by Joe Morphe
The image sensor of a camera is the primary measure of the camera's quality. This is a misconception because everything affects the quality the camera is about to output. However, the focus on the image sensor is justified since it is the design of the pixels that really determines the quality of the image. There are two types of technologies used to make the camera's image sensor.
These two types are the charge-coupled device, or CCD, and the complementary metal-oxide semiconductor, or CMOS. And despite being viewed as rivals in the camera industry, each type of image sensor really has its own strengths and weaknesses. So the better sensor depends on the situation it is to be used in.
CCD sensors were developed specifically to be used in cameras and for the purpose of capturing images. CMOS sensors were developed off standard technology already in use, such as memory chips in computers. However, CMOS sensors today are being developed further for the purpose of being in cameras and the image quality it provides is improving.
The main benefit of a CCD sensor over a CMOS sensor is the higher light sensitivity. Being more sensitive to light means it can produce a better image in conditions where lighting is low.
The two downsides to the CCD sensors are really the true advantages to CMOS sensors. The CCDs make the cameras more expensive since they are harder to put into a camera and an equivalent sensor uses almost one hundred times more power than a CMOS sensor.
With the CMOS sensor, it is very quickly closing the gap in terms of image quality to the CCD sensor. Cameras that are built with CMOS sensors are lower in cost because the cameras are much easier to build.
The CMOS sensors allow for much more integration possibilities and functions than the CCD could. It also has a faster readout which is important when you get into megapixels and require less energy and a smaller system size. You will find megapixel CMOS cameras much more than a megapixel CCD sensor simply because of the cost differentiation.
When it comes to megapixel sensors in cameras, the sensors themselves are about the same size or only slightly larger than traditional VGA sensors. This means that the size of each pixel is smaller. So while the megapixel camera can provide higher resolution and greater detail, it is less light sensitive since the pixel size is smaller and light reflected from an object is spread to more pixels.
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June 11 2009 | Security Cameras | No Comments »
by Adam Togo
Analog security cameras, known as CCTV, comes in two forms classified by the build of the image sensor. They are either CMOS based, which is cheaper and produced lower quality images than the CCD camera.
To determine the best security camera for your needs, you must first determine what your needs are. A camera that can single out faces in an outdoor crowd on a cloudy day is very different from a camera that is used to monitor general activity inside an office lobby.
There is a difference in cameras designed for indoor versus outdoor use. There are additional durability standards that the camera would need to ensure it survives the harsh conditions, unlike an indoor security camera.
Other things that will directly impact your buying decision include your budget, for the entire system as well as per individual security camera, as well as the size of your entire security system and the number of cameras you required. The number of cameras you require depends on the number of areas you wish to monitor.
One of most important consideration is lighting of the area you want to monitor. If you plan on installing an outdoor security camera to protect your detached car garage from thieves but buy a high quality day camera that isn't designed for low light environments, your video feed will be different shades of black frames.
In low light settings, black and white cameras are the best. They have lower light requirements to deliver image quality than regular colored cameras. There are also cameras that can sense the lighting levels of the enirvonment and transform from a day camera to a night camera.
There are also dedicated night vision cameras for true low light recording. The minimum amount of light required for the camera to record properly is measured by the LUX rating. A camera of lower LUX rating requires less light and a rating of 0 means the camera is designed for complete darkness.
When it comes to the sharpness of the image, this is measured in resolution. Higher resolution cameras will produce higher quality images. Entry level cameras will have resolutions of about 330 lines and up to 400 lines in higher end cameras.
There are more advanced monitoring systems that allow for panning and zooming the camera but for many a standard recording device will suffice. Most people will use a digital video recorder, or DVR to record directly onto a harddisk.
Tags:
camera,
electronics,
gadget,
home,
monitoring,
security,
Security Cameras,
security video,
surveillance,
technology,
video camera
May 26 2009 | Security Cameras | No Comments »