Pixim Wide Dynamic Range Video Technology
January 16, 2012
From: About.com
Now Your Security Cameras can Capture the Toughest Shots
The Problem with Bright Light
If you use security cameras, you already know that direct sunlight can make it almost impossible to capture a recognizable surveillance image. If your subject has direct sunlight or bright lights behind him, chances are all you'll capture on video is a dark silhouette.
From a surveillance standpoint, one of the most important images you can capture is a customer or visitor entering your building. Now what if your visitor is walking in through a doorway in the morning, and the sun is shining right over her shoulder? If you need to review that video after an accident or crime, you probably won't have any useful images.
Read More: The 4 Best Locations for Your Security Cameras
Wide Dynamic Range
Over the years, several technologies have been developed to try and mitigate this problem. One of the most reliable is called backlight compensation. A camera with backlight compensation is able to balance out the dynamic range in a scene caused by a bright light shining behind the image's subject. At best, a camera with backlight compensation can break a scene into several zones and balance the lighting in each zone individually. This technique served the industry well for many years, but there were still some shots that we just couldn't get.
The solution is to use a Wide Dynamic Range camera. In the simplest terms, Wide Dynamic Range refers to the difference between the brightest and darkest elements in a scene. For example, a bank lobby with fluorescent lighting will have a relatively narrow dynamic range. But let direct sunlight shine through the lobby windows and the dynamic range becomes very wide. The wider the dynamic range becomes, the harder it is for a camera to accurately reproduce the scene.
Pixim Technology
Pixim's Digital Pixel System® technology is a game changer. The foundation for this technology was developed at Stanford University in the 90's. Rather than try to balance out the dynamic range of the entire scene, a Pixim equipped camera adjusts the dynamic range on a pixel by pixel basis.
Every Pixel is a Camera
Every digital camera includes both an image sensor and an image processor. The image sensor receives light and the processor makes a decision based on that input. The relationship between the sensor and the processor is much like to relationship between your eye and brain. When your eye (the sensor) receives a bright light input, your brain (the processor) makes a decision to constrict your iris.
An image sensor for a high end surveillance camera is divided up into hundreds of thousands of pixels, each pixel being able to receive light information. The more pixels in an image sensor, the more detail the camera will be able to capture.
Pixim powered cameras are unique because each pixel is matched with its own analog to digital converter (ADC)and all information is processed on a pixel by pixel basis. In effect, each pixel becomes its own camera and its exposure time is set to optimize the image at that exact location.
Pixim Power
Pixim is not a camera manufacturer. Rather, they license the processing technology that other manufacturers harness to produce wide dynamic range cameras. Think of them as the Intel of the security camera industry. In my experience, the company that best implements this technology is deView. When you are shopping for a wide dynamic range camera, look of a Pixim powered device to give yourself the best possible chance at getting the shot you need.
