CCTV SECURITY SYSTEM NEWS – DVR Linux Security
IPTEC offers the rock solid operating system of Digital Video Recorders or DVR Linux Security. Our systems are complete standalone digital video systems that require nothing extra to run. They are not dependent on the Internet (although they can be used on the Internet if the owner chooses) and are therefore not subjected to hackers and other potential dangers.
Basically, today’s DVR market is segregated into two different groups according to operating systems, Linux or Windows based. Both operating systems have their pros and cons. For example, most people are familiar with the Windows operating environment and have very few or no problems using this software because of its familiarity.
On the other hand, Linux has proved itself to be a more stable operating environment; its functions are stable enough that seldom does one encounter screen freezes, repeated boot-ups, etc. What’s more is that the Linux OS handles different functions through the kernel in a different way compared to Windows. This creates a faster system that is even closer to UNIX (it actual parent system).
IPTEC considered these two systems and decided that Linux was the best operational choice. DVR Linux security offers most all of the functions of a Windows operating platform, but does so with greater speed and ease of use of its functions. When it comes to the functions of a DVR, this is extremely important because digital video processing places a heavy load on the CPU especially when recording, displaying, and storing eight different cameras at once for example.
Actually the full name for the Linux OS is called GNU/Linux. Linux is actually the kernel. The kernel is the system program that allocates the machines (in our case the DVR) resources to the other programs that are being run. The actual operating system (OS) is called GNU. Linux handled tasks so quickly that until just recently held the title of OS for the fastest supercomputer system.
Gnu/Linux is a free operating system and was specifically designed that way back in its earliest days around the mid to late 1980?s. Linux uses a type of public domain free software license, making the system free to just about anyone who chooses to use it. Of course this brings another advantage to the table for IPTEC; using free Linux software saves the buyer money.
DVRs that offer special functions such as automatic operation of a Pan-Tilt-Zoom or PTZ camera for object following and tracking often use programs pre-compiled for the this function. The latest CODEC being used by the DVR Linux Security System is fully compatible and useable for cross platform capture. (Cross platform capture means the CODEC, which stands for COmpression/DECompression can run easily on either operating system. The CODEC reduces the size of the video file while maintaining its quality.) That CODEC is the H.264 CODEC.
For an example of cross platform use, a video image could be taken using a Linux based DVR but could also play back by using a computer with a different OS (like Windows for example). This is crucial because not only does the CODEC shrink the file (which occurs on the DVR Linux Security System) but it also decompresses the file so that it may be viewed on a Windows Operating System.
In addition to the embedded Linux OS, IPTEC’s DVR Linux security system also comes with an embedded web server. These DVRs can be set to alert you via e-mail based on a variety of triggers that you choose. Plus, you can access your system directly with another computer or by using your smartphone if you have one. This means you can have total access to your DVR Linux Security system anywhere in the world that you can receiver 3G or 4G smartphone/Internet services. www.iptecworld.com ; Source : http:// www. security cameraking .com/ securityinfo /
CCTV SECURITY SYSTEM NEWS – Wide Dynamic Camera
A wide dynamic camera conjures images of an incredibly large (In a horizontal direction) camera, somewhat like an oversized wide-angle lens. However, that’s not what a wide dynamic camera is at all. In fact, some ultra-small hidden covert cameras are also wide dynamic cameras. So just exactly what is the wide dynamic range of a camera? Read on to find out.
A wide dynamic camera is actually a camera with a highly specialized function to assist the image capture process. When cameras possess the circuitry to support this function we say that they have Wide Dynamic Range or WDR.
The whole idea behind this business of a wide dynamic camera is to produce a superior image, at least superior when compared to the image from an exact same camera that does not support WDR. WDR helps to provide clear video images under unbalanced, poor lighting conditions: Specifically, when the intensity of the light varies such that that there are incredibly bright and dark areas that appear simultaneously in the field of view (which is destined to become the video image) of the camera.
Overly dark areas and overly saturated light areas, especially over saturation of back lighting is the problem that the wide dynamic camera is trying to solve. The better the WDR of a camera the better video image produced under undesirable backlighting conditions and other over contrast conditions.
Specifically, a wide dynamic camera filters the intensely bright back light that may surround an object therefore enhancing the ability to distinguish features and shapes on the subject that were “washed” out by the intense bright light. The dynamic range of a camera is normally defined as the ratio of the brightest point of an image to the darkest point of the same image. Some also refer to this situation as “maximum contrast.”
In essence, what happens in this situation is the intensely bright (back) light is causing the camera to adjust itself to that particular condition. When this happens, the video image produced is a washed out image near the light source and everything else being to dark to recognize. This does not necessarily apply to images with steady light sources; it can occur when momentary intense light appears (for what ever reason) throwing the entire camera off balance.
Perhaps one of the best examples of a problem wide dynamic range is when a camera attempts to capture an image in front of a large storefront window. The object inside the store appears far too dark with the sunlight pouring through the front window and washing out the details of most of the field of view of the camera.
There are several different approaches to the solution of this problem and although each method’s goal is the same result (a balanced, detailed video image) the process they use to go about correcting the situation may be different. Basically there are two major methods or technical solutions that are used to correct the problem and there are additional methods that “hybridize” the process by combing the two basic methods.
The first solution is “multi-frame imaging.” Here the wide dynamic camera captures more than one frame of the field of view. Each of these frames possess their own dynamic range and the camera combines the different frames to produce one WDR image or frame.
The second solution is the use of non-linear sensors (generally logarithmic sensors) where the sensitivity level of the sensor at different light intensities also varies providing the capture of the field of view in one wide dynamic camera frame.
Combinations of the two methods just mentioned are also used. For example, they may include parallel capturing by more than one sensor using a common optical path. Here each sensor captures different levels of the dynamic range of the scene by either different exposures, different optical attenuation in the final optical path, or different sensor sensitivity. There are many more combination methods that may be used as well.
The key is that if you intend to use a camera that will be capturing areas of extremely high contrast or that are back lit by an extremely bright light, you’ll want a good wide dynamic camera to capture the image. www.iptecworld.com ; Source : http:// www. security cameraking .com/ securityinfo /