Image Processing Device Gamma Correction for Vehicle Cameras

Solution Overview

Problem

Existing image processing techniques for liquid crystal display devices, particularly in vehicle-mounted camera systems, suffer from unnatural image generation due to sudden changes in gamma correction values between local areas with different characteristics, leading to degraded image quality and visibility issues that can obstruct safe driving.

Innovation Solution

An image processing device that calculates modulation gain values for both global and local areas, creates a correction intensity map, and applies these values to the input image, ensuring smooth transitions and preventing unnatural brightness reversals or overexposure/blackout between adjacent areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If gamma correction is performed for each local area unit to improve visibility, then brightness contrast is improved, but unnatural images with brightness reversal occur at local area boundaries

Engineering Contradiction:

Improvebrightness contrastVSAvoidimage quality

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies different gamma correction strategies to different regions: strong correction in local areas with large luminance differences, and weak or no correction in local areas with similar characteristics to adjacent regions. This prevents brightness reversal at boundaries while maintaining visibility improvement where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the gamma correction parameter (correction coefficient) based on the luminance characteristics of each local area. By changing this parameter according to local conditions, the system achieves both visibility improvement and natural transition at boundaries.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If linear interpolation is used to smooth gamma correction values at local area boundaries, then brightness reversal is prevented, but visibility improvement is reduced

Engineering Contradiction:

Improveimage naturalnessVSAvoidvisibility improvement

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent applies different gamma correction strategies to different regions: strong correction in local areas with large luminance differences, and weak or no correction in local areas with similar characteristics to adjacent regions. This prevents brightness reversal at boundaries while maintaining visibility improvement where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the gamma correction parameter (correction coefficient) based on the luminance characteristics of each local area. By changing this parameter according to local conditions, the system achieves both visibility improvement and natural transition at boundaries.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If strong gamma correction is applied to all local areas, then visibility is improved, but level difference noise increases in the entire image

Engineering Contradiction:

ImprovevisibilityVSAvoidimage quality

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies different gamma correction strategies to different regions: strong correction in local areas with large luminance differences, and weak or no correction in local areas with similar characteristics to adjacent regions. This prevents brightness reversal at boundaries while maintaining visibility improvement where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the gamma correction parameter (correction coefficient) based on the luminance characteristics of each local area. By changing this parameter according to local conditions, the system achieves both visibility improvement and natural transition at boundaries.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11718229B2Image processing device and image processing method

Publication Date: 2023.08.08 RENESAS ELECTRONICS CORP

AI summary

The image processing device acquires feature quantities (maximum value, minimum value, average value, histogram, etc.) of the entire area (GA) of the image and feature quantities of each local area (LA) of the image from the input image, and calculates a plurality of modulation gain values (gamma correction curves) for GA and each LA. Furthermore, the image processing device determines the correction intensity for each LA from the feature quantity of the GA and the feature quantity of each LA, and creates the LA correction intensity map. Finally, the image processing device finally applies the result of combining a plurality of modulation gain values based on the LA correction intensity map to the input image.