Tile-Based Image Generator for HUDs Reducing Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Head-up displays (HUDs) and helmet-mounted displays (HMDs) face challenges in reducing latency and certification complexity due to the power-hungry and short-lived nature of graphics processing units (GPUs), which lead to obsolescence and high re-certification costs, especially when a significant portion of the image is displayed as a uniform background color.
Innovation Solution
An image generator that divides the image area into tiles, storing only tiles with non-background color changes in memory, using a cache and buffer indices to minimize memory access and reduce latency, and employing a software-implemented interface with FPGA-based rendering to simplify certification and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a graphics processor unit (GPU) is used for image generation, then good performance is provided, but power consumption increases and device lifespan decreases
Solution Approach 1:
The patent extracts only the essential image generation functionality from a full GPU system, implementing a minimalistic renderer that handles only the critical rendering tasks required for HUD/HMD displays. This eliminates the need for power-hungry GPU components while maintaining adequate performance for the specific application.
Solution Approach 2:
The patent applies local quality by optimizing the rendering system specifically for the uniform background color characteristics of HUD/HMD displays. Instead of using a general-purpose GPU optimized for diverse graphics workloads, the system is tailored to handle the specific pattern of uniform background regions and foreground symbology, reducing overall power consumption while maintaining image generation performance.
2Productivity
If a graphics processor unit (GPU) is used for image generation, then good performance is provided, but device lifespan decreases
Solution Approach 1:
The patent extracts only the essential image generation functionality from a full GPU system, implementing a minimalistic renderer that handles only the critical rendering tasks required for HUD/HMD displays. This eliminates the need for power-hungry GPU components while maintaining adequate performance for the specific application.
Solution Approach 2:
The patent avoids using expensive, short-lived GPU components by implementing a simpler, more robust rendering architecture using FPGAs and custom logic that is designed for long-term reliability in avionic environments, matching the 25+ year service life requirements of aircraft systems.
3Productivity
If a graphics processor unit (GPU) is used for image generation, then good performance is provided, but certification complexity increases
Solution Approach 1:
The patent extracts only the essential image generation functionality from a full GPU system, implementing a minimalistic renderer that handles only the critical rendering tasks required for HUD/HMD displays. This eliminates the need for power-hungry GPU components while maintaining adequate performance for the specific application.
Solution Approach 2:
The patent changes the fundamental parameters of the rendering system from commercial GPU architecture to FPGA-based custom logic, which allows for deterministic behavior and easier certification to avionic standards such as DO-254 and DO-178C, while still achieving the required image generation performance for safety-critical displays.
4Reliability
If memory data for all tiles is stored, then complete image data is available, but memory bandwidth usage increases
Solution Approach 1:
The patent extracts only the essential pixels from each tile for storage in memory, specifically storing only non-background pixels and their coordinates. This selective extraction approach maintains image data completeness for rendering while dramatically reducing memory bandwidth requirements compared to storing complete tile data.
Solution Approach 2:
The patent applies partial action by storing only the necessary portion of tile data (non-background pixels) rather than complete tile data. This partial storage approach is sufficient for reconstructing the image during rendering while significantly reducing memory bandwidth consumption, especially for tiles dominated by uniform background colors.
5Adaptability or versatility
If image data is frequently accessed from memory, then rendering flexibility is maintained, but latency increases
Solution Approach 1:
The patent segments the image area into multiple tiles, allowing independent processing and rendering of each tile. This segmentation enables the system to process only the tiles containing non-background pixels, reducing overall rendering latency while maintaining the flexibility to handle different display scenarios by adjusting tile processing as needed.
Solution Approach 2:
The patent performs preliminary identification of non-background pixels within each tile before committing to full tile rendering or memory access. This preliminary action allows the system to skip processing for tiles that contain only background pixels, significantly reducing rendering latency while maintaining flexibility for tiles that do require rendering.
Data Source
AI summary
A method and apparatus are provided for generating image data for output to a display device such as an HUD or HMD defining pixels of an image for display. The image data for each pixel defines a predetermined background colour or a non-background colour. In an example implementation, the image generator comprises at least one image rendering module and a memory accessible by the at least one rendering module providing at least one frame buffer in which image data may be assembled. The at least one rendering module is arranged to process or to generate image data using a tile representation of an image for display, each tile comprising image data defining each of a predetermined number of pixels of the image. Furthermore, the at least one rendering module is arranged to store image data for the pixels of a tile in the at least one frame buffer only in the event that one or more pixels of the tile have respective image data defining a non-background colour or are enabled for display with a non-background colour, the pixels in the tile being otherwise assumed to be intended for display with the predetermined background colour. In this way the need to transfer data to and from the memory when generating and assembling image data is reduced, so reducing image rendering time.