IMAGE TRANSFER PROTOCOLS : TFTP, HTTP, RTSP, RTP/TCP,
RTP/UDP
H.264 (MPEG4, Part 10)
iris
focus
( FCC, CE, RoHS, UL )
What is Binning ?
A CCD chip is an array of rectangular
(generally square) light detecting
regions called pixels (for picture
elements). Sometimes pictures can be
taken by combining the information in
adjacent pixels and make them one
effective superpixel. The figures below
represent a detector of 144 pixels with
the red squares indicating the current
binning mode.
Can you zoom in on that license
plate? Can you zoom in on his face?
Why can't you make this image
clearer. These are questions that
many forensic video analysts deal
with on a daily basis. To illustrate
the answer to these questions, let's
consider this image:
This
Monitoring image comes from
an
Avigilon
system's 16 megapixel camera.
With the above image in mind, let's
consider the outstanding advice from
the UK's Home Office Scientific
Development Branch:
To judge the quality of images
that will be necessary, you will
need to take into account the
purpose
for which CCTV is used and the
level of quality that will be
necessary to achieve the
purpose. The
Home Office Scientific
Development Branch (HOSDB)
recommends identifying the needs
of a CCTV system
by using four categories:
Monitoring: to watch
the flow of traffic or the
movement of people where you
do not need to pick out
individual figures.
Detecting: to detect
the presence of a person in
the image, without needing
to see their face.
Recognising: to
recognise somebody you know,
or determine that somebody
is not known to you.
Identifying: to
record high quality facial
images which can be used in
court to prove someone’s
identity beyond reasonable
doubt.
Take a look at the picture
above. Can you make out faces or
license plates? No. So, if your
purpose is to identify these
items, that picture view just
won't do.
With Photoshop, we can zoom in.
Let's see what happens.
This Detecting view comes
from zooming in a 16 megapixel
image.
We can now see the people and
vehicles more clearly. We can gain a
general awareness of types of
vehicles. We are closer to
identifying them, but we don't have
anything yet that will help us to
prove identity beyond a reasonable
doubt. We can zoom in further to see
if we can Recognise anyone.
This
Recognising view comes from
zooming in a 16 megapixel image.
At this level of magnification,
someone who knows this person or car
should be able to say, "that's him"
or "that's not the man/car you are
looking for." At this point, we can
begin to accurately describe the
individual in the scene. Let's zoom
in some more to see if we can
positively identify this man and the
car.
This Identifying view comes
from zooming in a 16 megapixel
image.
With a 16 megapixel image, we can
even zoom in closer than this image.
But notice what's happened along the
way. We've sacrificed field of view
for detail. No longer are we looking
at the whole parking lot
(monitoring). We can't see the other
people who are walking around
(detecting). In order to identify
this individual, we've had to zoom
in so far that we've excluded much
of this scene from our view. A CCTV
Installer might position a
camera/lens combination at a choke
point specifically to get facial
recognition whilst installing other
cameras around the area to monitor
and detect movement of unauthorised
persons.
But what about real life. The good
folks at Avigilon have a small piece
of a very large market. What if that
same monitoring image was only 4CIF
or 2CIF. Could we still zoom in and
identify the individuals in the
scene? You be the judge.
The image from Avigilon contains
15,824,256 pixels and can come in a
lossless RAW format.
This image contains only 426,400
pixels and is compressed.
With an almost 97% reduction in the
amount of available pixels and the
additional compression, the results
speak for themselves.
The result of zooming in on a low
pixel count image.
In order to address issues of
standardization of IP video
surveillance, two industry groups
were formed in 2008: the Open
Network Video Interface Forum (ONVIF)
and the Physical Security
Interoperability Alliance (PSIA).
While the PSIA was founded by 20
member companies including
Honeywell,
GE Security and
Cisco, and ONVIF was founded by
Axis Communications,
Bosch and
Sony, each group now has
numerous members. As of January
2009, each group had released
version 1.0 of their specification.
On a conventional PTZ camera, when you pan and tilt you physically
rotate the camera using electrical
motors. The zoom is controlled by
mechanically moving two lenses
closer together or further apart
dependent on whether you are zooming
in or out with the effect that
objects in view appear larger or
smaller.
Digital PTZ cameras don’t work in
this manner. The camera will first
capture a full image, usually in
megapixel resolution. When a user
decides to zoom in they are provided
with a section of the overall
picture. The pixels in this are then
enlarged so that the cropped image
is the same size as the original.
This gives the appearance that you
have zoomed in as objects are now
larger.
Is a feature created to maximize
image quality in low light
conditions by reducing image noise.
This is a standard feature
throughout the CCTV industry that
has been improved upon by Arecont
Vision
The picture in picture feature
effectively creates 2 separate
streams on the same camera in order
to enable you to watch 2 separate
areas simultaneously on one screen.
This feature is typically used in
scenarios where you are required to
have an overview of the monitored
area and also need to be viewing an
area under increased magnification.
Simply put you can zoom in on one
thing while also viewing the main
area under surveillance.
Power over Ethernet or
PoE technology describes a system
to pass electrical power safely, along
with data, on Ethernet cabling. The IEEE
standard for PoE requires
Category 5 cable or higher for high
power levels, but can operate with
category 3 cable for low power
levels.
A Bayer filter mosaic
is a
color filter array (CFA) for
arranging
RGB color filters on a square grid
of photosensors. Its particular
arrangement of color filters is used in
most single-chip digital
image sensors used in digital
cameras, camcorders, and scanners to
create a color image. The filter pattern
is 50% green, 25% red and 25% blue.
==============================================================
Auto multi-matrix white balance
Multi matrix allows for selective color
enhancement or alteration. Any
particular color can be selected or
"grabbed" and have its hue changed over
a range of approximately 22.5 degrees.
This allows for secondary color
correction, normally only possible in
post-production and is performed at full
bit depth.
Simply put the camera automatically will
balance and blend whites to produce
images with higher contrast between
light and dark areas.
==============================================================
Auto backlight compensation
Strong/large sources of light coming
from behind the main subject (such as a
person indoors that is in front of a
window) cause the light meter to
underexpose for the main subject. This
is because the light meter is programmed
to average the light, and the backlight
shifts the exposure calculated by the
meter cause underexposure. Your eyes
have the ability to rapidly adjust
should you look first at the window and
then the person, so you will not
perceive a problem when you see a normal
face. The film and meter cannot handle
this variation. Cameras that provide
automatic backlight compensation will
increase the exposure by a predetermined
amount. Check your camera manual to
determine how much this will be. With
other cameras, you will have to use an
expousre compensation control, or
manually over-ride the aperature and/or
shutter speed to increase exposure.
Auto Exposure
(AE) and Gain Control (AGC) >120dB
Exposure is how long the camera takes to
take a picture.
A long exposure time gets a better and
higher quality image when the camera is
still.
A short exposure is when the camera may
move or something in the picture may
move. So to keep it from blurring the
camera captures an image for a fraction
of a second.
Auto exposure does this automatically
analysing whats happening in the picture
to create the best of both worlds
basically.
Privacy mask
A privacy mask is a setting that is on certain cameras that
will allow you distorted or completely
block out a certain portion of the
picture. This becomes especially handy
in areas that needs surveillance but
provides privacy as well. By selecting
certain areas of the picture frame you
can add complete privacy to sensitive
items in peoples lives.
This function becomes very cool in
PTZ cameras. When the camera is
panned, tilted or zoomed, the mask is
repositioned and re-sized so that it
continues to cover the original masked
area. This ensures the same object is
always hidden from view regardless of
PTZ position.
Flexible cropping
When sending over any network it is
always important to reduce the amount of
information sent in order to maximize
networking efficiency. With cameras that
have flexible cropping you now how the
power to record and send only very
particular areas of your designation. In
the past users were only able to define
boxed areas to exclude from recording.
Today we have the ability to define odd
shapes as required thanks to flexible
cropping.
( FCC, CE, RoHS,
UL )
FCC -
FCC is the abbreviation for the Federal Communications
Commission. The FCC is responsible for
rating personal computers and other
equipment as either Class A or Class B.
The ratings indicate how much radiation
a personal computer emits: this rating
process is often referred to as
"certification." Almost all personal
computers satisfy Class A requirements,
which means they are suitable for office
use. Class B machines, which are
suitable for anywhere, including the
home, must pass more stringent tests.
Class B indicates that the machine’s
radio frequency (RF) emissions are so
low that they do not interfere with
other devices such as radios and TVs.
The FCC should rate computer
components and systems before they are
released for sale. The rating process is
usually the responsibility of the
manufacturer. For instance, before AOpen
releases a new PC system for sale, the
entire system is submitted to the FCC
for rating. FCC rating (Class A or Class
B) should be listed on the specification
sheet or box of each product a
manufacturer sells. Many customers,
especially large corporate customers,
will only accept FCC rated systems.
CE -
CE certification refers to a
product’s eligibility to be sold in the
EU, which is short for European Union.
The trading region defined by the EU is
called the European Economic Area (EEA).
If a PC manufacturer wants to sell their
products to any of the countries in the
European Economic Area they must obtain
CE certification: this law has been in
effect since January 1996. CE certified
products are identified by the CE Mark.
A product bearing the CE Mark has been
tested to all of the relevant standards
that the EU demands. The purpose of CE
certification is to form one body of
product safety regulations that can be
used to protect all the citizens living
and working within the EEA. This
harmonization of regulations allows
manufacturers to sell products to all of
the countries in the EEA with the only
limitation being the requirement that
each product carry the CE Mark.
RoHS -
commonly referred to as the
Restriction of Hazardous Substances
Directive or RoHS) was
adopted in February 2003 by the
European Union.[1]
The RoHS
directive took effect on 1 July
2006, and is required to be enforced and
become law in each member state. This
directive restricts the use of six
hazardous materials in the manufacture
of various types of electronic and
electrical equipment. It is closely
linked with the
Waste Electrical and Electronic
Equipment Directive (WEEE)
2002/96/EC which sets collection,
recycling and recovery targets for
electrical goods and is part of a
legislative initiative to solve the
problem of huge amounts of toxic
e-waste.
UL -
UL is the abbreviation for Underwriters Laboratories,
which is the leading third-party
certification organization in the United
States and the largest in North America.
As a not for profit product safety
organization, UL has been evaluating
products in the interest of public
safety since 1894. Manufacturers of PC
equipment submit their products to UL
for testing against UL safety standards.
When a product meets the standards for
safe operation set by UL, the product is
rated as UL Listed, meaning it is one of
the products listed as meeting UL’s
standards. UL allows manufacturers whose
products are UL Listed to label their
products with the UL Mark, which is a
distinctive mark that identifies the
product bearing it as one that has meet
UL’s rigorous standards for safe
operation.
To determine if a product has
been certified by UL, check for the UL
Mark on the product itself, not the
packaging or store display. Only
products that have been evaluated by UL
and found to meet their safety standards
are eligible to carry the UL Mark.
opto-coupled input and output
The opto-coupler is generally thought of
as being used to transmit analogue of
digital information between circuits
while maintaining electrical isolation
at potentials up to 5 000 volts.
