Action Recognition Using Poselet Keyframes

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Solution Overview

Problem

Existing video-based action recognition models are computationally expensive and sensitive to changes in action duration and dropped frames, as they rely on computing features over long temporal trajectories.

Innovation Solution

Modeling human actions as a sequence of discriminative keyframes, where poselets are selected and encoded to represent key states of actions, with correlations between poselets used to determine action occurrence, reducing computational resources and sensitivity to duration changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If long temporal trajectories with many frames are used for action recognition, then descriptive accuracy is improved, but computational cost increases

Engineering Contradiction:
Improveaction recognition accuracyVSAvoidcomputational cost
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the most informative frames (keyframes) from the video sequence based on poselet detection confidence scores, rather than processing all frames. This selective extraction maintains action recognition accuracy while significantly reducing computational cost by focusing only on discriminative moments in the action sequence.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent processes only a subset of frames (keyframes) rather than the complete frame sequence. By identifying and processing only those frames that contain critical action information, the system achieves adequate action recognition with reduced computational effort, applying partial action processing to solve the contradiction.

Inventive Principle:
Principle #16Partial or excessive action

2Loss of information

If long temporal trajectories with many frames are used for action recognition, then action description quality is improved, but sensitivity to action duration changes increases

Engineering Contradiction:
Improveaction description qualityVSAvoidrobustness to duration changes
Core Design Contradiction:
Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent dynamically adapts the number of keyframes and their temporal spacing based on the detected action characteristics. The system adjusts the frame selection process to account for varying action durations, making the recognition model more robust to temporal variations while maintaining descriptive quality through adaptive keyframe sampling.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the temporal parameters of frame sampling based on detected action patterns. By adjusting the time intervals and number of keyframes according to the specific action being recognized, the system maintains high description quality while becoming less sensitive to duration changes through parameter adaptation.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If long temporal trajectories with many frames are used for action recognition, then action modeling completeness is improved, but sensitivity to dropped frames increases

Engineering Contradiction:
Improveaction modeling completenessVSAvoidrobustness to dropped frames
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent performs preliminary poselet detection and confidence scoring on all frames before selecting keyframes for detailed processing. This preliminary action identifies which frames contain critical action information, allowing the system to maintain modeling completeness while being robust to dropped frames by focusing computational resources on the most informative moments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the most critical frames for detailed action modeling, rather than requiring complete processing of all frames. This extraction approach maintains action modeling completeness by focusing on discriminative keyframes while naturally providing robustness to dropped frames, as the system does not depend on every intermediate frame being present.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS10223580B2Methods and systems for action recognition using poselet keyframes
Publication Date: 2019.03.05 DISNEY ENTERPRISES INC
  • US10223580B2 patent drawing
  • US10223580B2 patent drawing
  • US10223580B2 patent drawing

AI summary

Methods and systems for video action recognition using poselet keyframes are disclosed. An action recognition model may be implemented to spatially and temporally model discriminative action components as a set of discriminative keyframes. One method of action recognition may include the operations of selecting a plurality of poselets that are components of an action, encoding each of a plurality of video frames as a summary of the detection confidence of each of the plurality of poselets for the video frame, and encoding correlations between poselets in the encoded video frames.