Driver Assistance Systems using imaging elements (e. g. parking assistants, night vision systems etc.) are a rapidly growing segment in the market for automotive safety and assistance systems. In order to fulfil the highest prerequisites in terms of quality and video display capabilities, which means the absence of artefacts, a seamless cooperation of all system components is mandatory. The following paper describes a parking assistance system using four camera sensors. This system implements CMOS image sensors supplied by OmniVision Technologies which are connected to an FPGA baseboard delivered by Xilinx through the serialiser/deserialiser (SerDes) chipset DS90UB901QSQ-DS90UB902QSQ from National Semiconductor (NSC). The cameras may be connected for a 360° surround view or used separately – with or without image stitching algorithms which are supplied by IP partner Xylon (brand name: LogicBRICKS). The interface chipset from NSC provides a bidirectional control channel with a minimum latency and general purpose I/O (GPIO) functionalities enabling a seamless frame-synchronous processing of the individual video data streams. This makes it possible to provide the highest image quality when combining the individual images into one single birds-eye view picture.
According to studies conducted by IMS Research the number of automotive camera modules will grow from 6.1 million units in 2010 to more than 34 million units in 2017, whereas parking assistant systems are said to cover the majority of these cameras' application market. As the resolution of CMOS image sensors within camera imagers permanently increases the video interfaces will have to cope with permanently rising data rates of several Gbit/s. For this application SerDes chipsets (serialiser/deserialiser) using differential signalling provide an outstanding interface solution for thin flexible cable connections without the need for additional protocol overhead of a controller/video processor.
FPD-Link Product Families
The FPD-Link product family is designed for serial interfaces of embedded displays and camera sensor systems (figure 1). The first generation of the FPD-Link product family was designed in the mid-1990s targeted towards