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IP CCTV: What does pixel density mean exactly?

IN DEPTH An IP surveillance system may be used to observe and protect people, objects and people s activity inside and outside the objects, traffic and vehicles, money handling in banks, or games in casino environment. All of these objects of interest may have different clarity when displayed on a workstation screen. The image clarity depends primarily on the camera used, the imaging sensor, its lens and the distance from the object.

There is one parameter in IP CCTV that expresses the image clarity in a simple way with just one parameter: pixel density. The pixel density is usually expressed in pixels per metre (Pix/m), at the object plane, although it can be expressed in pixels per foot. Pixel density in IP CCTV sense should not be confused with the display pixel density quoted by various LCD display manufacturers which defines the screen density, in pixels per inch (PPI). The advantage of expressing object clarity with its pixel density is that it combines the sensor size, pixel count, focal length and distance to the object in just one parameter . When using pixel density metrics all variables are included and makes it universally understandable what details you will get on an operator s workstation screen. When designing a system, or a tender for a system, one can request pixel density for a particular image quality. So, instead of asking for a 6 mm lens for your camera in a particular location, for example (which means nothing without knowing the camera sensor it is used on), it would be much more useful if a particular pixel density is defined for the view. This will then be used to calculate the required lens for the particular camera used and the distance from the object. This will guarantee the clarity of the image (assuming the lens is focused optimally and there is sufficient light, of course).

Pixel density can be used for any object that IP CCTV user might be interested in: face, licence plate, playing card, money and similar. Let us now explore how many pixels per metre are attributed to various objects. One of the most commonly referred pixel densities is for Face Identification. Face Identification in CCTV means sufficient clarity of the image so that one can positively identify who the person on the screen is. According to Australian Standards AS4806.2, for Face Identification in analogue CCTV, we require 100% person s height to fit on the monitor screen display. The details of 100% person s height on a screen have been tested many times and it s been verified that they are sufficient for such a person to be identified. We know that PAL signal is composed of 576 active TV lines, so, according to AS4806.2, a person s height would occupy all of the active lines to make it 100%. Head occupies around 15% of a person s height, which is equivalent to around 86 lines (576 x 0.15 = 86.4), which is the same when converted to pixels (assuming recording is made full TV frame mode, which is equal to two TV fields). If we agree that an average person height is 170 cm, the head would occupy around 25 cm of that.

The pixel density at the object, which is required to make a positive Face Identification according to AS 4806.2, can be calculated to be 86 pixels at 25 cm of head height. Since there are 4 times 25 cm in 1 m of height, this becomes 4 x 86 = 344 pix/m. So, one can say that with pixel density of 344 pix/m at the objects plane it should be possible to positively identify a face, according to AS4806.2. Face Identification as per AS4806.2 Some other standards may require different values, and one such (newer) standard is the IEC 62676-4, which defines 250 pix/m to be sufficient (i.e. suggests that with slightly lesser pixel density than the AS standards one should be able to identify a person). Clearly, this number is not fixed in concrete, and it will depend on the observing ability of the operator, as well as other parameters (lens quality, illumination, compression artefacts, etc ), but the key is to understand that such a pixel density can be calculated for any type of camera, irrespective if that is SD, HD, 4k or any other format. The next image quality down, as defined by the standards is for Face Recognition. The details of Face Recognition image should be sufficient to recognise the gender of a person, what he/she is wearing and possibly make an assertion of who that person might be, if picked from a bunch of people that have already been identified somewhere else (e.g. passport or drivers licence photo).

This is basically an image with half the pixel density to the face identification, which according to AS4806.2 should be around 172 pix/m, while IEC62676-4 suggests 125 pix/m. Similarly, pixel density can be defined for vehicle licence plates visual recognition (not software automatic LPR). In the AS 4806.2, this is defined as 5% characters height on a display screen, which is around 30 TV lines (pixels) (to be very accurate 576 x 0.05 = 28.8). If we assume that a typical Australian number plate has characters of around 90 mm in height, than this equates to 11 x 30 pixels = 330 pix/m. The number 11 is obtained from dividing 1000 mm (1 m) with 90 mm. One may say that for visual licence plates recognition similar pixel density is required as for face identification. Licence plate recognition as per AS4806.2 When money and playing cards are observed in banks or casinos, many practical tests have shown that at least 50 pixels are required across the notes or cards longer side in order to positively identify the values. Standard playing cards dimensions are B8 according to ISO216 standard, which is 62 mm x 88 mm. So, we need the 88 mm card length to be covered with at least 50 pixels for proper identification.

This means around 550 pix/m (1000 mm / 88 mm = 11 => 50 pix x 11 = 550 pix/m) should be sufficient for playing cards. We may require slightly better pixel density for identifying money, since notes size is typically larger than playing cards, so if one takes the Face Inspection pixels density of 1000 pix/m, it should attain pretty good identification, although as it can be seen from the real life example below, even 770 pix/m might be sufficient. Playing cards and money shown above with 770 pix/m As it can be concluded from the above examples, the pixel density can be defined for any object and any camera, large or small. The beauty of the pixel density parameter is, as said at the very beginning, that includes all parameters influencing the clarity of the observed objects. For this reason, ViDi Labs has developed the ViDiLabs iOS calc (search the iTunes App Store under ViDiLabs calc ), a unique tool for the surveillance industry, which can also be used in cinematography, photography and any other imaging application dealing with objects details. So the following table can be used as a rough guide for various pixel densities. Free Download: The key to mitigating cybersecurity risks Exploiting IoT technology without creating cybersecurity vulnerabilities is one of the defining challenges in today s security landscape.

This report will help you to see why third parties should adhere to secure by design principles and why the necessary convergence of IT and security departments demands a holistic approach .

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Boblov 8GB 5x40mm HD Night Vision Monocular with 1.44 inch TFT LCD and Camera & Camcorder Function Takes 5mp Photo & Video from200m Distance for Hunting and Scouting Game / Security and Surveillance / Camping Fun / Exploring Caves / Nighttime Navigation / Night Fishing and Boating / Wildlife Observation / Search and Rescue / Nighttime Show/ Golf / Hiking / Bird Watching / Scenery @ securityblogs.co.uk

Boblov 8GB 5x40mm HD Night Vision Monocular with 1.44 inch TFT LCD and Camera & Camcorder Function Takes 5mp Photo & Video from200m Distance for Hunting and Scouting Game / Security and Surveillance / Camping Fun / Exploring Caves / Nighttime Navigation / Night Fishing and Boating / Wildlife Observation / Search and Rescue / Nighttime Show/ Golf / Hiking / Bird Watching / Scenery


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  • Magnification: 5x, Magnification and Objective: 5x 40mm
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  • Weight: 800g, Dimensions: 200x80x50mm. Viewing Range: 2m-200m (656 ft)
  • Battery Life: IR off is 1.5 Hours, IR on is 1 hours (included battery)
  • Rugged water-resistant housing; tripod mountable; Video out capability

” Specification
Outstanding optical clarity, high performance night vision
Wide field of view
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Images comparable to Gen 2+
5Mega Pixels CMOS vs image-intensifier tube
In-view 1.44″” TFT display
Adjustable eyepiece
Powerful infrared spotlight
200M viewing range


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Stoga Tcop1 Telescope 720P HD Display DVR Recording 12×32 Digital Photo Camera Outdoor Long Distance Binoculars with 2″Color LCD Screen @ securityblogs.co.uk

Stoga Tcop1 Telescope 720P HD Display DVR Recording 12×32 Digital Photo Camera Outdoor Long Distance Binoculars with 2″Color LCD Screen


List Price
£59.89

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£59.89


  • Battery: Built in rechargeable lithium battery.
  • Functions: The dual functions of telescope digital imaging and video recording and it can take a clear picture in darker environment,It has the function of HD imaging and HD video recording.
  • Simple to Use: No driver requested, easy to operation,and it is portable.
  • Superior Technology: High-definition digital telescope adopts excellent all-optical system and HD digital video function,it can capture instant wonderful pictures showing high resolution digital image to bring you the clear and beautiful visual enjoyment.
  • Applications: 1000 meters of vision.Best for outdoor sports, investigation of evidence, concerts, clubs, and adventure tourism enthusiasts Elegant,exquisite and fashionable.

Specifications:
LCD display: 2.0″ LTPS 4:3
Telescope Specification: 12 x 32
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Exit pupil diameter: 3.8mm
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Minimum focus distance: 8m
Video Format: AVI
Image resolution:1280*960/ 640*480
Video resolution:1280*960/ 640*480
Video Frame Rate: 30 fps
Still Image Format: JPEG
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Image sensor:1.3 Mega Pixels
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Support PC connect
Web Camera: Support/Free driving Language: Simplified Chinese, Traditional Chinese, Russian, Korean,
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Size: 193*141*77mm
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Dongres becomes new chief of president's security guards | Prague …

TK |

5 October 2012

Prague, Oct 4 (CTK) – Petr Dongres has become a new chief of the Czech president’s protection section to replace Jiri Sklenka who resigned after an airsoft gun attack on President Vaclav Klaus last week, Police Presidium spokesman Tomas Hulan told CTK Thursday.

Deputy police president Tomas Kuzel charged Dongres with heading the section on Wednesday, Hulan said.

The Lidovky.cz server has reported that Dongres is one of the most experienced members of the section.

A 26-year-old left-leaning man shot plastic pellets from an airsoft pistol from a close distance at Klaus in Chrastava, north Bohemia, last Friday. Then he left the site of the incident without Klaus’s bodyguards intervening and he even gave an interview to media before his arrest.

The attacker, Pavel Vondrous, said his act was to point to the fact that politicians did not listen to people.

Police later accused him of breach of the peace.

Klaus’s bodyguards probably failed. The General Inspection of Security Forces (GIBS) is checking their steps.

A group headed by Kuzel also looked into the circumstances of the incident.

It mainly blamed the bodyguards for not having detained the attacker.

The daily Pravo writes that the working group has concluded that the bodyguards failed as they had not taken the president to a safe place immediately after the incident.

Besides, the guards stood too far from one another.

An expert team also recommended to change tactics in similar situations. Kuzel was assigned to work out a concept of the personal protection services with the police.

Copyright 2011 by the Czech News Agency ( TK). All rights reserved.
Copying, dissemination or other publication of this article or parts thereof without the prior written consent of TK is expressly forbidden. The Prague Daily Monitor and Monitor CE are not responsible for its content.

KARE 2.4 GHz Wireless Security Camera System Video Audio Outdoor 8M IR 100M Wireless Transmission Distance @ securityblogs.co.uk

KARE 2.4 GHz Wireless Security Camera System Video Audio Outdoor 8M IR 100M Wireless Transmission Distance


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  • 380TV Lines for Clear Image Resolution and 24ft Infrared Night Vision
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Ideal Entry-level Security Solution for Home or Business
Protect Your Home & Secure Your Business – This wireless surveillance kit is great for your home, office, parking lot, supermarket or anywhere security is needed! This kit includes a 4CH receiver which features video audio output and 1 color night vision wireless camera for you to watch over your home or business.

Viewing the Cameras on your DVR/TV
Connect the receiver to a DVR for video recording using the video audio output. You can also connect the receiver directly to a TV for video watching without a DVR.

Day & Night/Indoor & Outdoor Video Surveillance
View live surveillance video any time of the day or night. The included camera with built-in infrared LEDs allow you to view up to a distance of 24 ft at
night for 24-hour surveillance. The LEDs automatically activate at night and the picture viewed turns to a black and white image. Also with sturdy weather resistant casing on camera, you can put it anywhere indoor or outdoor.

Wireless 2.4 GHz Transmission between Camera and Receiver up to 330ft
This wireless camera kit features a wireless transmission distance up to 330ft and night vision camera up to 24ft.

Built-in Microphone for Audio Monitoring
Enjoy listen-in audio from the built-in microphones.

Camera Features
* 1/4″ OV7930 CMOS
* 380 TV Lines for clear image resolution
* 8m infra-red night vision
* Wireless 2.4GHz transmission between camera & receiver up to 330ft (100m)
* Camera & receiver switchable between 2 cameras
* Sturdy weather resistant casing With Audio

What’s Include
2x 2.4GHz Wireless Night Vision Camera
1X 2.4GHz Wireless Receiver
1X Av input/output Cable
3X Power Supply Adapter
1x Remote Controller
1x User Manual


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