using a distance between a first feature vector of a first image and a second feature vector of a second image, which are relevant images and are obtained by applying the convolutional neural network, becomes smaller.