Video Content Analysis Essays

Video Content Analysis Essays Video Content Analysis Essay Video Content Analysis Essay Video Content Analysis, what is it and why would I want it? White Paper by Nick Hewitson November 2005. What is Video Content Analysis? There are a number of terms used in different industries and markets to describe Video Content Analysis: Analytics Behavior Recognition Content Analysis Concept Coding Intelligent Video Object Tracking Smart CCTV They all however describe the real time use of computer vision in a security environment to monitor the CCTV camera feeds and assist the guard in his or her decision making process. The UK is the country with the most CCTV cameras deployed, with over 4 million in se. Its claimed that if you walk through London you will be watched over 300 times, however this is clearly a misconception. While it is probably true that you will be in the field of view of a CCTV camera over 300 times during your walk through London it is certainly not true that you are observed that many times for number of reasons. Firstly CCTV control rooms have fewer monitors than there are cameras, in many cases a number of cameras are sequentially displayed on a single monitor. If for example five cameras are fed into a single monitor which then you obviously have nly a 20% chance of being viewed while in any individual cameras field of vi ew. Secondly the staff in the control room are often expected to deal with other issues as well as monitoring the CCTV. They will be responsible for issuing keys, badges and permits to both staff and visitors; they are also responsible for monitoring the access control and fire alarm systems, controlling radio communications with both their own foot patrols and possibly the local Police. In addition they will need to be away from their desks for breaks to visit the restrooms etc. During this time they are ot monitoring the CCTV images. Finally the design of CCTV control rooms expects the guard to watch a large number of monitors. According to ASS International, a human can effectively watch 9-12 cameras for only 15 minutes. Security guard shifts are often 12 hours long so 1 1 hours and 45 minutes are ineffective monitoring. CCTV Today in November 2005 estimated that the probability of an event being recognised and acted upon if it was clearly in the view of a CCTV camera was less than 1 in 1000. CCTV has historically been a forensic tool not a real time crime prevention system. The principal of Video Content analysis is to use computers to monitor all of the cameras all of the time and when something unusual happens to alert the security guard to it. For example in a retail shopping centre a person running is unusual. The system can detect that a persons running but is unable to differentiate between a benign event, a teenage girl running over to greet her boyfriend, or a criminal event where someone is running out of a shop with an armload of Jeans. However if the running event is drawn to the security guards attention he is able to make that ubjective decision easily and respond appropriately. Why would I want to use Intelligent Video? The following scenario is taken from a real test of a behavioural recognition system monitoring access to parked aircraft in the USA. It shows what the advantages of computer vision over human monitoring can be. There are 8 cameras monitoring a road that passes through a tunnel, above which is an area where commercial aircraft are parked. The system was tasked with looking for cars that stopped under the bridge and people climbing up the slope towards the aircraft. Over 1 month the system reported almost 300 events where vehicles were seen stopping. 298 of these were originally classified as false alarms caused by normal traffic flow problems. One event was due to a fender bender accident and one to a breakdown. There were no attempts to approach the parked aircraft. At first evaluation, it would seem that the value of the system was negligible, all it had produced were 298 false alarms out of 300 events. Previously the cameras were monitored by a guard on conventional CCTV monitors and no events at all had been reported in the month before. It was found that the 300 events would take the guard on average less than 30 seconds each to determine the risk. So instead of employing staff 24 / 7 for 30 days to monitor the tunnel only two and a half hours man hours were required over the whole 30 day period. In addition, in the previous month the guard reported no events, given that each of the 300 events reported by the system actually took place in the test month. It is probable that a similar number actually took place previously when the guard was supposed to be watching and he didnt notice them. It is therefore highly likely that if someone had stopped a car briefly to allow a passenger to get out and approach the aircraft, the event would have been missed, while the Intelligent Video system would have caught it. The Smart CCTV system had therefore raised the effectiveness of the monitoring from zero to 100% while reducing the operating costs from 720 man hours to 2. 5 man hours of labour. When the security manager looked at the cost effectiveness on this basis, he had no hesitation in purchasing a system. Key issues to determine before looking at Video Content Analysis. What are your operational requirements? As seen above, if it is to have a minimum number of false alarms then the human operator will be more effective, he failed to report any of the traffic events under the bridge, in fact he didnt report anything at all, so his false alarm rate was zero. What percentage of the cameras is best monitored by computer vision, and what percentage is better monitored by a human operator? In general, today computers do better on the cameras where nothing much happens (and therefore guards get bored) and people do better in busy scenarios where occlusion between people akes it hard for the software. A good example is an embassy that has a back alley where no one ever goes. This is covered by a CCTV camera and this was the only camera out of about 50 that was implemented at the beginning. The embassy realised that no one paid attention to this camera because nothing ever happened but if someone was in the alley they really needed to know about it fast. In the majority of applications today, only a percentage of the total number of the cameras are monitored by video content analysis, some are only recorded and some are monitored full time by the security staff. You need to determine what is the specific risk and the most appropriate method of monitoring for each point. Do the risks and scenarios change during the course of 24 hours? Can you build upgradeability into your plans? In many cases the number of cameras monitored by the software increases as experience of the benefits is gained. Video Content analysis is a tool that allows you to improve your operational effectiveness. It is not the all seeing Big Brother monitoring all activity. It helps you spot the needle in the haystack; CCTV provides huge amounts of mostly irrelevant data. Video Content Analysis extracts information from that data. It reduces your costs, manual monitoring is inconsistent and expensive. It reduces your risk by moving away from the limited human attention span of less than twenty minutes, and screening all of the video streams in parallel. It allows you to move from a forensic mindset of finding out what happened after the event has taken place towards real time analysis and decision making. You do still need to employ professional security staff to make the decisions on the information presented to them in a sensible manner. -End-

What to Know About Visual Basic

What to Know About Visual Basic In 2008 Microsoft stopped support for VB and declared it a Legacy software. Feel free to read this article written before that time. It provides good background for the current .NET software still in use today. Its a computer programming system developed and owned by Microsoft. Visual Basic was originally created to make it easier to write programs for the Windows computer operating system. The basis of Visual Basic is an earlier programming language called BASIC that was invented by Dartmouth College professors John Kemeny and Thomas Kurtz. Visual Basic is often referred to using just the initials, VB. Visual Basic is easily the most widely used computer programming system in the history of software. Is Visual Basic Just a Programming Language? Its more. Visual Basic was one of the first systems that made it practical to write programs for the Windows operating system. This was possible because VB included software tools to automatically create the detailed programming required by Windows. These software tools not only create Windows programs, but they also take full advantage of the graphical way that Windows works by letting programmers draw their systems with a mouse on the computer. This is why its called Visual Basic. Visual Basic also provides a unique and complete software architecture. Architecture is the way computer programs, such as Windows and VB programs, work together. One of the major reasons why Visual Basic has been so successful is that it includes everything that is necessary to write programs for Windows. Is there more than one version of Visual Basic? Yes. Since 1991 when it was first introduced by Microsoft, there have been nine versions of Visual Basic up to VB.NET 2005, the current version. The first six versions were all called Visual Basic. In 2002, Microsoft introduced Visual Basic .NET 1.0, a completely redesigned and rewritten version that was a key part of a much larger computer architecture. The first six versions were all backward compatible. That means that later versions of VB could handle programs written with an earlier version. Because the .NET architecture was such a radical change, earlier versions of Visual Basic have to be rewritten before they can be used with .NET. Many programmers still prefer Visual Basic 6.0 and a few use even earlier versions. Will Microsoft stop supporting Visual Basic 6 and earlier versions? This depends on what you mean by support but many programmers would say they already have. The next version of the Windows operating system, Windows Vista, will still run Visual Basic 6 programs and future versions of Windows might run them too. On the other hand, Microsoft now charges big fees for any help for VB 6 software problems and soon they wont provide it at all. Microsoft doesnt sell VB 6 anymore so its difficult to find. Its clear that Microsoft is doing everything they can to discourage the continued use of Visual Basic 6 and encourage the adoption of Visual Basic .NET. Many programmers believe that Microsoft was wrong to abandon Visual Basic 6 because their customers have put so much investment into it over more than ten years. As a result, Microsoft has earned a lot of ill will from some VB 6 programmers and some have moved to other languages rather than move to VB.NET. This might be a mistake. Is Visual Basic .NET really an improvement? Absolutely yes! All of .NET is truly revolutionary and gives programmers a much more capable, efficient and flexible way to write computer software. Visual Basic .NET is a key part of this revolution. At the same time, Visual Basic .NET is clearly more difficult to learn and use. The vastly improved capability does come at a fairly high cost of technical complexity. Microsoft helps to make up for this increased technical difficulty by providing even more software tools in .NET to help programmers. Most programmers agree that VB.NET is such a huge leap forward that its worth it. Isnt Visual Basic only for lower skilled programmers and simple systems? This was something that programmers using programming languages like C, C, and Java used to say before Visual Basic .NET. Back then, there was some truth to the charge, although on the other side of the argument was the fact that excellent programs could be written faster and cheaper with Visual Basic than with any of those languages. VB.NET is the equal of any programming technology anywhere. In fact, the resulting program using the .NET version of the C programming language, called C#.NET, is virtually identical with the same program written in VB.NET. The only real difference today is programmer preference. Is Visual Basic object-oriented? VB.NET certainly is. One of the big changes introduced by .NET was complete object-oriented architecture. Visual Basic 6 was mostly object-oriented but lacked a few features such as inheritance. The subject of object-oriented software is a big topic by itself and is beyond the scope of this article. What is the Visual Basic runtime and do we still need it? One of the big innovations introduced by Visual Basic was a way to split a program into two parts. One part is written by the programmer and does everything that makes that program unique, such as adding two specific values. The other part does all of the processing that any program might need such as the programming to add any values. The second part is called the runtime in Visual Basic 6 and earlier and is part of the Visual Basic system. The runtime is actually a specific program and each version of Visual Basic has a corresponding version of the runtime. In VB 6, the runtime is called MSVBVM60. (Several other files are also normally needed for a complete VB 6 runtime environment.) In .NET, the same concept is still used in a very general way, but its not called a runtime anymore (its part of the .NET Framework) and it does a lot more. What is the Visual Basic .NET Framework? Like the old Visual Basic runtimes, the Microsoft .NET Framework is combined with specific .NET programs written in Visual Basic .NET or any other .NET language to provide a complete system. The Framework is much more than a runtime, however. The .NET Framework is the basis of the entire .NET software architecture. One major part is a huge library of programming code called the Framework Class Library (FCL). The .NET Framework is separate from VB.NET and can be downloaded free of charge from Microsoft. The Framework is an included part of Windows Server 2003 and Windows Vista. What is Visual Basic for Applications (VBA) and how does it fit in? VBA is a version of Visual Basic 6.0 that is used as an internal programming language in many other systems such as Microsoft Office programs like Word and Excel. (Earlier versions of Visual Basic were used with earlier versions of Office.) Many other companies in addition to Microsoft have used VBA to add programming ability to their own systems. VBA makes it possible for another system, like Excel, to run a program internally and provide what is essentially a custom version of Excel for a particular purpose. For example, a program could be written in VBA that will make Excel create an accounting balance sheet using a series of accounting entries in a spreadsheet at the click of a button. VBA is the only version of VB 6 that is still sold and supported by Microsoft and only as an internal component of Office programs. Microsoft is developing a completely .NET capability (called VSTO, Visual Studio Tools for Office) but VBA continues to be used. How much does Visual Basic cost? Although Visual Basic 6 could be purchased by itself, Visual Basic .NET is only sold as part of what Microsoft calls Visual Studio .NET. Visual Studio .NET also includes the other Microsoft supported .NET languages, C#.NET, J#.NET and C.NET. Visual Studio comes in a variety of versions with different capabilities that go well beyond just the ability to write programs. In October 2006, Microsofts posted list prices for Visual Studio .NET ranged from $800 to $2,800 although various discounts are often available. Fortunately, Microsoft also provides a completely free version of Visual Basic called Visual Basic .NET 2005 Express Edition (VBE). This version of VB.NET is separate from the other languages and is also completely compatible with the more expensive versions. This version of VB.NET is very capable and doesnt feel at all like free software. Although some features of the more expensive versions arent included, most programmers wont notice anything missing. The system can be used for production quality programming and isnt crippled in any way like some free software. You can read more about VBE and download a copy at Microsofts web site.