Camera Zoom Contrast Correction via Dynamic Gamma Lookup
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Solution Overview
Problem
Digital cameras with optical zooming functions experience deteriorated contrast characteristics, particularly at high zoom magnification, leading to a 'flare' phenomenon where images lack contrast and appear black, which existing brightness correction methods, such as exposure control and software adjustments, cannot effectively address.
Innovation Solution
A digital camera system that includes an optical zooming unit, an imaging unit, a magnification acquiring unit, a gradation setting unit, and a correcting unit, which sets and applies gradation correcting information based on zoom magnification to correct image data gradation in real-time during photography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical zooming function is implemented to change enlarging ratio, then versatility of the photographing apparatus is improved, but contrast characteristics deteriorate at high zoom magnification
Solution Approach 1:
The patent applies dynamics by making the gradation correction amount variable based on zoom magnification level. The system dynamically adjusts correction parameters according to the current zoom state, transitioning from static correction to adaptive correction that responds to changing optical conditions during zooming operations.
Solution Approach 2:
The patent changes physical or chemical state parameters by adjusting gradation correction amounts and exposure correction values based on zoom magnification. The system modifies correction parameters dynamically to compensate for optical characteristics changes that occur at different zoom levels, thereby maintaining contrast characteristics across the zoom range.
2Illumination intensity
If exposure control is used to correct brightness, then brightness of the entire image can be adjusted, but contrast characteristics remain deteriorated due to zooming magnification
Solution Approach 1:
The patent segments the correction process into multiple independent correction amounts: exposure correction for overall brightness and gradation correction for contrast characteristics. This segmentation allows each correction to be optimized independently, with exposure correction handling luminance and gradation correction addressing the contrast degradation caused by zooming.
Solution Approach 2:
The patent applies local quality by providing different correction characteristics to different parts of the image data processing. Specifically, it applies exposure correction to adjust overall brightness while applying separate gradation correction to address contrast issues, thereby providing targeted corrections for different image quality aspects.
3Illumination intensity
If manual brightness correction software is used, then brightness can be corrected, but operation complexity and time consumption increase
Solution Approach 1:
The patent implements self-service by enabling the photographing apparatus to automatically perform brightness and contrast corrections based on detected zoom magnification. The system autonomously determines correction parameters without requiring user intervention, thereby eliminating the need for manual software processing and reducing operational complexity.
Solution Approach 2:
The patent applies preliminary action by pre-establishing correction amount tables and parameters that are ready to be applied automatically. The system prepares correction data in advance based on zoom magnification levels, so that when photographing occurs, corrections are applied immediately without requiring manual analysis or adjustment.
Data Source
AI summary
In a photographing apparatus, while a deterioration of a contrast characteristic caused by an optical zooming operation is prevented, superior photographic images are continuously acquired. Magnification set by an optical zooming function is acquired, and a gamma curve, namely gradation correcting information is set to a gamma lookup table, while the gamma curve is applied during a photographing operation based upon the acquired set magnification. A gamma correcting unit corrects gradation of image data (namely, RAW data) outputted from an imaging element by employing gradation correcting information set in this gamma lookup table.