Megapixels and Math

For the better part of a year, women in certain sections of Brooklyn, NY dreaded the walk home from the subway. A pervert was on the loose, sneaking up from behind, grabbing and groping them. Although he’d been caught on a surveillance camera and the video broadcast on all the local news stations, he remained at large. Viewers could see a youngish man in a black hoodie approaching and attacking but no one came forth to identify him.  The problem was that the quality of the video made it hard to make out the attacker’s face. In a black hoodie and jeans, he could have been any one of thousands, no make that millions of youths.

This was because the camera that captured the incident was a low-cost surveillance camera a  bodega owner had mounted on the entrance to his store, an  inexpensive analog cameras with low resolution and slow frame rate,  probably meant more to deter hold-ups than to give high resolution detail. The culprit was eventually arrested but a megapixel camera would have captured his face in clearer detail and resulted in an earlier arrest. A megapixel camera would also serve the bodega owner better should he ever be robbed.

What is a megapixel? A megapixel is one million pixels. So maybe the question should be what is a pixel?

A pixel is generally thought of as the smallest single component of a digital image, a single point in a graphic image. The word itself is taken from pix meaning pictures and element, short for picture element.         
The way a digital camera creates this copy of a color picture is with a CCD chip behind the lens, constructed with a grid of many tiny light-sensitive cells, or sensors, arranged to divide the total picture area into rows and columns of a huge number of very tiny subareas or light or pixels. The quality of an image, its resolution is dependent how many pixels are displayed and conversely the number of pixels depends on the size of the sensor. If a user wants to see facial features or license plate numbers, megapixel cameras will capture the most detail.

Typical Megapixel Camera Resolutions

Megapixels	Resolution	Total Pixels
1.3	1,280x1,024	1,310,720
2	1,600x1,200	1,920,000
3	2,048x1,536	3,145,728
5	2,592x1,944	5,038,848

To clarify things (no pun intended), let’s take a look at the “lowest” resolution camera in the table. It packs a frame with 1,280 x 1,024 pixels for a total of 1,310,720 pixels or to phrase it differently 1.3 megapixels. The highest non-megapixel camera a D1 using NTSC standards delivers 720x486 pixels per frame for a total of 349,920 pixels, 73 percent less pixels than the 1.3 mega. Not only does the megapixel camera offer finer detail than a non-megapixel but, with the use of the right software and web browser, it can also cover a wider field with the digital zoom feature. Higher resolution and greater coverage seems like a win/win situation. By minimizing the number of cameras he needs, a business owner can lower his costs without compromising his surveillance.
There is something else larger business owners contemplating IP camera networks should consider. The clarity of detail is dependent on the grid size of the camera’s image sensor: the denser the grid, the smaller the pixel ,the smaller the pixel, the higher the total pixel count of the frame. Yes, this results in better resolution but it also requires more bandwidth and increases storage requirements. And that is where compression comes in.
Video compressing is the process of reducing and removing redundant video data so that a video file can be transmitted using the least amount of bandwidth and stored using the least amount of bytes. An algorithm is applied to the source video to compress (encode) it and for viewing, the inverse algorithm is applied to (decode) produce a video that shows virtually the same content as the original source video. A pair of algorithms that work together is called a video codec (encoder/decoder). In   networks where some analog cameras are installed, a video encoder must be installed as well but in most IP networks the encoder is embedded in the IP camera
In order to insure compatibility and scalability (the ability to add more cameras) a codec must fit a standard. Different video compression standards use different methods to reduce data, resulting in different bit rates (transmission speeds), different latencies (the time it takes to compress, send, and decompress) and different quality of the viewed video. Different designers can use different tools to implement compression (encoding) and this is fine as long as the output meets the standard so that it can be decoded.
The different standards used are Motion JPEG, MPEG-4 part 2, and H.264.Within these standards lie different levels or degrees of capability to limit performance, bandwidth and memory requirements. The higher the resolution, the higher the level required. However for now it is sufficient to remember that each standard uses its own  algorithms. Thus  a MPEG-4 encoder will work with a MPEG-4 decoder but it will not work with a H.264 decoder, since it uses a different algorithm, and vice versa.
In our next entry we will explore features such as HD, PTZ capability, low light resolution, and the part software plays. Meanwhile if you are considering a  megapixel or any other type of surveillance camera, contact Kintronics at 800-431-1658 for information and sales. www.kintronics.com.

Solve the Access Control Problem: RFID +AVI = EZ AX-S

In the time you spent figuring out what the equation in the title means, The Tagmaster access control system could have verified the ID tag mounted in your car window and raised the entry arm to the parking lot.

 In case you’re still decoding, the answer is Radio Frequency Identification plus Automatic Vehicle Identification equals easy access. 

RFID is a tracking and identification solution using a wireless no-contact radio system to transfer data from a tag attached to an object for purposes of automatic identification. Unlike the ubiquitous barcode with its machine-readable parallel bars that store binary code, TFID tags have read and write capabilities. Thus data stored on them can be changed, updated, and locked. Another difference between the two is that while a bar code can only be read within line of sight, the RFID tag contains electronically stored information that can be read from yards away.

RFID when it was introduced in 1970, like any new technology, proved to be too expensive for wide usage. The transportation industry was among the first to adopt RFID tags, using them to to track large items, like cows, railroad cars and airline luggage, that were shipped over long distances. Mass production and time have lowered the cost and many business sectors have adopted its usage. The auto industry makes use of RFID tags to track the progress of an automobile through the assembly line. Pharmaceutical companies track drugs through their warehouses. Retail stores have adopted the technology to track inventory for stocking and marketing purposes. And it has become quite commonplace for employers to issue RFID tags in the form of access cards for entry to gated parking areas. This brings us back to the equation involving RFID and AVI.

TagMaster, a Swedish public company was a pioneer in the development of long-range identification systems uses radio frequency identification to identify vehicles at long distances with accuracy and speed. They have used the technology to effect secure and non-intrusive vehicle access control. At its most basic, a system is composed of a tag which holds the bearer’s unique identification data and a reader which can transfer the data for verification against a data base. Let’s take a look at one configuration.

The Reader

The LR-3, specially designed for parking applications, is a long range reader that operates on a 2.45 GHz radio wave frequency. It can identify ID tags as far away as ten feet. Thanks to its compact size it can be mounted on a pole or directly on the lane. The LR-3 requires a power supply ranging from 10 to 28V, and can be easily integrated into an existing access control systems using standard interfaces.

The ID tag

The ParkTag is partnered with the LR-3 for parking applications and operates on the same 2.45GHz frequency. When placed in the provided WinFix holder sleeve the tag’s information is read by the LR-3 as the vehicle approaches a lowered barrier or closed gate, and if verified, the driver gains access without ever taking her hands off the steering wheel or coming to a full stop. The ParkTag has a predictable three year life.

Tagmaster also has a solution for employees needing access to locked buildings and high security areas after they have parked their cars. 

 The CombiTag offers long range RFID enabled vehicle access as well as short-range personal access when installed with a selectable proximity solution such as HID’s IClass technology. The driver drives in to the parking facility with the CombiTag in place, then, once he has gained entrance takes it out of theWinFix holder on the windshield to use as a badge to enter any locked building or high security area whose entry doors are equipped with a proximity reader. There is no need to fish in purses or jacket pockets at the last moment.

If you are interested in finding out more about long range identification and access control feel free to call Kintronics at 800-431-1658 or visit is at www.kintronics.com

Analog Cameras vs IP Cameras: The Evolution of Resolution

Today we take a look at how your choice of an IP-based system of digital cameras or a CCTV system of analog cameras will impact the resolution of your surveillance video. 

Historically resolution was understood to mean limiting resolution or “the point at which adjacent elements of an image cease to be distinguished.” But the introduction of digital thickened the plot. For  our purposes, when we refer to a camera as being analog or digital we will be referring to the type of transmission it uses to send video to a computer or storage device: 

§  Analog transmission takes the video signal and modulates it into a continuous signal, amplifying its strength or varying its frequency then transmits it through coaxial cables to a security station for viewing on a PC or recording.  Upon reaching its destination, the wave is converted back to the original video signal. The term analog stems from the fact that the variations in the carrier wave are similar or analogous to that of the video signal itself.

In analog the term horizontal lines of resolution is important in understanding the clarity of an image. Horizontal resolution cannot be looked at without considering vertical resolution.  Horizontal resolution defines the capability of the system to resolve vertical lines thus affecting the clarity of an image on the screen. The vertical resolution is fixed by the standards defined by NTSC (525) or PAL (625 lines).  The terms originated with television and the test pattern below harks back to the good old days of TV. 

Engineers add converging vertical lines until they reach the point where the lines can no longer be distinguished one from another. This is called the measured resolution point. At this point the maximum resolution of the TV has been reached. Because the lines are stacked from left to right, the number of discernible lines across on the screen is called the horizontal resolution. This is expressed in a ratio. A television system with a 4:3 aspect ratio expresses the number of distinct vertical lines, alternately black and white which can be satisfactorily resolved in three quarters the width of a television screen.

Like TV, analog cameras use horizontal resolution as a measure of clarity, and since today’s cameras adhere to  established standards, the same number of scanned vertical lines is always transmitted depending on NTSC or PAL standard used. However, several factors impede the ability to display them as transmitted:

• The camera electronics
• The transmission
• The reception and reproduction of the picture
• The storage and re-processing of the picture.

Any of these can result in distortion, “noise”, or loss of clarity. But in the world of analog that is just a matter of fact, similar to pre-cable days when TV viewers  had little choice but to live with  interference, ghost images, and other vagaries associated with rabbit ear or roof antennas.

 As cable did for television, digital transformed viewing capability in IP cameras.

§  In digital transmission the signal is converted to binary form. Each sequence of numbers represents the color or brightness of a frame. Throughout its transmission, the signal retains this information  and  when it arrives at its destination, the computer or server takes all those 1’s and 0’s and reassembles them  back to the original frame. Digital as a term refers to this use of numbers code

A digital signal knows what it should be when it reaches the end of transmission and can correct any transmission errors that may have occurred. This translates into clearer, distortion-free images. Another advantage is that digital technology takes up a lot less space than analog with the result that a lot more 1’s and 0’s can fit into the same file that analog would use.

Each frame equates to one digital picture file and the more 1’s and 0’s, in that frame, the more information contained. While analog cameras measure resolution in terms of lines, digital technology measures it in units called pixels. The more detail and clarity captured, the more pixels used. Cameras capable of capturing detailed images are called megapixel cameras.

As with analog, horizontal and vertical fields are captured and blended together to make a single frame. Here too, the resolution is expressed in a ratio. In ascending order of clarity, the standard resolutions are

·         VGA (640x480 pixels),

·         SVGA (800x600 pixels) and

·         XGA (1024 x 768 pixels).

Obviously, the more pixels it contains, the larger the file. And here we run into the need for compression, a nice tidy break point if ever there was one!

In a future post we will discuss pixels, megapixel cameras, what they are capable of capturing, how the information is stored, and how the necessary compression translates to frames per second.

How Kintronics Engineers IP Systems

The Video Encoder Bridge

Put yourself in Mr.Bobka’s shoes. His company has invested in analog CCTV cameras over the years until they have quite an extensive network throughout his manufacturing facilities. Now he’s hearing there’s an IP camera revolution a-foot. If he converts to an IP-based surveillance system, he’ll see a quantum leap in the quality of his images; his costs will be lower due to the ease of scalability; and event management will be so much simpler using the intelligent video features available. Yes, it sounds good. Maybe he should update his security.

 But then he begins to crunch the numbers. He’s not looking at one or two cameras. And the ones he has aren’t giving him any problems. Discarding them would be like throwing money away. Same thing for the cabling; he’s invested quite a lot in laying coaxial cables. He’s not so sure this is what he wants to do.

Mr Bobka is not alone. It’s been estimated that of the more than 40,000,000 surveillance cameras operating on the planet, 95% are analog. And since the lifetime of your typical analog surveillance camera is five to seven years, many of them will be in good shape for years to come. Between the capital outlay and the necessary down time, replacing their analog cameras begins to look like a daunting proposition.

Well, Mr Bobka can just relax. The best of both worlds can be at his fingertips. He does not have to convert in one fell swoop. He can leave his analog cameras and cables in place and use them in conjunction with any new IP cameras he adds. What he needs is a video encoder. Also known as a  video server, a video encoder contains electronics that takes incoming analog video signals compresses and converts them into digital video. This video stream, identical to that of any coming from an IP camera, can now be transmitted for live viewing and video recording on any of the computers on the network. Video encoders use compression standards such as motion JPEG, MPEG-4 or H.164 so they are economical in the areas of storage and bandwidth as well as scalability.

With a video encoder Mr Bobka can avail himself of many functions attributed to an IP system such as

·         Controlling a pan/tilt/zoom  using  a joystick or mouse

·         Distribution of video motion detection

·         Tamper alarm

·         Event management

·         Audio support

·         Easy addition of more cameras that have megapixel capability

Since digital images retain their quality no matter how far they travel, standalone encoders with single or multi-channel connections positioned close to the analog cameras provide a solution for cameras in a remote facility or where the setup is some distance from a monitoring station, However security officers overseeing a large centralized system might choose high density racks with blade versions of encoders. Depending on the size of the operation, blades are available that can support one, four, or six channels. Racks can be outfitted with a mix of blades, thus accommodating anywhere from one to eighty four analog channels. 

It all sounds well and good, but Mr Bobka might have one last concern? Image quality. After all that’s what it’s all about, isn’t it? Yes, and here he’ll have to do due diligence for not all video encoders are equal. He wants to choose one that can give him image fine-tuning as well as aspect ratio correction to avoid PC screen distortion.  So there he has it, a flexible and expandable system for migrating all his analog installations to network video with resulting high resolution video, progressive scan, megapixels, and HDTV quality images. And when he adds or removes any of the blades, hot swapping means he won’t need to shut down the system.

Kintronics helps the Mr Bobkas of the world every day, customers who want to embark on a gradual evolution from analog while enjoying immediate IP images.  Sound like you? We’re here if you want to call. Contact us at 1-800-431-1358 (in the USA), or +914-944-3425 (outside the USA) or use our contact form.

The Road from Then to Now

 IP Camera Solutions:  Route One

2011 marked the fifteenth anniversary of the IP camera. The first network camera, the Axis 200 was introduced in 1996.With its low resolution images and its fps of one, it was not developed as a security application but rather as a nanny camera.  So how did we get from there to here? By travelling a long road filled with upgrades and innovations. Let’s travel it.

VCR-based analog CCTV system

For the past thirty years, analog cameras have been, and still are providing ample video surveillance.  Pre-IP, the typical set-up consisted of installed analog cameras feeding footage through analog coaxial cabling to a multiplexer to be viewed on a monitor or stored on a VCR.

DVR System

 DVR-based analog CCTV system  

The mid-nineties also witnessed the arrival of the DVR on the scene. It replaced the multiplexer and the VCR. It provided digital recording, not only improving image quality but also eliminating the need to change and store bulky cassettes. Finding exact video sequences in police investigations became less protracted. 

Network DVR-based analog CCTV systems

The addition of a network connection spread viewing capabilities beyond a single monitor. This was a two way street since it also allowed an operator at a remote PC to view as well as operate the camera. 

Video-encoder-based network video systems

The addition of the video encoder was a pivotal step on the way to an open IP-based video solution. Analog cameras were still employed but now along with video management software, video could be continuously transported over a network. 

IP Camera System

IP camera-based network video system

Many long time analog camera users are phasing them out and replacing them with IP cameras. Taking advantage of digital technology IP cameras supply consistent image quality and transport it to viewers at whatever location. Video Management Software adds endless applications and solutions.

This has been the interstate express route. In upcoming blogs we’ll explore a few scenic offshoots. So gear up and keep your engine running.

Next stop: Exploring video encoders - now and then.

Step Right Up. Look this Way

The day when access badges and PIN codes will be outdated may be coming. Facial Recognition Technology is a hot topic these days. It is popping up online, in newspapers, and on TV. All you’ll need to bring with you will be your face. And when that day comes your face may prove to be your best friend, or your worst enemy.

Trying to check your text messages? Can we see you first?

Recently, Google and Samsung introduced Galaxy Nexus, the first Smartphone to feature Android 4.0 Ice cream Sandwich platform.  One of the innovations this new mobile OS offers is facial recognition. Upon setup, the user looks into the screen so the phone can scan and store her image. That’s all it takes. On subsequent uses, she only has to look into it and if the real time scan matches the stored image, access is approved and the phone unlocks, all in less time than it takes to read this sentence.  

Are sure you’re not on the Most Wanted List? Let’s see

The FBI is preparing to inaugurate a nationwide facial recognition service by January 2012. Authorized personnel of participating states will be able to upload a photo of a suspect into the bureau’s biometric identification system. If there are possible matches, a file of mug shots ranked by similarity to the facial features of the person in the the photo will be sent to the inquiring agency. 

Are you on the VIP list? Let’s take a look.

In reality, there will be no VIP list, just faces. Facial recognition verification procedures are already established at business such as banks, retail stores and places of amusement where registered customer enjoys VIP privileges. When one applies for membership, her/his face is scanned into the system and on subsequent visits a real time scan must match up with the stored image in order to gain access. 

These practices all work will for one-on-one identity checks but what about time critical locations such as airports, train stations and sports arenas where steady streams of people pass through gates and checkpoints. Scanning faces one at a time would result in a huge bottleneck and a loud outcry. Kintronics is looking at solutions that would allow traveler’s scanned faces to be compared to images of terrorists on a watch list,   gamblers visiting casinos, to known card counters, and shoppers at shopping malls, to convicted shoplifters, all without slowing the pace of foot traffic. 

One such software product works with real time video. First off since this solution makes use of biometric analysis of facial features there are certain requisites that apply:

·         IP Cameras should be mounted at eye level of a person of average height.

·         The face should be visible in as close a frontal position as possible with a pan or tilt of no more than +/-15 .

·         It is critical that the eyes be visible.

·         Only minor parts of the face may be covered.

The video streams to a Tracking Station where it is analyzed for face visibility, position, and rotation angle, relying heavily on eye position.  Next the face is cropped from the frame, scaled, and rotated to a size of 128x128 pixels. The extracted face is then time stamped and given a camera identifier before being sent on to the Watch List station. 

Here it is compared to a data base of similarly configured images of persons on targeted watch lists of   terrorists, kidnappers, fugitives. If a match is made, an alert is issued and sent to manned alert monitors dedicated to receiving and displaying just such alerts, allowing security officials to focus on the identified person. 

Video content analysis like any analytic process is developed and tested in controlled cooperative parameters. Unfortunately video surveillance is neither controlled nor cooperative. Environmental problems abound. For example:

·         Cameras mounted improperly, e.g. on a ceiling mount, will give a bad pose angle

·         Bad illumination will result in indistinguishable texture information in the facial area

·         Thick lenses or sunglasses impede proper face recognition

·         An unstructured location offers suspects an opportunity to hide.

Some of these difficulties can be eliminated, the simplest and most direct, being camera placement. Since a frontal image offers the best chance of recognition cameras can be installed at the end of a long hallway approach or at the bottom of an escalator. One clever trick might be mounting a camera close to an information screen such as arrivals/departures in an airport. Illumination problems indoors can be minimized by adjusting the artificial lighting or using dim outs but outdoor cameras where the light changes as the day goes on proves more of a challenge. But if a person wants to take an indirect route behind pillars or crowds, hide behind dark or reflecting glasses, or cover his face with his hands there are no corrective measures and the system will be thwarted.

So, is this a replacement for trained officials manning video consoles? Absolutely not!  While the software will not fall prey to attention lapses brought on by viewing simultaneously streaming screens of video all day, its pinpoint precision can be compromised. Can it improve a comprehensive IP based video management system? Yes, in situations and locales such as those cited above, a video content analysis tool such as facial recognition can prove to be a valuable second set of eyes.