Strobable Lighting Synchronization for Flicker-Free Cinematography

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Solution Overview

Problem

Existing filming techniques with multiple lighting setups either result in visible flicker due to strobing lights or significantly shorten take lengths to avoid flicker, making them unacceptable for cinematic filming.

Innovation Solution

A camera and lighting system that synchronizes image captures with lighting setups, strobing each lighting setup at a fraction of the global frequency, ensuring a constant strobe rate above the flicker threshold, thereby eliminating visible flicker while allowing longer take lengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If lighting setups are strobed in sync with camera micro frames at 24 Hertz to maximize take length, then take length is improved, but visible flicker occurs on set

Engineering Contradiction:

Improvetake lengthVSAvoidvisible flicker

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent segments the macro frame into multiple micro frames, allowing the camera to capture images at a higher frequency while the lighting setups strobe at a lower, non-flickering rate. This segmentation enables the decoupling of camera frame rate from lighting strobe rate, resolving the contradiction between maximizing take length and eliminating visible flicker.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of lighting strobe rate from matching the camera frame rate (24 Hz) to a higher frequency (96 Hz or above). This parameter change ensures that the lighting appears continuous to human observers while still synchronizing with the camera's image capture moments, thereby eliminating visible flicker while maintaining acceptable take lengths.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If macro frame duration is reduced to 1/96th of a second to eliminate flicker perception, then visible flicker is eliminated, but take length is reduced to one quarter of the original

Engineering Contradiction:

Improvevisible flickerVSAvoidtake length

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The patent segments each macro frame into multiple micro frames (e.g., 4 micro frames per macro frame at 96 Hz lighting rate). This allows the system to use a longer macro frame duration (1/24th second) while the lighting strobes at the higher frequency (96 Hz), thereby eliminating flicker perception without sacrificing take length.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic lighting strobes at a frequency (96 Hz or above) that is above the human flicker fusion threshold. This periodic action at the optimized frequency ensures continuous light perception while maintaining synchronization with camera image capture, resolving the contradiction between eliminating flicker and maintaining take length.

Inventive Principle:

Principle #19Periodic action

3Productivity

If lighting setups strobe only during image capture micro frames, then image capture efficiency is improved, but flicker becomes visible to persons on set

Engineering Contradiction:

Improveimage capture efficiencyVSAvoidvisible flicker

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the lighting operation into two distinct phases: (1) synchronized strobing during micro frame capture for efficient image acquisition, and (2) continuous operation at high frequency for the remainder of the macro frame to eliminate visible flicker. This segmentation allows the system to achieve both image capture efficiency and flicker elimination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent maintains continuous lighting operation at a high frequency (96 Hz or above) throughout the entire macro frame duration, rather than interrupting the lighting between micro frame captures. This continuous action at the optimized frequency ensures that the lighting appears steady to human observers while still capturing images efficiently during the micro frame intervals.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS11985747B2Apparatus and method for filming a scene using lighting setups actuated repeatedly during each entire frame without visible flicker on set while acquiring images synchronously with the lighting setups only during a portion of each frame

Publication Date: 2024.05.14 VAN DE ROER CARLO

AI summary

Apparatus and method for filming a scene using a plurality of strobable lighting setups in rapid sequence to concurrently record a plurality of motion picture clips of the scene, one motion picture clip for each strobable lighting setup. The apparatus includes a plurality of strobable light sources that are coordinated to form the plurality of lighting setups, a controller to actuate the strobable lighting setups at a constant rate in a sequence that repeats multiple times during each macro frame, and a camera to capture a burst sequence of images within each macro frame. The burst sequence of images shows the scene illuminated by each one of the plurality of lighting setups in sequence during each macro frame. Since the constant rate is above the flicker threshold, people on set viewing the scene illuminated by the repeating sequence of strobable lighting setups perceive apparently continuous (non-flickering) illumination of the scene.