Tone Gain Functions for HDR Image Saturation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for tone mapping High-Dynamic-Range (HDR) image data often result in saturation, clipping, and data loss, leading to reduced visual quality and accuracy in object detection.

Innovation Solution

Applying separate tone gain functions to discrete tonal regions of HDR image data, allowing for optimal tone management by determining specific tone gain functions for different tonal ranges within the image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional tone mapping methods are applied to HDR image data, then the image can be converted to standard dynamic range, but saturation and clipping occur resulting in data loss and reduced visual quality

Engineering Contradiction:

Improveaccuracy of object detectionVSAvoiddata loss from saturation and clipping

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent divides the HDR image data into multiple discrete tonal regions (e.g., shadow, mid-tone, highlight regions) and applies separate tone gain functions to each region. This segmentation allows different parts of the image with different luminance characteristics to be processed independently, preventing saturation and clipping in any single region while maintaining overall image quality and detection accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different tone gain functions tailored to specific tonal regions rather than using a single global tone mapping function. Each region receives optimized processing parameters appropriate to its luminance characteristics, ensuring that dark regions maintain detail without excessive noise while bright regions preserve highlights without clipping, thereby minimizing information loss overall.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If conventional tone mapping is applied to HDR image data, then the image can be displayed on standard devices, but the visual benefits of HDR such as contrast and detail are reduced making the image appear washed-out

Engineering Contradiction:

Improvedisplay compatibilityVSAvoidcontrast and detail

Core Design Contradiction:

Ease of operationVSIllumination intensity

Solution Approach 1:

By segmenting the image into discrete tonal regions and applying region-specific tone gain functions, the patent preserves contrast and detail within each luminance range while still mapping the overall image to standard dynamic range displayable on conventional devices. This segmented approach prevents the washed-out appearance that results from uniform global tone mapping.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent modifies the tone gain parameters differently for each tonal region, adjusting contrast and brightness parameters locally rather than globally. This allows the image to maintain HDR-like visual quality with enhanced contrast and detail in each region while remaining compatible with standard display devices that cannot natively display HDR content.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12272040B2Tone management using tone gain functions for high dynamic range imaging applications

Publication Date: 2025.04.08 NVIDIA CORP

AI summary

Apparatuses, systems, and techniques to perform effective tone management for image data. In an embodiment, a set of contrast gain curves are generated corresponding to a set of tonal ranges of an input image. An output image may then be generated by at least applying corresponding contrast gain curves to tonal ranges of the input image.