Spatiotemporal Motion Analysis for Video Foreground Background Separation

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Solution Overview

Problem

Current methods for detecting and tracking moving objects in video sequences are computationally intensive and struggle to separate foreground motion from background motion caused by camera zooming and panning, especially in uncontrolled settings with varying illumination.

Innovation Solution

A method that analyzes a digital video sequence by converting it into a two-dimensional spatiotemporal representation, identifying trajectories, and distinguishing between foreground and background motion segments using a data processor, thereby reducing computational complexity and memory usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical flow estimation process is applied to analyze the video sequence, then pixel-level motion vectors are provided, but computational complexity increases and sensitivity to noise occurs

Engineering Contradiction:
Improvemotion vector precisionVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The video sequence is segmented into foreground and background portions, and motion analysis is performed separately on each segment. This allows the system to focus computational resources on relevant motion regions while simplifying the overall analysis complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the traditional spatial-domain frame-by-frame analysis into a spatiotemporal representation, adding the time dimension to the analysis. This dimensional transformation enables more efficient motion pattern recognition and separation of foreground/background motion without requiring computationally intensive optical flow calculations at every pixel location.

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

2Reliability

If background subtraction method is used to detect moving objects, then motion detection works well in controlled settings, but it breaks down when illumination varies or camera position changes

Engineering Contradiction:
Improvemotion detection reliabilityVSAvoidadaptability to varying conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

By transforming the analysis from spatial domain to spatiotemporal domain, the system can distinguish between background motion (caused by illumination changes or camera movement) and foreground motion (actual objects of interest) based on their different temporal patterns, thereby maintaining reliability across varying conditions.

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

Solution Approach 2:

The system dynamically adapts to varying illumination and camera conditions by analyzing motion patterns over time in the spatiotemporal representation, allowing it to distinguish between expected background variations and actual foreground motion regardless of environmental changes.

Inventive Principle:
Principle #15Dynamics

3Productivity

If frame-by-frame analysis is applied to detect and track objects, then object detection can be performed, but tracking requires additional initialization and remains frame-by-frame limited

Engineering Contradiction:
Improveobject detection efficiencyVSAvoidtracking initialization time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The spatiotemporal representation inherently incorporates temporal continuity, allowing the system to track objects across frames without separate initialization steps. Motion patterns are detected and followed continuously through the time dimension of the spatiotemporal volume, eliminating the need for frame-by-frame tracking initialization.

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

Data Source

PatentUS8335350B2Extracting motion information from digital video sequences
Publication Date: 2012.12.18 KODAK ALARIS LLC
  • US8335350B2 patent drawing
  • US8335350B2 patent drawing
  • US8335350B2 patent drawing

AI summary

A method for analyzing a digital video sequence of a scene to extract background motion information and foreground motion information, comprising: analyzing at least a portion of a plurality of image frames captured at different times to determine corresponding one-dimensional image frame representations; combining the one-dimensional frame representations to form a two-dimensional spatiotemporal representation of the video sequence; using a data processor to identify a set of trajectories in the two-dimensional spatiotemporal representation of the video sequence; analyzing the set of trajectories to identify a set of foreground trajectory segments representing foreground motion information and a set of background trajectory segments representing background motion information; and storing an indication of the foreground motion information or the background motion information or both in a processor-accessible memory.