Image Processing Apparatus Adaptive Cut-off Luminance

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Solution Overview

Problem

Existing image processing techniques that increase contrast often result in degradation of image quality, particularly due to 'blown out highlights' when a large cut-off region is set, making it difficult to maintain image visibility in bright conditions and reduce power consumption without compromising image clarity.

Innovation Solution

An image processing apparatus that calculates specific luminance values based on pixel distributions, adjusts the cut-off region to prevent blown out highlights, and corrects gradation levels proportionally, allowing for increased contrast while minimizing image quality degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a large cut-off region is set to increase contrast, then contrast is improved, but image quality degrades due to blown out highlights

Engineering Contradiction:
ImprovecontrastVSAvoidimage quality
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent dynamically adjusts the cut-off region parameter based on the histogram distribution of luminance values. Instead of using a fixed large cut-off region, the system calculates the appropriate cut-off point by analyzing pixel distribution, thereby changing the parameter adaptively to prevent highlight degradation while maintaining contrast enhancement.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If backlight luminance is reduced to save power, then power consumption is decreased, but image visibility deteriorates in bright conditions

Engineering Contradiction:
Improvepower consumptionVSAvoidimage visibility
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The system dynamically adjusts the backlight luminance parameter based on image content analysis. By examining the histogram and calculating appropriate luminance values, the system optimizes backlight intensity to maintain visibility while minimizing power consumption, rather than using a fixed reduced luminance setting.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If gradation correction is applied to increase contrast, then contrast is improved, but image quality degrades due to loss of highlight detail

Engineering Contradiction:
ImprovecontrastVSAvoidhighlight detail
Core Design Contradiction:
Illumination intensityVSLoss of information

Solution Approach 1:

The patent dynamically determines the cut-off luminance value parameter based on real-time histogram analysis of the image content. This adaptive parameter adjustment ensures that gradation correction is applied optimally, enhancing contrast while preserving highlight details by avoiding excessive correction in highlight regions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from histogram analysis to adjust the gradation correction process. By continuously monitoring the distribution of luminance values and adjusting the cut-off point accordingly, the system provides feedback-based control to prevent information loss in highlight regions while maintaining contrast enhancement.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2492907B1Image processing apparatus, storage medium storing image processing program, and image processing method
Publication Date: 2017.12.13 FUJITSU LTD
  • EP2492907B1 patent drawingFigure 1
  • EP2492907B1 patent drawingFigure 2A~2B
  • EP2492907B1 patent drawingFigure 3A~3B

AI summary

An image processing apparatus includes; a generation unit to generate a histogram of luminance values of a plurality of pixels included in an image; a luminance value calculation unit to calculate a first luminance value at which first ratio pixels of the plurality of pixels are present in descending order of the luminance values of the histogram, and a second luminance value at which second ratio pixels of the plurality of pixels are present, the second ratio pixels is larger than the first ratio pixels; a selection unit to compare the first luminance value and the second luminance value, and determine a third luminance value that is set a maximum luminance value in gradation correction; and a correction unit to perform the gradation correction that corrects the luminance values of the plurality of pixels on the basis of the third luminance value.