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 .

Download now

The fight against the total surveillance state in our schools | Intrepid …

I would say there is a school-to-prison pipeline, but there is also a prison-to-school pipeline. The use of security hardware (cameras, metal detectors and retina detectors) and the practice of treating students as suspects are strategies of the criminal justice system, and they have been flowing into the schools. It s like a two-way street, a two-way system that mixes the educational and criminal justice systems.

The end result is that we have schools in which the learning environment has been degraded and undermined because we are teaching kids to fear and feel that they are suspects at any particular time. Educators talk about the teachable moments. Unfortunately, public fear of kids, public hysteria around another Columbine, has prevented people from remembering that the mission of public schools is to educate.

Annette Fuentes, author of Lockdown High: When the Schoolhouse Becomes a Jail House

The battle playing out in San Antonio, Texas, over one student s refusal to comply with a public school campaign to microchip students has nothing to do with security concerns and even less to do with academic priorities. What is driving this particular program, which requires students to carry smart identification cards embedded with Radio Frequency Identification (RFID) tracking devices, is money, pure and simple or to put it more bluntly, this program is yet another example of the nefarious collusion between government bureaucracy and corporate America, a way for government officials to dance to the tune of the corporate state, while unhesitatingly selling students to the highest bidder.

Oblivious to the impact on students fundamental rights, school officials with the Northside Independent School District (NISD) in San Antonio, Texas, have embarked upon a crusade to foist ID badges embedded with RFID tags on about 4,200 students at Jay High School and Jones Middle School. These tags produce a radio signal that is tied to the students Social Security numbers, allowing the wearer s precise movements to be constantly monitored.

Although the school district already boasts 290 surveillance cameras, the cards which the students are required to wear will make it possible for school officials to track students whereabouts at all times. Teachers are even requiring students to wear the IDs when they want to use the bathroom. NISD officials plan to eventually expand the $500,000 program to the district s 112 schools, with a student population of 100,000.

Hoping to achieve full student compliance with the profit-driven Student Locator Project, school officials have actually gone so far as to offer gift cards, pizza parties and raffle prizes to classes with the highest ID badge participation rates.

By any other name, you would call this bribery. No such rewards, however, await the students like 15-year-old Andrea Hernandez who resist the program on principle. Since voicing her objection to the program on religious grounds, Andrea has been stigmatized, penalized and discriminated against.

Those who, like Andrea Hernandez, refuse to wear the SmartID badge will also be forced to stand in separate lunch lines, denied participation in student government and activities, and prohibited from making certain commercial exchanges at school.

School officials at Jay High School reportedly offered to quietly remove the tracking chip from Andrea Hernandez s card if the sophomore would agree to wear the new ID, stop criticizing the program and publicly support the initiative. Andrea refused on principle, because she believes wearing the chipless Student Locator ID badge would signal that she endorses a program that not only violates her conscience but also runs afoul of her constitutional rights. As a result, Andrea now faces expulsion for refusing to participate in the school s money-making scheme. (The parallels to another so-called necessary taxpayer-funded program, full-body x-ray scanners in airports, are evident.

Of course, those scanners, which are now being relegated to a moldering Texas warehouse, turned out to be little more than a pointless yet costly means of enriching the security industrial complex.)

Just to be clear, these tracking devices are not being employed to prevent students from cutting classes or foster better academics. It s a money game. Using the devices to account for the students whereabouts on campus, whether in class or not, school administrators can count students as being in school and thereby qualify for up to $1.7 million in funding from the state government.

As Pascual Gonzalez, Northside s communications director, explains, The revenues that are generated by locating kids who are not in their chairs to answer present, but are in the building in the counselor s office, in the cafeteria, in the hallway, in the gym if we can show they were, in fact, in school, then we can count them present.

While this Student Locator program is not yet widespread, it s only a matter of time before we see more students facing the same struggle. Other student tracking programs are currently being tested in Baltimore, Anaheim, Houston, and the Palos Heights School District near Chicago. Some cities already have fully implemented programs, including Houston, Texas, which began using RFID chips to track students as early as 2004.

Preschoolers in Richmond, Calif., have been tagged with RFID chips since 2010.

Attempts to impose these tracking chips on unsuspecting young people have not gone wholly unchallenged. For example, in 2005 a school district in Sutter, California was forced to abandon their RFID project after a backlash from the community. In 2008, an RFID proposal concerning school buses in Rhode Island was abandoned after parent objections.

Unfortunately, while parents and students have fought back in some instances, they have yet to discourage the financial interest of the security industrial complex, which has set its sights on the schools as a vast, rich market a $20 billion market, no less just waiting to be conquered.

Indeed, corporations stand to make a great deal of money if RFID tracking becomes the norm across the country. A variety of companies, including AIM Truancy Solutions, ID Card Group and DataCard, already market and sell RFID trackers to school districts throughout the country, and with big names such as AT&T and IBM entering the market, the pressure on school districts to adopt these systems and ensure compliance will only increase.

In fact, corporations are going to great lengths to secure their profits by discouraging government officials from allowing students to opt out of RFID programs. In 2011, the Texas legislature considered a bill that would have prohibited certain mandatory student identification methods, limiting schools to only an opt-in method of student identification, qualified with the permission of a student s parent or guardian.

Michael Wade, representing Wade Garcia & Associates, a consulting firm responsible for installing the technology in Northside school district, testified against the bill, protesting specifically against the opt-out policy. The bill died in committee.

RFID is only one aspect of what is an emerging industry in tracking, spying, and identification devices. For example, schools in Pinellas County, Fla., now use palm reading devices to allow children to purchase lunch.

The reader takes an infrared picture of the palm s vein structure, and then matches that information with the child s identity.

50,000 students in the county are using the readers, and another 60,000 are expected to soon join the program. Palm scanning identification devices are spreading to hospitals and schools across the country, and can be found in over 50 school systems and 160 hospital systems, spanning 15 states and Washington, DC.

Due in large part to the technological and profit-driven collusion between government and big business, every aspect of our society, from schooling, to banking, to shopping, to healthcare is becoming increasingly automated and surveillance oriented. RFID tags, for example, are expected to replace bar code scanning in retail goods, and they are already found in American passports.

Palm scanning is likely to enter other industries that rely on identification, including retail, banking, and cloud computing. There are already palm-reading ATMs in Japan.

Without strong safeguards for privacy now, it will not be long before these technologies sold to us as being for our good and aimed at making our lives safer, easier and more efficient will come to dominate every aspect of our lives. And those who resist, like young Andrea Hernandez, will be cut off from basic goods and services and treated like second-class citizens.

We are generally taught to fear the stock images of tyranny: the jackboots in marching formation, the jail cell door, the batons cracking down on innocent skulls.

Yet while we should be vigilant against these injustices, most are wholly unaware of the invasive technologies which are slowly spreading across America: the tyranny of radio waves and Wi-Fi signals, infrared cameras, biometric scanners and GPS tracking devices, among many others.

These tendrils of the corporate surveillance-state are slowly coming to control all our daily interactions, and our nation s public schools are merely the forefront of a movement to completely automate all human interaction and ensure that no one is able to escape the prying eyes of government officials and their corporate partners.

About John W. Whitehead: Constitutional attorney and author John W. Whitehead is founder and president of The Rutherford Institute.

His new book The Freedom Wars (TRI Press) is available online at

Whitehead can be contacted at [email protected].

Information about The Rutherford Institute is available at


  1. ^ [email protected] (
  2. ^ (

Honeywell launches ONVIF-compliant PTZ dome camera range

Honeywell launches ONVIF-compliant PTZ dome camera range 1080p models in the new series from the surveillance solutions developer offer high image quality, SD card back-up and guaranteed interoperability The first products in Honeywell’s ONVIF-compliant HDZ PTZ dome camera range are designed to deliver interoperability between any IP-based physical security product. These all-new 1080p models will allow installers and end users alike to design and build network video systems with devices from any manufacturer. For added peace of mind, the indoor and outdoor pendant cameras also capture video on a micro Secure Digital High Capacity (SDHC) memory card, in turn providing back-up to mitigate against any failure with the network.

Equipped with a 360 degree rotation function and a zoom lens, the cameras are capable of delivering exceptional image quality and, as such, are ideally suited to environments that require detailed surveillance, including cities, roads, airports, Government facilities, schools, campuses and industrial sites. They can capture pictures of up to two million pixels with 20 x optical zoom functionality, thus providing the sharp detail required for accurate identification. Models in the HDZ PTZ dome camera range are also versatile, having been specifically built to deliver high quality performance in challenging environments.

All models are equipped with wide dynamic range to cope with high contrast and changing light conditions. Reliable operation in extreme conditions The cameras are also capable of operating reliably in extreme climates and weather conditions. The outdoor model has a temperature range of -45 C to 55 C, and is protected from dust and rain in an IP66-rated housing with tamper-resistant fixings and a vandal-proof polycarbonate bubble.

Easy and secure installation is also central to the products design and several mounting options are available, allowing the security installer to adapt to the end user s specific site requirements. For added flexibility of installation the cameras also have a bracket accessory available for in-ceiling mounting. In designing the HDZ range, we focused on providing flexibility of installation and operation, including interoperability with IP-based products from other manufacturers without compromising on superb image quality, commented Mark Openshaw, product manager (EMEA) at Honeywell Security Group.

The result is a range that’s easy to install and capable of protecting people and assets in a range of different environments.

The HDZ s user interface is available in eleven languages.

Prison Public Schools Use RFID Chips to Track and …

Susanne Posel
Activist Post1
Thursday, August 30th, 2012

In the San Antonio school district, the Student Locator Project2 (SLP) is being beta-tested at Jay High School and Jones Middle School two schools in the Northside district. The SLP includes the use of radio frequency identification technology (RFID) to make schools safer, know where our students are while at school, increase revenues, and provide a general purpose smart ID card.

In order to check out school library books, register for classes, pay for school lunches, the smart ID card3 is being employed to trace and track students and their movements on campuses all across America. By using leverage of educators to coerce school districts to adopt this method of tracking students, the argument for the use of the RFID technology is campus safety, efficient registration, and food and library programs.

In Austin, Texas, collaboration with the Global Positioning System (GPS) and RFID technology is being used4 to deter students from skipping classes. In fact, those students having a negative record with the school they attend are being targeted to be under surveillance.

An estimated 1,700 students have already been pledged to the program with parental permission. These students are assigned a mentor who oversees the actions of the students and to whom the students must contact on a weekly basis to report to. This is reminiscent of having a parole officer for student who have not committed a crime, yet are being touted as pre-criminals.

We are already being tracked through several modes 5:

Traffic Cameras
Computer Cameras and Microphones
Public Sound Surveillance
Facial Recognition

Even neuroscientists at University of California Berkeley used a technique where they monitored the brain activity of individuals as they listened to words being spoken. As the subjects listened to the words being spoken, a computer program analyzed brain activity in the temporal lobe, and how the brain interpreted and recreated specific words or sounds.

IBM is working on mind reading technology and a bar code reader that can read your DNA.

RFID chips used6 in cell phones can track a user within centimeters of their GPS location thanks to new technology being employed in smartphones. Apple, Google and Microsoft have been tracking their customers for years, storing personal digital data and collaborating with law enforcement and the Department of Homeland Security (DHS).

The CIA is able to remotely intercept7 and access every email, phone call, text message, chat, and even direct conversation supposedly held in the privacy of your own home.

Public Schools Use RFID Chips to Track and Punish Students For Pre Crime 3CIA Director David Petraeus spoke before Congress, speculating about the internet of things . Petraeus said:

Items of interest will be located, identified, monitored, and remotely controlled through technologies such as radio-frequency identification RFID chips, sensor networks, tiny embedded servers, and energy harvesters all connected to the next-generation internet using abundant, low-cost, and high-power computing . . . the latter now going to cloud computing, in many areas greater and greater supercomputing, and, ultimately, heading to quantum computing.

An indicator of these plans can be found on the underside of any electronic device in your home. Even on the underside of a simple calculator, toaster oven, and even your refrigerator; you will find the following:

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

What this disclaimer means is that this device is not allowed to jam or block any signals and must accept any incoming signal given (by FCC regulations under Part 15 of the FCC Rules).

The uses of these chips appear sensible and harmless until you think about the implications of being remotely tracked by nearly everything you own and come into contact. When a technology is imbedded in all facets of our lives, then it may come to mind to question its purpose. The RFID chip can and has been used to gather information an individual would not otherwise readily give.

Print Print this page.

Comment Rules8

Leave a Reply

You must be logged in9 to post a comment.


  1. ^ Activist Post (
  2. ^ Student Locator Project (
  3. ^ smart ID card (
  4. ^ being used (
  5. ^ several modes (
  6. ^ used (
  7. ^ remotely intercept (
  8. ^ Comment Rules (
  9. ^ logged in (