Cypress CY62167EV18 Manual do Utilizador descarregar pdf (Página 17)

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8,121,078

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also

means

that

the

instantaneous

power

consumption

of

the

imager

can be

relatively

large

during

the

frame

capture

and

transfer

process.

In

an

alternative

energy

saving

implementa

tion,

the

compression

circuitry

including

the

required

memory

can

be

integrated

directly

onto

the

image

capturing

module

120

or

even

directly

onto

the

image

sensor

die.

This

further

integration

can

reduce

the

energy

needed

to

transfer

data

and

control

information

between

integrated

circuits.

The

sound

detection

module

122

can

generate

compressed

or

uncompressed

audio

data.

If

uncompressed

data

is

gener

ated

from

module

122

then

the

CPU

110

can

perform

the

compression.

The

sound

detection

module

122

can

also

oper

ate

at

low

power,

e.g.,

in

the

order

of

tens

of

micro

watts

and

provide

a

trigger

output

based

on

the

noise

level.

The

noise

level

triggering

event

can

be

detection

of

a

shock

wave,

detec

tion

of

breaking

or

shattering

glass

detection

or

other

similar

acoustic

detection

techniques.

In

some

implementations,

the

sound

detection

module

122

can

operate

continuously

and

a

positive

noise

trigger

output

can be

used

to activate

the

wire

less

camera 100

from

a

standby

mode.

Once

activated,

the

wireless

camera

100

can

initiate

the

various

processing

sec

tions

to

start

cycling

and,

for

example,

start

sending

the

sur

veillance

data

to

the

base

station

160.

In

another

noise-level

triggering

mode

the

sound

detection

module

122

and

the

image

capturing

module

120

can

con

tinuously

capture

and

store

an

on-going

window

of

surveil

lance

data

of

the

immediately

previous

seconds,

minutes

or

hours.

During

this

time

the

bulk

high-bandwidth

radio

104

can

be

inactive

in

order

to

save

power.

However,

once

motion

is

detected

some

or

all

of

the

previously

stored

information

can

be

transmitted

to

the

base

station

or

retrieved

in

other

ways.

This

allows

the

activities

that

occurred

in

the area

under

surveillance

prior

to

a

trigger

event

to

be

investigated.

In a

derivative

behavior

in

this

mode,

different

video

com

pression

algorithms

operating

at

different

rates

can

be

used

before

and

after

the

triggering

event.

For

example,

JPEG,

MJPEG

or

JPEG2000

type

compression

algorithms

can

be

used

during

the

pre-trigger

period

and

MPEG2

or

MPEG4

type

compression

algorithms

can

be

used

during

the

post

trigger

period.

This

can

avoid

losing

critical

captured

infor

mation

on

the

activities

in

the

surveillance

area

in

a

time

period

leading

up

to

the

triggering

event.

The

infrared

detection

module

124

can

operate

at

low

power,

in

the

order

of

tens

of micro

watts,

and

provide

a

trigger

output

that

indicates

motion

has

been

detected.

For

example,

the

infrared

detection

module

124 can

be

imple

mented

with

a

pyroelectric infrared

sensor

with

a

Fresnel

lens.

In

some

implementations,

the

infrared

detection

module

124

can

operate

continuously

and

a

positive

noise

trigger

output

will

activate

the

wireless

camera

100

from

a

standby

mode.

Once

activated,

the

wireless

camera

100

can

initiate

the

various

processing

sections

to

start

cycling

and,

for

example,

start

sending

the

surveillance

data

to

the

base

station

160.

The

ultrasonic

detection

module

126

can

operate

at

low

power,

in

the

order

of

tens

of micro

watts,

and

provide

a

trigger

output

that

indicates

motion

has

been

detected.

For

example,

the

ultrasonic

detection

module

126

can

be

imple

mented

with

a

ultrasonic

transmitter

that

sets

up

a

speci?c

sound

wave

pattern

that

is

received

by

an

ultrasonic

receiver.

Motion

of

objects

in

the

?eld

of

the

sound

pattern

can

affect

the

received

ultrasonic

pattern

by

the

receiver.

These

changes

can

be

detected

by

the

ultrasonic

receiver

circuitry

in

the

ultrasonic

receiver

and

this

event

can be

used

to

activate

the

wireless

camera

100

from

a

standby

mode.

Once

activated,

the

wireless

camera

100

can

initiate

the

various

processing

20

25

30

35

40

45

50

55

60

65

14

sections

to

start

cycling

and,

for

example,

start

sending

the

surveillance

data

to

the

base

station

160.

In

another

noise-level

triggering

mode

the

infrared

detec

tion

module

124

and/

or

the

ultrasonic

detection

module

126

and

the

compression

and/or

capture

processing

engine

can

continuously

capture

and

store

an

on-going

window

of

sur

veillance

data

of

the

immediately

previous

seconds,

minutes

or

hours.

During

this

time

the

bulk

high-bandwidth

radio

104

can

be

inactive

in

order

to

save

power.

However,

once

motion

is

detected

some

or

all

of

the

previously

stored

information

can

be

transmitted

to

the

base

station

or

retrieved

in

other

ways.

This

allows

the

activities

that

occurred

in

the area

under

surveillance

prior

to

a

trigger

event

to

be

investigated.

In

addition,

other

detection

methods

can

be

implemented

in

a

manner

similar

to that

described

above

for

the

infrared

or

ultrasonic

detection,

but

the

triggering

events

can

be

initiated

by

other

sensors

including

magnetic

sensors,

relay

or

micro

switches

and

window

screen

wired

detectors.

The

bulk

high-bandwidth

radio

104

can

be

a radio

fre

quency

and

baseband

chipset

that

implements

the

physical

layer

of

the

802.11

standard.

A

key

purpose

of

this

radio

transceiver

is

to

transfer

the

bulk

of

the

captured

and

com

pressed

surveillance

data

to

the

base

station

160.

The

MAC

and

other

circuitry

may

or

may

not

comply

with

802.11

standards.

The

chipset

transceiver

activities

can

be

power

cycled

based

on methods

which

will

be

discussed

in

further

detail

below.

Implementations

of

the

techniques

described

here

can

be

used

to

achieve

ef?cient

use

of

the

high-bandwidth

radio

104

in

terms

of

energy

per

bit

per

unit

of

range

(distance

between

transmitter

and

receiver)

transferred.

When

active

the

radio

can

draw

or

dissipate

relatively

large

amounts

of

power,

how

ever,

due

to

the

power

cycling

techniques,

the

power

con

sumption

of

the

wireless

camera

100

can

still

be

substantially

low.

In

particular,

modulation

techniques

that

use

broad

fre

quency

channels

in

the

order

of

5

MHZ

can

be

used.

This

is

because

these

techniques

exhibit

low

energy

per

bit

(of

data)

per

distance

of

transmission.

In

one

implementation,

a

multi

carrier

modulation

technique

such

as

orthogonal

frequency

division

modulation

(OFDM)

can

be

used.

In

another

imple

mentation,

a

spread

spectrum

modulation

scheme

such

as

code

division,

multiple access

(CDMA)

can

be

used.

The

low-bandwidth

radio

106

can

be,

e.g.,

a

low-overhead,

long-range

radio

transceiver.

The

low-bandwidth

radio

106

can be

a radio

frequency

and

baseband

chipset

that

imple

ments

any

low

power,

low-bandwidth

technique

that

will

likely

have

longer

reach

and

higher

reliability

than

the

bulk

high-bandwidth

radio

104.

One

purpose

of

the

low-band

width

radio

106

is

to

transfer

status,

control

and

alarm

infor

mation

to

and from

the

base

station

160.

In

receive

mode,

the

power

consumption

can be

extremely

low

in

comparison

to

the

bulk

radio

104

and

can

be

low

enough

to

allow

the

low

bandwidth

radio

106

to

operate

continuously.

For

example,

the

power

consumption

can be

in

of

the

order

of

tens

of

micro

watts.

Using

this

approach,

the

low-bandwidth

radio

106

has

a

low

power

mode

where

the radio

106

can

be

activated

to

respond

to

a

short

duration,

beacon

transmission

that

origi

nates

from

the

base

station

160.

The

bit

stream

information

contained

in

the

beacon

transmission

can

identify

the

correct

camera and

can

also

have

other

command/

status

information.

In

another

implementation,

the

low-bandwidth

radio

106

can

be

used

as

abackup

when

the

bulk

radio

104

fails

or

is

disable,

e.g.,

due

to

jamming

signals.

In

this

manner,

reliability

of

the

wireless

camera

100

can

be

increased

because

there

are

a

primary

high-bandwidth

radio

104

and

secondary

low-band

width

radio

106

for

redundancy.

In

certain

implementations,

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