Image Data Processing Frequency Component Segmentation
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Solution Overview
Problem
Image quality degradation occurs when performing image correction processes on compressed image data files, particularly due to block distortions introduced by high compression ratios, which are exacerbated by adjustments like gradation hardening.
Innovation Solution
The method involves splitting restored image data files into low-frequency and high-frequency components, performing image corrections only on the low-frequency component, and combining them to minimize block distortions and maintain image quality, specifically using techniques like unsharp masking and contrast-dependent USM for gradation and sharpness adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If image correction processes are performed on compressed image data files, then image correction functions can be provided, but image quality degrades due to block distortions from high compression ratios
Solution Approach 1:
The patent divides the image data into frequency components (low-frequency and high-frequency) and applies different processing strategies to each. The low-frequency component undergoes full image correction processes while the high-frequency component is processed separately or not at all, thereby preventing quality degradation from aggressive corrections on compressed data.
Solution Approach 2:
The patent applies different correction intensities to different frequency components. The low-frequency component receives full correction processing while the high-frequency component receives reduced or no processing, creating local quality differences that preserve overall image quality while enabling correction functionality.
2Illumination intensity
If gradation hardening operation is performed to obtain high contrast image, then image contrast improves, but block distortions are highlighted and image quality degrades
Solution Approach 1:
The patent segments the image into low-frequency and high-frequency components, applying gradation hardening only to the low-frequency component. This segmentation prevents the operation from amplifying block distortions in the high-frequency component while still achieving the desired contrast enhancement.
Solution Approach 2:
The patent applies gradation hardening locally only to the low-frequency component rather than the entire image. This localized application maintains contrast enhancement benefits while avoiding the highlighting of block distortions that would occur if the operation were applied to the complete image data.
3Quantity of substance
If compression ratio is increased to reduce data size, then transmission and storage burdens are reduced, but block distortions increase when restoring the image
Solution Approach 1:
The patent segments the restored image data into frequency components and applies correction processes selectively to the low-frequency component. This approach allows the system to work with highly compressed data while maintaining image quality through targeted processing that avoids amplifying compression artifacts.
Solution Approach 2:
The patent uses frequency component analysis as an intermediary step between the compressed image data and the final corrected image. By processing the low-frequency component separately and combining it with the high-frequency component, the system mediates between the quality degradation caused by compression and the desired correction outcomes.
Data Source
AI summary
An image data processing method and apparatus for performing image correction processes for a restored image data file obtained from a JPEG-compressed image data file which may prevent block distortions and provide a high quality image.A JPEG-compressed data file is read from the storage medium by the reading section, which is restored at the restoring section. The restored data is then split into a low-frequency component and a high-frequency component at the splitting section. The low-frequency component is subjected to the white balance, density, and gradation adjustments at the first image correction processing section and combined with the high-frequency component at the combining section to obtain a combined image data. The combined image data is then subjected to the sharpness adjustment at the sharpness adjusting section, which is outputted from the output section to a printer and reproduced as a printed image.