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Browse Prior Art Database

Delayed Vertical Sync Generation

IP.com Disclosure Number: IPCOM000234801D
Publication Date: 2014-Feb-06
Document File: 3 page(s) / 102K

Publishing Venue

The IP.com Prior Art Database

Abstract

For Head-up displays the image has to be warped in order to achieve a straight picture after the projection on a curved windscreen. Performing this warping in the loop as part of the display controller leads to a significant delay between the vertical sync gap of the display and the gap showing up in the pixel fetch of the display controller. This imposes a problem to actually configure the stages of the display controller for which a potential solution is described in this article

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Title: Delayed Vertical Sync Generation

Abstract

For Head-up displays the image has to be warped in order to achieve a straight picture after the projection on a curved windscreen. Performing this warping in the loop as part of the display controller leads to a significant delay between the vertical sync gap of the display and the gap showing up in the pixel fetch of the display controller. This imposes a problem to actually configure the stages of the display controller for which a potential solution is described in this article.

Article

When integrating a warping unit for a Head-up display (HUD) projector into a display controller the processing pipeline of the entire system gets longer. As the display controller can only be configured during the blanking period of the display (i.e. in the vertical synchronization gap) it is no longer easily possible to configure the different stages of the display pipeline at one point in time.

Figure 1: Display Controller with Warping Feature

Figure 1: Display Controller with Warping Feature shows the components of a display controller with HUD warping feature in more detail. It consists of the following sub-blocks:

·         Input Stage: fetching the required graphic data (pixels) from memory, generate an output which e.g. consists of several input images blended over each other.
The Controller uses configuration data (Layer Settings) which might be updated from frame to frame. Usually the Controller pre-fetches data to be less sensitive to varying memory latencies in the system. This pre-fetch causes a certain latency of this stage.

·         HUD Warping: the block applying the distortion actually takes the pixels output by the Input Stage and geometrically distorts the image. To fulfill this task the HUD Warping block has to store several lines internally which causes significant latency.

·         Output Stage: applying a gamma correction, outputting the data with the required timing signals to a display....