In-Vehicle Camera Image Processing for Blown-Out Highlights

Solution Overview

Problem

In-vehicle cameras face challenges in capturing clear images of bright subjects in dark environments due to blown-out highlights, which make it difficult to distinguish colors like traffic signals and vehicle lights, and existing solutions like HDR and WDR struggle to accurately separate light and dark areas, leading to increased noise and poor S/N ratio.

Innovation Solution

An image processing apparatus that separates color signals and luminance signals and controls color signals based on luminance values to enhance chroma in bright areas and reduce it in dark areas, using a color signal control unit to adjust chroma levels according to the luminance signal, allowing for clearer reproduction of bright subjects in dark images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If longer exposure time is applied to increase light reception, then dark areas become brighter, but bright areas become overexposed (blown-out highlights)

Engineering Contradiction:

Improvebrightness of dark areasVSAvoidcolor accuracy of bright areas

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent segments the image processing into two distinct exposure paths: a first image obtained with a longer exposure time for dark areas, and a second image obtained with a shorter exposure time for bright areas. This segmentation allows each path to be optimized for its specific luminance range, preventing blown-out highlights while brightening dark areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different exposure times for different regions of the image. The longer exposure time is applied to dark areas to brighten them, while the shorter exposure time is applied to bright areas to prevent overexposure. This localized approach ensures that each region receives the appropriate exposure treatment.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If shorter exposure time is applied to prevent blown-out highlights, then bright areas are preserved, but the entire image becomes dark

Engineering Contradiction:

Improvecolor accuracy of bright areasVSAvoidbrightness of dark areas

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent segments the image processing into two distinct exposure paths: a first image obtained with a longer exposure time for dark areas, and a second image obtained with a shorter exposure time for bright areas. This segmentation allows each path to be optimized for its specific luminance range, preventing blown-out highlights while brightening dark areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different exposure times for different regions of the image. The longer exposure time is applied to dark areas to brighten them, while the shorter exposure time is applied to bright areas to prevent overexposure. This localized approach ensures that each region receives the appropriate exposure treatment.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If HDR or WDR is used to expand dynamic range, then both bright and dark areas are captured, but noise increases and S/N ratio deteriorates

Engineering Contradiction:

Improvedynamic range coverageVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by using different exposure times for different regions of the image. The longer exposure time is applied to dark areas to brighten them, while the shorter exposure time is applied to bright areas to prevent overexposure. This localized approach ensures that each region receives the appropriate exposure treatment.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the exposure time parameter based on the luminance characteristics of different image regions. By selecting from multiple exposure time settings (first exposure time for dark areas, second exposure time for bright areas), the system adapts the exposure parameters to match the local luminance conditions, thereby capturing the full dynamic range while maintaining signal-to-noise ratio.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10063827B2Image processing apparatus, imaging apparatus, image processing program, and image processing method

Publication Date: 2018.08.28 RICOH CO LTD

AI summary

An image processing apparatus for performing image processing for image data. The image processing apparatus includes a signal separation unit configured to separate a color signal and a luminance signal included in the image data, and a color signal control unit configured to control chroma of the color signal used for the image processing based on a luminance value of the luminance signal.