Action Recognition on Resource-Constrained Devices

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Solution Overview

Problem

Current AI models for action recognition in videos require prohibitively large computational resources, making them impractical for deployment on resource-constrained devices like smartphones due to high computational costs and latency, which hinders their practical usage and deployment.

Innovation Solution

The proposed method employs a Temporal Cross-Resolution (TCR) module that splits feature tensors into full and low temporal resolution streams, allowing for efficient temporal downsampling while maintaining accuracy through feature reconstruction loss, enabling a dual-pathway neural network architecture that reduces GPU memory requirements and FLOP count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If 3D CNNs are used for action recognition, then temporal information is naturally captured, but computational cost becomes prohibitive

Engineering Contradiction:
Improvetemporal information captureVSAvoidcomputational cost
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent segments the video processing into independent 2D CNN frame processing followed by separate temporal aggregation. Instead of using 3D convolutions that process spatiotemporal information jointly, the method divides the computation into spatial (2D CNN per frame) and temporal (aggregation layer) segments, reducing computational complexity while maintaining temporal sensitivity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts temporal information separately from spatial features. Independent 2D CNNs extract spatial features from each frame, and then a temporal aggregation mechanism (such as temporal shift module or temporal pooling) extracts temporal patterns from the sequence of spatial features, separating the computational tasks of spatial and temporal analysis

Inventive Principle:
Principle #2Taking out (Extraction)

2Power

If independent 2D CNN forward passes are used for each frame, then computational cost is reduced, but temporal sensitivity is lost

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidtemporal sensitivity
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent introduces a temporal aggregation layer as an intermediary between independent 2D CNN frame processing and final action recognition. This intermediary component (such as temporal shift module, temporal pooling, or recurrent network) takes the spatial features from multiple frames and aggregates temporal information, enabling temporal sensitivity without requiring computationally expensive 3D convolutions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If standard single model baseline is trained, then action recognition accuracy is achieved, but training requires 4 top-spec GPUs and several days

Engineering Contradiction:
Improveaction recognition accuracyVSAvoidtraining speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the model training into independent 2D CNN training for spatial feature extraction and separate temporal aggregation training. This segmentation allows for more efficient parallelization and reduces the computational burden per training step, enabling faster convergence with fewer GPU resources while maintaining or improving accuracy

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If higher computational cost models are used, then action recognition accuracy improves, but latency and battery consumption increase

Engineering Contradiction:
Improveaction recognition accuracyVSAvoidlatency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the architectural parameters of the neural network to use lightweight 2D CNNs with temporal aggregation instead of heavy 3D CNNs. This parameter change (model architecture selection) achieves a favorable trade-off between accuracy and computational cost, reducing latency and battery consumption while maintaining competitive action recognition accuracy on edge devices

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11837025B2Method and apparatus for action recognition
Publication Date: 2023.12.05 SAMSUNG ELECTRONICS CO LTD
  • US11837025B2 patent drawing
  • US11837025B2 patent drawing
  • US11837025B2 patent drawing

AI summary

Broadly speaking, the present techniques relate to a method and apparatus for performing action recognition, and in particular to a computer-implemented method for performing action recognition on resource-constrained or lightweight devices such as smartphones. The ML model may be adjusted to achieve required accuracy and efficiency levels, while also taking into account the computational capability of the apparatus that is being used to implement the ML model. One way is to adjust the number of channels assigned to the first set of channels, i.e. the full temporal resolution channels. Another way is to adjust the point in the ML model where the temporal pooling layer or layers are applied.