Directionality Control for Camera-Microphone Misalignment

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Solution Overview

Problem

Existing monitoring systems face challenges in accurately collecting audio data in specific directions due to the misalignment of camera and microphone arrays, leading to inaccurate sound collection when they are not on the same plane or axis, which affects the precision of audio data capture in relation to video imaging.

Innovation Solution

A directionality control system that uses a camera and microphone array connected via a network, where the camera captures video and computes sound collection directionality coordinates (horizontal and vertical angles) to accurately direct the microphone array to collect audio data from a designated position, even when the camera and microphone are not aligned.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the camera and microphone array are disposed at different positions separately from each other, then the system has greater installation flexibility and adaptability to different monitoring scenarios, but the optical axis of the camera is different from the physical central axis of the microphone array, causing coordinates indicating camera imaging direction to cannot be directly used for microphone array sound collection direction

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidsound collection direction accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces a coordinate transformation mechanism as an intermediary between the camera coordinate system and the microphone array coordinate system. The directionality control apparatus receives imaging direction coordinates from the camera, transforms them into sound collection direction coordinates suitable for the microphone array, and outputs the transformed coordinates to control the microphone array's sound collection direction. This intermediary transformation process resolves the axis misalignment issue while maintaining installation flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the coordinate parameters from the camera's imaging coordinate system to the microphone array's sound collection coordinate system through mathematical transformation. By transforming the horizontal angle and vertical angle parameters between the two different coordinate systems, the system accurately maps the camera's line of sight to the microphone array's sound collection direction, solving the axis misalignment problem.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If only the panning direction of the camera is used to change the sound collection region of the microphone array, then the control system is simpler, but the microphone array is unlikely to collect sound in a specific direction with high accuracy in relation to videos of a monitoring target

Engineering Contradiction:
Improvecontrol system complexityVSAvoidsound collection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent extends the control from one-dimensional (horizontal panning only) to two-dimensional by incorporating both horizontal angle and vertical angle coordinates. The directionality control apparatus receives two-dimensional imaging direction coordinates from the camera and transforms them into corresponding two-dimensional sound collection direction coordinates for the microphone array, enabling accurate sound collection in both horizontal and vertical dimensions.

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

Data Source

PatentEP2958339B1Directionality control system and directionality control method
Publication Date: 2019.09.18 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2958339B1 patent drawingFigure 1(A)~1(B)
  • EP2958339B1 patent drawingFigure 2(A)~2(E)
  • EP2958339B1 patent drawingFigure 3

AI summary

Relative to the microphone array system, toward a location corresponding to the position specified by the image of the predetermined range in which the camera device is the image imaging to form a sound collection directivity of the sound, and sound collection audio data with high accuracy. The directivity control system 10, the signal processing unit 33, in response to designation of an arbitrary position from the user in the video data displayed on the screen of the display device 36, into the screen from the installation position of the microphone array system 2 It picked up toward the sound position corresponding to the position of the specified video data Te (8MAh, 8MAv) to derive. The signal processing section 33 forms a sound collection directivity of the sound data to the derived sound collection direction (8MAh, 8MAv).