Compensating Variable Display Latency in VR Scan-Out
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Virtual reality (VR) devices with scan-out display technology experience non-uniform latency across the display panel, leading to distorted perceptions and discomfort for users due to motion during image rendering, as different portions of the image are displayed at varying times.
Innovation Solution
A method that predicts motion during latency periods between activating different portions of the display device, using forward-prediction and late-stage reprojection techniques, combined with knowledge of display panel latency, to distort images accordingly and compensate for latency variations across the panel, ensuring a more undistorted perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rolling scan-out display device is used to render images, then the display can be activated sequentially from left to right and top to bottom, but there is a delay between display of certain portions of an image, with the largest delay from a top left portion being with a bottom right portion
Solution Approach 1:
The system performs preliminary action by predicting user head motion before the image is fully rendered and displayed. Motion prediction occurs during the latency period, and compensation transformations are applied in advance to the image data before it reaches the display device, ensuring that the perceived image remains undistorted despite the sequential scan-out delay
2Adaptability or versatility
If motion occurs during image display on a scan-out display device, then the image can be updated to reflect current scene, but distortion occurs due to the associated display latency during the motion
Solution Approach 1:
The system applies local quality by implementing spatially-varying compensation across different portions of the image. Each region of the image is distorted by a different amount based on its position and the predicted motion, with transformation matrices applied locally to compensate for the scan-out latency at each specific location on the display panel
Solution Approach 2:
The system applies preliminary anti-action by pre-distorting the image in the opposite direction of the predicted motion. Before the image is displayed and before motion occurs, the rendering system applies compensation transformations that counteract the expected distortion, so that when the image is sequentially displayed with latency, the net effect is an undistorted perception
Data Source
AI summary
Examples described herein generally relate to displaying an image on a display device where a motion during a latency between a first time associated with activating a first portion of the display device and a second time associated with activating a second portion of the display device is predicted. At least a second portion of an image, to be displayed at the second time, is distorted based at least in part on a function of the motion and the latency to compensate for the latency. A first portion of the image is displayed at the first time by activating the first portion of the display device. The second portion of the image, as distorted, is displayed at the second time by activating the second portion of the display device.