Local Contrast Tone Mapping for Noise-Controlled HDR Displays
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Solution Overview
Problem
Existing display devices struggle to accurately represent high dynamic range (HDR) images due to limited dynamic range, leading to digital noise and imbalanced contrast when tone mapping is performed, which affects the clarity and sharpness of images.
Innovation Solution
A display device and method that applies a global contrast curve to the entire image and generates local contrast curves based on local information for each region, adjusting noise and sharpness intensity to suppress digital noise and enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tone mapping is performed to convert HDR image to SDR image, then the image can be displayed on standard display devices, but digital noise is generated and image quality deteriorates
Solution Approach 1:
The patent divides the image into multiple local regions and applies different contrast curves to each region. By segmenting the image processing into global tone mapping and local contrast adjustment stages, the patent maintains compatibility with standard SDR displays while preserving local image quality through region-specific optimization.
Solution Approach 2:
The patent generates different contrast curves for different local regions based on local image characteristics. Each local region receives customized contrast adjustment, allowing the system to maintain high image quality in critical areas while ensuring overall compatibility with standard display devices through global tone mapping.
2Device complexity
If a single global contrast curve is applied to the entire image, then processing is simple and fast, but local image details are lost and contrast balance is poor
Solution Approach 1:
The patent segments the contrast adjustment process into global and local stages. The global contrast curve handles overall image adaptation to SDR displays, while local contrast curves address region-specific details. This segmentation enables the system to maintain reasonable processing complexity while significantly improving local contrast accuracy.
Solution Approach 2:
The patent applies contrast adjustment selectively to different local regions rather than uniformly across the entire image. By focusing detailed contrast optimization only where needed in local regions, the patent achieves high local contrast accuracy without proportionally increasing overall processing complexity.
3Manufacturing precision
If local contrast curve is applied to enhance local image quality, then clarity and sharpness improve, but digital noise increases in processed areas
Solution Approach 1:
The patent applies different contrast curve intensities to different local regions based on their specific characteristics. By adjusting the strength of local contrast enhancement according to local image content, the patent maximizes clarity improvement in suitable regions while minimizing noise generation in sensitive areas.
Solution Approach 2:
The patent dynamically adjusts parameters of the local contrast curve based on local image characteristics. By changing contrast curve parameters adaptively for each local region, the patent optimizes the balance between clarity enhancement and noise suppression, applying stronger enhancement only where it benefits image quality without excessive noise generation.
Data Source
AI summary
A display device according to an embodiment may include a display and a controller configured to apply a global contrast curve that adjusts a luminance of an entire region of an input image, generate a plurality of local contrast curves corresponding to each of a plurality of local regions based on a local information of each of the plurality of local regions included in the entire region, apply each local contrast curve to each local area, and adjust one or more of a noise processing intensity or a sharpness intensity of a local output image to which the local contrast curve is applied based on each local information.