Infrared Pre-Flash for RGB Camera Glare Reduction

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Solution Overview

Problem

Conventional image capture systems using visible light pre-flash result in glare and subject movement due to the relatively long duration of the flash, which can lead to suboptimal picture quality, especially in low-light conditions.

Innovation Solution

An image capture system employing an infrared light pre-flash, utilizing an infrared illuminator and image sensor sensitive to infrared light to determine exposure and focus settings, which are then scaled to visible settings, thereby reducing or eliminating visible light pulse length and associated glare.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visible light pre-flash is used to assist automatic focus, exposure, and white balance algorithms, then the algorithms can calculate suitable settings, but the pre-flash causes glare and subject movement due to its relatively long duration

Engineering Contradiction:

Improveautomatic algorithm calculation accuracyVSAvoidglare and subject movement

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the wavelength parameter of the pre-flash from visible light to infrared light. This parameter change allows the pre-flash to illuminate the scene for algorithm calculation without causing glare or subject movement, as infrared light is invisible to the human eye. The infrared pre-flash maintains the necessary illumination duration while eliminating the harmful visual effects of visible light pre-flash.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes visible light with infrared light for the pre-flash function. This substitution replaces the traditional visible light illumination mechanism with an infrared illumination mechanism that performs the same measurement function (providing illumination for automatic focus, exposure, and white balance calculation) without the harmful side effects of visible light.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If the visible light pre-flash duration is reduced to minimize glare, then subject movement is reduced, but the algorithms may not have sufficient time to calculate accurate settings

Engineering Contradiction:

Improveglare reductionVSAvoidalgorithm calculation accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

By changing the wavelength parameter from visible to infrared, the patent enables the pre-flash to maintain a longer duration without causing glare, since infrared light is invisible to subjects. This parameter change resolves the contradiction by allowing sufficient illumination time for accurate algorithm calculation while eliminating the harmful visual effects.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If infrared light pre-flash is used instead of visible light, then glare and subject movement are reduced, but the system requires an infrared-sensitive image sensor and infrared illuminator

Engineering Contradiction:

Improveglare eliminationVSAvoidinfrared components requirement

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by using an infrared-sensitive image sensor that can detect both infrared pre-flash light and visible light for final image capture. The same sensor and processing pipeline handle both infrared and visible light, reducing the need for completely separate systems and minimizing the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the infrared pre-flash illumination function with the visible light imaging function into a single integrated system. The infrared illuminator and infrared-sensitive sensor work together with the existing visible light camera components, combining multiple functions (infrared illumination, infrared detection, visible light capture) into a unified imaging system rather than separate independent systems.

Inventive Principle:

Principle #5Merging (Combining)

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

The use of infrared light pre-flash significantly reduces glare and subject movement, resulting in improved picture quality by allowing faster and more accurate focus and exposure adjustments without increasing image noise.

Implementation Method 1

an infrared illuminator configured to emit infrared light during pre-flash

Methodology Applied

Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

an image sensor configured to capture image data comprising at least one infrared image

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11418730B2Use of IR pre-flash for RGB camera's automatic algorithms

Publication Date: 2022.08.16 LUMILEDS SINGAPORE PTE LTD

AI summary

The image capture system of the present disclosure comprises an illuminator comprising at least one infrared light LED or laser and one visible light LED, an image sensor that is sensitive to infrared light and visible light, a memory configured to store instructions, and a processor configured to execute instructions to cause the image capture system to emit infrared light, receive image data comprising at least one infrared image, and determine depth maps, visible focus settings, or infrared exposure settings based on the infrared image data.