Virtual Background Timing Synchronization for Camera Exposure

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Solution Overview

Problem

In virtual image recording studios, insufficient synchronization between the camera's image capture frequency and the background display device's update frequency leads to uneven exposure of different areas of the camera's light-sensitive elements, resulting in image errors such as the 'tearing effect' and brightness differences, which affect the natural representation of the virtual background.

Innovation Solution

Synchronize the temporal control of the virtual background reproduction with the sequence of exposure times by linking the camera and background display device via a network, adjusting the frequency and phase of the background display device's updates to coincide with the camera's exposure times, ensuring that each area of the light-sensitive element registers the same number of light pulses during exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the background display device operates at a high update frequency to display dynamic virtual background content, then the representation of the virtual background is more vivid and realistic, but different areas of the camera's light-sensitive elements register different numbers of light pulses, causing brightness differences and the 'tearing effect' in recorded images

Engineering Contradiction:
Improveupdate frequency of background display deviceVSAvoiduniformity of light pulse registration across light-sensitive elements
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by determining the exposure time of the camera before controlling the background display device. The control device receives exposure time information from the camera, calculates the corresponding light pulse frequency in advance, and then configures the background display device to operate at that frequency. This ensures that during the camera's exposure period, each area of the light-sensitive element registers the same number of light pulses, eliminating brightness differences and the tearing effect while maintaining high update frequency for vivid virtual background display

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the operating parameters of the background display device based on the camera's exposure time. The control device calculates the light pulse frequency as a function of the exposure time (f = 1/(2t) or f = 1/(4t) depending on the shutter type), and configures the background display device to operate at this calculated frequency. This parameter adjustment ensures synchronous operation between the camera and background display device, resolving the contradiction between high update frequency and uniform light pulse registration

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If the exposure time of the camera is extended to capture more light for better image quality, then the brightness and detail of recorded images are improved, but the background display device may update multiple times during the exposure period, causing different areas to register different numbers of light pulses and resulting in the 'tearing effect'

Engineering Contradiction:
Improvebrightness of recorded imagesVSAvoidconsistency of light pulse registration across light-sensitive elements
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by establishing a mathematical relationship between exposure time and light pulse frequency. For cameras with different shutter types (focal plane shutter or mirror shutter), the control device calculates the appropriate light pulse frequency as f = 1/(2t) or f = 1/(4t) respectively, where t is the exposure time. This ensures that during the extended exposure period, the background display device updates in a controlled manner such that each area of the light-sensitive element registers the same number of light pulses, eliminating the tearing effect while maintaining the extended exposure time for better image brightness and detail

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies feedback by having the control device receive exposure time information from the camera and use this information to configure the background display device's operating frequency. The system continuously monitors the camera's exposure time settings and adjusts the background display device's light pulse frequency accordingly, ensuring synchronous operation and consistent light pulse registration across all areas of the light-sensitive element throughout the exposure period

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This synchronization prevents image errors by ensuring uniform illumination and avoids the 'tearing effect', resulting in a natural and consistent representation of the virtual background in the recorded images.

Implementation Method 1

an LED wall can be used, the light-emitting diodes of which can be controlled individually and/or in groups of adjacent light-emitting diodes or in arrays of light-emitting diodes

Methodology Applied
Scientific EffectLight-emitting diode: Light Emitting Diode

Implementation Method 2

each area of a light-sensitive element of the camera, in particular each row of sensor elements of an image sensor, registers the same number of light pulses during an exposure

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP4284010B1Background reproduction device, camera, and method for reproducing a representation of a virtual background
Publication Date: 2025.09.24 ARNOLD & RICHTER CINE TECHNIK GMBH & CO BETRIEBS KG
  • EP4284010B1 patent drawingFigure 1
  • EP4284010B1 patent drawingFigure 2
  • EP4284010B1 patent drawingFigure 3

AI summary

In a method for reproducing a virtual background using a background playback device for a camera recording in a virtual image recording studio, the reproduction of the virtual background is controlled by timing. The camera further records the reproduction of the virtual background according to a sequence of exposure times, and the timing of the reproduction of the virtual background and the sequence of exposure times are synchronized.