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Police Computer Systems

By:Daniel CarboneDerek MartinezDarius JonesBahiru Balicha

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Project54 Introduction The current Mobile Digital

Video System is a part of Project 54.

Project 54 system combines police vehicle equipment into an internal network.

The system is powered by an embedded computer that deals with all the internal data, provides control to the system via manual and voice interface, and coordinates remote access to the vehicle resources.

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Goals

Increase the quality and capacity for mobile video recording systems by recording evidence in digital video formats on high capacity digital storage media

Introduce more interaction with the environment to extend the Mobile Video System (MVS) functionality

Create a versatile easy-to-navigate video database allowing the tagging and embedding of related information

Provide wireless remote access capability

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Digital Video Recorder (DVR-54)

PC based. Running Windows (or Linux).

Several Software and/or Hardware video encoding engines.

“Hot-swap” high volume HDD. TCP/IP network connection Serial port for connection to the IDB

bus.

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MPEG2 format MPEG is a set of standards for digital video

and audio signal compression. Based upon a number of compression

techniques The main compression technique is based on the

Discrete Cosine Transform (DCT) The standard defines how the DCT and

subsequent quantization process is used to reduce the data rate and the way video and audio data packets are multiplexed together to form the compressed data stream.

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MPEG2 The DCT compression technique leverages the fact

that adjacent pixels in a picture are usually strongly correlated being close to a common shared value

The DCT operates on a local area of 64 pixels organized into blocks of 8 x 8 pixels.

The DCT transforms mathematically the image data in a way that tends to group the common digital signal elements in the block together.

The DCT concentrates the energy into the first few coefficients corresponding to low spatial frequency variation. Many of the higher frequency coefficients are often close to zero due to the fact that a strong correlation often exists between pixels in a small local neighborhood

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MPEG4 format

A fairly new format. 1-2 years on the market. Still “in development”

MPEG4 allows the creation of videos with very high visual quality and relatively low file sizes

One of the most popular MPEG4 CODEC is DivX. (http://www.divx.com)

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CODEC comparison

Product RealProducer VirtualVCR VirtualVCR Osprey2000

CODEC Name: Mode: Resolution:

RealVideo8 Normal Motion320x240

MS MPEG4 v2Default320x240

DivX 5.21-pass qual. based320x240

MPEG2Program Stream702x480

Processor Load

54-63 % 34-38% 34-38% —

File Size (5 min video)

16.5 Mb 76.4 Mb 128 Mb 95 Mb

Rec. time (40 Gb HDD)

202 hours 43.6 hours 26 hours 35 hours

Test system - CPU — AMD Athlon™ XP 1500+; RAM — 128 MbTest system - CPU — AMD Athlon™ XP 1500+; RAM — 128 Mb

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Data storage Today’s technology provides large capacity hard disks

at a reasonable cost. These disks can hold more high quality video than any VCR video tape on the market. It is a very convenient and cost effective solution.

Full Hard Drive

Headquarters Video Storage

Video files are stored to an

40-60-80-120 Gb “hot swap” hard drive, which is detached when desired and/or full.

Cruiser Video Storage

Empty Hard Drive

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Routing Video Signals

Video

Switch

To Embedded PC

for monitoring

To PC DVR

Mobile Wireless Camera

Front View Camera

Rear View Camera

Control data

MPEG-2 CODEC

Video capture card

Using a Video Switch introduces flexibility in recording evidence from different camera views

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Recording Scenarios

Patrol ModeVideo is recorded from the Front View camera using the medium quality video engine

Alarm Mode

Front view camera > high quality video engineRear view camera > medium quality video engineMobile camera can be switched manually by police officer

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Interacting with environment

The Video System is designed to be “smart” and will be able to “decide” automatically in what mode to record and when to switch between them

These decisions are based on information about the current situation. For instance if the light bar is switched on then the video system switches to the Alarm Mode

This information is acquired by observing the internal data bus (IDB Bus) messages

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IDB bus and event processorThe IDB bus is an information channel for

messaging between the main computer and peripheral devices such as lights, siren, video system itself and other devices.

By “listening” to the data traffic on the IDB bus and catching “important” events using an event processor, the video system knows what is happening around it. For instance, if the main PC sends a command for the siren to turn on, the video system knows it is a sign of emergency and performs appropriately.

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Archiving Video The Video Database has to be a

synchronized set of video files and related text information. Non video information, such as GPS, radar readings, time/date, and notes must be correlated to the video data.

An easy way of database navigation must be provided (i.e., it is not an easy task to find a short fragment among tens of hours of video)

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Video Database Structure

MPEG4 video files

MPEG2 video files

Timeline

entries in *.log fileSiren Siren ActivActiv

ee

Siren Siren ActivActiv

ee

Siren Siren ActivActiv

eeNotes->

Notes->

Notes->

Notes->

GPS,Radar

GPS,Radar ->->

GPS,Radar

GPS,Radar ->->

Emergency marks such us “Siren Active” are introduced for search purposes: with them it is easier to locate an “important” video fragment

HDD

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“Endless Recording” feature

This feature introduces an optimization in evidence recording. Since video recording is

conducted continuously, a lot of disk space is wasted on “recording traffic flow”.

Video files that do not contain any evidence can be deleted, and a significant amount of disk space can be recovered.

Routine recoding

Emergency recording Siren

Active

THE ACCIDENT

There is always a delay between an accident and the reaction to it

This file isn’t important

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Remote Access Feature

It is assumed that the police cruiser will have a data link to main control office. Let us call it the “Dispatcher”.

Such a Dispatcher allows us to implement some additional features that will make the Video System more accessible, more autonomous, and from some point of view, more “intelligent”.

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Remote Access Features Remote Access to Video Database

Navigate the Database Download Evidence Obtain relevant system information (e.g.,

free space on the media) Remote Troubleshooting

The system can send SMTP (e-mail) messages to the Dispatcher regarding technical problems related to the video system in the car.

A technician can then log into the system using Telnet and attempt to fix the problem remotely

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Navigating the Video Database

The Dynamically generated web page reflects current DVR-54 information.

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Downloading Video It is desirable to allow access from the

cruiser remotely in cases of emergency. The major constraint in using this feature is

low speed data link (9600 bps is often a maximum)

There are several ways to decrease the size of visual information to transmit: Cut a small piece of video from a big file. Leave

only important scenes for transmission. Make snapshots from video files. Make a slideshow. It is more informative than a

snapshot but smaller than continuous video.

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The MVS Prototype:

IDB controller

IDB VideoSwitch

Virtual VCR

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Video Switch Design

IN0

IN1

IN2

IN3

OUT0

OUT1

OUT2

OUT3

IDB Bus

Front cam.

Rear cam.

Wireless cam.

User Input

Monitor

DVR-54 MPEG2

DVR-54 MPEG4.

User output

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Video Switch Design

IDB Board Circuitry

Video SwitchCircuitry

Power Supply CircuitryPower Supply Circuitry-5V +5V

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Video Switch Circuitry

to PIC controller + 5V

- 5V

GND

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Power Circuitry

+ 13.8V

- 5V

GND

Voltage inverter• -5V• 40 mA

Voltage regulator • 5V• 80 mA

+ 13.8V + 5V

Total current consumption is 120 mA

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Video Switch Design Features There have been reported issues regarding

the use of IDB boards and the quality of police radio reception which have been traced to EMI.

The following actions were taken to reduce EM noise from the video switch board : Ground planes cover top and bottom sides of

the board Shielded components are used where

necessary

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Video Switch Advantage The IDB Video Switch was not

designed exclusively for the DVR-54. The IDB Video Switch makes it

possible to upgrade the current Project 54 system with multiple cameras using existing in vehicle video equipment

Demonstration: ID Control video recorder with multiple camera set.

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Embedded platform for DVR-54

- CPU: AMD Athlon™ XP 1500+; - RAM: 128 Mb- Case: Aluminum chassis 200(w) x 181(h) x 280(d) mm- TV-Out and S-Video Out

PCI Slot x 2; USB port x 4: IEEE1394 port x2Serial Ports: COM1 COM210/100Mb Fast Ethernet LAN

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DVR-54 Software DesignDvr.java

Video Switch

MPEG2 hardware encoder

Video Capture

Card

IDB Bus

IDBcontroller

Video Data Base

WebServer.java

To cameras

IDBport.java Event

processor

DVRsharedVariables.java

dataLogger.java Log filePlaylist file

Virtu

al V

CR

enco

de.e

xe

MPEGrecorder.javaAVIrecorder.java

commandParser.java

TCP/IPconnection

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Remote Access

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Playback on Embedded PC

VideoPictureArea

Progress/navigation slider VolumeBrightness

Control Buttons

Video File Description field

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Playback on Embedded PC

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Other features (continue)

Monitoring

T.A.W MobileDigi-View Digital Eyewitness Scout Cam

Project 54 + DVR-54

In order to decrease the cost even more the Embedded PC and the DVR-54 can be integrated into a single unit

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Other features (continue)

Remote audio transmitter. This optional feature is used by many mobile video

systems. The DVR-54 has audio inputs that can be connected to several audio sources like internal MIC or Wireless receiver.

Triggering events for starting recording may include: light bar activation event, brake activation, airbag release, etc.

Triggers that do not have “access” to the IDB bus may obtain one in following way

IDB box

It is similar to “push-to-talk” button implementation

IDB Bus TTL inTTL in

brake activation switch

airbag release switch

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Conclusion This system has huge potential, but is

still in developmental stages. Cost is unknown as of yet, but the

system will most likely be ready for use by late 2004/early 2005.

Thanks to the University of New Hampshire for most of the information contained in this presentation.