Developing an AVM Based on an In

(Source: QSI)
Network and System
Developing an AVM Based on an
In-Vehicle Infotainment Processor
The Around View Monitor (AVM) is a support technology for Advanced
Driver Assistance Systems (ADAS). The AVM system processes video
from four cameras which are mounted in the car, displaying the composite footage on the screen. The driver has a better viewing angle of
the surrounding objects. Hence, with the help of AVM, drivers will feel
more comfortable parking the car or driving through a narrow alley.
By Wen-Jing Lin
A
n around view monitor helps the
driver visually confirm the position of the car relative to the
lines around parking spaces and adjacent objects. So, how does it work? The
traditional AVM system uses a dedicated electronic control unit (ECU) for
two reasons:
➜ ➜The AVM system needs a lot of computing power because it has to perform continuous video processing
on four video channels. The video
frame rate is about 25~30 fps, frames
must not be lost and a dedicated ECU
is a simple solution to achieve it.
➜ ➜The AVM system (four wide-angle
cameras plus dedicated ECU) is ex-
26
pensive and mainly installed in highend vehicles. An AVM ECU can output
video signals to the display panel of
a head unit. For this kind of modular
design, the AVM ECU can be easily
connected to an existing head unit
as an external video input. But, this
comes at a cost and makes the popularization of AVM systems difficult.
Inside the AVM ECU, the main video
processing unit may be a video-grade
DSP or a high-speed, general-purpose
SoC. Both of them need lots of RAM to
store multiple video frames and ROM
to store the binary program. The interface to the four cameras is also important. An interface to four analog com-
Elektronik automotive Special Issue MOST 2014
posite cameras needs four individual
video decoders that convert analog
video signals to digital domain signals.
An interface to four digital uncompressed video cameras (LVDS etc.) needs
four individual digital high-speed receivers. Between four channels of digitized video signals and the video processing unit, there might be a video
multiplexer that can put all four videos
signals into one interface, so the video
processing unit has access to it. These
above components make up the AVM
ECU with a high bill of material.
At the same time, the evolution of
head units has sped up significantly. The
requests for true color, fancy user interfaces, 3D navigation and 1080p video
decoding as well as multiple displays
for Rear Seat Entertainment (RSE) have
forced chip vendors to design more
powerful, automotive-grade infotainment processors. Benefiting from the
fast evolution of embedded SoCs for
smartphones and tablets, the development of new infotainment processors
can also keep up with the trend. For
example, inside an infotainment processor there are:
Network and System
➜ ➜multi-core high-speed CPU
➜ ➜powerful hardware video codec engine (VPU)
➜ ➜3D graphics engine with OpenGL ES
support (GPU)
With such powerful mainstream automotive infotainment processors, Quanta Storage (QSI) can leverage the technology by developing more valueadded software functions. Examples
such as built-in Wi-Fi, internet access
and smartphone connection have become mainstream features for car manufacturers.
After evaluating the processor architecture, the AVM video processing functions could also be accomplished by the
infotainment processor inside the head
unit. Therefore, the development was
started from the analog camera AVM
system which coexists with infotainment
functions and executes simultaneously
on the same processor.
Analog cameras cannot achieve high
resolution and are vulnerable to car noise.
Therefore, a step forward to digital HD
camera AVM on the head unit is more
attractive. AVM with higher video quality
and less noise interference on a highresolution display is always welcome. QSI
has designed a multi-purpose platform
(Figure) for the development of head unit
MOST150 camera AVM and MOST50 RSE.
MOST150 cameras
Four MOST150 cameras, all built with
wide angle lenses, provide the video
sources for AVM. Each MOST150 camera
can be powered by a coaxial cable, and
the same cable also transmits low-latency and high-definition, I-frame-only
H.264-compressed video. The only
connection is the coaxial cable, which
is easy to install and reduces the need
for extra power and ground cables.
MOST150 interface board
QSI designed a multiple coaxial interface board that can support multiple
MOST150 devices/cameras in a star topology instead of the original MOST150
ring configuration. So, it eliminates the
reliability concern that ring topology is
not suitable for ADAS applications. This
board will also provide power and receive video streams from the same cable. Furthermore, the board acts as the
bridge between the infotainment processor and MOST150 cameras.
MOST50 rear seat entertainment
also includes MirrorLink, MiraCast, Apple iOS device link and more of the
latest popular technology via USB and
Wi-Fi modules.
Results: The latency is less than
100 ms between real objects and the
images shown on the AVM display. The
Besides the MOST150 AVM development
on this platform, QSI has also developed
MOST50 rear seat entertainment for
vans, MPVs and luxury sedans. The
MOST50 RSE is connected with the head
unit or other MOST50 RSE via
the MOST50 UTP network. It
MOST50 RSE MOST50 RSE
gets the audio and video from
the head unit and displays on
MOST150 Star Network
the LCD panel. Users can also
Power on Coaxial
MOST50 UTP Network
operate the buttons or the
touch panel and the RSE system
MOST50 Interface Board
MOST150
Interface
will send these control comVideo Video MOST50
Board
Encoder Encoder INIC
mands to the head unit, which
is capable of multiple display
interaction. That means no inMOST 150
Wi-Fi,
LC
fotainment processor is needed
Cameras
USB, BT
SoC
Display
MHL/HDMI
in the RSE. With this configuration, future system upgrades are
Multi-Purpose Head Unit
simplified by only upgrading
the head unit itself, prolonging
Figure. Architecture of multi-purpose platform.
(Source: Quanta Storage)
the life cycle of the RSE unit. For
CPU performance is less than 15 percent
example, rear seat passengers can view
for MOST150 AVM when using a 4-core
their cloud contents on MOST50 RSE via
infotainment processor. With its
the 3G/LTE radio in the head unit or
MOST150 AVM low resource requirethrough a smart phone connection.
ment, it allows 3D navigation, multiple
MOST50 interface board
fancy UI and audio playback to run simultaneously on MOST150 AVM.
The system can show different 3D UI on
The MOST50 interface board can send
four displays. And with the help of
multiple audio and video channels into
hardware video codecs in the infotainthe MOST50 network. Each video chanment processor, it can play back mulnel needs a video encoder to encode
tiple 1080p video files. In today’s ever
the uncompressed digital video signal
demanding automotive infotainment
generated from the infotainment promarket, such a setup (HU+2RSE) has
cessor. The compressed video then
become the new trend and will be
feeds into MOST50 UTP networks for
widely adopted by manufacturers.
the MOST50 RSE display. Besides audio
and video transmission, it can also acAs a result, the same hardware/softcess data from the MOST50 network,
ware platform can be reused to implewhich can extend applications like dual
ment the MOST150 AVM infotainment
head unit architecture.
head unit system along with MOST50
RSE support. The system can be enhanced further by integrating audio,
Multi-purpose head unit
video or navigation. Most welcome
advantage: The platform simplifies the
With a single mainstream automotive
overall system structure by reducing the
infotainment processor in the head unit,
number of ECUs within a car.
eck
the platform allows MOST150/MOST50
interface boards to run at the same time.
For MOST150 AVM function, the infoWen-Jing Lin
tainment processor has to decode four
is software manager of the
channels of 720p H.264 video streams
Automotive Business Unit at
of MOST150 networks. Each decoded
Quanta Storage Inc. (QSI), Taidigital video has to do fish-eye correcwan. He has designed and detion, view angle matrix transformation
veloped car infotainment and
and stitch all four videos, then output
ADAS integrated system archito LCD display to view the AVM video.
tecture.
Besides consolidating the AVM and RSE
[email protected]
functions, the multi-purpose head unit
Elektronik automotive Special Issue MOST 201427

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