Low-Luminance GSDF Display Extension
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Solution Overview
Problem
Current image display devices struggle to display images with gradation characteristics compatible with the GSDF standard at luminance levels below 0.05 cd/m2, as the DICOM standard does not specify JND indices for such low luminance levels, leading to non-compliance with the GSDF.
Innovation Solution
The implementation of an image display device with an image processing unit that defines and extends gradation characteristics to include luminance levels below 0.05 cd/m2 by using a relationship between JND values and corresponding luminances, employing a Barten-Model-based approach to calculate target luminances and JND indices, including negative integers and real numbers, to ensure compatibility with the GSDF standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the minimum luminance preset for the image display device is less than 0.05 (cd/m2), then the image display device can display images with high contrast ratio, but the luminance of the low-gradation display image is outside the GSDF and cannot comply with the DICOM standard
Solution Approach 1:
The patent extends the GSDF gradation characteristic to luminance levels below 0.05 cd/m2 by introducing a second gradation characteristic that satisfies the JND-luminance relationship. This parameter extension allows the display device to operate in ultra-low luminance ranges while maintaining perceptual uniformity through the Barten-Model-based JND calculations, thereby resolving the contradiction between expanded luminance range and GSDF compliance.
2Reliability
If the image display device uses the first gradation characteristic (luminance ≥ 0.05 cd/m2) to comply with GSDF, then it satisfies the DICOM standard, but it cannot display images with luminance less than 0.05 (cd/m2) effectively
Solution Approach 1:
The patent segments the gradation characteristic into two distinct ranges: a first gradation characteristic for luminance ≥ 0.05 cd/m2 that complies with standard GSDF, and a second gradation characteristic for luminance < 0.05 cd/m2 that extends the JND-luminance relationship. This segmentation allows the display device to maintain GSDF compliance in the standard range while enabling effective display in the ultra-low luminance range through the extended second characteristic.
3Illumination intensity
If the image display device extends gradation characteristics to luminance less than 0.05 (cd/m2), then it can display high contrast ratio images, but the JND Index for such luminance is not clearly indicated in the DICOM
Solution Approach 1:
The patent performs preliminary action by pre-defining the extended second gradation characteristic based on the Barten-Model and JND theory before actual display operations. The image processing unit stores and applies this extended characteristic, ensuring that JND indices are properly defined for luminance levels below 0.05 cd/m2. This preliminary establishment of the extended characteristic eliminates information loss when displaying ultra-low luminance images.
Data Source
AI summary
An image display device, image display system, image display method and computer program which are configured so that not only the gradation characteristic at the luminance over 0.05 (cd/m2) but also the gradation characteristic at the luminance less than 0.05 (cd/m2) satisfies the DICOM. The image display device includes an image display unit; and an image processing unit. The image processing unit is configured to display the image data on the image display unit based on first and second gradation characteristics, a luminance of the first gradation characteristic is 0.05 (cd/m2) or more, a luminance of the second gradation characteristic is less than 0.05 (cd/m2), the first gradation characteristic complies with GSDF (Grayscale Standard Display Function) gradation characteristic of DICOM standard, and the first and second gradation characteristics are defined to satisfy a relationship between a JND value and a corresponding luminance.