Phase-Based Motion Detection Using Gaussian Windowed FFT

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Solution Overview

Problem

Current computer-based motion detection algorithms, such as those using optic flow techniques, face high computational demands, making real-time implementation challenging, and there is a need for an improved technique that can efficiently detect visual motion with reduced complexity.

Innovation Solution

A phase-based motion detection method that involves constructing a multi-dimensional Gaussian window, dividing frames into blocks, multiplying each pixel with the Gaussian window, computing the multidimensional FFT to obtain amplitude and phase, and detecting motion based on the phase of the windowed signal blocks, which can be implemented using a processor and memory system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optic flow techniques are used for motion detection, then accurate motion estimation is achieved, but computational complexity becomes too high for real-time implementation

Engineering Contradiction:
Improvemotion estimation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential phase information from the Fourier transform of image blocks, discarding amplitude and other non-essential data. This extraction of critical motion-related phase data reduces computational complexity while maintaining motion detection accuracy, directly resolving the contradiction between precise motion estimation and computational burden

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent divides the image into multiple blocks and processes each block independently through FFT to extract local phase information. This segmentation enables parallel processing of different image regions, significantly reducing overall computational complexity while preserving accurate motion estimation through localized phase analysis

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If complex motion detection algorithms are implemented, then detection accuracy is improved, but processing speed decreases

Engineering Contradiction:
Improvemotion detection accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent extracts only phase information from the Fourier transform, ignoring amplitude and other complex computations. This selective extraction maintains motion detection accuracy by focusing on the most relevant data while dramatically reducing processing time and computational overhead

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the motion detection problem from intensity-based analysis to phase-based analysis by computing the Fourier transform and extracting phase information. This parameter transformation enables faster processing through efficient FFT algorithms while maintaining or improving motion detection accuracy through phase congruency measures

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9892518B2Systems and methods for detecting motion using local phase information
Publication Date: 2018.02.13 THE TRUSTEES OF COLUMBIA UNIV IN THE CITY OF NEW YORK
  • US9892518B2 patent drawing
  • US9892518B2 patent drawing
  • US9892518B2 patent drawing

AI summary

Systems and methods for the detection of motion in a multi-dimensional signal are provided. According to aspects of the disclosure, data representing a time sequence of frames of a video stream is received. A multi-dimensional Gaussian window in is then constructed. Each frame of the received data is divided into a plurality of blocks and, for each block in the plurality of blocks, each pixel in the block is multiplied with a corresponding pixel of the Gaussian window to obtain a windowed video block. The FFT of the windowed video block is computed to obtain an amplitude and phase thereof. The occurrence of motion in the block is then determined based on the computed phase of the windowed video block.