video based industry control

IEEE GMC2004 Oct.12 Shanghai

Wireless Applications in Video Based Industry Control

Dr. Jun Huang

Adjunct Professor, Carleton University

[email protected]

CTO, GenieView Incorporated

Communications Research Center, Bldg143701 Carling Ave. Ottawa, ON K2H 8S2, CANADA

www.genieview.com


http://www.delson.org/3g-4g/


Overview

• Abstract

• I: Video Based Wireless Monitoring and Control System

• II: Integrated Video Solutions and Applications

• III: Lab Simulation Results

• IV: Implementation and Field Experiments

• V: Summary


Abstract

- To describe the:- basic concept of Internet video based wireless

monitoring and control system- main characteristics and related

performances of wireless and Internet applications


I. Intro. to Video Based Wireless Monitoring and Control Systems

• The following topics will serve as an introduction and an overview to Wireless Applications in video based industry control.

• Video based monitoring systems went through three generations:- G1. Analogue Video Surveillance- G2. Digital Video Recording and Control- G3. Integrated Packet based Wireless Communication Control Command Coordination (C4) System


• Features:• Video and audio capture, transmission, and storage are all

analog• Mature in technology and functionality

• Drawbacks:• Suitable for small areas Low scalability• Cannot exchange data with computer network• Monitoring carried out only in the monitoring center Less

flexibility• Control & Automation functions cannot be easily added as an

integrated part of the entire system.

I. G1. Analog System


I. G2. Digital Video Recording (DVR)

• Most of these systems run on Windows and PC platforms with others running on Linux

• Two types of DVR:– VCR replacement: frame-by-frame compression and

multiplexing using JPEG/Wavelet compression or other proprietary algorithms

– Streaming video-based recording: based on H.263 or MPEG2/Sub-band type recording


I. G2. Digital Video Recording• Features:

– Video and audio’s capture and storage are digitized at the Control Center

– Exchanges data with other information systems– Transmission from monitoring point (camera) to monitoring control

center is in analog format

• Drawbacks:– From remote control point of view, transport media generally requires

expensive optical cable– Needs separate telemetry & command lines to the drop-side control-

point, parallel to the analog transmission line– New concepts like the distributed instant alarm system cannot be

implemented easily.


I. G3. Wireless and Packet Based System

• Based on IP

1) Video and audio are encoded and compressed using MPEG4 packet encapsulated into IP packet.

2) The packet is then transmitted through both wireless and wired network such as GSM GPRS or 3GPP network and Internet V4 or V6.

3) The signal is then processed by intelligent software in the monitoring center; the center will issue the reactive command to the remote site.


I. G3. Wireless and Packet Based C4 System

Advantage:•Originally these were three separate systems each dedicated to 2-way communications, feedback, control and command, and backup emergency coordination.

• Wireless IP allows the three networks to be merged into one integrated Communication/Control/Command/Coordination (C4) system, reducing both infrastructure and operation costs.

Challenge:• Providing robust link along the transmission/transport path that allows little error and low delay remote operations (ex. virtual reality/ tele-present) without unexpected stall of highly compressed data.

• Enough intelligence has to be embedded in different layers of the integrated communication and control system.


II: Integrated Video Solutions and Applications

• MJPEG• H.261/H.263/H.264• MPEG1/2/4• Multi-Layer Coding• Variable Length Encoding• Software Defined Devices and Databases• Fractal Video Decoding• Power Line Applications


II. MJPEG• MJPEG = Motion JPEG• Every frame is a compressed independent image• MJPEG Video stream = frame stream of JPEG images• Every frame is accessible• Used in video editing systems to produce high-quality and full-

screen HDTV video.

• Applications:– Tele-medicine, tele-home care and monitoring oil/gas/pipeline

construction– Used with 4G devices

• Drawbacks:– Low compression rate– High bandwidth (~2Mbps, E1/T1 required)


II. H.261/H.263/H.264• H.261 and H.263 are recommendations from the ITU.

Based on a similar technique they were designed mainly for teleconference over telephone lines. Also useful for scenic situations with less movement

• H.264 has included and improved MPEG algorithms. ex. In some remote control situation, for example,

unmanned power station, the high voltage switch can move very fast, to capture such movement, H.264 has to be employed.

Note that the computation complexity is still relatively high in the moment, if the battery is the only source of power.


II. MPEG1/2• MPEG1 ( VCD standard )

– video compression includes techniques for efficient coding of a life video sequence.

– targeted towards storage and retrieval of A/V on compact disk.

– coding bit rate goes up to 4~5Mbps

• MPEG2 ( DVD standard )– Goal: higher quality broadcasting– Has higher bandwidth usage


II. MPEG4• MPEG4 makes the best of mpeg1 and mpeg2. - Small file(mpeg1) with high quality (mpeg2)- Focuses on interactivity, flexibility, and scalability as well as

encoding/decoding of A/V under certain bit rates- Supports bandwidth from 5kbps to 6Mbps- Delivers a compression ratio in the range of 20-200. - Supports arbitrary size of resolution from 8x8 to 2048X2048.- Is being adopted by 3G multimedia phones

- MPEG4 is the most suitable technology available for interactive video service and hand held remote monitoring and control. Typical applications are unmanned vehicle/robot control and monitoring, temporary portable device for river flood monitoring, or similar event monitoring.


II. Multi-layer Coding• This paper proposes a multi-layer coding for video over

wireless control system working at ISM band or 2.5G/3G bands.

Basic Concept:• Using multi-layer FEC (Forward Error Correction) to

code both two way control, live video and still image signals, such that the reliable transmission can be realized.

• Overall architecture is displayed on the following slide


II. Overall architecture of GV Sensor Network


II. Multi-layer Adaptive Coding• A video receiver site, running on a laptop with minimum attached hw,

contains a deinterleaving system having an input configured to receive information, and a number of deinterleavers having corresponding de-interleaving lengths, each de-interleaver being configured to deinterleave the information (JPEG, MPEG or Control Signal) according to its associated deinterleaving length.

• A dynamic algorithm of processing information is proposed to receive information over the communication link, analyzing the received information to determine conditions on the communication link, adapting an interleaving length based on the determined conditions, and interleaving content to be subsequently transmitted on the communication link using the adapted interleaving length.


II. Variable Length Encryption*• In some mission critical applications the encryption of original

signal is mandatory.

• Ex 1: Communications between nuclear submarines, or submarine to satellite through repeaters on buoys

• Ex 2: video monitoring of nuclear power plant (strong encryption is highly appreciated)

• An interleaving system can work in conjunction with an encryption system, to reduce the cost.

• * Note: Patent pending.


II. Software Defined Devices & Database

• The software defined wireless communication radio architecture, for the above nuclear plant or submarine control and command applications, contains:– a configurable communication hardware component

for implementation at a non-wired communication device, and

– a central software component for implementation at a central computer (database) with which the communication device is configured to communicate.


II. Fractal Video Decoding• An interpolator is also provided in this study for

concealing errors in a damaged block of frame of an information stream comprising a number of blocks of information.

• The interpolator is configured to determine a distance between the damaged block and an undamaged block of information in the information stream, and to apply a weight based on the distance to thereby interpolate the damaged block, wherein the weight is one of weights that follow a Fractal distribution proportional to the distance.


III: Lab Simulation Results

• Simulation was performed in MATLAB

• Wireless channel and Internet loss model were used

• Simulated systems consists of one control and command center, four wireless drop side cameras, one Internet remote controller, and another GPRS remote reviewer.

• Aggregated upstream and downstream RF system payload data rate was set to 41.6 Kbps, 50 hops per second, with one beacon to synchronize transmitter and receiver, operating in TDD (Time Division Duplex) mode.


III: Lab Calculation Results

• Theoretical buffer size was calculated using modified BMPA/G/1 queuing model.

• The simulation value is obtained from a simple M/M/1 approximation.

• Emulation value is obtained using actual MPEG4 trace feed into a queue with vacation. Where the vacation time is about 10 % of the service time, representing the Windows MFC thread switching time within Control Center software.

• 10% is the hard real time target suggested by Open, Modular, Architecture Control (OMAC) user group for .NET mobile platform.


III: Lab Emulation Results


IV: Field Experiment

• Shown here is the preliminary Phase I experimental data collected for FCC stipulated hopping pattern, and MPEG4 Level 1 simple profile.

• The theoretical calculation assumes the link margin of 20 dB, BER of 3x10-8, Noise Figure of 20dB.

• Table 2 shows the result for the experimental setting where both FEC (including Error Concealment), ARQ (including CRC) are turned off, the purpose is to obtain the worst-case scenarios.


IV: Implementation and Field Experiment


IV: System Field Trial• In phase II test, we have turned on ARQ, with limited retransmissions,

between 1 to 10 times. The result shows that with increased allowed number of retransmission; the unit’s airtime is constantly being improved, from a number of minutes to few hours.

• In phase III test, we turn on both FEC and ARQ, the result is very promising, estimated reachable distance is 3km. However, due to the space limitation, the detail Phase III experiment data will be published in next paper.

• Figure 2 shows the boards made for the experiment.

Tx Rx

Camera Ethernet


IV: GPRS Experiment

• The test for 2.5G system (commercial GPRS network) is not quite acceptable for transmitting live video, the maximum reached frame rate is only 1 to 3 frame per second depending on the service provider’s bandwidth offering.

• The test for International Internet link is acceptable, firewall can cause some performance degrade.

• The live video is very well synchronized with Long distance voice call.

• Another test over International Satellite link is also acceptable perceived by our collaborators.


V: Summary

• Both simulation and implementation have shown that the transmitting bandwidth of current legacy spread spectrum system or 2.5G GPRS in operation is just enough to convey the MPEG4 video with moderate or very low frame rate.

• The overall system design needs to be very carefully engineered to balance the buffer size with error correction overhead, e.g. when we double the buffer size, the delay increasing allows us to tolerant up to 15% of FEC overhead.

• The structure of interleave should match with the error and loss pattern, otherwise the video quality degrades.


AcknowledgementsThanks to:

Prof. Dusan Mudric, Prof. Peter Liu, Prof. Amir Banihash, and their Master students Cathy Miao, Dick Chen at Carleton University Prof. XinShen Zhao at Southeast University

for initial discussions.Thanks to:

Ms. Mariana Vukic at Ottawa University andMr. Huaming Li at 3H Networks HongKong

for preparing the slides.

video based industry control

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