ResNeXt-3D Groupwise Convolution for Video Analysis
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Solution Overview
Problem
Current video classification models, such as I3D and R(2+1)D, are computationally expensive due to the use of 3D convolutional layers on large tensors, and it is unclear whether 3D groupwise convolution can reduce computational costs and maintain accuracy in video classification tasks.
Innovation Solution
The implementation of a 3D convolutional neural network with groupwise convolutions, specifically ResNeXt-3D, which extends image models based on groupwise convolution to the video domain, optimizing computational efficiency while maintaining or improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 3D convolutional layers are used on large tensors for video classification, then classification accuracy is improved, but computational cost increases significantly
Solution Approach 1:
The patent applies groupwise convolution by dividing the convolutional operation into multiple independent groups. Each group processes a subset of input channels separately, reducing the computational complexity from O(k^3 * C_in * C_out) to O(k^3 * C_in * C_out / g) where g is the number of groups. This segmentation allows the model to maintain accuracy while significantly reducing computational cost and energy consumption.
2Measurement precision
If conventional 3D convolutional networks are used for video classification, then model accuracy is maintained, but processing speed is slow
Solution Approach 1:
By segmenting the convolutional layers into independent groups that can be processed in parallel, the patent achieves faster processing speeds while maintaining model accuracy. The grouped convolution operation reduces redundant computations across different channel groups, enabling more efficient video frame processing.
3Loss of information
If standard convolutional operations are applied to video data, then comprehensive feature extraction is achieved, but computational complexity increases
Solution Approach 1:
The patent segments the feature extraction process into multiple independent groupwise convolution operations. Each group focuses on extracting specific feature patterns from different channel subsets, collectively achieving comprehensive feature extraction. This segmentation reduces computational complexity by eliminating redundant cross-channel interactions that are unnecessary for many video classification tasks.
Data Source
AI summary
In one embodiment, a method includes receiving a request for information associated with a video, determining the information associated with the video by processing the video using a machine-learning model which is based on a convolutional neural network comprising a plurality of layers, wherein at least one of the plurality of layers comprises one or more building blocks, wherein at least one of the one or more building blocks comprises a first filter configured to perform a three-dimensional (3D) pointwise convolutional operation and a second filter configured to perform a three-dimensional (3D) groupwise convolutional operation, and outputting the information associated with the video in response to the request.


