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What is CCTV Camera Resolution
A camera could be referred to has standard definition which basically means it is not a megapixel camera. However a camera may be called a High Resolution camera but it is still a standard definition camera.
Now an analog camera or IP camera for that matter could be 380 TV lines of resolution and it would be called a low res camera.
However, a camera with 540 TV lines would be called a high res camera. However they could both be considered standard definition cameras because they are not megapixel cameras or HDTV cameras.
In CCTV Video Security Systems the main differences of resolution are capture, storage resolution and display.
Capture or Camera resolutions for analog cameras
When reading a security camera specification sheet, you will see two sets of numbers rating the sensor of the camera. One lists the number of pixels (768 H X 494 V) for the sensor and the other rates the horizontal resolution (TVL) of the camera.
Effective pixels = 768 (Horizontal) X 494 (Vertical) pixels
Horizontal resolution = 540 TV lines
The difference between the two is pixel aspect ratio and picture aspect ratio. The pixel aspect ratio has to do with the actual number of pixels that sensor is able to capture. The picture aspect ratio is based on what the NTSC standard for analog signals (composite video) has been designed to process. The numbers are different but using the math behind it you can calculate how the two relate. We will avoid the math for this discussion.
Since analog standard definition security cameras do not have square pixels there are two types of picture aspect ratio. There is storage aspect ratio and display aspect ratio.
Storage Aspect Ratio
The storage aspect ratio is the digital size of the image as it is stored on digital media. For instance the highest stored resolution using composite video (which is what comes from an analog camera) is 720x480. That is the same as a standard
definition DVD movie.When storing video on an analog security DVR you have several resolution options. The typical settings available for storage are CIF, 2CIF and 4CIF.
• CIF = 352 x240 pixels
• 2CIF = 704 x 240 pixels
• 4CIF = 704 x 480 pixels
Display Aspect RatioNewer standards for TV have introduced High Definition TV with an aspect ration of 16:9 which allows for a greater number of lines of resolution to be displayed. Newer technology of cameras are now able to capture higher resolutions which will now allow for storing and displaying these higher resolutions.
Megapixel resolution IP Camerass
Just a note about megapixel IP cameras. Megapixelcameras can capture video at much higher resolutions but are not necessarily the same as High Definition as in HDTV. HDTV has a very specific set of resolutions available. 720p HDTV is 1280 x 720 and 1080p HDTV is 1920 x 1080. HDTV also operates at 30fps
A megapixel camera that is 1.3 megapixels has a resolution of 1280 x 1024. From there the megapixels go up. 2, 3, 5, and on up to 16mp. However they are not able to capture images at 30 fps. They typically are only capturing 3 to 7 fps. Megapixel cameras can display higher than HDTV resolutions on PC monitors that support higher resolutions.Take a look at the chart below to see how some of the more common resolutions compare. Other Resolutions Compared
Designation = H x V pixels
• CIF = 352x 240
• 2CIF = 704 x 240
• 4CIF = 704 x 480
• D1 = 720 x 480
• 720p HDTV = 1280 x 720
• 1.3MP = 1280 x 1024
• 2MP = 1600 x 1200
• 1080p HDTV = 1920 x 1080
• 3MP = 2048 x 1536
• 5MP = 2592 x 1944
• 11MP = 4000 x 2656
• 16MP = 4872 x 3248
