Target detection by analog security camera

by Gaurav
(India)

Question:


I have a camera which has a resolution of 480 lines and an FOV of 70 degrees.
To detect the target, the requirement states that it should occupy 2 pixels x 2 pixels of an image.
What is the resolution of the sensor of my camera in 'pixels x pixels', so that I can calculate the IFOV of each pixel and thus the height at which to place the camera ?

Help me please !

Answer:

If the requirement is focused on pixel by pixel than you may need to be using an IP security camera instead of an analog security camera.

If you check the specifications of your camera it should provide the information on the size of the sensor being used as a measurement of pixels. It might be 700px by 300px (just rough numbers there!).

Then you can estimate the pixels that way.

That is a ton of brain damage though.

I would focus on what is it that you are actually trying to capture and what is the actual physical size that the Field of View needs to be. If its a 1 foot by 1 foot space and its 10 feet away you can determine the size of lens you need to figure it out.

Even if you are using IP cameras you still need to evaluate that.

The advantage though of an IP camera that is maybe 3 to 5 megapixels is that after you have captured the image you can zoom in on it digitally and still maintain enough resolution to reach a minimum requirement for the amount of pixels available in order to make it a good image.

Of course you still have to factor in lighting conditions, speed of moment, etc.

I probably need a lot more information to really answer this properly but hopefully this will steer you in the right direction.

Thanks,

Peter Brissette
Security Camera Expert

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Jan 15, 2012
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Usual resolution in pixel
by: Michail

The question was about resolution of video sensor of analog camera which corresponds to 480 lvl in specification.
Usual resolutions of sensors of such cameras is 752x582 effective pixels.

To get min target size you should calculate FOV width (or height) in meters(foot) on required distance using any of free lens calculator.
Then you should divide obtained width (or height) by appropriate number of pixel 752 (582 for height) and get real width (height) in meters(foot) on the scene which corresponds to one pixel on the sensor.

We offer CCTV design software which can help to solve such tasks and many other ones.
http://www.cctvcad.com

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