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Three Dirty Little Secrets about Video Surveillance Systems

Dirty Little Secret #1 - Security Cameras Rarely Serve as a Deterrent to Crime

Despite an almost universal belief otherwise, there is no conclusive evidence that video surveillance systems serve as a deterrent to crime. While a few studies have shown that there may be a decrease in crime when cameras are installed in certain settings, such as publically-operated parking garages, there are many more studies that have shown that the installation of security cameras has no effect whatsoever on crime rates.

While more independent studies are needed, the evidence at this point suggests that security cameras rarely prevent crimes from occurring, and almost certainly don't deter crime to the degree that is implied by many sellers and installers of video surveillance equipment.

As security consultants, we receive video recordings from our clients almost weekly showing criminal acts in progress. Most of these acts are committed brazenly in front of a camera, confirming that the presence of a camera served as no deterrent.


The following should be considered when contemplating the deterrent effect of video surveillance cameras:

  • Most people who engage in criminal behavior don't have the same thought processes that honest people do and don't consider the long-term consequences of their actions.

  • Many people who commit crimes aren't thinking rationally at the time they commit them. They may be drunk, high on drugs, or suffering from some form of mental illness.

  • Smart criminals are well-aware of the limitations of video surveillance systems and may plan their crimes around them. They may commit crimes just outside of the range of cameras, or wear simple disguises to conceal their identity.

  • People become desensitized to the presence of video cameras after a short time. While there may be an awareness of cameras when they are first installed, they soon become part of the environment, making regular occupants of the area almost oblivious to their presence.

  • Many law enforcement agencies lack the resources to investigate and prosecute minor property crimes, even if  good images of the perpetrators are available. Many criminals know this and blatantly commit crimes in front of video cameras, knowing that there is little chance that they will be caught or prosecuted.


Dirty Little Secret #2 - Most Recorded Video is Useless as Evidence

The goal of most video surveillance systems is to provide recorded evidence when a crime has been committed, allowing the criminal suspect to be quickly identified, captured, and prosecuted. Ideally, the recorded video would show the criminal in the act: stealing the computer, vandalizing the car, or assaulting the victim. Images on the recorded video would provide a good picture of the suspect, allowing his facial features, clothing, and any distinguishing marks to be clearly recognized. When the suspect is captured and brought to trial, the video evidence would be compelling enough that a jury would be convinced of the suspect's guilt "beyond a reasonable doubt".

While this type of scenario is often played out on television shows and in movies, it rarely occurs in the real world. Most users of commercial video surveillance systems are deeply disappointed when they discover that the system that they have purchased can't provide recorded video that is useful as evidence. This dissatisfaction usually comes to light when the user reviews recorded images in an attempt to investigate a crime after the fact. Complaints frequently heard are: “I can see the person, but can’t identify who it is”; “I can see the person, but I can’t see what they are carrying”; "I can see a car, but can't tell the make or model or read the license plate"; “when I enlarge the picture, it is nothing but a blur!” ; "the view of the camera is blocked in exactly the area that I want to see".

Most problems related to the quality of recorded images can be attributed to the following:

  • Too few cameras with too wide a field-of-view: Cameras can view a wide area, or provide a high-level of detail, but not both. Many cameras are set to view an excessively large area, which makes it impossible to positively identify people at most points within the scene. A study by the FBI suggested that, in order for a person's face to be positively identified, the person must equal approximately 120% of the vertical height of the video image. To get this type of image requires an extremely narrow field of view, allowing each camera to cover only a very small area. While not everyone agrees with this study, almost everyone admits that most cameras installed today have fields of view that are set too wide to allow facial recognition throughout most of their coverage area.

  • Improper viewing angle: To best identify a person, a camera needs to have a relatively straight-on shot of the person's face. Many cameras are installed too high, at the wrong angle, or pointed so that they only see the side of the face or the back of the head. For example, at building entrances, it is common to only have a camera inside pointing out towards the door. While this camera can provide a good view of someone entering the building, it can only see the back side of a person exiting.

  • Blind spots in coverage area: There are lots of obstructions in settings such as parking garages or warehouses. Cameras can't see through structural columns, parked trucks or stacks of pallets, often creating conditions where large portions of the facility cannot be seen by a camera.

  • Improper lighting conditions: Cameras need to have an adequate amount of light in order to see. More importantly, the lighting needs to be uniform throughout the viewing area. Too little light or the combination of bright areas and dark areas within the viewing area will usually produce a poor quality image.

  • Improper recording resolution setting: There is a trade-off between the video resolution used for recording and the amount of time that images can be stored on the recording device. The higher the resolution, the less recording time. In many cases, the resolution setting has been set to an unacceptably low rate in an attempt to maximize recording time.


While all of the problems identified above are solvable, the cost of doing so can be prohibitive in many applications.

Although it is relatively easy and cost effective to get good quality recorded video in small, confined areas such as at building entrances or at teller's windows, it can be much more challenging and expensive to cover large open areas such as parking garages and warehouses. 

Most property owners don't want to spend the money that it takes to properly provide evidentiary quality video coverage throughout their facilities, as this can require many more cameras and much more recording equipment than they originally planned on installing. Instead, they choose to install far fewer cameras than are actually needed and hope for the best. They are often aided and abetted in this effort by security integrators, who would rather sell just a few cameras than none at all. 

The net result: a video surveillance system that fails to meet the owner's needs and is incapable of providing recorded video that is useful as evidence.

Dirty Little Secret #3 - "Megapixel" Security Cameras Won't Cure All Video Surveillance Problems

New high-resolution video cameras have been introduced in recent years and these cameras are now becoming popular in the video surveillance industry. Offering resolutions of up to 16 megapixels (MP) and higher, these cameras promise to provide a quality of video that is substantially better than that provided by traditional standard definition (SD) cameras.

Many manufacturers and security integrators have been quick to tout the benefits of these cameras, claiming that they are the cure to all of the weaknesses of traditional video surveillance systems. Some of the claims that we have heard by manufacturers include: "one megapixel camera can replace up to ten of your standard fixed-position cameras"; "there is no longer any need for pan-tilt-zoom cameras - our 360 degree megapixel camera can view and record all areas all the time"; and "our megapixel cameras will finally allow you to positively identify faces and read license plates throughout your parking lots"…, etc.

Our actual experiences in seeing megapixel cameras in use at some of our clients facilities paints a somewhat less flattering picture. While megapixel cameras can be beneficial in many applications, it is our opinion that the capabilities of megapixel camera have been greatly oversold by many manufacturers.

Some of our findings include:

  • Megapixel cameras work best in indoor applications where lighting is adequate and doesn't vary significantly throughout the day. In these conditions, megapixel cameras are capable of providing a significantly better quality image than that provided by a standard definition camera.

  • Using high megapixel cameras in outdoor applications can pose challenges.  While the image quality provided during the day can be great, the image quality at night can suffer when lighting conditions are less than ideal. 

  • The increased resolution provided by megapixel cameras can provide an improved ability to make out facial details and license plates when the camera's field of view is properly focused on the area of interest and lighting conditions are correct. In some cases, this may allow the use of fewer cameras to cover the same scene, however it is still unrealistic to expect a single megapixel camera to cover a large area. Thinking that you can install just a handful of megapixel cameras to get evidentiary quality video coverage throughout your entire parking garage is unrealistic.

  • The installation of megapixel cameras can't solve problems such as blockage of view, improper viewing angle, and poor lighting conditions.

  • The quality of images produced by megapixel cameras can vary greatly by manufacturer, particularly in real-world surveillance applications. Cameras with a higher megapixel rating don't necessarily produce better quality images than cameras with a lower megapixel rating.


Our conclusions: megapixel cameras can provide improved performance in some applications, but they are not a "magic bullet" that will automatically solve all of your video surveillance problems.



Video surveillance systems can be a useful tool when designed and installed correctly, and when the user has realistic expectations about what they can and cannot accomplish. In many cases, users will install video surveillance cameras as a "quick fix" when they are having a security problem, without considering that cameras may not be the correct solution. Cameras installed under these circumstances are almost always a waste of money.

We recommend that clients develop a comprehensive security plan for their facility before making the decision to install security cameras. This plan should be based on a security risk assessment and address all aspects of security including security policies and procedures, employee training, architectural security, and electronic security systems.

While video cameras can be part of your overall security plan, they are rarely a security solution in themselves.


If you need help in assessing your security needs, preparing a security plan, or reviewing your video surveillance system, please contact us.

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