Binocular 3D Image Tone Mapping for Preserved Depth Contrast

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Solution Overview

Problem

Tone mapping of binocular 3D images reduces brightness and global or local contrast, impairing user perception.

Innovation Solution

An image processing method that generates a second tone mapping curve based on the disparity map and contrast of a binocular image to compensate for reduced contrast, ensuring a minimum disparity variation for 3D perception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If tone mapping is performed on binocular HDR image, then brightness is reduced to fit display device, but contrast is reduced and 3D perception is impaired

Engineering Contradiction:
ImprovebrightnessVSAvoid3D perception
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies different tone mapping strategies to different regions of the binocular image based on disparity information. Regions with high disparity (important for 3D perception) receive different processing than regions with low disparity, preserving local contrast where it matters most for stereoscopic vision while still performing overall brightness reduction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the tone mapping curve parameters based on the disparity map of the binocular image. By changing the mapping parameters according to disparity information, the system preserves contrast in regions that contribute most to 3D perception while maintaining brightness reduction for display compatibility.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If conventional tone mapping curve is used, then image brightness is adjusted, but contrast loss occurs and minimum disparity variation requirement is not met

Engineering Contradiction:
Improvebrightness adjustmentVSAvoidcontrast precision
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent uses the disparity map as feedback information to guide the tone mapping process. The disparity information provides feedback about which regions are critical for 3D perception, allowing the tone mapping algorithm to adjust contrast preservation accordingly while maintaining brightness adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary calculation of the disparity map before tone mapping. This preliminary action provides the necessary information about depth structure and disparity distribution, enabling the subsequent tone mapping to preserve contrast in critical regions while adjusting brightness.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If tone mapping is performed to adapt HDR image to display device, then display compatibility is improved, but visual perception quality deteriorates

Engineering Contradiction:
Improvedisplay compatibilityVSAvoidvisual perception
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the binocular image processing into two independent stages: disparity analysis and tone mapping. This segmentation allows the system to first understand the depth structure through disparity mapping, then apply tone mapping that respects this structure, achieving both display compatibility and preserved visual perception.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The disparity map serves as an intermediary between the HDR binocular image and the tone mapping process. It mediates the transformation by providing information about which regions require contrast preservation for 3D perception, enabling the system to achieve display compatibility without sacrificing visual perception quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4322524B1Image processing method, device and system
Publication Date: 2025.10.01 HUAWEI TECH CO LTD
  • EP4322524B1 patent drawingFigure 1
  • EP4322524B1 patent drawingFigure 2
  • EP4322524B1 patent drawingFigure 3

AI summary

This application relates to the field of image processing technologies, and discloses an image processing method and system, and a device, to resolve a problem that tone mapping greatly affects perception of a binocular 3D image. Based on a disparity map of a binocular image, a tone mapping curve is determined for a display device to display an image, instead of being generated merely based on image content. This makes a contrast of a tone mapped binocular image reach at least a level before tone mapping, thereby meeting a minimum disparity variation requirement for 3D perception by human eyes, and improving 3D perception of a 3D image displayed by the display device.