Stereo Camera Dark Flash Photography Using Invisible Light

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Solution Overview

Problem

Low-light photography often results in high noise or blurred images due to the limitations of flash illumination, which can irritate subjects and cause over-illumination, while longer exposure times or multiple exposures lead to motion-related blurring.

Innovation Solution

Utilizing invisible wavelengths like infrared or ultraviolet light for illumination, combined with visible light imaging, to generate improved images by augmenting visible-light image information with structural details from invisible light, using artificial neural networks to combine and process the data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a flash is used to illuminate the scene, then the image quality is improved, but the subjects are irritated and the contents appear washed-out

Engineering Contradiction:
Improveimage qualityVSAvoidirritation to subjects
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (aesthetic agent) that mediates between the flash illumination and the subjects. This agent absorbs excess light energy and converts it into beneficial aesthetic effects, allowing the flash to illuminate the scene effectively while preventing direct irritation to subjects' eyes and preventing over-illumination washout.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the exposure time is increased to overcome low-light limitations, then the noise is reduced, but motion blur increases

Engineering Contradiction:
Improvenoise levelVSAvoidsharpness
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent changes the illumination parameter by introducing a flash with specific temporal characteristics. The flash provides high-intensity illumination for a brief duration, allowing the camera to use shorter exposure times that capture sharp images while the flash illuminates the scene sufficiently to reduce noise without requiring prolonged exposure that would cause motion blur.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple images are taken and computationally combined, then the noise is reduced, but the complexity and time required increase

Engineering Contradiction:
Improvenoise levelVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by using the aesthetic agent to enhance the quality of individual images before computational processing is needed. By improving the signal-to-noise ratio at the capture stage through optimized flash illumination and aesthetic agent interaction, the need for complex post-processing of multiple images is reduced, as fewer images require processing and the processing becomes less intensive.

Inventive Principle:
Principle #10Preliminary action

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 approach reduces noise and blurring, provides more accurate and aesthetically pleasing images by leveraging the structural information from invisible light while maintaining color accuracy, effectively addressing the limitations of traditional low-light photography.

Implementation Method 1

a flash configured to generate illumination at a first invisible wavelength

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

invisible wavelengths like infrared or ultraviolet light for illumination

Methodology Applied
Scientific EffectUltraviolet radiation:

Implementation Method 3

a camera configured to generate image information for the scene at respective sets of wavelengths

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3844567B1Dark flash photography with a stereo camera
Publication Date: 2025.01.15 GOOGLE LLC
  • EP3844567B1 patent drawingFigure 1A~1B
  • EP3844567B1 patent drawingFigure 2~3
  • EP3844567B1 patent drawingFigure 4A~4B

AI summary

Scenes can be imaged under low-light conditions using flash photography. However, the flash can be irritating to individuals being photographed, especially when those individuals' eyes have adapted to the dark. Additionally, portions of images generated using a flash can appear washed-out or otherwise negatively affected by the flash. These issues can he addressed by using a flash at an invisible wavelength, e.g., an infrared and/or ultraviolet flash. At the same time a scene is being imaged, at the in visible wavelength of the invisible flash, the scene can also be imaged at visible wavelengths. This can include simultaneously using both a standard RGB camera and a modified visible-plus-invisible-wavelengths camera (e.g., an "IR- G-UV" camera). The visible and invisible image data can then be combined to generate an improved visible-light image of the scene, e.g., that approximates a visible light image of the scene, had the scene been illuminated during daytime light conditions.