CG Video Brightness Compression for Wide Dynamic Range Display
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Solution Overview
Problem
Current display systems face challenges in accurately displaying computer-generated (CG) video images with a wide dynamic range due to limitations in brightness control, particularly in dark scenes, where the gradation property is poor and dynamic range expansion is difficult using general-purpose interfaces.
Innovation Solution
A processing device and method that generate a video signal for displaying CG video images by normalizing and compressing pixel brightness based on scene-specific brightness information, using a brightness control signal to optimize the output of the display device for each frame, thereby expanding the dynamic range and improving gradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general-purpose interface (HDMI, DisplayPort, etc.) is used for controlling display brightness, then the interface compatibility is improved, but the brightness control precision and frame-by-frame adjustment capability deteriorate
Solution Approach 1:
The patent segments the brightness control function into two parts: a general-purpose interface for basic brightness adjustment and a dedicated control interface for precise frame-by-frame brightness control. This allows the system to maintain compatibility through the general interface while achieving precise control through the dedicated interface, resolving the contradiction between versatility and precision.
2Ease of operation
If display brightness is controlled alone to expand dynamic range, then the control simplicity is improved, but the gradation property in dark video images deteriorates
Solution Approach 1:
The patent merges brightness control with video signal processing by implementing tone mapping that simultaneously adjusts both the video signal levels and display brightness. This combined approach maintains simple operation through unified control while improving gradation properties in dark scenes through coordinated signal and brightness adjustment.
3Device complexity
If the display device's constant dynamic range is used, then the device simplicity is improved, but the ability to display wide dynamic range CG video images deteriorates
Solution Approach 1:
The patent applies parameter changes through tone mapping that transforms the wide dynamic range CG video image parameters into the display device's constant dynamic range parameters. By adjusting the mapping parameters based on scene brightness information, the system maintains device simplicity while achieving wide dynamic range display capability through parameter transformation.
4Adaptability or versatility
If brightness compression is applied to pixels in the brightness compression range, then the dynamic range expansion is improved, but the processing complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-calculating the brightness compression parameters and creating lookup tables for the tone mapping process. This preprocessing approach enables efficient real-time brightness compression without adding significant processing complexity during video playback, as the complex calculations are performed in advance.
Data Source
AI summary
A display system, a display device, a processing device, a display method, and a program capable of displaying a CG video image with a wide dynamic range are provided. A display system according to an embodiment includes a processor that generates a CG video image according to a scene, and a projector that display the CG video image. The display system generates a normalizing level, a brightness compression level, and a brightness control signal based on brightness information of the scene. The display system generates a video signal including pixel data of a display video image from a rendering video image by compressing brightness of a pixel present in a brightness compression range specified by the brightness compression level and the normalizing level in the rendering video image.