Using an image. How to get the best results and reduce costs on CCTV systems.
Despite the global economic downturn, CCTV, as it has been for almost the last 10 years, continues to be the fastest growing sector of the security industry, in which large sums of money are invested by both individuals and government organizations.
The explosive growth has been driven by several factors, both cost control and cost-effective management, and by the desire of citizens to feel safer in a post-9/11 world. Whereas in the distant days of analog CCTV systems, each camera required its own dedicated wire, today’s digital CCTV cameras operate on more flexible and scalable IP networks that can be accessed in real time by approved users from virtually anywhere in the world. They are based on industry standards, are reliable, vendor-neutral, and can be easily and cost-effectively integrated. Intelligence is now built into the entire network video surveillance system, intelligent in line with current technology (e.g., in the camera or video encoder), determining when and where to send video, at what frame rate and resolution, and when to alert a specific operator for monitoring and/or response. The result: cost-effective, future-proof, and adaptable to evolving CCTV installation needs.
The digital revolution has made all this possible. New, more powerful, more functional cameras, laptops and mobile phones constantly tempt modern consumers. The network video market is also regularly updated with new products that provide users with more and more options. Image quality is often the main proclaimed advantage. Like their counterparts in the consumer video market, many of today's security camera manufacturers are involved in a race to increase image resolution. The assumption is that the higher the resolution, the clearer the image can be, and therefore the more satisfaction it will bring to the user.
User Focus
What this approach completely ignores is the actual needs of the application. Do you need overview video surveillance or detailed snapshots? Will the video be viewed in real time or will it be recorded and stored for months or even years? IP networks must be able to handle high-resolution video, and storage requirements can quickly grow to terabytes, so these criteria are critical.
In my opinion, there are six simple steps to creating a successful end-user CCTV solution. The first two involve making decisions regarding hardware, software or systems. The third and fourth involve implementing the decisions made, and the last two take place during the commissioning of the customer's CCTV system. The professional experience of the consultant or integrator will determine the correctness of the execution and will be a significant guarantee of an economical investment in CCTV during operation.
It all starts with a thorough analysis of the actual user needs.
1. Defining the goal.
Only a thorough analysis of the goals of video surveillance will allow us to determine the appropriate installation requirements.
The first step before selecting equipment or systems is to determine how the output will be used. This may be to obtain a general picture of people moving around the area being monitored, or to obtain high-resolution details (such as recognizing faces or license plates). A full installation will often include both purposes, so it is important to consider each in its own context to obtain the most effective solution.
Different types of cameras are suitable for different purposes. The ideal solution is often a combination of HDTV, megapixel, and standard definition network cameras, optimized to meet different requirements such as pan/tilt/zoom control, high light sensitivity, or cost effectiveness.
In order to optimize the installation process, it is also necessary to consider the entire system, not just the camera. Often, the choice of video management software, as well as network and video storage requirements, become the limiting factors in the choice of image resolution and frame rate.
2. Analysis of surveillance objects
After defining the general goals, it is necessary to determine the requirements for individual cameras in each application. In addition to the level of detail, the following is taken into account:
Viewing area. Determine the number of zones of interest in the selected surveillance area, as well as the degree of their remoteness from each other. This will help determine the type and number of cameras needed.
Lighting conditions. Most network cameras allow 24/7 video surveillance with some limitations. Is the lighting limited? Is it possible to use artificial lighting?
Indoor or outdoor installation. Depending on the level of light, it may be necessary to use cameras for 24/7 surveillance or additional lighting equipment, as well as housings that protect the cameras from dust, moisture, and vandalism. These are important risks that may be encountered when installing cameras outdoors, but they are often also important to consider when using cameras indoors.
Obvious or covert surveillance. Highly visible security cameras can be effective in deterring potential intruders, but they can also invite vandalism. In addition, the choice of cameras is influenced by the distance between their installation locations, as well as the housings and mounts.
3. Choosing a Camera
Selecting cameras is a key step in achieving your video security goals. Take the time to consider this complex topic so you can make the best informed choice.
Image resolution is one of the most important technical parameters of any network camera. Much attention has been paid to this parameter in recent years. From this point of view, three main categories of network cameras are distinguished: megapixel, HDTV (high definition television) and standard definition (analog cameras connected via video encoders also fall into this category).
Megapixel network cameras are designed to meet industry guidelines, but no standards apply to them. The number of megapixels corresponds to the number of elements in the camera's image sensor. Megapixel network cameras provide highly detailed images at a lower frame rate. Some even allow different video streams to be received from different areas of a single video image. Cameras with megapixel resolution are successfully used in security video surveillance systems for banks, transport enterprises, and other premises.
HDTV cameras deliver stunning images with maximum frame rates and excellent color reproduction, and support widescreen (16:9 aspect ratio). HDTV cameras comply with major industry standards, such as the SMPTE standard. HDTV cameras are ideal for applications that require maximum frame rates, such as airports, casinos, urban surveillance sites, and passport control.
Standard definition cameras are typically those with VGA (640 x 480 pixels) or multiples of it, and are the oldest category in the security camera market. However, they still have a legitimate use: with powerful optical zoom, VGA cameras are a great choice for many surveillance needs. In challenging lighting conditions, VGA cameras with super-high light sensitivity and wide dynamic range can outperform both HDTV and megapixel network cameras. Some VGA cameras offer frame rates in excess of 25-30 fps, which is ideal for monitoring moving objects.
Regardless of the category, the following factors are critical to consider when choosing a camera:
Frame Rate: 25-30 frames per second (fps) is the PAL and NTSC standard. In the absence of incidents, 1-4 fps is sufficient for recording.
Optics and Lenses: The lens determines the viewing angle, limits the amount of light reaching the image sensor, and focuses the camera, determining image quality and supporting a range of video surveillance capabilities.
Light sensitivity. Measure the illumination of the subject under various lighting conditions, and then test the camera carefully to ensure that it meets the light sensitivity requirements.
WDR (Wide Dynamic Range). Cameras with a wide dynamic range can handle a wide range of illumination on the same subject by using different exposures for different areas of the same image.
Noise reduction. Noise can come from the light itself or from another source, such as the image sensor or other electronic component in the camera.
Iris control capability. Plays an important role in obtaining quality images. The iris can be fixed or adjustable. Iris control can be manual or automatic.
Video compression. Allows for smaller file sizes and more efficient transmission and storage of images. Ensure that standardized compression technologies are used for compatibility.
Scanning technology. Today, there are two technologies for reading and displaying video data: interlaced scanning and sequential scanning. The latter is preferable, since it reduces image blur.
4. Camera installation
Choosing the right location for installing a camera will help you achieve the best image quality. In order to choose the best location for installing a camera, you need professional advice. However, there are a number of factors that need to be taken into account.
The purpose of security video surveillance. Make sure that the camera is suitable for the task at hand and is positioned correctly.
Add lighting if necessary. The easiest and most cost-effective way to provide the necessary lighting to produce high-quality video is to add additional light sources.
Avoid direct sunlight. Otherwise, it can “blind” the camera and reduce the performance of the image sensor. If possible, install the camera so that the observation area is in front of it and the sun is behind it.
Avoid backlighting. This can be a problem if the surveillance location is in front of a window or a strong light source. If repositioning the camera is not possible, use cameras that support a wide dynamic range.
Reduce the dynamic range. When used outdoors, having too much sky in the field of view often results in a dynamic range that is too wide. If the camera does not support a wide dynamic range, plan to mount it high above the ground.
Set up your camera. You may need to adjust white balance, brightness, and sharpness to achieve optimal image quality. In low light conditions, you may need to prioritize frame rate or image quality.
Legal Considerations. Security video surveillance may be prohibited by law. Be sure to check your local laws before installing a security video surveillance system.
5. Camera Configuration
Configuration involves adjusting or fine-tuning the installed cameras to take full advantage of their capabilities, such as:
Remote zoom. Allows you to make final adjustments to the zoom level using a computer. This allows you to achieve a viewing angle optimized for the observation location and image resolution.
Remote focus. Eliminates the need to manually focus the camera at its location. Also allows you to make the necessary adjustments using a computer.
Pixel Count: Allows the user to draw a rectangle on the screen around a desired area to quickly obtain the size of that area of the image and ensure that the installation meets the customer's pixel count requirements.
6. Calibrate the Screen for Viewing
To fully appreciate video surveillance, your computer or TV screen must be properly calibrated. Check the following four settings on your screen to ensure proper calibration:
Brightness: Adjust according to your requirements.
Contrast: If the value is too low, dark areas of the image will merge. If the value is too high, light areas will merge.
Gamma: Measures the level of contrast, which affects the midtones in the image. Select the most suitable mode.
Sharpness: Compare the boundaries between tones in different parts of the image and determine the most suitable sharpness level.
Conclusion
For the best possible CCTV installation, image usage should be considered first and should serve as a litmus test for all other decisions. This is easy to achieve if the project is developed in the right sequence, and the results are likely to be more satisfactory and cost-effective.
