Iterative Video Activity Detection via Pseudo Temporal Labels

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Solution Overview

Problem

Current weakly supervised temporal activity detection methods fail to accurately mine locating and semantic information from class activation sequences, resulting in low localization accuracy for action detection in videos.

Innovation Solution

A weakly supervised video activity detection method and system based on iterative learning, which extracts spatial-temporal features, constructs a neural network model group, trains the models using class labels and pseudo temporal labels, and selects the model with the highest detection accuracy for action detection, incorporating loss calculations and parameter updates to enhance localization accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If weakly supervised temporal activity detection methods use multi-instance learning or attention mechanism to output class activation sequence, then the method can classify video actions with less manual annotation, but the localization accuracy of actions remains relatively low

Engineering Contradiction:
Improveease of annotationVSAvoidlocalization accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent divides the video into multiple clips and processes each clip through the neural network model to generate class activation sequences for each clip. This segmentation allows the model to learn temporal patterns at the clip level while maintaining weak supervision, thereby improving localization accuracy without requiring frame-level annotations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the class activation sequence from a one-dimensional temporal representation into a two-dimensional structure by organizing activation scores across multiple clips and action classes. This dimensional transformation enables the model to capture both temporal and semantic relationships, improving localization precision while maintaining annotation efficiency.

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

2Productivity

If the neural network model is trained only with class labels without temporal information, then the training process is simpler and faster, but the model cannot accurately locate action boundaries in time

Engineering Contradiction:
Improvetraining speedVSAvoidtemporal localization accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary feature extraction on video clips before training the neural network model. By pre-processing the video into clips and extracting initial features, the model can focus on learning temporal patterns during training rather than processing raw video data, thus maintaining training speed while improving temporal localization capability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the class activation sequences generated by the model as feedback to guide further training and refinement. The activation sequences provide temporal localization signals that are fed back into the model during iterative training, enabling the model to progressively improve its temporal boundary detection without requiring manual temporal annotations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11721130B2Weakly supervised video activity detection method and system based on iterative learning
Publication Date: 2023.08.08 NANJING UNIV OF SCI & TECH
  • US11721130B2 patent drawing
  • US11721130B2 patent drawing
  • US11721130B2 patent drawing

AI summary

The present disclosure relates to a weakly supervised video activity detection method and system based on iterative learning. The method includes: extracting spatial-temporal features of a video that contains actions; constructing a neural network model group; training a first neural network model according to the class label of the video, a class activation sequence output by the first neural network model, and a video feature output by the first neural network model; training the next neural network model according to the class label of the video, a pseudo temporal label output by the current neural network model, a class activation sequence output by the next neural network model, and a video feature output by the next neural network model; and performing action detection on the test video according to the neural network model corresponding to the highest detection accuracy value.