AHD Cameras – The Latest in Closed-Circuit TV Video Surveillance Technology
AHD cameras are a new closed-circuit television video surveillance technology that uses coax cable to transmit HD Video from cameras to DVRs. They support 720p and 1080p resolution. They use the same wiring as traditional analog 960h so customers can upgrade over time and still keep their old system.
AHD cameras are great for commercial driver monitoring. They provide clear imagery in low and no light conditions, allowing you to monitor driver fatigue and drowsiness.
High Definition
High definition video has a higher number of pixels in its images, resulting in sharper and more detailed footage. This resolution has become the standard for TV broadcasts, hd ahd camera streaming services, and home devices such as cameras and monitors.
As the size of display screens on desktops, TVs, projectors, hand-held devices and others has increased over the past 10+ years, so too has the need for cameras to yield images that are able to be displayed with this high resolution. This puts a greater demand on cameras to deliver high resolution with a wider field of view and also to have a wide dynamic range to be able to capture the details in dark and light areas of a scene.
Commercial-grade cameras use a special hardware and software solution to address the need for more dynamic range called HDR. This technology takes two exposures of the same scene, one with a lower shutter speed than the other, and then uses a post-processing algorithm to combine these images into a single image that is properly exposed in both light and dark areas.
This process is very effective and results in an image that looks natural, even when the subject is moving fast. This is especially important for a security camera where the goal is to recognize license plates and intruders, as well as keeping the movement of people in and out of your business under control.
Wide Dynamic Range
Whether you’re an experienced professional in the security industry or simply interested in improving your home video surveillance, wide dynamic range (WDR) is a feature that will significantly enhance your footage quality. This technology is designed to combat glare and dark spots in an image while recording bright areas without overexposure.
WDR works by taking two images at different exposures and then merging them into a single image. This helps balance the lighting between dark and light areas, allowing the camera to capture more detail in darker regions than would otherwise be possible.
This is a much more advanced technology than Backlight Compensation (BLC), which was once the standard for cameras. BLC splits a scene into several smaller regions and then applies a different exposure to each region, which prevents overexposure in dark areas and keeps lighter areas of the picture looking natural. However, BLC has its limitations when it comes to extreme differences in light between foreground and background.
As more and more cameras are equipped with WDR, this feature is becoming increasingly popular in the industry. But before ahd cameras you decide to add this feature to your home or business security system, it’s important to understand the difference between true and digital WDR. Digital WDR is a software-based solution that uses the camera’s digital signal processor to adjust for challenging lighting conditions, while true WDR uses hardware changes to improve the performance of a camera’s image sensor.
IR LEDs
A camera with IR LEDs is ideal for use in low-light conditions or at night. Infrared light is invisible to the human eye but cameras can detect it. IR LEDs emit infrared light in the 700 to 1000nm range which allows the camera to capture details of an image even in complete darkness. In order to maximize the effectiveness of IR LEDs, it is important that nothing obstructs them. If anything does obstruct the IR LEDs, it will cause the camera to compensate and over expose objects that are closer by lighting them up too much. This can cause them to become white and difficult to see in your video footage.
One common cause of this is water or dust on the glass dome. Another issue is if the foam ring on the camera body is not properly seated. It must be seated flush with the IR board or base of the lens to ensure that it does not obstruct the IR LEDs.
A security camera with Smart IR will automatically adjust the intensity of its IR LEDs to compensate for the distance of objects that it is tracking. This will prevent your images from becoming washed out or over exposed. This feature is available on most ahd cameras and is ideal for surveillance systems in which the camera is being deployed in an open area where it would be susceptible to wind and other factors that may cause the illumination level to fluctuate.
Power Over Coax
Power Over Coax cameras combine both video and power over the same coaxial cable, eliminating the need for separate wires. This makes it perfect for upgrading an existing analog CCTV system or even new installations that want to reduce overall costs and cable run lengths.
This technology works a bit like Power Over Ethernet (PoE) but differs in that the camera gets its power from the same cable it downloads data over – a standard network / Cat5e or higher wire. Typically this is either from the NVR or via a PoE injector or PoE network switch.
With PoC, a twist-fit BNC connector is used to draw power from the same cable that transmits the camera signal. This means that only one wire needs to be connected to the camera – your installation guy will be happy.
The power that is drawn from the coaxial cable depends on the camera’s specifications – 720p videos can run up to 1800 feet over RG59, while 1080p runs about 1300ft – again depending on the resolution and video quality. The voltage drops that occur over long wire runs are compensated for with the help of a series of built-in components called a serializer and deserializer located within the camera. This prevents the DC current from being fed through the video line, protecting the camera and reducing the risk of damage to other equipment in the system.