Chapter 1- Introduction, definitions

            What is a  video surveillance system?

        The video surveillance system (CCTV- closed circuit television) is a television system that operates within a closed cicle.From the point of view of public television, that is available for every person wich has a TV receptor, the images obtained from the surveillance system are available only to those connected to the cycle and having acces rights.

   The first CCTV  video surveillance system was used in 1950 and since then it became an important element in every  professional security system. The most simple video surveillance system is formed out of a camera connected to a   monitor. CCTV systems that are more complex include a big number of cameras, control devices, recording devices and more advanced images. Altough the equipments forming a  video surveillance system are various,  but the operation principle is  the same.
“The cycle”  is a  phisical conection -  a carrier cable of images    generated by the camera  and recorded/ visualised  on a surveillance monitor. With very few exceptions, the images are carried out  under a video signal format- called  composite (as it is  composed)  of an  75 ohmi impedance with a value of  1 V   (peak at peak).       When we need a higher resolution  (> 480 TV lines), some  equipments offer the posibility  of  transmissioning  a Y/C  signal type <<  lightness information (luminanta –Y)  - render separately  from the colour information ( cromatic signal -C)>>.

  On very  long distances  the transmission  by optical fibre  of the signal  became quite popular.Altough,  where these option is too expensive , the ISDN lines , the internet, the private  virtual  networks VPN   offer  an efficient alternative, specially  for those  surbeillance systems  that respond to the event.

The components of a video surveillance system

A video surveillance system  has 3 main components that operate togheter. Though many use to  grade the importance of these 3 components we assure you that each element  is extremely important because  neglecting one of them leads to vain planification of the other 2  elements.

Each element consists of an assembly of  very important elements wich I shall succint itemize rejoining with more detailed explications along  this manual.

1. Image assuming devices – described by video surveillance cameras (analog or digital), objects, pan/tilt propelling enabling vertical or horizontal movement of the camera, power supplies, etc.

2. Video signal   backgroud transmission also has 2 important components:                                            

3. Recording/Control/Processing/Visualization devices  include all equipments at wich the user has acces.
a.  Stand alone DVR or  capture boards installed on one or many video surveillance servers.
b. The software enabling recording/restoring images
c. Multiplexing devices
d. Equipment control devices PTZ (pan tilt zoom)
e. Surveillance monitor

Designing a video surveillance system

Designing a video surveillance system is a process that may seem easy at the beginning, but has important repercurssions on the obtained results.

Most of the time the user has precise  targets in his mind but does a  general cataloguation of the system. Try to define clearly what you want to see in that proper target:
a) to see if someone is out there (detection)?
b) what does the person do there (recognize)
c)to find out who is that person (identification)?

Also have in mind that near the target there is a known element as shape and colour. It will be a good comparison element because the shape of an object displayed on the monitor can be deceptive how much more so cameras privesc sub un anumit unghi.

 Atention! The human eye is much more impruved than many video surveillance cameras

Preconfiguration system


a) Where will your system be installed: interior, exterior, mixed?
b) Where will the surveillance cameras be located: hall, rooms, parkings, perimeter?Determine the light level in extreme conditions (ex: moonless night, day times when the sun lights up the perimeter directly, etc)
c) What kind of frames do you want: large angle (more than 90 degrees), normal angles (aproximately 70-40 degrees) or variable approaching/ backwoods.
d) What kind of power supply do you have? 240, 24 or 12V a.c
e) What the entire number of the cameras? (how many bodyguards would you hire for tracking the certain place. Atention, mainly they must be considered in inmovable places. The surveillance cameras that can “move” exist and can be expensive)
f) It is necessary for left-right  (Pan), up-down (Tilt), proximity (Zoom) movement of surveillance cameras.
g) Will the movement mechanism be used intensive in the interior (if needed)?
h) Will the movement mechanism have to bear extra charges (if needed) in the exterior ( snow layer, extreme wind conditions,etc)?
i) The installing pylons of the surveillance cameras  will be for: wall, ceiling or bulwark?
j) The contro, mechanism systems Pan& Tilt& Zoom will be self-acting (the camera has presetted movement chanells that follows) or manual (an operator uses these functions to monitor  the perimeter)?
k) The monitor will be:  14”, 17”, 19”, 21”? (it depends on the space you have, on the needs and budget)
l) What recording method do you preffer- PC with a capture board, video surveillance presetted server or digital recorder? (depends on  needs and budget)
m) What transission background is necessary –  coaxial cable , optical fibre?

Step 1: Choosing the video surveillance cameras. We can provide you any type of professional cameras. Elaborate the application and we'll recommand you the appropiate surveillance camera. If you want to choose by yourself please study the informations about cameras and their accesories.
Step 2: Chossing the objectives. Give us the details you want to see and the background where the camera will be installed. Take in consideration the distance from the subject and the terms of illumination  for a period of 24 hours. In case you want to record durring night time you can choose day/night cameras with or without infrared LED. 
Step 3: Choose the equipment you want to disply the images. Colour monitor, your own TV, PC, laptop. Piece of advice: In real life, when you wish to recognize someone, probably you'll have to see his face. The same thing happens with video surveillance cameras. To be able to recognize a person the  proper angle of approach is to locate a camera in his face.
Step 4: Choose what you want to record (attention you don't have to record even the empty halls durring night time. You can take in consideration a classical Video Time Lapse recorder or recently and much more efficient digital recorders. Also take in consideration human intervention at least).
Step 5: Do you want to record more cameras at once? Until few years ago the multiplexor was the only solutions. Now you can consider purchasing a digital recorder. Altough more expensive at the surface, it is much more efficient.
Step 6: Place your cameras. Do youalso want a self-control of their position? Then you need Pan& Tilt mechanism.
         The advantages of video surveillance systems:
          Beside property protection systems and application control, video surveillance systems present the following advantages:

• Assisting the authorities in traffic monitoring and implementing prompt reactions in case of emergency.
• Assisting industry managers in monitoring the technological  flows, loss identification and implemets corrective measures imediately.
• Monitoring hostile enviroments that aren't accessible to humans, for example nuclear reactors, furnaces, etc

Video surveillance systems offer an enhanced efficiency and a quicker problem  detection. The advantages of this type of system are:

• cost reduction respecting security;
• quicker answer in crisis situation;
• easier identification of the suspects:
• an increased safety feeling;
• simplicity and reliability;
• a better control on behalf of administration personnel beside their employees;
• a  discouragement psychological  effect for the potential bandits  (available for visible tracking systems)
  
  
  
• Chapter 2.  Video surveillance cameras
  
  Commonnesses
  
  The right choise of  a CCTV camera for a video surveillance system is not always easy to do, especially for those not having adequate experience in the field. There are many parameters that must be taken into consideration: technical specifications, the application they are used for, specifically needs of the client, the project's budget, and  last but not least the physical retrains of the location area.
  If we take into consideration the diversified proposals on the market at the moment (there are hundreds or maybe thowsands   camera types) it really is challenge to succed taking a decision, advisedly, so you can satisfy all the needs including the budgetary ones.
  

Most of the time is hard even for a professional fitter to choose the optimal ratio between price and quality.
Understanding CCTV variables offers the possibilty of making the right choise. The most important element from a surveillance camera is the image sensor CMOS  or CCD (Charged Coupled Device). This sensor converts the  light  focussed on it from the object into an adequate electrical signal. The signal is then analyzed by the electronic part of the camera sent off to a monitor where it is reconverted into image. In one word  this represents the image's track  from capture till visualization.
The “processing”way of image from the interior of the video  surveillance camera is very important.
Thus, from the point of view of signal processing we can talk about two types of  TV cameras: analogue and most recent, digital cameras.
Besides in closed TV circuits there are:

• Monochrome video surveillance cameras (black/white)(obsolescent)
• Colour video surveillance cameras
• Day/Night cameras that ensure  colour image durring day time and monochrome when the light intensity comes down a certain level. (recent)
• IR sensitive video surveillance cameras (the newest, colour) they can see both natural light and infrared radiation.

From the point of view of image quality- resolution- video surveillance cameras can be divided in:

• Monochrome (black/white) medium resolution  video surveillance cameras (320-420 TV lines)
• Monochrome high resolution  video surveillance cameras (500-600 TV lines)
• Colour low resolution video surveillance cameras (< 320 TV lines)
• Colour medium resolution video surveillance cameras (380-420 TV lines)
• Colour high resolution video surveillance cameras  (480-600 TV lines)
  
  An obsessive question- Cheap cameras?

On the market we can find a lot of  cheap cameras brought mainly from Asia. Although many would tend to include them in the cheap stuff(chinezarii) category from the beginning, the things aren't like that at all. We must take into consideration that approximate 90% of the calculating technique comes from Asia. Suchlike we could include an Intel Core QUAD processor in the cheap stuff category as it is made in Malaysia.
As long as this cameras have technical specifications according to reality and answer to our needs, they can be used without any backsets. I was surprised to observe that there are asian equipments like MC W 106 F having lesser RMA rate than pretences equipments like Bosch LTC 0440.  The production processor is nothing less than a sumary assembly action (CCD sensor production involve a very big  investment and the worlwide producers are very few: Sony, Sharp, Interline, LG). We must have in mind that  big names in the field have asian origins(Geovision, Provideo, Genway, Inovision, Everfocus, Acti, Eyeview, Mafco).

• The simplest and cheaper cameras offer a very good solution for unpretense residences, for small shops, grocery stores, small concerns and mostly where a safety plus is needed, with discounted budget.
  
  
  
  
  CMOS sensor vs. CCD sensor
  
  A video surveillance cameras's sensor is a component assuming luminous information focussed on the cameras's objective and change it in to electrical impulses. A simplified way to look on a sensor's structure is to think at  it like a bidimensional array with a few million photosensitive  cells. Every cell takes over a pixel of  luminous information.
  In the worl there are two different types of sensors well known. One of them is CCD (charged coupled device) and the recent rival CMOS (complementary metal oxide semiconductor).
  A question like :”Wich type of sensor is  better?” hasn't a clear response. There are too many variables to consider, from the producer and the sensor's model till  the camera in wich it is embedded. As we can't offer you a direct response to  this question  we'll give you a few details about each sensor.
  CCD sensor (charge coupled device) is the first sensor of his kind on the market. Obviously higher than the recent CMOS  this is made only by a few producers in  entire world ( Sony, Sharp, LG, Interline) thus the techological construction  process is  expensive.
  The characteristic of this sensor is that the luminous information transformed in to electrical impulses is displaced on the  sensor's surfaceand and  read  at the most proximate corner. An ADC device (Analog to digital converter) then converts the analogue information of each pixel into a digital value through measuring the charge's intensity. The result of this process is a very precise image with a low noise level and a high resolution increasing directly  proportion with the sensor's size. Another advantage of the CCD sensors is vechimea giving them a bigger maturity than their counterpart CMOS.
  

CMOS sensor (complementary metal oxide semiconductor) is newer than CCD.  If at the beginning it wanted to be a way of reducing costs it also meant a  qualitative reduction of the image, after that it became a thoughtful competitor of his predecesor.  Unlike CCD sensor, CMOS  has for each pixel (photodiode) a few miniature transistors that amplify and convert the signal from analog to digital and transport the information through conductors. The generated signal by the CMOS sensor is a digital one so it needs ADC devices. The great disadvantage is the fact that photons, out of wich the light pumping the sensor is composed, hit not only the photodiods but
also the incorporated  transistors due to the decrease of  sensor's light sensitivity. An advantage of the CMOS sensor is 100 times lesser  than a CCD sensor, making it ideal for digital photo cameras.
To resume what I've told above:
a) The CCD sensor is more sensitive that CMOS sensor (it creates a better image in terms of low illumination)
b) CCD sensor  creates an image with less noise that CMOS sensor.
c) CMOS sensor uses up 100 times less energy than a CCD sensor.
d) CMOS sensor costs less than CCD sensor because it can be made in huge amounts.

g) The majority of CMOS image sensors from cheap cameras on the market are low quality and that is why we recommend our clients to eighth CCD solutions.

Image sensor's dimension

CCD Sonny vs Shapr vs. Interline vs LG sensors

Tha's  another hard question. Mainly it is a problem of  subjective appraisal. From my own experience  I've seen that a Sony sensor creates a smoother image while a Sharp sensor  generates
pointed edges. I'm sure I haven't managed to enlighten you, but the truth is that we have clients that consider more qualitative Sharp CCD cameras than Sony CCD.
If I was to do a  sensor's rating based on my own preferences, this would be the order:

Monochrome or Color?

Is color a  trifle? Of course not, because color is part of the environment we live in. Besides shape, color is an important component  of visual information base on what  our brain analyses and makes  decisions. A human been recalls better the color things – it's easier to track and to identify a red jacket blond with bluejeans than a female in tones of gray. Color video surveillance cameras  bring a valuable extra information. And yet calssic color video surveillance cameras have a certain disadvantage (which begun disappearing once with the new technologies ).
In other words they need a lot more light than the monochrome ones to produce an usable image. Plus,  some monochrome cameras can also offer the possibility of infrared visualization, option used where the location of an extra lighting  source is not possible. The same thing is proof for the newest Day'Night cameras, which durring day time they're color and durring  night time tey became White/Black and can track an infrared  lighten scene.

Analog or digital camera?

Up to 1 or 2 years ago the main  majority of the CCTV cameras were analog, producing a satisfactory image at an acceptable price.
Lately, on  market started to appear spreadinglyIP Digital or Analog  Cameras with digital signal processing. The introduction of Digital Signal Processing (DSP) amplified the versatility of security cameras, also increasing the quality of color image.
The main element of a DSP camera is a PROCESSOR that commutes integrated circuits from the ancient CCTV cameras. This thing allowed video surveillance camera  manufacturers to offer on the market products with higher characteristics and easier to use.
DSP cameras divide into four categories:

• Video DSP surveillance cameras – Offering mainly a better  image in a larger light specter than analog counterparts and having a better price.
• Premium DSP video surveillance cameras- functionary speaking are more showing, enabling connecting-up in much more complex systems. These cameras include – intelligent BLC (WDR- Wide Dynamic Range- allowing different digital processing of several  independent segments)- automatic compensation,  inteligenta a contraluminii, movement video detection, distance adjust and control possibility (so called OSD cameras – on screen display).
• Normal camera – BLC camera, WDR camera
• SWDR camera (Super Wide Dynamic Range)- newer, allow individual processing of each pixel, thus enabling the extract of excellent images at any luminous conditions.

IP video surveillance cameras offer  digital into analog signal conversion advantage immediately after the take over thus improving the image quality especially on very long distances.

Advanced  functions of OSD (on screen display ) cameras:
Usually video surveillance camera's adjustment it's made with the help of some Dip- Switch, some  mini potentiometre, and many other adjustment specialized devices . As the new cameras were having more and more adjustment possibilities, it became practically impossible the use of switch traditional method. Thus two different ways imposed. The first way and also the cheapest, is functions automation, offering the best results maintaining the price relatively low.
Sometimes, when we talk about expensive/ brand  cameras  it came to a “classical” method used in computers and other instructions menus.  This way, the fitter can select the menus appearing on the monitor, all adjustment possibilities he wishes to modify thus obtaining a CCTV camera improved image. If at the beginning, this type of adjustment was locally made,  by means of a service monitor and of some buttons installed  on the TV camera, nowadays there are video surveillance cameras with long distance adjustment, or with the help of extra cables forming an own RS 485 protocols  net, and even newer, directly through coaxial cable. At coaxial cable a data converter is wired- cutie de comanda – allowing signal transformation from the computer through a RS 232/C  interface into a  coaxial cable conveyed signal. These adjustment signals are being decoded  in the long distance video surveillance camera.

BLC (Back  Light Compensation )
Camera divides it's slide into a number of areas  based on it's constructive type. These areas have, most of the time, different luminous levels. DSP calculates average radiation from these areas and form an usable image. The video surveillance camera adjusts the image  so that only clear objects should appear on it, otherwise we would only see shapes.
This innovation is ideal- for example- when the camera “watches” at a store's window. In the morning the sun can be in the left side of the window, so that on the left side  we would have brightened image while on the right side the image would be dark. Durring day time the sun places itself  so that in the afternoon we find it  on the right side of the window.
Most of the video surveillance conventional cameras (also cheap) can only offer a low image regardless the sun's position.
Digital cameras with Back Light Compensation intelligent circuit BCL/WDR/SWDR always calculate their position from which the disturbance is coming, adjusting their  parameters so that the image obtained it's clear.
 
Light-  an extreme agent in video surveillance

Estimating the quantity of  light in the area that needs to be monitored it's very important, when choosing surveillance cameras out of which a CCTV system would be composed. Without any exaggeration, the right estimation of light from a video supervised perimeter and it's periodical or any other kind of  changes, enables the increase till 30-40 %  of image quality generated by the surveillance system.
Although the human eye and camera's objective seem alike they operate in totally different ways.
While the human eye adapts quickly to light variations, the video surveillance camera it's much more flexible. In a video surveillance system, the luminous must be adequately  provided-  designed from the beginning to obtain the best result. The light type used and the right placement
of light sources  are essential to obtain clearer images.
The “Lux”- represents the international measurement unit of light level from a given area.  In well lighted up  areas a medium performance camera would be enough, from this point of view. Yet, for the areas where light is under 1 Lux you will need much more performant (performant) cameras. To determine the luminous level from a given area,  an equipment called “luxmeter” is used. Still, you might not have an equipment like this and that is why you should take in consideration the followings:

Day light- white light- is actually a compound of  different frequencies “color”light. Color video surveillance systems are more responsive to certain colors than others. A CCD  typical efficiency chart related to the wavelength  shows clearly that the maximum efficiency level is touched around  550 nm wavelength corresponding to green light. The best result are obtained when  camera's  spectral answer matches the type of light  existing on the tracked area.

 
This manual was elaborated by the Technical Department of  S.C. ELSI MULTIMEDIA S.R.L    and it's exclusive  addressed to resellers and to our clients. The manual is allocated free of charge. Not any part of the manual can be multiplied without written agreement of S.C. ELSI MULTIMEDIA S.R.L