Video Concept Classification via Conditional Markov Random Field

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Solution Overview

Problem

Existing classification methods fail to accurately and efficiently classify static and dynamic concepts in videos, as they do not adequately account for temporal and non-temporal interdependencies, leading to reduced accuracy and increased computational costs.

Innovation Solution

A probabilistic graphical model, specifically a conditional Markov random field (CRF) model, is used to jointly classify static and dynamic concepts by associating object and action concept types with spatio-temporal segments, where action concept types are independent and indirectly linked via a global concept type, and object concept types are linked to the global concept type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic Bayesian networks are used to model temporal dependencies, then temporal pattern recognition is improved, but computational complexity increases and static concept classification becomes intractable

Engineering Contradiction:
Improvetemporal pattern recognition accuracyVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the video analysis task into separate static concept classification and action concept classification components. The static concept classifier processes frame-level data independently, while the action concept classifier processes temporal sequences. This segmentation allows each component to use appropriate models (MRF for static, DBN for dynamic) without the computational burden of trying to model both simultaneously in a single complex system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a global concept type as an intermediary variable that links static and action concept types. This intermediary allows the system to capture temporal dependencies through the global concept while maintaining the ability to classify static concepts independently using simpler MRF models. The intermediary bridges the gap between the computational simplicity required for static concepts and the temporal modeling capabilities needed for dynamic concepts.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If joint classification is performed to exploit interdependencies between labels, then classification accuracy is improved, but computational costs increase

Engineering Contradiction:
Improveclassification accuracyVSAvoidcomputational cost
Core Design Contradiction:
Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent segments the classification problem into static concept classification and action concept classification. By separating these tasks, the system can use efficient MRF models for static concepts (which have simpler, non-temporal dependencies) and reserve more computationally intensive DBN models only for action concepts where temporal dependencies are necessary. This segmentation reduces overall computational cost while maintaining high accuracy through specialized modeling of each concept type.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different modeling approaches to different concept types based on their specific requirements. Static concept types use MRF models with simpler computational characteristics, while action concept types use DBN models that capture temporal patterns. This local quality approach allows the system to optimize computational resources by applying complex temporal modeling only where necessary (for actions) rather than uniformly across all concept types.

Inventive Principle:
Principle #3Local quality

3Reliability

If higher order temporal dependencies are modeled in DBN, then action recognition is improved, but inference becomes intractable

Engineering Contradiction:
Improveaction recognition accuracyVSAvoidinference efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments temporal dependency modeling by separating static and action concept classification. Action concepts, which require temporal modeling, are processed independently from static concepts. This segmentation allows the system to use DBN models with higher order temporal dependencies for action recognition without the computational burden of simultaneously modeling these dependencies across all concept types, thereby maintaining inference efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies temporal dependency modeling (DBN) only partially to action concept types rather than universally to all concept types. By restricting higher order temporal dependencies to only where they are actually needed (for actions), the system achieves improved action recognition accuracy while avoiding the intractability that would result from attempting to model these complex temporal dependencies across the entire video data including static concepts.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS10565454B2Imaging system and method for classifying a concept type in video
Publication Date: 2020.02.18 CANON KK
  • US10565454B2 patent drawing
  • US10565454B2 patent drawing
  • US10565454B2 patent drawing

AI summary

A method and associated imaging system for classifying at least one concept type in a video segment is disclosed. The method associates an object concept type in the video segment with a spatio-temporal segment of the video segment. The method then associates a plurality of action concept types with the spatio-temporal segment, where each action concept type of the plurality of action concept types is associated with a subset of the spatio-temporal segment associated with the object concept type. The method then classifies the action concept types and the object concept types associated with the video segment using a conditional Markov random field (CRF) model where the CRF model is structured with the plurality of action concept types being independent and indirectly linked via a global concept type assigned to the video segment, and the object concept type is linked to the global concept type.